Has anyone been able to create supply type purchase orders without creating production order?

Example:

1. You have a raw material (stock item)
2. You send this raw material out to get modified by a vendor (let’s say adding color to it)
3. They do whatever they need to do to modify it
4. They send it back to you and you receive it in as a different stock item (for us it’s another raw material we will then use for a production order) 

I understand creating the bill of materials with the service and the raw materials, but creating a production order to do this does not align with what we are doing (that is suppliers responsibility to have a production order).  So this is creating additional work for something that is a rather simple process. We simply want to create a vendor purchase order, pick the material needed to the purchase order and then receive it in as another item. 

I can’t find a way to pick raw materials to purchase order to capture that cost and include the traceability