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Topaz error/Inaccurate Fiducials

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#81959

Topaz error/Inaccurate Fiducials | 13 February, 2019

We have several issues with components placing properly onto designated leads without having to offset our boards fiducials before population. For several of our boards, we cannot set our fiducials "dead center" but rather offset them in various directions. For some of our boards, setting the fiducials directly in the middle works fine but for a lot as I said if we set them dead center, some components will place correctly while others place way off their lead or all of them will be wrong. We operate a regular Topaz as well as a Topaz X pick and place. We have this issue with both of them. Any ideas on how to fix this issue? I have images attached as examples.

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#81970

Topaz error/Inaccurate Fiducials | 13 February, 2019

I don't see any attachments.....?

Are the fiducials consistently well finished (perfectly round, shiny without splotches or other imperfections), or do they vary in quality?

When you do a fid offset, is the correction consistent or do you get varied placement results?

How are you generating placement coordinates for your programs? Do you use customer provided X-Y table or do you program by jogging the machine to the placement position using the camera?

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#81972

Topaz error/Inaccurate Fiducials | 13 February, 2019

we do see some inconsistencies with fiducials. We use X, Y references in the machine but still find them with the camera to populate pcbs. But just can't always center the cross-hairs in the fiducial. Most of the time we have to offset the cross-hairs so components center on their designated pads. But it is not like this with all of our products.

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#81973

Topaz error/Inaccurate Fiducials | 13 February, 2019

The reason I asked about using X-Y data (originated from the pcb files) is that if you bombsite the locations with the camera and program or adjust them individually, you run the risk of having to do it over and over when fiducials change, your fixture moves a little, etc..

If you never change individual component locations from the pcb layout coordinates, then they should all be off the same, if they're not dead-on, according to whatever fiducial error you have.

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