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Chip capacitor size - Fuji CP6

Chip capacitor size - Fuji CP6

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Hi all, At our Fuji CP-6 machines we place a lot of 0402:s,... - Aug 19, 2006 by Mika

Hi Mika, I used to work for the largest chip cap manufact... - Aug 21, 2006 by

I Think I understand your problem. But I think it would be b... - Aug 21, 2006 by vikkaraja

Hello Mika, I just checked a windmill and a test nozzle we ... - Aug 21, 2006 by

mika could you send a e-mail to ... - Aug 22, 2006 by

Thanks all for Your input. The thing is that we want to av... - Aug 25, 2006 by Mika

Many Thanks to You all. I think we should be ok with the ma... - Aug 27, 2006 by Mika

Why? Motorola is a component vendor to us, but not for the c... - Aug 27, 2006 by Mika

Yeah, changing it while you run is ridiculous. I would take ... - Aug 28, 2006 by

Mika

#43432

Chip capacitor size - Fuji CP6 | 19 August, 2006

Hi all, At our Fuji CP-6 machines we place a lot of 0402:s, 0603:s and 0805:s chip capacitors. Our problem is that the height of the components can sometime be very extreme from different vendors. I am sure you all have experience of this phenomenon. For ex. a 0603 cap with dimension of 1.6 x 0.9 x 0.9 mm with a certain partnumber can vary as much as 0.6 mm in height. T= 0.7-1.3 mm There are also circumstances that the caps will vary in x-y size. Our company must have at least 3 or more vendors for the majority of the components. So It is out of the question to stick with only one vendor. There are absolutely No problem with the resistors. We have been talking to the vendors, but...

The problem: let say we have a certain comp. with a height of 1.3 mm and this is also the numbers set in the pattern program/comp. databse for that specific part nr. Suddenly there are another wendor of that comp. that has the height of 0.7 mm. Now, during the placement cycle the nozzle will stop some tenth's of a mm above the pcb and cause the comp. to drop on the board. You can imagine the rest...

This is my question to You since our local Fuji guys fail to come up with an adequate answer: is it possible to set the comp. height in the comp. database for the minimum height of the comp. that we use and then when the comp. reel neeeds to be replaced with a comp. from another vendor with a much higher height of the comp; will the nozzle still handle that, since it is springloaded? How many tenth of a mm can the nozzles handle in Z-axis before they will be stuck in the head?

On the other hand, if we have a comp. height set to the lower end; let say 0.6 mm height and after a reel/comp. exchange from another vendor with a comp. height of 1.3mm Will this cause a potential stress/crack at the comp. so it will fail "out in the field"? Of course I am talking about the extremes, but we are facing this.

Please be so kind to tell me if I have been unclear of this matter. I am Sorry for my poor english & grammar. /Sincerly

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Rob

#43435

Chip capacitor size - Fuji CP6 | 21 August, 2006

Hi Mika,

I used to work for the largest chip cap manufacturer in the world, and by far the largest problem we would see was cracking due to incorrect z height adjustment on Chipshooters. It can also cause solderballs and bad joints by displacing the paste. Customers usually had one footprint per case size for all 0402 (1005), 0603 (1608), 0805 (2125) etc. devices.

Lower volume customers tended to use x-y gantry machines instead of turrets, and a lot of these have sprung heads so you don't see that problem.

The thickness changes are due to the number & thickness of layers required to get the capacitance, and as technology, materials & yeilds imporve they tend to get thinner.

Rob.

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vikkaraja

#43448

Chip capacitor size - Fuji CP6 | 21 August, 2006

I Think I understand your problem. But I think it would be best if you just go in the program and change/check your componet height as needed. It does not take much time. Check your cap height, modify shape data as needed, generate your program and transmit to the machine. Machine nozzles can hadle up to .3mm max. Anymore than that you are asking for trouble. If your height is setup too high or too low, parts are going to be all over the PCB. And there are some instance, these small components can land underneath the ICs and you won't know it until PCB goes through Xray/inspection of some sort. If you find any info provided useful, use it or just disregard it.

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FredC

#43450

Chip capacitor size - Fuji CP6 | 21 August, 2006

Hello Mika, I just checked a windmill and a test nozzle we have on the bench. The useful travel of the nozzle before the risk of the crosspin getting stuck in the loading gate is 1.5mm, if it gets stuck it is the nozzle is 1.7 up. If the cross pin is bottomed out where you would have a danger of cracking the component it has traveled 1.95mm. There are several other variables other than preload and component thickness that will use up your 1.5mm of safe travel. Some of these are nozzle variation and wear, board thickness and warp, windmill variation, headshaft height and cam roller wear. FredC

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mika

#43465

Chip capacitor size - Fuji CP6 | 22 August, 2006

mika could you send a e-mail to jmaldonado@motorola.com

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Mika

#43587

Chip capacitor size - Fuji CP6 | 25 August, 2006

Thanks all for Your input. The thing is that we want to avoid to go in to the pattern program and change the height in the middle of running a board. For ex. We start a product, feeders are loaded in advance in the feeder preparation area, operators get the trolleys together with all the extra comp. reels necessary for this product, op. change the program in the machines, op. load the comp. feeders into the machine and start production. Now in the middle of the placement sequence, one (or more) feeder runs out of comps. so the operator takes out the feeder and reload it and put it back and press start button. Suddenly we have a cap from another vendor with diferent dimensions. It is not that easy to start changing the comp. data in the pattern program, re-create the program and then send it up to the machine, while we are in the middle of a half populated board.

But this is what we are doing today and we don't like it at all. I must say that it is not all the caps's but there are some. /

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Mika

#43602

Chip capacitor size - Fuji CP6 | 27 August, 2006

Many Thanks to You all. I think we should be ok with the majorty of our cap's if we set the comp. thicknes to 0.2 mm less than the actual size to be able to compensate for the variable thicknes from different wendors for a certain component. Do You think this is ok?

We still have to struggle with the extremes, I guess. How about You guys, don't You have this problem att all?? /Sincerly

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Mika

#43603

Chip capacitor size - Fuji CP6 | 27 August, 2006

Why? Motorola is a component vendor to us, but not for the chips. Please explain. BTW. I like Your name. /Sincerly

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#43609

Chip capacitor size - Fuji CP6 | 28 August, 2006

Yeah, changing it while you run is ridiculous. I would take my thinnest part and play with the thickness, until you make it as thick as you can (and still place the part with good results). Then use that thickness for all. You can put a dial indicator on top of the nozzle to see how much deflection you get on your thickest parts, then see if that is acceptable. My guess is if make your thinnest part as thick as possible In the PD) it'll work for all.

good luck, pr

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