While I know there are techniques for planning for co-products and by-products in manufacturing, are there any good methods for doing the same when we are making purchases? For example, if we have a mode that produces a top and bottom of a part, we treat them as two parts, but our contract manufacturer will always run them together in a single mold. We then cut a PO for X quantity for the top part and X quantity for the bottom part.
Occasionally we miss including one of the items on the PO and I'm trying to find methods we could use to help ensure we are buying these items together all the time.
Another scenario we run into and may need a different solution is different variants of the same product, for example, one item packaged in a different configuration. Think about cans of soda that are packaged in 6 pack, 12 pack, and 24 pack. We have a minimum order size of X thousands of cans and price breaks for larger quantities but the supplier doesn't care how many of each configuration we buy. How do other companies plan for this or at least notify a buyer they should be considering ordering the different variants simultaneously?