Quantity of parts to send to contract assembler

I would ask them.

OK, here are some thoughts. If the parts available come from a 100% quality-assured source then one might be tempted to send only the correct number of parts for each board multiplied by the number of boards, i.e. no surplus. Contractually, if the Supplier is paid by the working, finished board, any faults that occur as a result of the Supplier's malpractices would need to be put right at the Supplier's expense, which may be included in the costing, though there may be a timing issue as a result.

Would it matter if the Supplier returned all the screwed-up and surplus parts along he finished boards shipment? If so, how would the Customer sort the good ones from the duds ready for the next batch of boards? And how does the Customer verify that the finished boards are all working correctly and that the supplier hasn't fitted dud parts to the boards just to get paid? All relationships are built on trust. How far can the Supplier be trusted?

It all depends on what the Contract says and what the balance of risk is in this particular situation. Most of this requires good judgement by the poster rather than a reliance upon custom.

In this case, completing the thought process and negotiating the Contract is more important than expressing the answers here. Please don't post the names of the involved parties on CR4!

We haven't chosen a contract assembler yet. I'm just now making a formal BOM and kitting the parts.

They won't be doing any testing and would be paid as long as the boards pass a visual inspection.

If I send the exact amount and they were to call and say they were short one part (for whatever reason) it wouldn't be a problem to send them one. It's just that it feels odd somehow to be counting out the exact number of resistors etc. I know that when boards are stuffed by hand its not all that unusual for an assembler to need an extra part because one was damaged or visually defective or something, and it just seems more efficient to send a few extra.

I'd have thaught you'd just hand over the whole job...parts list and boards...let them supply the parts as they probably have a lot of the stuff as standard parts bought at a better rate than you will get buying in small qtys. Idea arrangement is if they do some functional test too.

Del is right.

They may also prefer the components on a reel. (Depending on their placing machine)

Having worked for a contract manufacturer for a few years (nasty business, really), I would suggest to send some extra parts (at least the ones that don't cost a lot) as most placing machines will "waste" a few parts on setup alone (placing the parts in the feeder)!! Although most shops have bulk feeders (for loose parts), very few have enough of these to accomodate a complete job; usually just a few for the odd parts.

We used to ask the client to supply 5% extra for the resistor/cap stuff (cheap) and 2% extra for anything more expensive. We'd return all the left-overs. Time delays would be a lot more expensive then shipping a few parts extra.

That's my experience with it .....

n.b. If you can afford to send the reels (with them returning the unused portion), it'll make their much easier and faster - less frustrating)

R.

Sending extra components would save for any delay in case of shortage/lost/damaged ones. If you do, make sure you enclose a separate list as to what is provided. Otherwise, as I've found, an overage may invoke them to be calling you ("we have extra parts not indicated on the bom, where do they go?").

If you are having them provide the parts, make sure your bom is specific on mfr and full description of components you have qualified. If you don't, they may make substitutions which may affect the end product performance and reliability.