SMT Rework Systems

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Hi, We are looking for a new SMT report system, you know ... - Mar 03, 2007 by Grant

>>We have looked at a few, and some use the removal time to ... - Mar 04, 2007 by

Hi guys, I kind of disagree with this. First, how can you... - Mar 04, 2007 by Erhan

Grant

#48136

SMT Rework Systems | 3 March, 2007

Hi,

We are looking for a new SMT report system, you know the ones that let you align and easily solder BGA's and the newer lead-less packages that are small and have leads under the package.

We have looked at a few, and some use the removal time to calculate the placement time, which seems like a good idea.

Does anyone on the forum have recommendations of systems that are working well in-house for them?

Regards,

Grant

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Jim

#48137

SMT Rework Systems | 4 March, 2007

>>We have looked at a few, and some use the removal time to >>calculate the placement time, which seems like a good idea.

The problem with this method is that you can't develop an accurate removal/installation profile. You are removing a component as soon as the balls have reached a melting point. Developing a profile so that the joint temperature is 15-20 deg. C above the melting point does not seem possible.

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Erhan

#48138

SMT Rework Systems | 4 March, 2007

Hi guys,

I kind of disagree with this. First, how can you tell whether ALL balls reached the melting point or not? you can't... For that reason, on one machine I know quite well, a "melting point reached" button appears. When you think you see the balls are melting, or when you can even remove the component from one end upwards by using a hook, then you click on this button. The system then still adds a 10-15 seconds to the profile, just to make sure all balls are at the melting point.

By using the thermocouples, you can control the max temp of the component, as well as the preheat temp for the PCB.

My 2 cents.

Erhan

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