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How SMT Line Change over is measured?

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#68085

How SMT Line Change over is measured? | 3 February, 2013

how do you measure the overall change over time of an smt line? where does it starts and end? lets standardize

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#68088

How SMT Line Change over is measured? | 4 February, 2013

Changeover starts when the last board from the work order goes into the reflow oven.

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#68089

How SMT Line Change over is measured? | 4 February, 2013

Agreed, and stops when the first completed PCB of the next run goes in the oven. After 1st piece verification.

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#68098

How SMT Line Change over is measured? | 4 February, 2013

Thanks a lot. btw, is there a standard for this measure or technical paper to where we can base?

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#68154

How SMT Line Change over is measured? | 10 February, 2013

anybody can share if there are publications/whitepaper relating how SMT Change-over is Measured? thanks in advance

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#68252

How SMT Line Change over is measured? | 20 February, 2013

If you stop when the first completed PCB of the next run goes in the oven, wouldn't you be including the loading time for that PCB in your change over time?

Wouldn't change over time be from the time your p-n-p machine stops loading the last board of a batch until your p-n-p machine starts loading the first board of the next batch?

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#68256

How SMT Line Change over is measured? | 20 February, 2013

Actually, we calculate it BOTH ways, and track each of the two times. TOTAL changeover time starts when the last board of the previous run enters the oven and stops when the first board of the next board enters the oven. (Much the same way you would calculate Cycle Time). Machine Down Time Due to Changeover would start whan the last SMT Machine completes the last PCB of the previous run, and stops when the first PCB of the next job enters the first SMT Machine.

The reason we track both times is because Total Changeover is more than just downtime of the machines. It should include the time needed to verify the first assembly. (1st Article Inspection) By recording these times independantly, it's easier to see what areas need improvement.

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#68274

How SMT Line Change over is measured? | 22 February, 2013

Hi Frazzled Man,did you mean this way?

end - 1st piece of product "B" goes into the oven after 1st piece verification.

does 1st piece of product "B" means it is the second piece of Product "B"

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#68275

How SMT Line Change over is measured? | 22 February, 2013

Hi Frazzled Man,did you mean this way?

end - 1st piece of product "B" goes into the oven after 1st piece verification.

does 1st piece of product "B" means it is the second piece of Product "B"

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#68276

How SMT Line Change over is measured? | 22 February, 2013

We've had a lot of turnover with our operators, so currently we do a complete 1st article inspection before sending any PCBs in to the Reflow Oven. So our first PCB in the oven is the 1st PCB of the new job. (after it's been inspected).

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#68312

How SMT Line Change over is measured? | 26 February, 2013

Do you also measure job run time? IF you don't I"m sure if the change over time is measured but not the run time then the run time will go up almost as much as the change over time goes down.

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#68313

How SMT Line Change over is measured? | 26 February, 2013

Stephen,

Changeover is the time we are not running the line, but we are changing for another product. Job run on the other hand depends on the quantity you have to build. For some manufacturers running the job will take weeks or months. For other it might be 10 min.

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#68316

How SMT Line Change over is measured? | 26 February, 2013

Hello,

We measure changeover time from when the last CCA leaves the pnp to when the first piece of the new job leaves the pnp. Our average is 20-40 minutes per changeover and we have 6-14 changeovers a day"depending on job size and components per CCA.

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#68317

How SMT Line Change over is measured? | 26 February, 2013

Yes but if you start measuring it from last board into the oven and don't measure run time then that last board of the previous run might just sit a while before going into the oven...

All I"m saying is be careful how you set your metrics, people don't alway meet them the way you might want.

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#68319

How SMT Line Change over is measured? | 26 February, 2013

Stephen,

That's true and I am going to include the reflow time in our changeovers. That way if its taking to long to change the oven temperature it will show up in our metrics. I agree, if we miss a step in the changeover process our metrics will be inaccurate......

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Plasma Prior to Conformal Coating

Reflow Oven