Having worked in the apparel industry for a while now, I sometimes have to take a step back to see how much goes into the design, production and selling of just one item. The goal is to work out all of the bugs before an item goes into production. Still, things can and do go wrong and those things can affect the size of an item. Where can things go wrong?
1. Pattern making and grading
A poor pattern or poor grading certainly affects the size. Inadequate seam allowances, missing notches. There are a lot of little things that can go wrong, though if you read the rest of the list, you can see there are a lot of other areas that can cause problems.
Marking is the process of laying pieces out in preparation for cutting. Many markers are now made by computer, some automatically. There are various setting that allow the marker maker to bump pieces closer together, tilt, or rotate pieces. Each of these options can affect the final outcome, so they must be used rarely.
Spreading is the process of laying fabric on a cutting table in layers. Certain fabrics stretch during this process and need a certain amount of time to relax. If the style is cut without the fabric being allowed to relax, then the pieces will relax after being cut and the item will end up too small. Layers can also shift and move.
Accurate cutting is the only way to ensure the item ends up as intended.
Taking too big or too small of a seam allowance affects a size. Seam allowances should allow a cut off allowance because nearly all operators trim off a little bit.
Finishing includes steaming or ironing. Too hot a temperature can shrink an item.
These problems can be minimized by implementing systems and policies during each phase of development and production. One company I worked for had a quality audit system that checked each step of production. Anything that had finally made it to production had been perfected, for the most part. There was that one style that shared patterns with another style. A problem came up in production where the obvious solution was to make a new pattern for the new fabric, but that never happened. Production just had to deal with it. But those situations are rare.
In any event, systems (procedures/policies) have to be implemented for development, production, and finishing to catch problems before the item is shipped to the customer..
This blog entry was inspired by the article Production systems, garment specifications, and sizing by S. P. Ashdown, L. M. Lyman-Clark, J. Smith, and S. Loker in the book Sizing in Clothing.