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Missing componentafter chip placer.

Eric

#17502

Missing componentafter chip placer. | 6 September, 2001

We see alot of missing component ( on/off ) after chip mounter, and had check on the component height, is correct. Nozzles had change, vaccume strong enough and table height. But we still have missing component.

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Poon Man

#17503

Missing componentafter chip placer. | 6 September, 2001

Eric,

There are a lot of factors leading to lose components. Suppose your machine works properly. Firstly, is there any gap between the support pins and PCB? If yes, the components may be �dancing� during placement. Have you checked the placement speed? Low speed is preferable at the placement step. Does the table move fast? The last point is that how many mounters in-line. If more than two, pls check the conveyor speed. Hope it can help you.

Poon Man

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CAL

#17508

Missing componentafter chip placer. | 7 September, 2001

Can you confirm the components are being picked up from the feeders? If the Feeder table calibration is incorrect the components could be picked up off from the begining. This would result in 1) nozzle barely picking up the part and as the head moves the part falls off 2) the component stays in the carrier tape and is never picked up. I would think a vision error would result. Also, check the nozzle size you may not have the correct nozzle size for the component.

Caldon W. Driscoll ACI USA 610-362-1200 cdriscoll@aciusa.org

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Hussman

#17509

Missing componentafter chip placer. | 7 September, 2001

Board support will almost always cause the part to be miss-mounted. The bouncing affect of the board can cause the part to bouce off the board. BUT, you never stated where the ends up or anything like that. Is the part on the board but just flopping around? Do you have a machine that verifies that you truely did indeed pick up the part before placeing? You say it's on/off, so I can assume that you are placing the part correctly some of the time? If so, it prob. will be board support.

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Claude Couture

#17518

Missing componentafter chip placer. | 7 September, 2001

What kind/brand of machine are we talking about? Are the missing parts randomly distributed or are specific to a feeder/placement/pattern? Does your machine remember where to resume placement if you reset it in the middle of a pattern placement? We have a machine that forgets where it was when trouble stops the machine in mid-placement. So the operator has to remember where to resume the placement to complete the pcb after clearing the trouble.

Also, make sure the rejected parts are ejected from the nozzle. We had a machine that failed to do that so the part stayed on the nozzle after passing the reject bin, went around the pick-up stage and back to being place on the pcb. result was wrong part placed in some locations. Took us weeks to figure that one!

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#17536

Missing componentafter chip placer. | 9 September, 2001

Eric Whenever I see a board come out of the chipshooter missing parts the first thing to check is the support pins. However if you have checked table and part height I assume that you have also checked the pins. So the next thing to check is the vacuum nozzle since most chipshooters have a filter at or near the nozzle these will become plugged during use and can cause parts to pass vision and still not make it to the board. This problem will start as a random pickup or placement error and get progressively worse. Hope this helps.

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#17549

Missing componentafter chip placer. | 10 September, 2001

We recently trialled a range of different solder pastes. Some just did not have the "green strength" to hold the components when placed by the higher speed machines. I'd never seen this before and spent a day and a half checking all the things everyone has mentioned, recal, the whole works. Components jumpin',jivin', dancin' and missin' all over the joint. A regulay hootenanny. - "aaahhh, it couldn't be the paste could it?" " No way, eerrr, definitely not - ummm, let's try it." Result - problem solved. As we had been using the same paste for many years I had never considered this to be an issue, neither had most of the paste vendors for that matter. Even different formulations within the one brand made a difference. Worth a check anyway.

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