Prevent sewing defects
The other day when I published How to get people to change, I neglected to mention another nifty way that modular (lean) production lowers your sewing costs. First, a quick reminder; batch processing means one person does one operation on a bundle of goods, stacking it as completed, rebundling it in readiness for the next sewing operator. Depending on how well or poorly the place is organized, it’s possible that bundle won’t be worked on again for a couple of weeks(!). Lean does away with bundling. One person will make the item start to finish. Technically speaking, the item is “hand made” and considered to be of higher quality. This entry is about how having items hand made can save you money by reducing the number of errantly sewn goods from continuing through the process. But first the observation that made me think to mention this to you.
When we were observing the team sewing demonstration at SPESA, I noticed the operator incorrectly sewed the first seam -a shoulder seam. As you would hope, she laid this garment aside and began an entirely different garment. I’ll bet most of you are thinking “so what?” or “that’s what she’s supposed to do” and while you may be right, if you’re using a bundle/batch method, this just isn’t going to happen. No way. Her laying of the defective garment aside and beginning another is close to revolutionary -when you consider how things are typically done in the average plant.
In traditional batch processing (bundling), one operator will do one operation per their bundle and perhaps sew one or more of those items wrong but rather than set the defective ones aside, they’ll continue to stack and complete their bundle that will then move onto the next operator and operation. This is often because of pay and logistics. In spite of the name -piece work- operators aren’t really paid by the piece, they’re paid by the bundle of which the pay is determined by individual parts, say 10 or a dozen units. Operators are less likely to set aside defective parts because there is no mechanism to allow for “broken” bundles, by this meaning bundles that are now incomplete owing to the defective unit that should be pulled. If an operator were to pull one item from the bundle, subsequent related bundles would be affected because individual components are ticketed with piece numbers, unique to the spread (in the case of spreading fabrics from different dye lots -there’s more on this in my book, also see 22692 Bundling & bagging) and the organization of the sewing set up isn’t structured to facilitate the pulling of the components that belong to the defective unit. Depending on the garment complexity, a sewing supervisor (that’s who’d get stuck doing it) would have to track down all of the affected bundles in process and pull those as yet unsewn pieces belonging to the defective unit. In other words, for a stitcher to own up to a mistake in the bundle system would mean one is creating a lot of logistical work for other people.
Consequently, the defective unit is passed along in the bundle and subsequent operators have to manage the previously mis-sewn seam with varying degrees of success until such point that the defect can’t be concealed any longer and at which point it is either discarded or set aside for repair. This is more costly than it would be if you produced things singly. First, you’ve got the loss of upstream processes and materials (cutting etc) which you’d have either way but you didn’t need to incur the costs of the subsequent paid operations that were applied to the defective unit. If the defect had been set aside at the time it occurred, it would have been less costly in terms of reduced operations and likelihood of repair-ability. But as I said, if you’re using a bundle sewing organization, this isn’t likely to happen.
Adopting a lean process means that the operator is more likely to discard a defect at the outset, knowing that she has to sew the entire thing herself, there’s no one to pass it off to (perhaps weeks in the future so who’d know who’s to blame) which means you’ve got some accountability. Since the sewing operator knows she can’t complete the garment successfully, she’s going to cut her losses -and yours- and start another.
Another way that lean saves you money is related to learning and the ability to self correct. For example, if an operator is only doing one step in the process as with bundling, the operator may not realize they’re doing an operation incorrectly. If they’re producing the entire garment, it will soon become evident further along in the process even if they don’t know to whom or what they can attribute the problem.
Speaking of sewing problems, lean sewing can have corrective benefits upstream from the operator in terms of pattern quality. Traditionally and ideally, it is the sample maker who finds and reports pattern problems but if using a mod/pod system, then in effect, everyone becomes a sample sewer. Therefore, if difficulty with an operation has escaped the notice of the original sample maker, it can be caught in the production line and corrected before subsequent cuts are ordered. If there’s only one stitcher complaining about a given operation, it is given far less weight than if everybody else complains about it -but if you’re not using a modular system, no one else is in a position to know there’s a problem.