SHIRT ‘EM UP! DE­COD­ING VAR­I­OUS WAYS MEN’S SHIRTS ARE MADE!

Stitch World - - NEWS -

Prob­a­bly known as one of the most un­fash­ion­able and un­changed prod­ucts since the last cen­tury, men’s shirt re­mains one of the con­stant prod­ucts of the ap­parel in­dus­try with ap­prox­i­mately 18 com­po­nents sewn to­gether. That fixed two-piece col­lar, sin­gle patch pocket at left front, sleeve open­ing with cuff, dou­ble layer yoke, stan­dard straight knife cut­ting for body parts and die-cut­ting or band knife cut­ting for cuff-col­lar, con­tin­u­ous bed fus­ing for col­lars and cuffs and some­times front placket, ev­ery­thing in men’s shirt is set like a stan­dard man­u­fac­tur­ing process. But in­ter­est­ingly no two shirts’ sewing lines are sim­i­lar! Op­er­a­tion break­down of ex­actly the same shirt will be dif­fer­ent in two dif­fer­ent fac­to­ries. While the prod­uct re­mains stan­dard, why is the process so dif­fer­ent? Dr. Pra­bir Jana, Pro­fes­sor, NIFT, Delhi ex­plores….

Sewing a men’s shirt can take any­thing from 20 min­utes to 30 min­utes. The time vari­a­tion is due to process and tech­nol­ogy vari­a­tion. Although, there is ref­er­ence of one 12-minute shirt by Ko­gos In­ter­na­tional Cor­po­ra­tion, NY, I as­sume it was man­u­fac­tured with over­lock­ing arm­holes and side seams. Any over­lock seam, although cov­er­ing the raw edge, re­sults in vis­i­bly pro­trud­ing edge at the back side of the gar­ment. The ba­sic char­ac­ter­is­tic of a stan­dard men’s shirt is that there should not be any vis­i­ble pro­trud­ing edge in­side or out­side of the gar­ment; all seams should be flat as far as pos­si­ble. A stan­dard men’s shirt is as­sumed to have dou­ble piece yoke, arm­hole joined by flat & fell seam and two nee­dle chain­stitch sewing of lap seam (us­ing feed of arm) at side and sleeve. Firstly, the over­lock sewing process is ap­prox­i­mately 20-25 per cent faster than lock­stitch (301) or dou­ble chain­stitch (401); se­condly the over­lock join­ing is al­ways done by su­per­im­posed seam, re­sult­ing in easy han­dling of com­po­nents dur­ing sewing. There­fore, many mass-shirt brands re­sort to over­lock­ing of arm­hole and side seam to in­crease the pro­duc­tiv­ity. Most of the brands also use multi-nee­dle dou­ble chain­stitch (401) at front placket to in­crease pro­duc­tiv­ity and re­duce propen­sity to­wards seam pucker.

Vari­a­tion in gar­ment con­struc­tion

A ta­ble of process vari­a­tion of two op­er­a­tions will ex­plain why any two shirt-mak­ing fac­to­ries may not have the same op­er­a­tion break­down. The sleeve placket mak­ing can have four

The ba­sic char­ac­ter­is­tic of a stan­dard men’s shirt is that there should not be any vis­i­ble pro­trud­ing edge in­side or out­side of the gar­ment; all seams should be flat as far as pos­si­ble. A stan­dard men’s shirt is as­sumed to have dou­ble piece yoke, arm­hole joined by flat & fell seam and two nee­dle chain­stitch sewing of lap seam (us­ing feed of arm) at side and sleeve.

dif­fer­ent vari­a­tions while the front placket mak­ing can have six dif­fer­ent vari­a­tions. It is im­por­tant to note that all vari­a­tions do not nec­es­sar­ily show up any ma­jor vis­i­ble dis­tin­guished fea­ture in the shirt’s ap­pear­ance, and the process vari­a­tion does not af­fect the per­for­mance of the gar­ment.

