GARMENT GATHERING Mailing list NETIKET
(update on February 26th 2007)
Http://asia.groups.yahoo.com/group/Garment_Gathering
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1. FOR EVERYONE AND FROM EVERYONE
Mailing list ini ditujukan untuk memfasilitasikan kebersamaan kita.. yang selama ini berkecimpung di dunia garment.. jadi tak ada limitasi daripada jabatan, company member berasal, dll .. setelah join dgn mailing list ini .. kita semua bersahabat.
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2. NO CAPS LOCK ... JUST EMOTICON
Hindari menulis email dengan Caps Lock (HURUF BESAR).
Email yang pesannya ditulis dengan huruf besar dapat diartikan dgn BERTERIAK atau malah MEMBENTAK .. so untuk mengindikasikan emosi kita pada orang lain, gunakan Emoticon .. :-)
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3. SOPAN, BERTANGGUNG JAWAB, NO SARA & ADU DOMBA
Silahkan berbagi informasi yang berguna untuk sesama rekan, selama sopan dan bertanggung jawab .
Harap disadari bahwa setiap e-mail yang anda kirimkan , akan dibaca oleh semua member. pertahankan motto "KEBERSAMAAN"
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4. NET RULES
- Hanya menggunakan email dengan format plain text tanpa visual(karena tidak semua reader bisa menerima htmlnya)bila mengirim email ke jalur umum.
- Spamming dlm bentuk apapun dlm arti semi-spamming atau spamming-dengan-niat-baik termasuk advertising mlm(multi level marketing)dilarang keras dlm komunitas ini.
- Setiap masalah yang di kemukakan / dibahas di mailing list diwajibkan untuk mencantumkan subject yang sesuai dengan topik yang dibahas, dengan rules sebagai berikut
*(EDU) education.... untuk ilmu2 MD, QA, garment, tekstil, dll
*(JOB) lowongan kerja
*(Q&A) menanyakan supplier, factory, contact person, dll
*(ADV) promosi product/usaha (DILUAR MLM)
*(OOT) gak ada hubungannya dgn garment... memposting joke, cerita2, dll
dan selanjutnya untuk anggota milis lain yang akan memberikan komentar atau jawaban dengan topik yang sama mohon tinggal direply saja jadi tidak usah membuat subjek baru lagi dan sebelum me-reply suatu email, harap mengedit dulu draft email tersebut dengan menghapus baris2 / kalimat2 yang tidak perlu/tidak relevan, termasuk signature dan footer dari millis
untuk jawaban thank's, terimakasih, private email dll, harap dikirim via JA-PRI (ke yg bersangkutan saja), tidak usah diposting ke millis
harap cek dan re-check dulu email anda sebelum memposting ke millis, jangan nanti ada reply lagi : "oopssss... sorry kebablasan td gak ngeh alamatnya salah ... "
- Para members diperkenankan untuk melakukan promosi usaha/produk di forum ini yg mana memang komoditas tsb memang milik para anggota sendiri dgn arti bukan barang org lain diluar para members.
- Moderator Team berhak menetapkan status BANNED kepada member yang melanggar ketentuan diatas, jika member tidak mengindahkan pemberitahuan yang telah dikirimkan oleh Moderator team secara JA-PRI.
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5. FUN FRIENDSHIP FOREVER
Terima kasih atas kerjasamanya dan Sukses selalu!
Friday, February 6, 2009
EASY WAY TO JOIN GG Mailing List
EASY WAY TO JOIN GG mailing list :
- send blank e-mail to Garment_Gathering-subscribe@yahoogroups.com
- open mailing list address :
http://asia.groups.yahoo.com/group/garment_gathering/
then join in (PS: only for those who have yahoo id)
- send info to invite to GG milist
(by member who recommend their friends to join)
moderator team will invite..
n related person just need to accept invitation
See GG website at
www.garment-gatherings.blogspot.com
GG on Friendster..
http://profiles.friendster.com/13932936
just add with e-mail add: garment_gathering@yahoo.com
GG on Facebook
http://www.facebook.com/group.php?gid=38317806759
- send blank e-mail to Garment_Gathering-subscribe@yahoogroups.com
- open mailing list address :
http://asia.groups.yahoo.com/group/garment_gathering/
then join in (PS: only for those who have yahoo id)
- send info to invite to GG milist
(by member who recommend their friends to join)
moderator team will invite..
n related person just need to accept invitation
See GG website at
www.garment-gatherings.blogspot.com
GG on Friendster..
http://profiles.friendster.com/13932936
just add with e-mail add: garment_gathering@yahoo.com
GG on Facebook
http://www.facebook.com/group.php?gid=38317806759
Wednesday, February 4, 2009
Choosing the Right Thread
Thread is an integral part of many items that we use daily. Certainly
the various components of our apparel are joined with thread but what
about the string that is attached to our tea bags?
What would happen to upholstery, seat belts, and head liner of an
automobile if the thread were removed? What about the seams in our
tents, back packs, sleeping bags, and other camping equipment? How
are the components of baseballs and footballs joined?
Each of these products requires a thread with different physical
properties to achieve optimum performance. If you consider the many
uses of thread, the complexity of designing a thread becomes
apparent. Consideration must be given to: Sewability, loop strength,
linear strength, elongation, shrinkage, abrasion resistance,
colorfastness, and resistance to chemicals, heat, light, etc. Each
can affect the desirability of a thread for a particular end-use. A&E
threads are designed for many general and specific end-uses.
Selecting the proper thread for your product can be simplified if
these basic factors are considered: required seam strength; type of
seam; stitch type and number of stitches per inch; type of material
being sewn; type of sewing machines and related equipment; conditions
under which the product must perform; normal life of the product; and
cost effectiveness.
Analyzing these factors would give an indication of which physical
properties are most important in the thread. Selection then becomes a
matter of choosing a thread with the most desirable properties. Of
course, thorough testing is necessary to confirm that the thread
chosen is indeed the correct one
the various components of our apparel are joined with thread but what
about the string that is attached to our tea bags?
What would happen to upholstery, seat belts, and head liner of an
automobile if the thread were removed? What about the seams in our
tents, back packs, sleeping bags, and other camping equipment? How
are the components of baseballs and footballs joined?
Each of these products requires a thread with different physical
properties to achieve optimum performance. If you consider the many
uses of thread, the complexity of designing a thread becomes
apparent. Consideration must be given to: Sewability, loop strength,
linear strength, elongation, shrinkage, abrasion resistance,
colorfastness, and resistance to chemicals, heat, light, etc. Each
can affect the desirability of a thread for a particular end-use. A&E
threads are designed for many general and specific end-uses.
Selecting the proper thread for your product can be simplified if
these basic factors are considered: required seam strength; type of
seam; stitch type and number of stitches per inch; type of material
being sewn; type of sewing machines and related equipment; conditions
under which the product must perform; normal life of the product; and
cost effectiveness.
Analyzing these factors would give an indication of which physical
properties are most important in the thread. Selection then becomes a
matter of choosing a thread with the most desirable properties. Of
course, thorough testing is necessary to confirm that the thread
chosen is indeed the correct one
Saturday, January 31, 2009
Accurate Fabric Cost
Developing Fact-based Yield Estimates and Costing Partnershipsby Robert Broadhead
In this article I address the process of estimating fabric yields, the complications involved in offshore contracting, and how to be as accurate as possible in predicting/negotiating fabric costs.
Fabric is 25-40% of the cost of manufacturing a garment in the US and 50-70% in package programs overseas, so accuracy here is worthy of attention. (We've heard this a lot over the years, but it's worth repeating. No other single refinement in production can provide substantial cost savings as easily as fabric control.) Controlling or negotiating fabric costs has become more complicated as overseas manufacturing and cut-make-trim (CMT) / package programs have grown. Before work went offshore, in-house fabric yield estimates and final production consumption reflected cutting department work (either the manufacturers or a local contractors) that was readily known and monitored. However, it is surprising that many businesses do not track the variance between the actual cost of fabric at the end of production and the estimated cost of fabric on the bill of materials. This can significantly impact the bottom line.
CMT Programs
With CMT programs, contractors are essentially being paid for their labor while the Retailer or Manufacturer (R/M) supplies the fabric; therefore, tracking fabric yield often does not get the attention it warrants from the contractor. Cutting department procedures may vary in other countries and problems of time, distance, and culture may also effect results. However, the R/M still controls the patterning and yield estimating process and should have a good idea of expected usage.
Regardless of who does the production markers it is important to reach an agreement in advance of production about how variances in consumption will be handled.
Package Programs
Package programs further complicate estimating and negotiating accurate fabric yields. Retailers and Manufacturers are asking Contractors to bid on package programs based on limited information (e.g., a spec sheet, sample garment, and, perhaps, a "block" pattern) with a short period of time to return a bid. Both parties understand that all the information needed to establish an accurate fabric yield is not available at the time of the price negotiation and everyone wants to avoid up charges and renegotiating costs after their final pricing and margins are set.
