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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Beat rate

#7587

Beat rate | 4 February, 2000

For a single board that takes 5 minutes to build on my machine, is it better to do it as a single board or a 4 up panalized board that will take 20 minutes to build? And why?

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Dean

#7588

Re: Beat rate | 5 February, 2000

It would be helpful to have some additional info on your line and process. Lets make some assumptions...

Consider: re-tooling costs for your fab supplier. Can your supplier hold the additional tollerences for a larger panel. Can your supplier fab in your required dimensions. Any unused board material (loss / waste) will be charged to you as: cost of waste divided by # of images per panel size added to each image. In fact due to loss (X'd out boards + panel waste) it may cost you more for a panelized version (vendor and product design specific){I have experienced this first hand}

Additionally: Is this a stand alone machine or a 100 yard line? If a line you don't want to wait 20 minutes to begin filling the "pipeline". Also consider exposure time for solder paste. No clean or organic? Could make a difference. Operator idleness?

Is the cost of depanelizing offset by the reduction of handling / machine idleness (waiting for next board). Will you need special depanel equipment?

The larger the panel, you typically see an increase in "droop" on edge hold conveyor reflow ovens. Can you compensate for this? What will it cost? It may add process time in other depts. Not just your own.

What are your volumes? 1, 10, 1,000 or 1,000,000 units per month? Prototype? One time shot? Stable forecasting from planning dept. ?

How effective is your optimizer? Larger panels may take longer to process as your pick to place distance increases linearly from the feeder(s). Some machine types are more susceptible to this than others (fixed feeder vs moving feeder banks).

Hope this helps.

Dean

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#7589

Re: Beat rate | 5 February, 2000

JS: The issue is not how efficiently/effectively that you can run your placement machine, probably. The issue is how efficiently you can run that part of your assembly process that is the bottleneck. Other than improving quality, optimizing any part of the process other than the bottleneck is a waste of time and money.

Addressing your question directly, forgetting tact, index, and that ilk time, because they�re all function of the components on your board, and that not going to change whether a board is panelized or not, as you implied in your question. What you are gaining on your placement machine by panelizing are: � Reducing time to transport boards to be and after being populated. � Hopefully, eliminating conveyor width set-up when changing between products. But you really need to think about the broader issue, as Dean says.

Good luck

Dave F

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Rob Cass

#7590

Re: Beat rate | 7 February, 2000

Takes 5 minutes?? Does that include the 3 - 5 seconds for loading and fiducial inspection. If so it 12 - 20 seconds you will save with a panel. Depending on the panel you may be able to use just a board break fixture. Reduce handling when you can.

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#7591

Re: Beat rate | 11 February, 2000

To be more specific we have a single Contact 3AV that can run the board in question in 5 minutes from placing the board into the machine till the time it comes out. Volume is expected to be low initially but expected to pick up. It just doesn't feel right to me if the board is panelized 4 up it will then take 20 minutes to place. Also it would be an 8" x 12" approx. panel with scoring and no center support.

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