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SPC software use with vision check data

James Butler

#23653

SPC software use with vision check data | 4 March, 2003

Hi Mike, I have had a number of contract manufacturers, and SMT equipment makers looking at using our SPC software to monitor process control on SMT machine production with the data coming off the vision check machines. (There seems to be a huge surge in interest this year.)

The most common approach I have seen is to cature/record the variation on the X-axis, Y-axis, and Theta rotation for each placement, run IR charts and record/alarm on exceptions in realtime, then store the data and do capability analysis on various groupings of the data. Part vs Part, machine vs machine, batch vs batch or whatever direction the exceptions point to.

This seems to work, but I'm not really an SMT expert so I'd like to know what you think about this approach to process control on SMT lines so I can make better recommendations if they are available.

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#23663

SPC software use with vision check data | 5 March, 2003

Hello James, That sounds very interesting. I didn't know a system like this was available. What is a vision check machine? Is it a software monitoring tool that is installed on manufacturers equipment to evaluate the conditions you mentioned? I'd like to know more about how this works. The question I have is what is the accurate reference point that the system uses to measure variability? With the variability present in production materials and considerable age of machines in some cases, how do you know that you're not monitoring bad peformance and just don't realize it? I think this could be a great way to monitor process control, but you must be certain that the functional attributes you are measuring (X-axis, Y-axis variations, etc. ) meet a quality performance specification. This spec is always established by the manufacturer which hopefully guarantees that the machine will operate within an accurate and repeatable process window. If you have a customer interested in a case study for optimized performance through machine capability measurements and long term process monitoring with your tools, I'd be interested in working together to implement solutions like this! Let me know if you require additional assistance. Thanks!

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James Butler

#23671

SPC software use with vision check data | 5 March, 2003

Thanks for the questions/interest Mike. I only work with the data provided by customers myself and do not know a lot about how it is generated, other than a vision inspection machine looks at a completed card and provides the x,y and theta variation data on each placement position. UIC (Universal Instruments) is one company I know is developing an SPC system based on this. If someone wants to see how the data is handled in some example SPC analysis, I can provide a trial copy of the QA software I'm using with a set of generic demonstration vision check SPC data files. I just need a ship to address, e-mail, and phone number. I agree it would sure be interesting to see how results from this approach compare to others.

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#23673

SPC software use with vision check data | 5 March, 2003

Hello James, It sounds like the system that's being used to gather this data is an AOI system. I will investigte this more because I'm very curious of the process in which this works. I'll keep an eye out for someone using this setup and may get back to you for the trial software. Let me know if you require additional assistance. Thanks!

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