Given this climate the Contractor is in a bind. They don't want to bid too low and lose profit margin but also don't want to bid too high and lose the business. The result is often a moderately high bid from the contractor to allow for changes in the final patterning and other unsettled aspects of final production.
The R/M also has limited ways to evaluate the accuracy of the yield since they no longer create a finished pattern. An important question for the R/M is whether it is worth it to create a pattern and develop it sufficiently to provided an accurate estimate for negotiating fabric costs.
In an environment of faster turn times and less information to work with, we'll look at the possible ways to estimate fabric usage and the pros and cons of using each in Local / CMT / Package programs. But first, let's look at the main factors effecting final production consumption, which is what we want to estimate.
What Happens in the Cutting Department
Graded patterns are marked to produce the quantities ordered in each size. These markers reflect the final fit patterning, proper grading of sizes, fabric cuttable width, and the percentage of production being produced in each size. In spreading fabric, the marker sections are overlapped at the ends by a small amount and this also adds to fabric consumption. Fabric quality effects how much damaged material is going to be lost in the spreading process, so there is a "damage cut out percentage" that can be quantified at the end of production. Other impacts on material utilization are allowances for fabric quality testing, bias, and re-cutting garment parts.
Fabric consumption at the end of production, then, is dependent on these components
- Final fit pattern
- Pattern grade
- Fabric cuttable width
- Distribution of units in the size range
- Marker section overlaps
- Damages cut out in spreading
- If applicable, fabric quality testing, bias, and re-cuts
- Estimating Production Yield
A design estimate may be made early in the design phase to determine if the style can be produced profitably. This is the least accurate "ballpark" estimate because the final determination of patterning, fit, and fabric cuttable width and quality may still be in development.
Once a style has been adopted as part of a line a fabric purchase estimate is needed. Accuracy here is very important since 25-40% of the cost of manufacturing will be spent using this "yards per garment" number. Most of the components of production yield are nearly in their final form, so good estimate numbers are possible
That is, the pattern is close to final fit approval and the fabric source/cuttable width/quality are available. The fabric quality, in the form of an inspection report from the mill, can be converted into an anticipated damage percentage that will be cut out in spreading (more on this later). While a significant percentage of sales numbers are still missing, if any at all are available, past season's sales percentages by size are available for a similar style and are a sound basis for yield estimate calculations
The final estimated yield is made going into production in the form of a cut plan. The cut plan can be made for a single order or for the entire season's production on the style. Production markers are made to cut the quantities sold in each size. They reflect the verified cuttable width of the fabric. The historic or calculated damage cut out percentage is added to the marker yield, as is the historic or standardized marker section overlap allowance.
When final production units and yardage used are recorded, this actual yield is compared to the design, fabric purchase, and cut plan estimates to calculate the percent error at each stage. Tracking estimate error allows gain/loss calculations and the opportunity to identify improvements in the process.
Let's examine the methods available to estimate fabric yield and which are best applied to each type of program.
Duplicate the production process. I worked for a children's wear screen printing firm that sold only a few basic styles, in a fixed ratio, in a limited number of fabrics, year after year.
Nearly all the components of production yield were known and only the screen printing varied. We made full sets of ratio production markers for fabric purchase estimates and were very accurate in our estimates of final production usage. Due to the simplicity of the patterns this was cost effective and could be done within our design and production time schedule. Design estimates were not needed as our production history provided the ballpark yields needed. Cut plans were made on an order by order basis but not for the season, since the fabric purchase estimates were very accurate. This was an unusual situation as most companies cannot afford the time or cost of fitting, grading, or production marking early in the production cycle.
Use Graded patterns for estimate markers. Graded patterns usually offer a more accurate way to estimate yield than using the sample size pattern.
For example, look at an 8-18 size range with a sample size 10.
size 8 10 12 14 16 18
% of Production 8 17 25 25 17 8 = 100%
Sales Ratio 1 2 3 3 2 1
Using a size 12-14 combination in the estimate marker has two advantages: 1) these sizes represent 50% of production, and 2) they fall in the middle of the size range and so they more accurately represent the yield of the 10-16 and 8-18 size combination production markers. To this "marker yard per garment" yield can be added allowances for damage, overlap, etc. For Local and CMT programs, the improved accuracy of the fabric purchase estimate usually justifies the time and expense of grading. For Package programs, the main question is how much work is going to be done on patterning, if any, for the sake of evaluating bids and negotiating fabric costs. The simple answer on this is - patterning is worth it! More on this later.
Use sample size patterns for estimate markers and average the other components of production. This is one of the most common procedures but has serious limitations. In the above 8-18 example the sample size 10 represents only 17% of production and the marker layout does not represent the 12-14, 10-16, or 8-18 pattern arrangements. An average percentage can be added to the size 10 estimate marker to compensate for this discrepancy but there will be a significant error in this averaging from fabric to fabric and style to style, even within a body type. An additional source of error is that most sales numbers do not occur in a convenient 1-2-3-3-2-1 ratio, as in this example. For Local/CMT/Package programs, marking a sample size pattern and adding a lumped average percentage (representing grading, damages, etc.) at any stage of estimating yield leads to a high error rate that can be avoided.
Estimate yield using a similar style from a previous season that has a known production yield. Without a pattern, the accuracy of the estimate gets even more erratic. Small patterning differences can cause larger than expected yield variances. A review of 17 styles of women's 5-pocket jeans all marked at 61.5" showed final production yields from 1.11 to 1.32 yards per garment - a 19% difference! Trying to mathematically convert the yield of a similar style marked at one width (e.g. 62") to a new style at a different width (e.g. 54") will skew the results further. With Package programs the R/M that chooses not to develop a patterned estimate is vulnerable to overcharges on fabric. A company recently approached me saying that by evaluating bids based on similar styles their average negotiated fabric cost was 15% high.
Estmarktm software is a new offering to the apparel industry that accurately estimates fabric yield by itemizing all the components of production into its calculation. The accuracy of the results depends on the quality of the data entered. If the seven components of final production consumption, listed above, are used with a sample size estimate marker the results can be accurate to within one percent of the actual final production consumption. If a "block" or non-final-fit pattern is used and averages are itemized for each of the other components the error can be held to under five percent, on the average. The fabric purchase estimate for Local/CMT/Package programs will fall within a 1-5% error depending on the accuracy of the data input. The software also includes a conversion program in which the damage cut out percentage is calculated by inputting a fabric inspection report; a useful tool since inspection reports are readily available from fabric mills and damage cut out percentages vary widely.
Using the infant's wear example below in the size range Small-5XL with a sample size Medium estimate marker, it becomes easier to see how this process is better than the others.
Size S M L XL 2XL 3XL 4XL 5XL
% of Production 6 9 18 19 16 15 11 6 = 100%
Pattern Grade % 9 0 8 17 26 35 42 48
Using any simple combination of graded sizes, much less the sample size, in an estimate marker will not adequately represent the pattern grade or the distribution of production within the size range. With Estmarktm, each percentage of pattern grade and unit distribution within the size range is used in the calculation, so there is no averaging. The resulting estimated yield can only be improved on by making a full set of production markers.
Estmarktm is a tool for Retailers/Manufacturers/Import Brokers/Contractors to achieve a fact-based partnership. The calculated yield is as accurate as it can be using the best data available at the time. If any of the items in the calculation change (e.g., fabric width/quality or patterning), the itemized process provides the fact-based recalculation format for any yield adjustment
Accurate Fabric Cost
Developing Fact-based Yield Estimates and Costing Partnershipsby Robert Broadhead
In this article I address the process of estimating fabric yields, the complications involved in offshore contracting, and how to be as accurate as possible in predicting/negotiating fabric costs.
Fabric is 25-40% of the cost of manufacturing a garment in the US and 50-70% in package programs overseas, so accuracy here is worthy of attention. (We've heard this a lot over the years, but it's worth repeating. No other single refinement in production can provide substantial cost savings as easily as fabric control.) Controlling or negotiating fabric costs has become more complicated as overseas manufacturing and cut-make-trim (CMT) / package programs have grown. Before work went offshore, in-house fabric yield estimates and final production consumption reflected cutting department work (either the manufacturers or a local contractors) that was readily known and monitored. However, it is surprising that many businesses do not track the variance between the actual cost of fabric at the end of production and the estimated cost of fabric on the bill of materials. This can significantly impact the bottom line.
CMT Programs
With CMT programs, contractors are essentially being paid for their labor while the Retailer or Manufacturer (R/M) supplies the fabric; therefore, tracking fabric yield often does not get the attention it warrants from the contractor. Cutting department procedures may vary in other countries and problems of time, distance, and culture may also effect results. However, the R/M still controls the patterning and yield estimating process and should have a good idea of expected usage.
