Do you provide a BOM? Use this to control the mounting position and material number. There are many PCBA parts, which cannot be understood by just talking. Each position has a silk screen. It is recommended that you use BOM or bill of materials to manage it!
For each production line processing order, you must clearly know what the requirements are. This requires you to provide the requirements, and the processing factory will do it according to your requirements. Only in this way can the products be consistent with the requirements. Your requirements are consistent. Otherwise, if you wait until the product is produced and then ask for modifications, it will cause unnecessary waste of heavy work, and the effects of PCBA heavy iron welding and reflow oven processes are completely different! Hope to adopt it!
I am currently engaged in PCBA processing. If you don’t understand, you can discuss it in detail!