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