Some things to consider when sourcing a CNC Machine Shop(Page 3 of 3)

More Questions

After you have narrowed your probable choices down, talk to the estimators to get a sense of how they are going to handle your job.  Do they seem comfortable with this part?   Have they had experience with the material and processes?   How do they intend to handle the secondary processes (if any)?  Are they going to be responsible for the secondary processes, or is that something your company is going to be responsible for?

What is the lead-time going to be?  If there are delays, will there be moving lead-time updates from them?   All of these concerns need to be addressed before you can assign the job.

Incoming Inspection

OK, you have made your decision and cut the PO, the parts have come back and there is a major discrepancy.   A critical finish is not to specification.  Now what?  Your assembly needs this "out-of-spec" part and this could shut down your line.

Also, on another tack, are you going to have to start this vendor search all over?  Was it all a waste of time?

Don’t despair!  Mistakes happen despite the best preparation and efforts.

All good machine shops will do their best to re-do the part to your satisfaction and at no expense to you.

They will also put the part first in the queue so the lead-time will be greatly shortened.

Sometimes the machine shop that has made a mistake and has been allowed to correct it will be the company that always does it well in the future.  I say this for several reasons.

Many machine shops use CNC machines.  This computerized equipment is less prone to error once the program is proven. So, if the bugs are worked out of the program, there is smaller likelihood of an error re-occurring.

Also, once a problem is recognized, the machinists are very careful to not repeat the same mistake again!

The NCR and Product Inspection Report

I have included a sample Non-Conformance Report and Product Inspection Report

If you want to use a more formalized approach to recording and reporting errors, you are welcome to download these and use them in communicating with your machine shop vendors.  They are filled out with information from the sample part and are fairly self-explanatory. Also included is a Sample Print Marked Up for Inspection. This print matches the Product Inspection Report