Regardless of who does the production markers it is important to reach an agreement in advance of production about how variances in consumption will be handled.
Package Programs
Package programs further complicate estimating and negotiating accurate fabric yields. Retailers and Manufacturers are asking Contractors to bid on package programs based on limited information (e.g., a spec sheet, sample garment, and, perhaps, a "block" pattern) with a short period of time to return a bid. Both parties understand that all the information needed to establish an accurate fabric yield is not available at the time of the price negotiation and everyone wants to avoid up charges and renegotiating costs after their final pricing and margins are set.
Given this climate the Contractor is in a bind. They don't want to bid too low and lose profit margin but also don't want to bid too high and lose the business. The result is often a moderately high bid from the contractor to allow for changes in the final patterning and other unsettled aspects of final production.
The R/M also has limited ways to evaluate the accuracy of the yield since they no longer create a finished pattern. An important question for the R/M is whether it is worth it to create a pattern and develop it sufficiently to provided an accurate estimate for negotiating fabric costs.
In an environment of faster turn times and less information to work with, we'll look at the possible ways to estimate fabric usage and the pros and cons of using each in Local / CMT / Package programs. But first, let's look at the main factors effecting final production consumption, which is what we want to estimate.
What Happens in the Cutting Department
Graded patterns are marked to produce the quantities ordered in each size. These markers reflect the final fit patterning, proper grading of sizes, fabric cuttable width, and the percentage of production being produced in each size. In spreading fabric, the marker sections are overlapped at the ends by a small amount and this also adds to fabric consumption. Fabric quality effects how much damaged material is going to be lost in the spreading process, so there is a "damage cut out percentage" that can be quantified at the end of production. Other impacts on material utilization are allowances for fabric quality testing, bias, and re-cutting garment parts.
Fabric consumption at the end of production, then, is dependent on these components
- Final fit pattern
- Pattern grade
- Fabric cuttable width
- Distribution of units in the size range
- Marker section overlaps
- Damages cut out in spreading
- If applicable, fabric quality testing, bias, and re-cuts
- Estimating Production Yield
A design estimate may be made early in the design phase to determine if the style can be produced profitably. This is the least accurate "ballpark" estimate because the final determination of patterning, fit, and fabric cuttable width and quality may still be in development.
Once a style has been adopted as part of a line a fabric purchase estimate is needed. Accuracy here is very important since 25-40% of the cost of manufacturing will be spent using this "yards per garment" number. Most of the components of production yield are nearly in their final form, so good estimate numbers are possible
That is, the pattern is close to final fit approval and the fabric source/cuttable width/quality are available. The fabric quality, in the form of an inspection report from the mill, can be converted into an anticipated damage percentage that will be cut out in spreading (more on this later). While a significant percentage of sales numbers are still missing, if any at all are available, past season's sales percentages by size are available for a similar style and are a sound basis for yield estimate calculations
The final estimated yield is made going into production in the form of a cut plan. The cut plan can be made for a single order or for the entire season's production on the style. Production markers are made to cut the quantities sold in each size. They reflect the verified cuttable width of the fabric. The historic or calculated damage cut out percentage is added to the marker yield, as is the historic or standardized marker section overlap allowance.
When final production units and yardage used are recorded, this actual yield is compared to the design, fabric purchase, and cut plan estimates to calculate the percent error at each stage. Tracking estimate error allows gain/loss calculations and the opportunity to identify improvements in the process.
Let's examine the methods available to estimate fabric yield and which are best applied to each type of program.
Duplicate the production process. I worked for a children's wear screen printing firm that sold only a few basic styles, in a fixed ratio, in a limited number of fabrics, year after year.
Nearly all the components of production yield were known and only the screen printing varied. We made full sets of ratio production markers for fabric purchase estimates and were very accurate in our estimates of final production usage. Due to the simplicity of the patterns this was cost effective and could be done within our design and production time schedule. Design estimates were not needed as our production history provided the ballpark yields needed. Cut plans were made on an order by order basis but not for the season, since the fabric purchase estimates were very accurate. This was an unusual situation as most companies cannot afford the time or cost of fitting, grading, or production marking early in the production cycle.
Use Graded patterns for estimate markers. Graded patterns usually offer a more accurate way to estimate yield than using the sample size pattern.
For example, look at an 8-18 size range with a sample size 10.
size 8 10 12 14 16 18
% of Production 8 17 25 25 17 8 = 100%
Sales Ratio 1 2 3 3 2 1
Using a size 12-14 combination in the estimate marker has two advantages: 1) these sizes represent 50% of production, and 2) they fall in the middle of the size range and so they more accurately represent the yield of the 10-16 and 8-18 size combination production markers. To this "marker yard per garment" yield can be added allowances for damage, overlap, etc. For Local and CMT programs, the improved accuracy of the fabric purchase estimate usually justifies the time and expense of grading. For Package programs, the main question is how much work is going to be done on patterning, if any, for the sake of evaluating bids and negotiating fabric costs. The simple answer on this is - patterning is worth it! More on this later.
Use sample size patterns for estimate markers and average the other components of production. This is one of the most common procedures but has serious limitations. In the above 8-18 example the sample size 10 represents only 17% of production and the marker layout does not represent the 12-14, 10-16, or 8-18 pattern arrangements. An average percentage can be added to the size 10 estimate marker to compensate for this discrepancy but there will be a significant error in this averaging from fabric to fabric and style to style, even within a body type. An additional source of error is that most sales numbers do not occur in a convenient 1-2-3-3-2-1 ratio, as in this example. For Local/CMT/Package programs, marking a sample size pattern and adding a lumped average percentage (representing grading, damages, etc.) at any stage of estimating yield leads to a high error rate that can be avoided.
Estimate yield using a similar style from a previous season that has a known production yield. Without a pattern, the accuracy of the estimate gets even more erratic. Small patterning differences can cause larger than expected yield variances. A review of 17 styles of women's 5-pocket jeans all marked at 61.5" showed final production yields from 1.11 to 1.32 yards per garment - a 19% difference! Trying to mathematically convert the yield of a similar style marked at one width (e.g. 62") to a new style at a different width (e.g. 54") will skew the results further. With Package programs the R/M that chooses not to develop a patterned estimate is vulnerable to overcharges on fabric. A company recently approached me saying that by evaluating bids based on similar styles their average negotiated fabric cost was 15% high.
Estmarktm software is a new offering to the apparel industry that accurately estimates fabric yield by itemizing all the components of production into its calculation. The accuracy of the results depends on the quality of the data entered. If the seven components of final production consumption, listed above, are used with a sample size estimate marker the results can be accurate to within one percent of the actual final production consumption. If a "block" or non-final-fit pattern is used and averages are itemized for each of the other components the error can be held to under five percent, on the average. The fabric purchase estimate for Local/CMT/Package programs will fall within a 1-5% error depending on the accuracy of the data input. The software also includes a conversion program in which the damage cut out percentage is calculated by inputting a fabric inspection report; a useful tool since inspection reports are readily available from fabric mills and damage cut out percentages vary widely.
Using the infant's wear example below in the size range Small-5XL with a sample size Medium estimate marker, it becomes easier to see how this process is better than the others.
Size S M L XL 2XL 3XL 4XL 5XL
% of Production 6 9 18 19 16 15 11 6 = 100%
Pattern Grade % 9 0 8 17 26 35 42 48
Using any simple combination of graded sizes, much less the sample size, in an estimate marker will not adequately represent the pattern grade or the distribution of production within the size range. With Estmarktm, each percentage of pattern grade and unit distribution within the size range is used in the calculation, so there is no averaging. The resulting estimated yield can only be improved on by making a full set of production markers.
Estmarktm is a tool for Retailers/Manufacturers/Import Brokers/Contractors to achieve a fact-based partnership. The calculated yield is as accurate as it can be using the best data available at the time. If any of the items in the calculation change (e.g., fabric width/quality or patterning), the itemized process provides the fact-based recalculation format for any yield adjustment
Minimizing Needle Heat
Introduction
Today, most high-speed industrial sewing machines sew at very high speeds from 4,000 to 10,000 stitches per minute. Also, the most common sewing threads used for the manufacturing of apparel or non-apparel items are either polyester or nylon that have been produced using a melt-spinning process. Many of the fabrics being sewn are made from synthetic fibers that can be impacted by excessive heat.Some needle holes that appear to be needle cuts are actually caused by excessively hot needles. In this bulletin, we will discuss what causes needle heat and what can be done to minimize needle heat.
What Causes Needle Heat
The friction between the needle blade and the fabric creates needle heat. The following factors can have an impact on the amount of heat that is generated:
" Fabric thickness
" Fabric finish or density
" Fabric color or density (darker colors normally are worse than lighter colors)
" Sewing machine speed
" Needle contact surface
" Needle Size or diameter
" Needle length
" Type of needle blade
" Type of needle finish
Needle heat is usually more of a problem when sewing either synthetic threads and / or synthetic fabrics and can cause excessive thread breakage and / or damage to the fabric being sewn.
