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Equipment/Line Capability Study

greg

#2943

Equipment/Line Capability Study | 25 September, 2000

Hi, I've been assigned to evaluate or do a capability study of our SMT line/equipment for our new products...what are the concerns that I need to look into?

thanks and regards,

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#2944

Re: Equipment/Line Capability Study | 25 September, 2000

Greg, Its an open ended question your asking here. What are you trying to do? Determine if your equipment is able to do what you need? E Determine your floor spacing? Determine what, if any, inspection equipment is needed? Determine constraints/line balance, Ergonomics/human factors? Ok, my list is long enough....

larry

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#2945

Re: Equipment/Line Capability Study | 26 September, 2000

Greg: You might look for : - smallest board size - largest board size - finest pitch you are able to handle (safe) - Parts/hour - units/hour (If you find your bottleneck it will be easy to determine) - number and kind of feeders, components per line - odd part capabilities - repeatability - first past yield you get (or expect) with your line as it is now - clean/noclean process - abilities to do class 1,2 or 3 manufacturing

This might tell you if you meet the requirements for the new product.

Good luck

Wolfgang

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#2946

Re: Equipment/Line Capability Study | 26 September, 2000

I forgot: - smallest part you can handle - Rework capabilities (espec. QFP, BGA) - Test capabilities (inline, offline, AOI, X-ray, ICT, boundary scan etc.)

Wolfgang

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#2947

Re: Equipment/Line Capability Study | 26 September, 2000

I agree with Wolfgang that a check list, like he proposes, is very useful in evaluating your ability to assemble products. No sense designing a 16 inch board if the throat of your wave is 15 inches.

Taking a different tact � what if you define your capability to do something (ie, place a component, maintain a temperature, bowl strikes, etc.) in terms of how well you do that thing time and time again? The SMTnet "Terms And Definitions" states:

Process Capability. Competence. A measure of the process variation about a defined target value. Cp and Cpk are common process characterization indexes.

If you place an QFP208 on the spot (maintain the heat on a QFP208 for a certain time over liquidous) [throw a ball down a lane] and then compare the actual position (time) [pins knocked down] with the intended position (period) [300], you�d get a measure of your capability to hit the target. If you repeated that many times, you get a good idea of just how good you are. That�s your capability.

From that, measuring process capability doesn�t sound like something you want to do very often or for very many things, but it sure would give you an good idea of how well your process will perform. And it would be a baseline for determining if the process was still in control. And it might be one tool to use to determine if the fancyschmancy equipment you purchase will meet your expectations.

That�s what I was babbling about last week when DEK was googooing their top-end printer with a Cpk of 2. Until recently, no equipment supplier wanted to talk about Cpk. Then Siemens and UIC began chirping about their 3s, but the printer and oven houses kept mum and tried to pass it off as a "placement machine measure." Yano why? Their Cpk are 1.67. From a big picture standpoint, that�s like the word for drawing water through a straw. Relative to similar equipment it�s pretty good.

If this is what you�re talking about, there is a great body knowledge on this that builds on basic SPC concepts. Look to AAIG, ASQC, and authors like Harry and Breyfogle for help in learning more. This is a subset of six sigma stuff. Consider that the SMTnet archives may be a excellent source, also.

reply »

#2948

Re: Equipment/Line Capability Study | 26 September, 2000

I agree with Wolfgang that a check list, like he proposes, is very useful in evaluating your ability to assemble products. No sense designing a 16 inch board if the throat of your wave is 15 inches.

Taking a different tact � what if you define your capability to do something (ie, place a component, maintain a temperature, bowl strikes, etc.) in terms of how well you do that thing time and time again? The SMTnet "Terms And Definitions" states:

Process Capability. Competence. A measure of the process variation about a defined target value. Cp and Cpk are common process characterization indexes.

If you place an QFP208 on the spot (maintain the heat on a QFP208 for a certain time over liquidous) [throw a ball down a lane] and then compare the actual position (time) [pins knocked down] with the intended position (period) [300], you�d get a measure of your capability to hit the target. If you repeated that many times, you get a good idea of just how good you are. That�s your capability.

From that, measuring process capability doesn�t sound like something you want to do very often or for very many things, but it sure would give you an good idea of how well your process will perform. And it would be a baseline for determining if the process was still in control. And it might be one tool to use to determine if the fancyschmancy equipment you purchase will meet your expectations.

That�s what I was babbling about last week when DEK was googooing their top-end printer with a Cpk of 2. Until recently, no equipment supplier wanted to talk about Cpk. Then Siemens and UIC began chirping about their 3s, but the printer and oven houses kept mum and tried to pass it off as a "placement machine measure." Yano why? Their Cpk are 1.67. From a big picture standpoint, that�s like the word for drawing water through a straw. Relative to similar equipment it�s pretty good.

If this is what you�re talking about, there is a great body knowledge on this that builds on basic SPC concepts. Look to AAIG, ASQC, and authors like Harry and Breyfogle for help in learning more. This is a subset of six sigma stuff. Consider that the SMTnet archives may be a excellent source, also.

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