Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Chip placement pressure check.

Eric

#28232

Chip placement pressure check. | 26 April, 2004

Hi,

I'm looking for an equipment which able to check those chip mounter machine placement pressure. Could someone recommend is there an equipment check those pressure during mounting....

Thanks, Eric Chua

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bilbo baggins

#28250

Chip placement pressure check. | 26 April, 2004

What type of machine? Most placement machines have built-in diagnostics that will tell you...though a maintenance tech may be necessary.

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Eric

#28251

Chip placement pressure check. | 26 April, 2004

Hi,

I'm using the Fuji CP643 and QP341.

Thanks, Eric Chua

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#28288

Chip placement pressure check. | 28 April, 2004

By "placement pressure" I assume you mean force. I don't know of placement machines that have transducers mounted on the placement spindles that actually measure force. We made a board with a force sensor mounted through a hole so that it was the same height as the top surface of the board. We were then able to run the machine and place components directly on the top of the sensor (by sensor I mean a load cell).

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Eric

#28306

Chip placement pressure check. | 28 April, 2004

Hi,

Appreciate you could share with me more datail how this is make.....and how you downlaod or monitor the pressure force....

Thanks, Eric Chua

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#28319

Chip placement pressure check. | 29 April, 2004

Start with a load cell (force sensor), you will need one that can handle the force range you will be placing. Someone please correct me on this if I'm wrong but I seem to recall that placement force runs in the range of a couple hundred grams. Check into this and give yourself some room. We have a cell able to measure as high as 1500 grams.

Next you need an amp that will work with this type of bridge circuit. When you pick out the load cell the same person will probably selling amplifiers, see what the specs of the amps are and look around.

Finally, we took a good, flat piece of aluminum, milled the ends so it could be clamped in the machine, and also milled a hole in the center of it that the sensor could be mounted through. Holes were drilled in this plate and the sensor was mounted so that it was the same height as the board.

We used a storage scope to record placement forces, conversion will be grams/volt. There is a warmup period and some calibration of the amp so some precision weights will be needed.

Be careful of placements, a wrong part thickness or parts being stacked can damage the load cell.

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