Generally, needle heat will cause thread breakage when the operator stops sewing after a long run and the thread comes to rest in the needle eye….NOT during sewing. The result is that the polyester or nylon thread melts and breaks. Both polyester and nylon have a melt point of approximately 485° F or 252° C. Whenever the needle reaches a temperature higher than the melt point of the thread, the thread will melt. Needle thread breakage due to needle heat can be detected by checking the end of the thread to see if there is a hard nodule where the thread melted and re-solidified.
Good Thread Company puts a thread lubricant on the thread to help minimize needle heat and give the thread good frictional characteristics to set a uniform balanced stitch. Usually, larger sizes of thread that are sewn into to heavier weight garments have a heavier lube application to protect the thread against needle heat.
Ways of Minimizing Needle Heat
Use a smaller diameter needle whenever possible. A smaller diameter needle will definitely minimize needle heat and may be the solution in marginal situations. Use a "ball eye" needle. A "ball eye" needle is where the diameter across the eye is generally .003 or .004 inch larger than the blade diameter, therefore, it opens up a larger hole, minimizing the friction on the needle blade.
Many needle manufacturers even have an "oversized ball eye" needle in some classes of needles that are commonly used for sewing heavy fabrics. On leather, vinyl, and other homogeneous fabrics, use a needle with cutting edges like a diamond, triangle, or wedge point.
These needle point types actually cut through the fabric minimizing the penetration resistance and needle heat. Cutting point needles are not recommended for woven or knitted fabrics used for making apparel due to fabric damage.
Try needles with special low friction surfaces. Most needles have a low friction chrome plating, however, there are other special needle coatings like Teflon or Tungsten that will minimize the friction between the needle and the fabric.
Use needle coolers or devices that blow compressed air on the needle during sewing. This requires the availability of compressed air and lines carrying this air to the sewing machines. Machines should have control switches that conserve the consumption of compressed air and only supplies air on the needle during sewing.
Use a cotton wrapped polyester corespun thread.The cotton wrapper acts as an insulator protecting the thread from the heat. Ask you thread supplier if they have products available with heavier lube levels.
The danger of using excessively high lube applications is finish migration in to the seam.
Equip the machine with a needle positioner that positions the needle down after long high-speed runs. This allows the fabric to help dissipate heat and hopefully prevents the thread from melting; however, it can cause more needle holes on synthetic fabrics. Slow the sewing machines down to an acceptable level to minimize thread breakage due to needle heat
Today, most high-speed industrial sewing machines sew at very high speeds from 4,000 to 10,000 stitches per minute. Also, the most common sewing threads used for the manufacturing of apparel or non-apparel items are either polyester or nylon that have been produced using a melt-spinning process. Many of the fabrics being sewn are made from synthetic fibers that can be impacted by excessive heat.Some needle holes that appear to be needle cuts are actually caused by excessively hot needles. In this bulletin, we will discuss what causes needle heat and what can be done to minimize needle heat.
What Causes Needle Heat
The friction between the needle blade and the fabric creates needle heat. The following factors can have an impact on the amount of heat that is generated:
" Fabric thickness
" Fabric finish or density
" Fabric color or density (darker colors normally are worse than lighter colors)
" Sewing machine speed
" Needle contact surface
" Needle Size or diameter
" Needle length
" Type of needle blade
" Type of needle finish
Needle heat is usually more of a problem when sewing either synthetic threads and / or synthetic fabrics and can cause excessive thread breakage and / or damage to the fabric being sewn.
Generally, needle heat will cause thread breakage when the operator stops sewing after a long run and the thread comes to rest in the needle eye….NOT during sewing. The result is that the polyester or nylon thread melts and breaks. Both polyester and nylon have a melt point of approximately 485° F or 252° C. Whenever the needle reaches a temperature higher than the melt point of the thread, the thread will melt. Needle thread breakage due to needle heat can be detected by checking the end of the thread to see if there is a hard nodule where the thread melted and re-solidified.
Good Thread Company puts a thread lubricant on the thread to help minimize needle heat and give the thread good frictional characteristics to set a uniform balanced stitch. Usually, larger sizes of thread that are sewn into to heavier weight garments have a heavier lube application to protect the thread against needle heat.
Ways of Minimizing Needle Heat
Use a smaller diameter needle whenever possible. A smaller diameter needle will definitely minimize needle heat and may be the solution in marginal situations. Use a "ball eye" needle. A "ball eye" needle is where the diameter across the eye is generally .003 or .004 inch larger than the blade diameter, therefore, it opens up a larger hole, minimizing the friction on the needle blade.
Many needle manufacturers even have an "oversized ball eye" needle in some classes of needles that are commonly used for sewing heavy fabrics. On leather, vinyl, and other homogeneous fabrics, use a needle with cutting edges like a diamond, triangle, or wedge point.
These needle point types actually cut through the fabric minimizing the penetration resistance and needle heat. Cutting point needles are not recommended for woven or knitted fabrics used for making apparel due to fabric damage.
Try needles with special low friction surfaces. Most needles have a low friction chrome plating, however, there are other special needle coatings like Teflon or Tungsten that will minimize the friction between the needle and the fabric.
Use needle coolers or devices that blow compressed air on the needle during sewing. This requires the availability of compressed air and lines carrying this air to the sewing machines. Machines should have control switches that conserve the consumption of compressed air and only supplies air on the needle during sewing.
Use a cotton wrapped polyester corespun thread.The cotton wrapper acts as an insulator protecting the thread from the heat. Ask you thread supplier if they have products available with heavier lube levels.
The danger of using excessively high lube applications is finish migration in to the seam.
Equip the machine with a needle positioner that positions the needle down after long high-speed runs. This allows the fabric to help dissipate heat and hopefully prevents the thread from melting; however, it can cause more needle holes on synthetic fabrics. Slow the sewing machines down to an acceptable level to minimize thread breakage due to needle heat
Thread Price vs Thread Cost
Introduction
Thread price and thread cost are terms that are sometimes used synonymously but may actually have very different meanings. Thread price usually refers to the price you pay to get the thread to your plant and may or may not include shipping and transportation charges. The cost refers to all the costs related to thread performance including the purchase price. Thread, whenever it is given any consideration at all, is often treated as the primary item where a manufacturer or contractor can cut costs. Many think, "All threads are equal in performance and the same - so what colors do you have and what is your price?" However, consider that, "Thread generally makes up only a small percent of the total cost of a sewn product, but shares fully 50% of the responsibility of the seam."
For example, a manufacturer in the Far East was making cargo pants and then subjecting them to a stone-wash finishing process. They were averaging 48 percent repairs after laundering. After evaluating their situation, we recommended that they switch from a locally produced low-priced spun polyester thread to a poly-wrapped core thread.
Initially, they were very resistant to even consider this change due to the higher selling price, but they agreed to a large garment trial. When this sewing trial was completed the analysis showed that they were now averaging less than 2% repairs after laundering using
the higher performance thread. They also had fewer thread breaks on the sewing floor so they had fewer re-stitched seams and produced a better quality garment … not to mention that their sewing operators were able to achieve production output and therefore lower their overall sewing costs!
The plant manager still hesitated in purchasing this higher performance thread and stated that labor costs in his country was very inexpensive and he could afford to repair the garments. During our discussion, we acknowledged that the core thread was more
expensive and his labor rates were low, however, we pointed out that there were other costs related to the thread performance. They included:
More equipment & operators required: Additional sewing machines are costly anywhere in the world. Higher overhead costs: Floor space, utilities and power, training costs, and higher maintenance costs. Longer In-process times. Penalties due to shipment delays.
Charge-backs from Retailer when poor quality is found. Seconds due to poor quality that could not be repaired: Material and other trim costs are very expensive. Being recognized as a low quality producer. The realization of these 'hidden' costs convinced this customer to make the right choice by switching to the higher performing thread to minimize their overall thread cost. Furthermore, there are additional ways to reduce thread costs without compromising sewability and seaming performance.
How to Reduce Overall Thread Cost
The following list includes practical ways to reduce thread cost other than just using a cheaper thread
- Use natural or white wherever possible.
- Change to a less expensive thread type on loopers and on inside overedge seams.
- Change to smaller thread sizes wherever possible: Looper threads on chainstitch, overedge and coverstitch operations and generally on component parts like cuffs, and pocket flaps.
- Reduce thread consumption.
Changing to Smaller Thread Sizes
Smaller thread sizes are generally less expensive than larger thread sizes and, therefore, smaller thread sizes should be used whenever possible. The table to the right shows the difference in thread cost by going to a smaller thread size in the Topstitching only.
On chainstitch and overedge seams, smaller looper threads can be used without sacrificing seam strength.
In many cases, this can reduce the thread cost for a sewn product by 10 to 15%.
