Business models for having a PnP

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scsi
 
Posts: 30
Joined: Sun Jan 10, 2010 9:09 pm

Re: Business models for having a PnP

Post by scsi »

charliex wrote:steve ciciora built a slow, relatively cheap machine, one paste, one PnP
http://ciciora.com/index.html
I'm not sure that Steve's Taig mill PnP can handle 0.5mm pitch devices with any rate of success. It may work for 0805's and SOIC, but anything smaller will be very challenging without any vision assist.

bootstrap
 
Posts: 73
Joined: Wed Jun 02, 2010 8:47 pm

Re: Business models for having a PnP

Post by bootstrap »

scsi wrote:
charliex wrote:steve ciciora built a slow, relatively cheap machine, one paste, one PnP
http://ciciora.com/index.html
I'm not sure that Steve's Taig mill PnP can handle 0.5mm pitch devices with any rate of success. It may work for 0805's and SOIC, but anything smaller will be very challenging without any vision assist.
Yes, I was doubting the component centering system works well enough for smaller components. I say that because the packages of some of the ICs I purchased for my prototype PCBs are not well centered with the BGA balls beneath.

In particular, the 74AUC32374s in micro-BGA packages I got have about 0.50mm of thin PCB-like material sticking out one side of the ceramic. The ceramic above the balls appears centered, but any mechanical centering system will surely center against the little piece of thin PCB-like material sticking out. However, I'm afraid that many or most vision systems would make the same mistake!

Have any of you with pick-and-place machines (mechanical centering or otherwise) had problems with out-of-specifications packages like this? And this 74AUC32374 is a TI part too... not some fly-by-night outfit (unless I got counterfeit parts from digikey, which I hope not!!!).

scsi
 
Posts: 30
Joined: Sun Jan 10, 2010 9:09 pm

Re: Business models for having a PnP

Post by scsi »

bootstrap wrote:Have any of you with pick-and-place machines (mechanical centering or otherwise) had problems with out-of-specifications packages like this? And this 74AUC32374 is a TI part too... not some fly-by-night outfit (unless I got counterfeit parts from digikey, which I hope not!!!).
I don't know how it's done with other machines, but in Madell's software it is possible to take the mask picture of the ball grid alone by simply limiting the capture area. Attached is a crappy example that works. The up looking camera will look for this pattern and simply ignore everything else.
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bootstrap
 
Posts: 73
Joined: Wed Jun 02, 2010 8:47 pm

Re: Business models for having a PnP

Post by bootstrap »

scsi wrote:
bootstrap wrote:Have any of you with pick-and-place machines (mechanical centering or otherwise) had problems with out-of-specifications packages like this? And this 74AUC32374 is a TI part too... not some fly-by-night outfit (unless I got counterfeit parts from digikey, which I hope not!!!).
I don't know how it's done with other machines, but in Madell's software it is possible to take the mask picture of the ball grid alone by simply limiting the capture area. Attached is a crappy example that works. The up looking camera will look for this pattern and simply ignore everything else.
As long as the vision system is looking for balls or pads, and not the outline of the package, then any upward-looking camera vision system should work perfectly well. But mechanical systems are screwed, and any upward-looking camera vision system that tries to find the outline of the package is also screwed (but hopefully nobody does anything as stupido as that).

charliex
 
Posts: 179
Joined: Sat Nov 28, 2009 5:54 pm

Re: Business models for having a PnP

Post by charliex »

scsi wrote:
charliex wrote:steve ciciora built a slow, relatively cheap machine, one paste, one PnP
http://ciciora.com/index.html
I'm not sure that Steve's Taig mill PnP can handle 0.5mm pitch devices with any rate of success. It may work for 0805's and SOIC, but anything smaller will be very challenging without any vision assist.
yes agreed but its a step towards it. i talked to accuratecnc guys about doing some sort of mod, but they're not into it.

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