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PCB interval during reflow process

Charley Qin

#8345

PCB interval during reflow process | 3 December, 1999

Is there a generally acknowledged loading interval of PCB for Reflow proces?

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#8346

Re: PCB interval during reflow process | 3 December, 1999

Hi Charly,

For batch ovens there is no discussion. For inline loading interval depends on the oven you use, the amount of heat the PCB takes out of the zone and the capability of the oven to get it back in. The approximate time for the PCB to stay in the oven is about 3 to 4 minutes. If the assembly time matches with that there�s normally no problem. If it�s shorter it should be checked by asking the oven manufactorer and or better by profiling. I used to have some old boards of all kind, small, large, medium for such testings. We had no problems with a comparably small oven (4 zones, each about 30cm) to send in PCBs with one still in the reflow zone. Modern equipment should be even better.

Check it out Wolfgang

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#8347

Re: PCB interval during reflow process | 3 December, 1999

Charley: As Wolfgang says, you're unlikely to be able to put enough (average) boards in a modern reflow oven to be able to thermally load the machine.

Ta

Dave F

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dreamsniper

#8348

Re: PCB interval during reflow process | 5 December, 1999

Charley,

Though my reply is quite late, it might be a good info for you and i hope that this info could help or could provide you some views. Some companies practice at least 1 board gap, which means the length of the pcb you are currently loading, others 1 1/2 of that leangth. It depends on the capabilities of your Reflow Oven as what Wolfgang said. If you are using some fixtures/pallets (ceramic type)you need to have a longer gap. We experienced a ladder profile inside our Heller 1800W when using a palletised PCB which is made up of ceramics (and is 7 mm thick 230mm x 340mm). The pallet absorbs great heat and is visible (from the profile) while in between heaters. We replaced our Blowers etc... but to no avail...But for products without using a pallet we noticed that the profile is perfect.

chow

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sosina outry

#8349

Re: PCB interval during reflow process | 7 December, 1999

I had read all three reply to the interval of pcb in the reflow process already. Like Wolfgang said, base on the profiling and the temp that you set in there. The interval will be base on that temp. Some might have a gap of one pcb lenght, some might have about 2 to 5 inches gap. So i suggest you run the profile mole and test it with a couple of board in there at the same time to see how the profile look like.

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