Ask for cus­tom­ized sewing au­tomats

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Au­to­ma­tion and robotics in ap­parel man­u­fac­tur­ing are hot top­ics of dis­cus­sion nowa­days! They were the favourite top­ics of machine man­u­fac­tur­ers and re­searchers dur­ing ’90s, and now they are mak­ing a sec­ond com­ing with a greater vigour and ev­ery pos­si­bil­ity to suc­ceed. The tran­si­tion started with mech­a­niza­tion to au­to­ma­tion and now robotics. Au­to­ma­tion and robotics are of­ten used par­al­lel to each other with only a fine line of dif­fer­ence. Whereas au­to­ma­tion can only fol­low one set of op­er­a­tions, which can­not be changed once pro­grammed, ro­bots on the other hand are made to per­form sev­eral jobs at once, and the se­quence of op­er­a­tions can be switched around to make the pro­cesses more ef­fi­cient.

It seems that there is growth in th­ese ar­eas since mass man­u­fac­tur­ers in Asia are ex­plor­ing newer prod­uct seg­ments (both ap­parel as well as non-ap­parel) and be­spoke man­u­fac­tur­ers ( for whom scale of man­u­fac­tur­ing was never an ad­van­tage) are also fac­ing se­vere short­age of skilled labour. The nor­mal pay­back pe­riod based on US wage rate is gen­er­ally be­tween 12-18 months.

Cus­tom au­tomats gen­er­ally have higher per­cent­age of suc­cess or adop­tion as the equip­ment and so­lu­tions are cus­tom- de­signed for spe­cific needs keep­ing all the work­ing pa­ram­e­ters in mind. Off-the-shelf au­tomats some­times face re­sis­tance from shopfloor due to the rigid­ity of their op­er­a­tions. In this new se­ries, Dr. Pra­bir Jana, Pro­fes­sor, NIFT and Frank Hen­der­son, Pres­i­dent of Hen­der­son Sewing Machine, USA bring to you an ex­pe­ri­ence of cus­tom­ized au­tomats for sewing.

Au­to­ma­tion in essence re­duces the flex­i­bil­ity ( gen­er­al­ity) of any op­er­a­tion and in­creases stan­dard­iza­tion. The pos­si­ble au­toma­tions for op­er­a­tions in com­mod­ity gar­ments are al­ready done, com­mer­cial­ized, copied and now af­ford­able to many. How­ever, the ever- chang­ing style and de­vel­op­ment of in­no­va­tive raw ma­te­rial poses chal­lenge to off-the-shelf au­tomats. There­fore, stan­dard au­tomats of­fered by many sewing machine man­u­fac­tur­ing com­pa­nies are of­ten not ap­pro­pri­ate for a par­tic­u­lar op­er­a­tion. Thus, the need for cus­tom­ized au­tomats arises. There are many ven­dors in US, EU and Ja­pan who have the ca­pa­bil­ity, tech­ni­cal know- how and ex­per­tise to cre­ate au­to­ma­tion us­ing the sewing heads of es­tab­lished sewing brands.

Here we will dis­cuss about the three cases of cus­tom­ized au­tomats be­ing de­vel­oped

While th­ese au­ton­o­mous work cells do not re­quire any hu­man in­ter­ven­tion (i.e. all three pro­cesses – load­ing, sewing and un­load­ing, are au­to­mated), th­ese can be re-pro­grammed to sew dif­fer­ent pro­files or dif­fer­ent sides and thus can be called ap­pli­ca­tion of robotics.

for sewing non-ap­parel prod­ucts. Al­though the cases are for non-ap­parel and ex­e­cuted in USA, sim­i­lar in­ter­ven­tion is very much a re­al­ity in Asia.