Using White or Natural Instead of Dyed Thread
White or natural threads are generally less expensive than dyed threads because they don't have to be wet processed. The least expensive cotton or cotton wrapped core thread is natural or an "off-white" color. Since the natural color of polyester thread is white,
then the least expensive polyester thread is white and not "natural" color. If a "natural" or "off-white" thread is specified, the white polyester thread will have to be dyed increasing its cost.
Change to a Less Expensive Thread Type
Changing to a less expensive thread type is always an alternative, however, as stated above, this can detract from the finished quality of the sewn product unless considerable testing is performed. Generally, inside threads can be changed with less of an impact on
the seam quality or sewability. For example, a spun polyester, air entangled, or textured polyester looper thread can replace a more expensive core spun thread on loopers and overedge seams to reduce the total thread cost.
Reducing Thread Consumption to Minimize Thread Cost
Another alternative to reducing thread cost is to minimize thread consumption. This can be done by changing stitch types, using automatic start/stop devices on the sewing machines, and monitoring thread waste. A two thread overedge stitch consumes approximately 21% less thread than a three thread overedge. If this stitch is only
being used to cover the edge to prevent it from unraveling, this might be a good alternative particularly considering that overedge stitches make up a large percentage of the total thread consumed in a sewn product.
^^Summary^^
As you can see from the information presented above, there are many ways to reduce thread cost other than just using the cheapest thread.
There is a difference between thread price and thread cost. Any thread company worthy of your business should have training professionals who can help you make the right choice to optimize your quality and cost.
Thread price and thread cost are terms that are sometimes used synonymously but may actually have very different meanings. Thread price usually refers to the price you pay to get the thread to your plant and may or may not include shipping and transportation charges. The cost refers to all the costs related to thread performance including the purchase price. Thread, whenever it is given any consideration at all, is often treated as the primary item where a manufacturer or contractor can cut costs. Many think, "All threads are equal in performance and the same - so what colors do you have and what is your price?" However, consider that, "Thread generally makes up only a small percent of the total cost of a sewn product, but shares fully 50% of the responsibility of the seam."
For example, a manufacturer in the Far East was making cargo pants and then subjecting them to a stone-wash finishing process. They were averaging 48 percent repairs after laundering. After evaluating their situation, we recommended that they switch from a locally produced low-priced spun polyester thread to a poly-wrapped core thread.
Initially, they were very resistant to even consider this change due to the higher selling price, but they agreed to a large garment trial. When this sewing trial was completed the analysis showed that they were now averaging less than 2% repairs after laundering using
the higher performance thread. They also had fewer thread breaks on the sewing floor so they had fewer re-stitched seams and produced a better quality garment … not to mention that their sewing operators were able to achieve production output and therefore lower their overall sewing costs!
The plant manager still hesitated in purchasing this higher performance thread and stated that labor costs in his country was very inexpensive and he could afford to repair the garments. During our discussion, we acknowledged that the core thread was more
expensive and his labor rates were low, however, we pointed out that there were other costs related to the thread performance. They included:
More equipment & operators required: Additional sewing machines are costly anywhere in the world. Higher overhead costs: Floor space, utilities and power, training costs, and higher maintenance costs. Longer In-process times. Penalties due to shipment delays.
Charge-backs from Retailer when poor quality is found. Seconds due to poor quality that could not be repaired: Material and other trim costs are very expensive. Being recognized as a low quality producer. The realization of these 'hidden' costs convinced this customer to make the right choice by switching to the higher performing thread to minimize their overall thread cost. Furthermore, there are additional ways to reduce thread costs without compromising sewability and seaming performance.
How to Reduce Overall Thread Cost
The following list includes practical ways to reduce thread cost other than just using a cheaper thread
- Use natural or white wherever possible.
- Change to a less expensive thread type on loopers and on inside overedge seams.
- Change to smaller thread sizes wherever possible: Looper threads on chainstitch, overedge and coverstitch operations and generally on component parts like cuffs, and pocket flaps.
- Reduce thread consumption.
Changing to Smaller Thread Sizes
Smaller thread sizes are generally less expensive than larger thread sizes and, therefore, smaller thread sizes should be used whenever possible. The table to the right shows the difference in thread cost by going to a smaller thread size in the Topstitching only.
On chainstitch and overedge seams, smaller looper threads can be used without sacrificing seam strength.
In many cases, this can reduce the thread cost for a sewn product by 10 to 15%.
Using White or Natural Instead of Dyed Thread
White or natural threads are generally less expensive than dyed threads because they don't have to be wet processed. The least expensive cotton or cotton wrapped core thread is natural or an "off-white" color. Since the natural color of polyester thread is white,
then the least expensive polyester thread is white and not "natural" color. If a "natural" or "off-white" thread is specified, the white polyester thread will have to be dyed increasing its cost.
Change to a Less Expensive Thread Type
Changing to a less expensive thread type is always an alternative, however, as stated above, this can detract from the finished quality of the sewn product unless considerable testing is performed. Generally, inside threads can be changed with less of an impact on
the seam quality or sewability. For example, a spun polyester, air entangled, or textured polyester looper thread can replace a more expensive core spun thread on loopers and overedge seams to reduce the total thread cost.
Reducing Thread Consumption to Minimize Thread Cost
Another alternative to reducing thread cost is to minimize thread consumption. This can be done by changing stitch types, using automatic start/stop devices on the sewing machines, and monitoring thread waste. A two thread overedge stitch consumes approximately 21% less thread than a three thread overedge. If this stitch is only
being used to cover the edge to prevent it from unraveling, this might be a good alternative particularly considering that overedge stitches make up a large percentage of the total thread consumed in a sewn product.
^^Summary^^
As you can see from the information presented above, there are many ways to reduce thread cost other than just using the cheapest thread.
There is a difference between thread price and thread cost. Any thread company worthy of your business should have training professionals who can help you make the right choice to optimize your quality and cost.
Estimating Thread Consumption
Introduction
It is important to know the amount of thread consumed in a sewn product so you can:
1) Estimate the number of cones needed; and
2) Calculate the cost of the thread needed to manufacture the finished product. Thread consumption can be determined in several ways.
To calculate the amount of thread in a seam, you can:
- Measure the actual amount of thread consumed in a specific length of seam.
- Calculate the thread consumption by using mathematical stitch formulas based on the thickness of the seam and the number of stitches per inch.
- Calculate the thread consumption using thread consumption estimates.
Measuring Actual Thread Consumed
A specified length of the seam, for example 3 inches, is measured on the seam and then the thread is removed by carefully unraveling the stitch. You can then calculate the amount of thread consumed in one inch and multiply this factor times the total length of the seam measured in inches. (Obviously, you must do this for each seam to determine the total amount of thread consumed in the finished product.)
Example:
Length of seam is 42 inches or 1.17 yards.
Stitch and seam construction: 401 SSa-1.
Specified length of thread removed from a seam equals 3 inches.
Needle thread removed = 9 inches
Looper thread removed = 8 inches
Calculation:
Needle thread factor = 9 ¸ 3 = 3 inches of needle thread per inch of seam.
Looper thread factor = 8 ¸ 3 = 2.67 inches of looper thread per inch of seam.
Total needle thread consumed = factor 3 X 1.17yds = 3.51 yds
Total looper thread consumed = factor 2.67 X 1.17yds = 3.12 yds
Total Thread = 3.51 + 3.12 = 6.63 yards per seam.
Generally a 15 to 20% waste factor is added due to chaining-off, thread breaks, repairs, etc.
If a waste factor of 15% is selected then: 6.63 yards/seam X 1.15 = 7.62 yards/seam including 15% waste factor.
Thread Consumption Formulas
Union Special Machine Company published a "Thread Consumption Booklet" that consists of a number of thread consumption formulas for various stitch types based on the stitch length and thickness of the seam. These mathematically derived consumption factors can be multiplied times the length of the seam to estimate the combined amount of top and bottom thread. On some overedge and coverstitch types it is necessary to also know the seam width or needle spacing to properly calculate the amount of thread consumed.
Union Special 401 Chainstitch Chart
Seam Thickness 8 SPI
.055 4.88
.060 4.96
.065 5.04
.070 5.12
.075 5.20
Example:
Stitch and seam: 401 SSa-1
Stitches per inch: 8
Thickness of the seam: .075 inches (measured with a micrometer)
Length of the seam: 42 inches or 1.17 yds.
Calculation (Consumption based on the mathematical equation):
C = 4 + 2ts
C = 4 + 2(.075 X 8) = 5.20
t = thickness of the seam
s = stitches per inch
1.17 yds X 5.20 = 6.08 yds / seam.
6.08 yds/seam X 1.15 = 7.00 yds per seam including a 15% waste factor.
Estimating Thread Consumption
As you can see from the Union Special chart, the more stitches per inch and the thickness of the seam impacts the amount of thread consumed.
