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Question about Oven Profiles

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#79954

Question about Oven Profiles | 12 March, 2018

Drives me nuts.

When I first started here, the SMT operators would create oven recipes where the bottom heater zones were colder than the tops. Their logic was that then when running the second side, the parts wouldn't fall off because they wouldn't reflow.

Some of them are still stuck on that notion, no matter how many times I call BS.

Has anyone else run into this?

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#79956

Question about Oven Profiles | 12 March, 2018

It is BS.

Solder is either liquid or it isn't. Getting it hotter doesn't make it more liquid.

Its very easy to prove them wrong. Have them create a profile with the bottom heater turned down. Run boards and see how many parts fall off.

You create a profile where the top and bottom heater set points match. Run boards and measure how many parts fall off.

If there is a difference you have something else going on.

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#79957

Question about Oven Profiles | 12 March, 2018

I take that back, there are some alloys that have a "pasty range" but that is another subject.

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#79958

Question about Oven Profiles | 12 March, 2018

Oh I know it's BS. It's not like the mesh belt creates a barrier between top and bottom. There is very little delta from top to bottom.

Whenever I see a recipe with different temps from top to bottom, I just delete it.

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#80076

Question about Oven Profiles | 26 March, 2018

First of all, shouldn't allow SMT operators to edit/create recipes, only grant access to the well-trained only. You will put yourself at risk if you don't have good process rule of oven recipes. Newer oven models should come with software that has multiple user levels. Normal SMT operators should only allow to open/run, set conveyor width and shut down. Temperature & speed setting are for higher level (trained) operator. By having these rules, you will have less headache.

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