The last few weeks I’ve been digging in to how we might be able to make our entire sole right here in the U.S. Currently several parts of the sole are being made in China. The factories that make those parts do a fine job but I keep thinking that we ought to be able to make them even better here. There are not many factories here in the U.S. still making shoe sole parts and none that I know of that are set up to do the specific type of insert/vertical injection molding process that we’d like to use. But I have found some wonderful resources, starting with the University of Virginia (UVa) Engineering Library which encourages its faculty to check out books and keep them indefinitely until someone else requests them (this helps conserve library space).
Injection molding is simply shooting a melted material under high pressure into a mold cavity. Remarkably, five wonderful, and apparently never-been-opened books on injection molding, were available. It did not take me long to read them all (real page turners(!), though I somehow wasn’t able to organize a book club around them…) before adding them to the ever-growing OESH/UVa Manufacturing Library.
With that, I could have some “not too naive” conversations with various folks here in the U.S who are injection molding all sorts of things. I’ve also been talking with different material suppliers in the U.S. as well as with folks who are selling injection molding equipment. Here is the type of injection molding machine that we would use (the picture doesn’t do it justice, it’s at least eleven feet high), which we would then need to customize:
What is super cool is how tremendously encouraging everyone who I have been talking to has been. They feel, like I do, that we absolutely can and should make these pieces here in the U.S.
So I’ll continue to research this. For now we’re appreciative that those factories in China are making those sole pieces for us.