How Does a Factory Make Shoes?
When you walk into a modern shoe factory anywhere in the world, you will see the same footwear manufacturing processes. In China, America, Brazil, or Italy the shoemaking art is almost exactly the same. You will also see that the giant 20,000 shoe city in China, and the high-end London handmade shoe shop, actually have a lot in common.
The same basic techniques for making the modern athletic, fashion, hiking, hunting, or casual shoes are used by all the major shoe companies. Nike, Adidas, and Reebok all use the same techniques and in many cases the same factories.
How To Make Shoes
The first thing you need to make a shoe is called the LAST. The shoe last is a wood, plastic, or metal form that gives the shoe its shape. You would think the last would follow the shape of the human foot…
The answer is, it does..sort of. Each style of shoe requires its own last to set its shape and size. Each and every shoe size requires a last, left and right. So, to make a standard 14 size run you will need at least 28 lasts. Actually, if you want to use a modern high-speed assembly line and make 2,000 pairs of shoes a day, you will need around 700 pairs of lasts!
The Shell Pattern
Once the last has been selected for the specific style of shoe you are making, you will need to make a SHELL PATTERN to follow this last. The shell pattern is simply the flat shape that can be stretched over the last into a 3-dimensional shape. This is part of the shoemaker or patternmakers art. The technical term is SPRINGING the pattern. With the shell pattern complete, the designer and pattern master can make the design for the shoe parts.
Once the shoe pattern is designed, the factory will cut the pattern parts for the shoe upper. This is the job of the shoe factories’ cutting department. The factory will use giant cookie cutters, computer-controlled knives, laser, water, or hand cutting to make all the parts. Again, each part of the shoe, inside and out, padding and reinforcements, etc… must be cut out. If a shoe has 20 parts, the factory will need 20 cutting dies x 14 sizes. It is not unusual to have thousands and thousands of cutting dies!
The stitching department
Once all the parts are cut and organized into kits, the stitchers can go to work. This part of the factory is called the stitching department or stitching line. A single stitching line may have 50 to 100 workers depending on the complexity of the shoe. Generally, two stitching lines can support one assembly line. The stitchers put together the shoes outer shell, inside lining, and tongue parts. The stitchers will also add the reinforcements, hardware, lace loops, collar foam, and heel counters. The stitching department will also handle the heel and toe forming operations. The final stitching operation is to attach the pattern part that closes the bottom of the finished upper. This is called the strobel sock. When you look inside a sports shoe, the strobel stitch is the caterpillar-like stitching that runs along the bottom edge.
With the stitching complete it is time for FINAL ASSEMBLY. This is done on the ASSEMBLY LINE. Not to be confused with the stitching or stock fitting lines. This is when the shoe upper is joined with the outsole.
This first step is called lasting. At this point this shoe is still loose and floppy, it is not shaped like a shoe or a human foot. Shoe lasting is the process when you pull this upper over a form (the last) that allows it to stretch and take the shape of a real shoe. The last can be made of wood, plastic, or metal depending on the kind of shoe you are making and the cementing process. The upper may be steam heated to aid the lasting process. There are many different ways to last a shoe. (see the articles Shoe Lasting and Shoe Lasts to learn more)
Add the outsole
Once you have the upper lasted it’s time to apply the bottom. This can be done several ways: contact cement, vulcanizing, nailing, or sewing operations. (See the article Cold Cement vs Vulcanized Shoe Construction) In the case of cementing, the lasted upper (with the last still inside) and the outsole units are primed and cemented together. A pressing operation ensures a good bond. Once the last is removed the shoe is laced up, cleaned, and checked by quality control operators before packing.