However, most heavy fabrics are sewn with fewer stitches per inch and most light fabrics are sewn with more stitches per inch. Therefore we have come up with the following estimates based on typical seam thickness and stitch length.
Example:
Stitch & seam: 401 SSa-1
Length of seam: 42 inches or 1.17 yards
Fabric weight: Light weight
Estimated Thread Consumption:
1.17 yds. X 5.0 (Ratio) = 5.85 yds. / seam
5.85 yds/seam X 1.15 = 6.73 yds/seam, including a 15% waste factor
Estimated needle thread: 6.73 X 40% = 2.69 yds
Estimated looper thread: 6.73 X 60% = 4.04 yds
Stitch Type Est.Total Consumption Ratio / Needle thread Bottom thread
301 Lockstitch 3.0 to 4.0(1) 50% 50%
401 Chainstitch 5.0 to 7.0 (2) 40% 60%
503 Overedge (2 thread) 7.0 to 10.0 60% 40%
504 Overedge (3 thread) 12.0 to 16.0 25% 75%
15 Safetystitch (4 thread) 12.0 to 17.0 55% 45%
516 Safetystitch (5 thread) 17.0 to 23.0 37% 63%
Use lower estimated thread consumption numbers for light-weight fabrics or long stitch lengths.
On the chainstitch construction, the amount of looper thread does not change unless the stitches per inch changes. On the other hand, the needle thread will change based on the thickness of the seam. Therefore, the percentage of needle thread goes up when the fabric gets heavier. Lt. Wt. (light weight) is generally like shirts and blouses; M. Wt. (medium weight) is generally like slacks or chinos; and H. Wt. (heavy weight) is generally like denim applications.
Average Thread Consumption Totals by Garment
The following is a list of sewn products and thread consumption totals based on thread consumption reports conducted by our Technical Service Department. These thread consumption figures include a 25% waste factor and are based on a typical garment construction.
Estimating Thread Cost
The thread cost can be estimated by multiplying the thread consumed times the cost of thread in the same units. For example:
Men's Dress Shirt thread consumption:
25% waste factor = 131 yds.
Average Cost of T-24 Poly Wrapped Core Thread:
$4.50 / 6000 yard cone
Cost per yard $4,500:
6000 yard cone = $.00075/yard
Calculation:
131 yds./shirt X $.00075/yard = $.09825/shirt
Product Sewn
Total Yds/
Garment
Product Sewn
Total Yds/
Garment
Men's
Boy's
Slack 225 Jeans 168
Jean 200 Pants 183
Jean Short 160 Jacket 175
Work Pants 238 Dress Shirt 101
Suit Coat 175 Knit Shirt 83
Dress Shirt– long sleeve 131 Baseball Cap 44
Work Shirt 115
Knit Polo Shirt 130
Fleece Sweat Shirt 280
Tee Shirt 63
Tank Top 58
Knit Brief 68
Women's Girl's
Lined Coat 246 Blouse 73
Blazer 153 Dress 118
Dress 141 Swim Suit 65
Skirt 192
Blouse 122
Pants 162
Jeans 250
Shorts 151
Robe 300
Night Gown 135
Panties 62
Bra 63
It is important to know the amount of thread consumed in a sewn product so you can:
1) Estimate the number of cones needed; and
2) Calculate the cost of the thread needed to manufacture the finished product. Thread consumption can be determined in several ways.
To calculate the amount of thread in a seam, you can:
- Measure the actual amount of thread consumed in a specific length of seam.
- Calculate the thread consumption by using mathematical stitch formulas based on the thickness of the seam and the number of stitches per inch.
- Calculate the thread consumption using thread consumption estimates.
Measuring Actual Thread Consumed
A specified length of the seam, for example 3 inches, is measured on the seam and then the thread is removed by carefully unraveling the stitch. You can then calculate the amount of thread consumed in one inch and multiply this factor times the total length of the seam measured in inches. (Obviously, you must do this for each seam to determine the total amount of thread consumed in the finished product.)
Example:
Length of seam is 42 inches or 1.17 yards.
Stitch and seam construction: 401 SSa-1.
Specified length of thread removed from a seam equals 3 inches.
Needle thread removed = 9 inches
Looper thread removed = 8 inches
Calculation:
Needle thread factor = 9 ¸ 3 = 3 inches of needle thread per inch of seam.
Looper thread factor = 8 ¸ 3 = 2.67 inches of looper thread per inch of seam.
Total needle thread consumed = factor 3 X 1.17yds = 3.51 yds
Total looper thread consumed = factor 2.67 X 1.17yds = 3.12 yds
Total Thread = 3.51 + 3.12 = 6.63 yards per seam.
Generally a 15 to 20% waste factor is added due to chaining-off, thread breaks, repairs, etc.
If a waste factor of 15% is selected then: 6.63 yards/seam X 1.15 = 7.62 yards/seam including 15% waste factor.
Thread Consumption Formulas
Union Special Machine Company published a "Thread Consumption Booklet" that consists of a number of thread consumption formulas for various stitch types based on the stitch length and thickness of the seam. These mathematically derived consumption factors can be multiplied times the length of the seam to estimate the combined amount of top and bottom thread. On some overedge and coverstitch types it is necessary to also know the seam width or needle spacing to properly calculate the amount of thread consumed.
Union Special 401 Chainstitch Chart
Seam Thickness 8 SPI
.055 4.88
.060 4.96
.065 5.04
.070 5.12
.075 5.20
Example:
Stitch and seam: 401 SSa-1
Stitches per inch: 8
Thickness of the seam: .075 inches (measured with a micrometer)
Length of the seam: 42 inches or 1.17 yds.
Calculation (Consumption based on the mathematical equation):
C = 4 + 2ts
C = 4 + 2(.075 X 8) = 5.20
t = thickness of the seam
s = stitches per inch
1.17 yds X 5.20 = 6.08 yds / seam.
6.08 yds/seam X 1.15 = 7.00 yds per seam including a 15% waste factor.
Estimating Thread Consumption
As you can see from the Union Special chart, the more stitches per inch and the thickness of the seam impacts the amount of thread consumed.
However, most heavy fabrics are sewn with fewer stitches per inch and most light fabrics are sewn with more stitches per inch. Therefore we have come up with the following estimates based on typical seam thickness and stitch length.
Example:
Stitch & seam: 401 SSa-1
Length of seam: 42 inches or 1.17 yards
Fabric weight: Light weight
Estimated Thread Consumption:
1.17 yds. X 5.0 (Ratio) = 5.85 yds. / seam
5.85 yds/seam X 1.15 = 6.73 yds/seam, including a 15% waste factor
Estimated needle thread: 6.73 X 40% = 2.69 yds
Estimated looper thread: 6.73 X 60% = 4.04 yds
Stitch Type Est.Total Consumption Ratio / Needle thread Bottom thread
301 Lockstitch 3.0 to 4.0(1) 50% 50%
401 Chainstitch 5.0 to 7.0 (2) 40% 60%
503 Overedge (2 thread) 7.0 to 10.0 60% 40%
504 Overedge (3 thread) 12.0 to 16.0 25% 75%
15 Safetystitch (4 thread) 12.0 to 17.0 55% 45%
516 Safetystitch (5 thread) 17.0 to 23.0 37% 63%
Use lower estimated thread consumption numbers for light-weight fabrics or long stitch lengths.
On the chainstitch construction, the amount of looper thread does not change unless the stitches per inch changes. On the other hand, the needle thread will change based on the thickness of the seam. Therefore, the percentage of needle thread goes up when the fabric gets heavier. Lt. Wt. (light weight) is generally like shirts and blouses; M. Wt. (medium weight) is generally like slacks or chinos; and H. Wt. (heavy weight) is generally like denim applications.
Average Thread Consumption Totals by Garment
The following is a list of sewn products and thread consumption totals based on thread consumption reports conducted by our Technical Service Department. These thread consumption figures include a 25% waste factor and are based on a typical garment construction.
Estimating Thread Cost
The thread cost can be estimated by multiplying the thread consumed times the cost of thread in the same units. For example:
Men's Dress Shirt thread consumption:
25% waste factor = 131 yds.
Average Cost of T-24 Poly Wrapped Core Thread:
$4.50 / 6000 yard cone
Cost per yard $4,500:
6000 yard cone = $.00075/yard
Calculation:
131 yds./shirt X $.00075/yard = $.09825/shirt
Product Sewn
Total Yds/
Garment
Product Sewn
Total Yds/
Garment
Men's
Boy's
Slack 225 Jeans 168
Jean 200 Pants 183
Jean Short 160 Jacket 175
Work Pants 238 Dress Shirt 101
Suit Coat 175 Knit Shirt 83
Dress Shirt– long sleeve 131 Baseball Cap 44
Work Shirt 115
Knit Polo Shirt 130
Fleece Sweat Shirt 280
Tee Shirt 63
Tank Top 58
Knit Brief 68
Women's Girl's
Lined Coat 246 Blouse 73
Blazer 153 Dress 118
Dress 141 Swim Suit 65
Skirt 192
Blouse 122
Pants 162
Jeans 250
Shorts 151
Robe 300
Night Gown 135
Panties 62
Bra 63
Seam Engineering
Introduction
One of the forgotten elements in sewing manufacturing is seam engineering. For example, a typical pair of branded five pocket jeans retailing for $30 to $75 is sewn with approximately 250 yards (200 meters) of thread. The cost of a quality thread for these jeans is approximately $0.25 U.S. per garment.
