Single Pass vs Double Pass SMT production line

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Throughout the years in SMT PCBA production I have seen OEM'... - Dec 08, 2021 by scotceltic

It's funny, we expanded with 2 additional lines a few years ... - Dec 08, 2021 by Chris

With the bottom followed by the top set up, how do you even... - Dec 09, 2021 by Stephen

The question is what exactly are you trying to achieve and a... - Dec 09, 2021 by Evtimov

my two cents is double sided lines aren't worth the trouble ... - Dec 09, 2021 by DWL

scotceltic

#87397

Single Pass vs Double Pass SMT production line | 8 December, 2021

Throughout the years in SMT PCBA production I have seen OEM's and contract houses move away from a Double-Sided PCBA Line setup. Ex Single pass for bottom-side and then straight into duplicate equipment for top-side.

The norm these days seems to be a Single SMT line that handles both sides of the PCBA. Ex. Bottomside completes into a Magazine Unloader and the full magazine is brought back to the start of the same line for Top-side processing.

Just wondering what peoples justification is for this ? Is it because it is less capital costs, equipment footprint etc. ? Just curious.

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Chris

#87398

Single Pass vs Double Pass SMT production line | 8 December, 2021

It's funny, we expanded with 2 additional lines a few years back. Set them up for exactly what you're saying, the end of one is 5 feet from the beginning of another. Operator would only have to pull the magazine from the mag loader, turn around and load it in the other line unloader. To date have not used it in this capacity. We are low mix, high volume setup. Only about 15% double sided. I believe that number was higher when the lines were set.

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Stephen

#87400

Single Pass vs Double Pass SMT production line | 9 December, 2021

With the bottom followed by the top set up, how do you even come close to balancing that? For a lot of boards that I have seen you would need five or more top lines just to handle one bottom line. Or have the bottom line on a very low duty cycle.

But seriously I think the biggest difference is who you have been looking at. I personally have only read about the lines where both sides are done on one double line with a flipper. And I think only for extremely high volumes.

Personally I've only seen boards done on one side then the other side is done. Sometimes with two lines but first line most certainly didn't wait for the second line to catch up.

One thing I have seen a couple of times is boards panlized with top and bottom on the same side of the panel. You run both top and bottom on one side of the panel then flip it over and run the other side.

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Evtimov

#87405

Single Pass vs Double Pass SMT production line | 9 December, 2021

The question is what exactly are you trying to achieve and at what cost? There is not unique recipe to answer this question, cause we don't know what product is running on this line. Sometimes very short line gives us much more throughput compared to super long line if product is simple - just because travels less and has less handling.

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DWL

#87409

Single Pass vs Double Pass SMT production line | 9 December, 2021

my two cents is double sided lines aren't worth the trouble if you are low volume/high mix. As others have said, balancing this is a nightmare. There are tradeoffs, of course. You will build up WIP, and this is especially problematic if there are MSD parts.

For High volume, low mix, double sided, balanced to the product is the way to go.

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