Pro­file sewing of fur­ni­ture fab­ric with Dacron

Fur­ni­ture in­dus­try re­quires fab­ric, Dacron and foam for up­hol­stery where Dacron, a kind of polyester bat­ting ( cladding sheet) is added to any foam sur­face so that the foam does not get ex­posed di­rectly to the fab­ric. Sewing such a fab­ric with Dacron is a very sim­ple pro­file sewing op­er­a­tion in­volv­ing large fab­ric com­po­nent. The shape of the pro­file varies from straight line to curves, and the mea­sure­ment of one side of pro­file can ex­ceed one me­tre. As the sewing op­er­a­tion does not re­quire much man­ual skill and re­quires han­dling of large mass of fab­ric (vul­ner­a­ble to repet­i­tive strain in­jury to the op­er­a­tor), the op­er­a­tion was deemed fit for au­to­ma­tion.

This au­ton­o­mous work cell was de­vel­oped with a gantry style ro­bot that loads and sews Dacron and a fur­ni­ture fab­ric panel to­gether with a sin­gle nee­dle lock­stitch uni­son feed machine. The Dacron and fab­ric com­po­nent are loaded into a set po­si­tion on the work sur­face in front of the ro­bot and sewing head. The gantry style sin­gle beam ro­bot po­si­tions the car­rier plate on top of the Dacron and fab­ric com­po­nent hold­ing both cut com­po­nents in align­ment. The ro­bot plate moves the cut com­po­nents into the sewing head. As the sewing process be­gins, the ro­bot is syn­chro­nized with the sewing head and moves the prod­uct around the to­tal cir­cum­fer­ence of the outer edge of the fab­ric com­po­nents un­til both com­po­nents are joined to­gether. The machine pauses mo­men­tar­ily to trim the thread and moves the fin­ished sewn com­po­nents into a set po­si­tion where a stack­ing arm will re­move the fin­ished panel and stack into a dropframe re­cep­ta­cle un­der­neath the machine’s work sur­face. And the process con­tin­ues repet­i­tively. The load­ing time is 10 sec­onds, while the sewing time for sixsided pro­file is 43 sec­onds and stack­ing time is 20 sec­onds.

Gantry ro­bot load and sew iron­ing board cov­ers

Pro­file sewing of iron­ing board cov­ers is done us­ing over­lock machine in man­ual mode. The first op­tion con­sid­ered to sew iron­ing board cover was serger type off-the-shelf au­tomat. Even in such an op­tion, the man­ual load­ing of com­po­nent was re­quired. As the fab­ric- layer in this case is di­men­sion­ally sta­ble, it was de­cided to au­to­mate the load­ing process us­ing gantry ro­bot. This work cell takes pre­cut iron­ing board cov­ers and loads and sews the fab­ric cover with a 1- nee­dle, 3-thread over­lock machine. The iron­ing board fab­ric com­po­nent is loaded from a stack into a set po­si­tion on the work sur­face in front of the gantry ro­bot and over­lock sewing head. The gantry style sin­gle beam ro­bot po­si­tions the car­rier plate on top of the fab­ric cover com­po­nents and moves the cut com­po­nents into the sewing head and around the cir­cum­fer­ence shape of the iron­ing board cover. The ro­bot is syn­chro­nized with the over­lock sewing head and moves the outer edge of the fab­ric com­po­nents around the plate thus sewing the iron­ing board fab­ric com­pletely around. The ro­bot pauses briefly to trim the over­lock thread, then moves the fin­ished sewn fab­ric com­po­nent to the rear of the machine and through a re­moval slot to the rear of the work sur­face and be­hind the sewing machine head dropping the panel into a re­cep­ta­cle un­der­neath the machine’s work sur­face. The process con­tin­ues repet­i­tively after each fin­ished com­po­nent. While load­ing and un­load­ing take 3 sec­onds each, the sewing takes 11 sec­onds to com­plete all sides of sewing and trim­ming to­gether.

Stan­dard au­tomats of­fered by many sewing machine man­u­fac­tur­ing com­pa­nies are of­ten not ap­pro­pri­ate for a par­tic­u­lar op­er­a­tion. Thus, the need for cus­tom­ized au­tomats arises.

Frank Hen­der­son, Pres­i­dent, Hen­der­son Sewing Machine

Dr. Pra­bir Jana, Pro­fes­sor, NIFT Delhi

Pro­file sewing of fur­ni­ture fab­ric with Dacron

Gantry ro­bot sewing iron­ing board cov­ers

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