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SMT electronics assembly manufacturing forum.

Quality control in manufacturing

Views: 8089


Quality control in manufacturing | 23 August, 2011

Hello everyone, we are contract manufacturer and I am wondering if we can save some time from inspection and verification. We will usually inspect the bare boards, then, verify program to BOM, then feeders to BOM and Feeders to program,then paste inspection then after placement inspection with BOM(polarities and values) then AOI and X-ray if needed. We also check 1/5 boards when in production.

How do you guys do it? How do you verify that you are building everything right? Any input will be appreciated.

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Quality control in manufacturing | 31 August, 2011

AOI if needed? I take it your AOI/AXI is not inline. Too bad. Our AOI is the first line of defense against induced errors in the mfg process. It's invaluable. How do you know it's not needed, or that it won't be needed in the future? Do you have guarantee in your process of no errors? You still use humans, correct?

We use ICT as well for electrical testing. We couldn't live without (I don't know how we went w/o the AOI for so long). We use to have enormous amounts of backlog until the edict was handed down to purchase a fixture for everything that we build.

There's valuable data collection to be had from both systems that our QC dept. acquires on a weekly basic as an indication of the status of our process and if anything needs to be addressed or improved.

We also perform weekly and daily audit inspections of finished goods to ensure product was assembled correctly. In your case, it would be auditing of the finished product, perhaps sample auditing.

What do you mean "We also check 1/5 of the boards in production."? Check how? Sample audit, test, etc.?

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Quality control in manufacturing | 1 September, 2011

Hi Reese,

unfortunetely our AOI isnot in line and yes we check first article for each board on the AOI.One of each five boards 1/5 we give to inspector to check and we X-ray if needed.

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Quality control in manufacturing | 1 September, 2011

Well, sample inspection should be saving some time already. What other fat are you trying to trim here? Where is your bottleneck?

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Quality control in manufacturing | 2 September, 2011

Overkill for sure!

Program to BOM: Shouldn't have to verify the program to the BOM once it's been verified unless there is a change. Feeder to BOM" There should be some type of instruction that specifies that part goes on what feeder and where the feeder goes. Again, this shouldn't have to be verifed again unless there is a change. Placement to BOM: If the part to feeder was verified then this is not necessary. AOI is next to useless unless it is in line. 1/5 board check: Instead on checking every 1 out 5, only check the next board after a reel/tray/tube change. Then only check the part that changed.

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Quality control in manufacturing | 2 September, 2011

I agree that if information is processed correctly up front in process down stream QA becomes less expensive ie AOI etc as AOI at end of lines is telling you you have made mistakes in up stream. I better to eliminate mistakes or have process to avoid mistakes. COrrect software tools can help greatly here.

AOI is great to have no doubt, but I would think more 3DSPI first 60%-80% defects can be sourced generally from printing (stop bad prints before placement), then AOI before reflow to capture parts missplacement and stop reflow of incorrect PCB, then last add AOI adding to end of line. As you go down line rework costs increase each step.

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Quality control in manufacturing | 6 September, 2011

Thank you dor your inputs! I was also thinking that once we verified the program to BOM and feeders, we shouldnt check to the BOM after palcement, but we should just AOI. Can you see any other weak points?

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