Many jean manufacturers will spend anywhere from $1 to $6 per jean to have them stone washed, acid washed, or sandblasted. Incredibly, the thread is expected to hold the seams together for the life of the
garment regardless of what abuse it has been exposed to! In such cases, what some forget is that…
Though thread makes up a small percent of the cost of the garment, it shares 50% of the responsibility of seam quality. If a manufacturer has frequently returned garments for excessive seam "unqualities," such as, re-stitched seams or seam failure due to the thread rupturing, we would say the garment is "under-threaded," meaning that either the wrong type or size of thread is being used.
Quality seam engineering relates to many areas of concern including seam strength and seam durability. Obviously thread plays an important role in all of these areas that are controlled by the factors described below. Seam Engineering - Thread Size
We are frequently asked by sewing factories if they should use the same size thread throughout the sewn product or if they could save money by using a smaller thread size on the underside of the seam or
in overedge seams. Before these questions can be answered, the manufacturer should first take into consideration:
• The number of colors that will be sewn in a season.
• If it is even feasible to use more than one thread size.
If you are sewing childrenswear or womenswear where there are always many colors being sewn at any one time, then we would recommend staying with the same type and size of thread throughout the
garment. On the other hand, if you are sewing products that consist of several basic colors, the best option is to use smaller threads on the inside of the garment to significantly reduce the thread cost.
Another factor that should be considered is the affect that this downsizing of thread will have on your seam strength. Following are some common-sense "rules of thumb" for thread size selection on seams sewn with 301 lockstitch, 401 chainstitch, and 504 overedge.
301 Lockstitch Seams
For 301 lockstitch seams, we generally recommend using the same needle thread size as the bobbin thread size in the seam. Why? Because "a chain is only as strong as its weakest link."
If a smaller, weaker thread is used in the bobbin, then the seam will only be as strong as the bobbin thread. This is particularly true with lockstitch seams because of the way the needle and bobbin threads are interlocked together.
In some cases though, this does have exceptions. Sometimes a smaller size thread with a different fiber type and/or thread construction can be used and still maintain seam performance. An example would be
to use a higher tenacity Corespun in place of a Spun thread. monocord bobbin instead of a spun or corespun thread in the seam. Also, exceptions can be made when a larger topstitching thread is desired to give a bold appearance on the outside of the garment when it is not necessarily being used to add strength or durability to the seam.
401 Chainstitch
Notice that in the diagram of the 401 chainstitch, a loop of looper thread is holding the needle thread through the seam. Also, notice that the threads are interlooped rather than interlocked as we saw on
the lockstitch seam. This allows a looper thread to be downsized to at least 60% of the needle thread size without adversely affecting the seam strength (for example: T-60 needle thread – T-40 looper thread). This is one way to reduce thread cost without adversely affecting the seam quality.
However, you need to determine if carrying another SKU (stock keeping unit) will significantly increase the cost of inventory and supervision on the sewing floor to make sure the right size thread is being used in the correct position.
504 Overedge Seams
504 Overedge seams have basically the same needle thread formation as the needle thread on a 401 chainstitch seam. Therefore, the same rule applies. You can use a looper thread approximately 60% of the
needle thread size without adversely affecting the seam strength (for example: T-24 needle thread – T-18 looper threads). Just remember that smaller looper threads will not give the seam coverage of larger
thread sizes.
Factors that Affect Seam Strength
Five factors that determine the strength of a seam include:
• Fabric type and weight.
• Thread fiber type, construction, and size.
• Stitch and seam construction.
• Stitches per inch.
• Stitch balance.
Any one of these factors can adversely affect the performance of a sewn product depending on the end-use of the sewn product. Following are a few general comments related to the factors listed above.
.
Fabric Type and Weight
Fabric type and weight can affect seam performance depending on the following:
• Fiber content (100% cotton, cotton/polyester blend, nylon).
• Fabric construction:
o Woven or knit.
o Type of weave used (plain, twill, jersey, tricot).
o Fill count.
o Yarn type and size.
• Pattern placement and seam direction.
• Propensity of the yarns in the seam to shift or pull out of the seam.
When engineering seams, we recommend doing tensile tests on the fabric to determine its strength. You cannot specify seam strength requirements that are stronger than the fabric itself.
Thread Fiber Type, Construction, and Size
These all have a definite effect on seam strength including the following factors:
• Fiber Type:
o Some fibers are stronger than others and have greater loop strength contributing to greater seam strength. For example, a 100% spun polyester thread will give greater seam strength than a 100%
cotton thread of the same size.
o Synthetic fibers like polyester and nylon are much more resistant to abrasion and chemical degradation (such as bleach) than cellulosic fibers. Cellulosic fibers on the other hand have superior heat resistance.
o Kevlar® and Nomex® threads were designed to resist high temperatures in protective clothing.
• Thread Construction (Spun, Core, Textured, Multifilament, etc.):
o Core threads, made with continuous filament polyester core, generally will provide higher seam strength than spun and textured threads.
o Continuous filament polyester or nylon thread construction will provide greater resistance to abrasion and seam degredation.
o Some thread constructions are less subject to shearing or cutting each other when interlooped together in the seam. Air entangled, textured, and monocord thread constructions exhibit the best loop strength characteristics.
• Thread Finish (Soft, Mercerized, Glaced, Bonded, Etc.):
o Glace or bond finished threads generally have superior abrasion resistance to soft finished threads.
o Mercerized threads are stronger than soft cotton threads of the same fiber type and size.
• Thread Size (Tex, Metric, Yarn Size):
o Given a specific fiber type and thread construction, the larger the thread size, the greater the seam strength. As previously mentioned, different fiber types and thread constructions have different loop-strength characteristics. In many cases, a smaller thread size will imbed itself in the seam making it less prone to surface abrasion.
Stitch and Seam Construction
• Stitch Types:
o Generally, the more thread consumed in a stitch, the greater the seam strength. This holds true when comparing 301 lockstitch seams to 401 chainstitch seams.
o Threads used in 301 lockstitch seams are more susceptible to shearing each other than 401 chainstitch and 504 overedge seams because of the way the threads are interlocked together rather than interlooped together.
• Seam Types:
o Many seam constructions are more resistant to both stress and abrasion than other constructions. For example, a Fed. Spec 751a `LSc' or ISO 4916 2.04.06 felled seam is the strongest of all seams because the stress is shared by the fabric and the thread.
Stitches per Inch
• Generally, the greater the number of stitches per inch in a seam, the greater the seam strength. This refers back to the point that the more thread you put in the seam, the stronger the seam. However, on some fabrics, too many stitches can cause damage to the fabric by cutting the yarns enough to weaken it.
• Excessive stitches per inch can also contribute to seam puckering and reduce the speed through the machine resulting in loss of production.
Stitch Balance
• As a rule, the more needle thread that can be put into a seam, the greater the seam strength. This can be accomplished by adjusting the sewing machine thread tensions, thread control guides, and eyelets, etc.
• Care should be taken not to put too much needle thread in the seam to cause the seam to "grin" or open up when stress is applied to it. Excessive sewing machine thread tension will cause reduced seam strength as well as create other sewing problems. Estimating Seam Strength on Wovens. To the right are two formulas that were developed for estimating the seam strength on woven fabrics. To do the calculations, you need to
know the following:
• Stitch type (301 Lockstitch or 401 Chainstitch)
• Thread Strength (Single-end breaking strength of the thread, measured in pounds)
• Stitches per inch
301 Lockstitch Formula
SPI X THD. Strength X 1.5* = Estimated Seam Strength
For example: 10 X 4.0 lbs. X 1.5 = 60 lbs.
* Factor based on normal loop strength of threads used for apparel.
401 Chainstitch Formula
SPI X THD. Strength X 1.7* = Estimated Seam Strength
For example: 10 X 4.0 lbs. X 1.7 = 68 lbs.
*Factor based on normal loop strength of threads using double loop on underside.
Abrasion Resistance
Abrasion resistance has always been an important factor to upholstery, footwear, and carpet manufacturers. Recently, abrasion resistance has also become important in apparel due to the stringent laundering cycles and pre-wash processes used in garment preparation. Factors that affect the abrasion resistance of a sewing thread in a seam include:
• Fiber Type (nylon, polyester, cotton, etc.).
