Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


What to measure at an AOI

phil

#24618

What to measure at an AOI | 28 May, 2003

Hi All,

I have currently got several AOI Machines that I want to collect data from for some SPC analysis. However, can someone please guide me to what I can and should measure with this equipment such as Cpk etc, and if possible provide some methods of how it can be achived within Excel or Access. (As I have a tight budget, a custom system cannot be purchased). I hope you can help, in any case, thank you.

Thanks in advance.

Phil (QA)

reply »

#24621

What to measure at an AOI | 29 May, 2003

Phil, as a rule of thumb, measuring machines (such as Zeiss, View and others) should be ten times more accurate, than the placement machine, in order to provide measuring values (CPK). AOI are meant to detect missing and wrong components, but not measuring the placement accuracy. If your AOI machine indeed provides these data, I would be quite cautious to feed these data back to the process.

reply »

#24623

What to measure at an AOI | 29 May, 2003

Teradyne says, "How does one evaluate the competency of a particular AOI system? At the highest level, all potential customers must judge any viable AOI system using the following qualities: * Throughput must be able to match the line rate on the manufacturing floor. * High level of fault coverage. * High fault coverage must bring with it a very low level of false flags and escapes. * Repeatable results, both on the same machine, and any other identically configured machine."

reply »

#24625

What to measure at an AOI | 29 May, 2003

Phil, is this a post or pre reflow application, it makes a big difference on how you collect and use the data.

reply »

phil

#24632

What to measure at an AOI | 29 May, 2003

Hi swagner,

I am collecting from both Post and pre reflow applications. Any help would be much appreciated, thanks again.

Regards

Phil (QA)

reply »

#24633

What to measure at an AOI | 29 May, 2003

Thanks for the clarification, I have worked with both application, especially pre reflow. The data you should consider collecting pre reflow is missing, skew degrees, x,y shift, bill boarding, polarity and match the failure data (ref. desg.) to feeder and if possible nozzle type and location. If you have the luxury of a bar code reader prior to inspection that would be a big bonus to your ability to match post reflow failures to the component inspection data to see if your tolerances are too liberal. Post reflow I would recommend missing, tombstone and x,y shift, polarity. The problem with post reflow x,y shift is the fact that the reflow process will move the components, you might not always get accurate placement data to feed back to the smd equipment. As before try to tie all of the data together with the ref desg, feeder and nozzle type and position. Hope this helps!

reply »

Solder Paste Inspection