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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


SPC

#23693

SPC | 6 March, 2003

Hello Mike,

Recently a customer questioned why my company does not perform SPC readings. My answer was simple, we collected data for about a year without any major problems that couldn't be determined by simply looking at the pcb. It has been about 6-7 months since we've collected any data still no problems have arisen. My major question is this; What is the industry standard ( as you know it ) on SPC. Do most companies only perform this at customer request or for personal log keeping? Since starting in SMT I have worked for three different employers and each seemed to have a different take on SPC data collection. My first two were major coporations, they informed to collect spc every 5-10 boards. At my current company, which is a very small company I have a hard time validating the time it takes to stop every 5 or even 10 boards to take a reading. Any suggestions on this would be appreciated greatly,

Thanks, George

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#23698

SPC | 6 March, 2003

Hello George, SPC can be time consuming but if you don't track or make recordings consistently then how do you measure your process performance and overall line quality?I'm sure your customer is asking because they want you to demonstrate that your process is in control. To your question, everything I've seen is hit and miss, probably 20% actually track defects and use SPC to validate their process where 80% do nothing, don't track, don't know where to begin, don't have time, don't want to have the time because revenue is more important. To satisfy your customer and find a manageable solution for tracking SPC in your facility might be to increase the frequency between boards getting 100% inspected (1 in 15 or 20 maybe?)or to select critical technology components for more frequent partial inspection. You'll need to know each product and select certain part ID's for an inspector to catch every 3-5 boards. In the latter suggestion if an operator is trained to find the part ID's and quickly scan the board you may find that they'll find more than you might expect. I absolutely recommend first pass board verification down the line through to ICT before that 2nd board is even printed. I also recommend following some format of SPC, you'll easily demonstrate process control to existing and new potential customers and you'll be able to track long term quality performance. You just need to find a happy balance in how much you inspect while keeping the line pulse steady. Let me know if you require additional assistance. Thanks!

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