• Fiber size and shape (denier per fil, round, trilobal, etc.).
• Thread construction (monocord, corespun, spun, air entangled, etc.).
• Thread size.
• Stitch and seam construction.
One of the forgotten elements in sewing manufacturing is seam engineering. For example, a typical pair of branded five pocket jeans retailing for $30 to $75 is sewn with approximately 250 yards (200 meters) of thread. The cost of a quality thread for these jeans is approximately $0.25 U.S. per garment.
Many jean manufacturers will spend anywhere from $1 to $6 per jean to have them stone washed, acid washed, or sandblasted. Incredibly, the thread is expected to hold the seams together for the life of the
garment regardless of what abuse it has been exposed to! In such cases, what some forget is that…
Though thread makes up a small percent of the cost of the garment, it shares 50% of the responsibility of seam quality. If a manufacturer has frequently returned garments for excessive seam "unqualities," such as, re-stitched seams or seam failure due to the thread rupturing, we would say the garment is "under-threaded," meaning that either the wrong type or size of thread is being used.
Quality seam engineering relates to many areas of concern including seam strength and seam durability. Obviously thread plays an important role in all of these areas that are controlled by the factors described below. Seam Engineering - Thread Size
We are frequently asked by sewing factories if they should use the same size thread throughout the sewn product or if they could save money by using a smaller thread size on the underside of the seam or
in overedge seams. Before these questions can be answered, the manufacturer should first take into consideration:
• The number of colors that will be sewn in a season.
• If it is even feasible to use more than one thread size.
If you are sewing childrenswear or womenswear where there are always many colors being sewn at any one time, then we would recommend staying with the same type and size of thread throughout the
garment. On the other hand, if you are sewing products that consist of several basic colors, the best option is to use smaller threads on the inside of the garment to significantly reduce the thread cost.
Another factor that should be considered is the affect that this downsizing of thread will have on your seam strength. Following are some common-sense "rules of thumb" for thread size selection on seams sewn with 301 lockstitch, 401 chainstitch, and 504 overedge.
301 Lockstitch Seams
For 301 lockstitch seams, we generally recommend using the same needle thread size as the bobbin thread size in the seam. Why? Because "a chain is only as strong as its weakest link."
If a smaller, weaker thread is used in the bobbin, then the seam will only be as strong as the bobbin thread. This is particularly true with lockstitch seams because of the way the needle and bobbin threads are interlocked together.
In some cases though, this does have exceptions. Sometimes a smaller size thread with a different fiber type and/or thread construction can be used and still maintain seam performance. An example would be
to use a higher tenacity Corespun in place of a Spun thread. monocord bobbin instead of a spun or corespun thread in the seam. Also, exceptions can be made when a larger topstitching thread is desired to give a bold appearance on the outside of the garment when it is not necessarily being used to add strength or durability to the seam.
401 Chainstitch
Notice that in the diagram of the 401 chainstitch, a loop of looper thread is holding the needle thread through the seam. Also, notice that the threads are interlooped rather than interlocked as we saw on
the lockstitch seam. This allows a looper thread to be downsized to at least 60% of the needle thread size without adversely affecting the seam strength (for example: T-60 needle thread – T-40 looper thread). This is one way to reduce thread cost without adversely affecting the seam quality.
However, you need to determine if carrying another SKU (stock keeping unit) will significantly increase the cost of inventory and supervision on the sewing floor to make sure the right size thread is being used in the correct position.
504 Overedge Seams
504 Overedge seams have basically the same needle thread formation as the needle thread on a 401 chainstitch seam. Therefore, the same rule applies. You can use a looper thread approximately 60% of the
needle thread size without adversely affecting the seam strength (for example: T-24 needle thread – T-18 looper threads). Just remember that smaller looper threads will not give the seam coverage of larger
thread sizes.
Factors that Affect Seam Strength
Five factors that determine the strength of a seam include:
• Fabric type and weight.
• Thread fiber type, construction, and size.
• Stitch and seam construction.
• Stitches per inch.
• Stitch balance.
Any one of these factors can adversely affect the performance of a sewn product depending on the end-use of the sewn product. Following are a few general comments related to the factors listed above.
.
Fabric Type and Weight
Fabric type and weight can affect seam performance depending on the following:
• Fiber content (100% cotton, cotton/polyester blend, nylon).
• Fabric construction:
o Woven or knit.
o Type of weave used (plain, twill, jersey, tricot).
o Fill count.
o Yarn type and size.
• Pattern placement and seam direction.
• Propensity of the yarns in the seam to shift or pull out of the seam.
When engineering seams, we recommend doing tensile tests on the fabric to determine its strength. You cannot specify seam strength requirements that are stronger than the fabric itself.
Thread Fiber Type, Construction, and Size
These all have a definite effect on seam strength including the following factors:
• Fiber Type:
o Some fibers are stronger than others and have greater loop strength contributing to greater seam strength. For example, a 100% spun polyester thread will give greater seam strength than a 100%
cotton thread of the same size.
o Synthetic fibers like polyester and nylon are much more resistant to abrasion and chemical degradation (such as bleach) than cellulosic fibers. Cellulosic fibers on the other hand have superior heat resistance.
o Kevlar® and Nomex® threads were designed to resist high temperatures in protective clothing.
• Thread Construction (Spun, Core, Textured, Multifilament, etc.):
o Core threads, made with continuous filament polyester core, generally will provide higher seam strength than spun and textured threads.
o Continuous filament polyester or nylon thread construction will provide greater resistance to abrasion and seam degredation.
o Some thread constructions are less subject to shearing or cutting each other when interlooped together in the seam. Air entangled, textured, and monocord thread constructions exhibit the best loop strength characteristics.
• Thread Finish (Soft, Mercerized, Glaced, Bonded, Etc.):
o Glace or bond finished threads generally have superior abrasion resistance to soft finished threads.
o Mercerized threads are stronger than soft cotton threads of the same fiber type and size.
• Thread Size (Tex, Metric, Yarn Size):
o Given a specific fiber type and thread construction, the larger the thread size, the greater the seam strength. As previously mentioned, different fiber types and thread constructions have different loop-strength characteristics. In many cases, a smaller thread size will imbed itself in the seam making it less prone to surface abrasion.
Stitch and Seam Construction
• Stitch Types:
o Generally, the more thread consumed in a stitch, the greater the seam strength. This holds true when comparing 301 lockstitch seams to 401 chainstitch seams.
o Threads used in 301 lockstitch seams are more susceptible to shearing each other than 401 chainstitch and 504 overedge seams because of the way the threads are interlocked together rather than interlooped together.
• Seam Types:
o Many seam constructions are more resistant to both stress and abrasion than other constructions. For example, a Fed. Spec 751a `LSc' or ISO 4916 2.04.06 felled seam is the strongest of all seams because the stress is shared by the fabric and the thread.
Stitches per Inch
• Generally, the greater the number of stitches per inch in a seam, the greater the seam strength. This refers back to the point that the more thread you put in the seam, the stronger the seam. However, on some fabrics, too many stitches can cause damage to the fabric by cutting the yarns enough to weaken it.
• Excessive stitches per inch can also contribute to seam puckering and reduce the speed through the machine resulting in loss of production.
Stitch Balance
• As a rule, the more needle thread that can be put into a seam, the greater the seam strength. This can be accomplished by adjusting the sewing machine thread tensions, thread control guides, and eyelets, etc.
• Care should be taken not to put too much needle thread in the seam to cause the seam to "grin" or open up when stress is applied to it. Excessive sewing machine thread tension will cause reduced seam strength as well as create other sewing problems. Estimating Seam Strength on Wovens. To the right are two formulas that were developed for estimating the seam strength on woven fabrics. To do the calculations, you need to
know the following:
• Stitch type (301 Lockstitch or 401 Chainstitch)
• Thread Strength (Single-end breaking strength of the thread, measured in pounds)
• Stitches per inch
301 Lockstitch Formula
SPI X THD. Strength X 1.5* = Estimated Seam Strength
For example: 10 X 4.0 lbs. X 1.5 = 60 lbs.
* Factor based on normal loop strength of threads used for apparel.
401 Chainstitch Formula
SPI X THD. Strength X 1.7* = Estimated Seam Strength
For example: 10 X 4.0 lbs. X 1.7 = 68 lbs.
*Factor based on normal loop strength of threads using double loop on underside.
Abrasion Resistance
Abrasion resistance has always been an important factor to upholstery, footwear, and carpet manufacturers. Recently, abrasion resistance has also become important in apparel due to the stringent laundering cycles and pre-wash processes used in garment preparation. Factors that affect the abrasion resistance of a sewing thread in a seam include:
• Fiber Type (nylon, polyester, cotton, etc.).
• Fiber size and shape (denier per fil, round, trilobal, etc.).
• Thread construction (monocord, corespun, spun, air entangled, etc.).
• Thread size.
• Stitch and seam construction.
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