If we mix and match the sleeve placket and left front placket vari­a­tions, we get 6X4=24 vari­a­tions. If we com­bine right front placket which are mainly of two types, we get 24X2=48 dif­fer­ent ways to sew only three op­er­a­tions in the men’s shirt. Although, the to­tal num­ber of op­er­a­tions in a shirt are nearly 40+, if hy­po­thet­i­cally 6 of the op­er­a­tions can be done in 3 dif­fer­ent ways, the to­tal num­ber of vari­a­tions will be a mind-bog­gling

36 = 729. Ev­ery dif­fer­ent vari­a­tion has dif­fer­ent SMV and dif­fer­ent USP or style fea­ture (although of­ten un­no­tice­able) for any brand.

Vari­a­tion in man­u­fac­tur­ing process

Apart from vari­a­tions in con­struc­tion process, the man­u­fac­tur­ing process (the di­vi­sion of labour and ma­te­rial han­dling be­tween two sewing op­er­a­tions) also dif­fers on many ac­counts. Shirt sewing can be tra­di­tion­ally bro­ken down into six sec­tions: front, back, sleeve, col­lar, cuff, and as­sem­bly. While some man­u­fac­tur­ers in­cor­po­rate all sec­tions in one sewing line, oth­ers main­tain sep­a­rate sec­tions as sep­a­rate sewing lines. The sec­tion­al­i­sa­tion is also not stan­dard­ised; as some man­u­fac­tur­ers (large or­der quan­tity) cre­ate only three sec­tions, namely small part prepa­ra­tion (col­lar and cuff sec­tions com­bined), large part prepa­ra­tion (front, back and sleeve sec­tion com­bined) and as­sem­bly sec­tion, and pre­fer to work with dif­fer­ent sec­tions where these sec­tions are man­aged by dif­fer­ent line su­per­vi­sors with sep­a­rate tar­gets and huge WIP is main­tained be­tween dif­fer­ent sec­tions. While com­pa­nies with short run (low vol­ume or­der) pre­fer to com­bine all sec­tions into one line.

Pre­sented here is the op­er­a­tion break­down of men’s dress shirt from five dif­fer­ent sources ( Ta­ble 2); one is men­tioned by an Ital­ian con­sul­tant in an ar­ti­cle pub­lished by SW, the sec­ond one has been men­tioned by an In­dian do­mes­tic man­u­fac­turer, the third one is from Bin­ran ( Juki), the fourth one is by an In­dian ex­port man­u­fac­turer, and the fifth one is a 12-minute shirt from Ko­gos. The to­tal num­ber of op­er­a­tions vary from 41 to 53, which although in some cases are in­clu­sive of fi­nal press and in some cases are ex­clu­sive.

Shirt sewing can be tra­di­tion­ally bro­ken down into six sec­tions: front, back, sleeve, col­lar, cuff, and as­sem­bly. While some man­u­fac­tur­ers in­cor­po­rate all sec­tions in one sewing line, oth­ers main­tain sep­a­rate sec­tions as sep­a­rate sewing lines.

The SMV varies from 18.53 to 28.00 min­utes (ex­cep­tion be­ing the 12-minute shirt which in­cludes fi­nal press & fin­ish).

The col­lar & cuff sec­tion to­gether ac­count for max­i­mum num­ber of op­er­a­tions (from 39 per cent to 47 per cent) from 17 min­i­mum (do­mes­tic) to 24 max­i­mum (Bin­ran). It is in­ter­est­ing to note that there is no con­sis­tent pat­tern of op­er­a­tion break­down and SMV thereof. The as­sem­bly sec­tion SMV is the low­est in case of ‘do­mes­tic’ (i.e. 26 per cent), while the as­sem­bly sec­tion of SW is the high­est at 46 per cent. The SMV is al­most equally dis­trib­uted (31 per cent – 36 per cent ap­prox­i­mately) be­tween small part, large part, and as­sem­bly sec­tion in case of ex­port shirt. The or­gan­i­sa­tions that wish to in­stall over­head ma­te­rial han­dling sys­tem (OMHS) in shirt-sewing plant will ide­ally use it for as­sem­bly sec­tion only; that is less than one fourth of the to­tal sewing op­er­a­tions. Although not ad­vis­able, some of the com­pa­nies do in­stall over­head ma­te­rial han­dling sys­tem in large part sec­tion to bring to­tal num­ber of op­er­a­tions un­der OMHS to near 50 per cent.

True pitch time is to­tal SMV di­vided by num­ber of op­er­a­tors avail­able to do the job. The num­ber of op­er­a­tors avail­able may be more or less than to­tal num­ber of op­er­a­tions, de­pend­ing upon the tar­get to achieve. True pitch is cal­cu­lated for op­er­a­tor al­lo­ca­tion and bal­anc­ing the line. Mock pitch time is cal­cu­lated by di­vid­ing SMV by to­tal num­ber of op­er­a­tions. Mock pitch time gives an idea about vari­abil­ity of op­er­a­tion break­down of any gar­ment. If we look at the sec­tion­alised SAM and re­spec­tive ‘Mock Pitch Time’ of four dif­fer­ent shirts ( Ta­ble 3), it is ev­i­dent why most of the large shirt man­u­fac­tur­ing plants work on sec­tion­alised line sys­tem. The mock pitch time of large part sec­tion for SW shirt is al­most dou­ble the small part sec­tion while nearly half the as­sem­bly sec­tion. There­fore, if we run the sewing sec­tion of SW shirt as one com­plete line of 42 op­er­a­tions, the bal­ance ef­fi­ciency will be very low. How­ever, if the SW shirt line is seg­re­gated as three sep­a­rate lines of large part, small part and as­sem­bly, and then ev­ery sec­tion is separately bal­anced, and we can have higher bal­ance ef­fi­ciency in­di­vid­u­ally. Sim­i­larly, if we com­pare do­mes­tic and ex­port shirt, the over­all mock pitch time is same, but the sec­tional mock pitch time varies a lot. It is equally in­ter­est­ing to note that the as­sem­bly mock pitch time for all four shirt vari­a­tions is one-and-a-half times to two times higher than small parts or large parts sec­tion (Fig­ure 1). This re-em­pha­sises that even if any or­gan­i­sa­tion de­cides to com­bine the small parts and large parts sewing sec­tion into one line, the as­sem­bly sec­tion should prefer­ably be kept as sep­a­rate line to in­crease bal­ance ef­fi­ciency.

The ef­fect of DeS­tan­dard­i­s­a­tion (on au­to­ma­tion)

Any process stan­dard­i­s­a­tion leads to prob­a­ble au­to­ma­tion. With In­dus­try 4.0 beck­on­ing the gar­ment man­u­fac­tur­ing process, it is im­per­a­tive that some stan­dard­i­s­a­tion takes place for the over­all ben­e­fit of the in­dus­try. Dur­ing the peak of dom­i­nance of qual­ity as­sur­ance ( QA) in early 2000, one of the large re­tail­ers was asked to in­spect the gar­ment from the cus­tomer’s point of view and not from QA’s point of view. The mes­sage was clear, “Don’t find fault for the sake of find­ing a fault, ask your­self whether a cus­tomer will be able to spot the fault if he/ she buys the mer­chan­dise? Or, is the fault go­ing to af­fect any aes­thet­ics or per­for­mance value of the gar­ment?” The same logic holds true for de­sign USP; just for the sake of dif­fer­en­ti­a­tion from the rest ( of brands), of­ten de­sign dif­fer­en­ti­a­tion was cre­ated in the mer­chan­dise with­out any use­ful im­pact on the end cus­tomer. The de­sign­ers need to ask them­selves, “Will the cus­tomer be able to spot the dif­fer­ence and pay for the same?” The con­struc­tion process of stan­dard­i­s­a­tion is to be in­te­grated with pre­dom­i­nantly in­flu­en­tial de­sign func­tion to pave the way for au­to­ma­tion. More­over, the aes­thetic dif­fer­en­ti­a­tion should not com­pro­mise the tech­ni­cal and aes­thetic per­for­mance of the gar­ment dur­ing both pre- and post- pur­chase.

True pitch time is to­tal SMV di­vided by num­ber of op­er­a­tors avail­able to do the job. The num­ber of op­er­a­tors avail­able may be more or less than to­tal num­ber of op­er­a­tions, de­pend­ing upon the tar­get to achieve. True pitch is cal­cu­lated for op­er­a­tor al­lo­ca­tion and bal­anc­ing the line.

Fig­ure 1: Mock Pitch Time in dif­fer­ent sewing sec­tions

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