Brad, Thank you. It looks like my pad might be rotated 90deg from yours. The long side of my pad (0.6mm) is parallel with the long side of the part. Is yours the same?
Our manufacturing engineer helped me understand the homeplate process. I'd never encountered it before. He remembers this being more prevalent in the early 90's with IR soldering. Why do you use homeplate? Do you use lead free paste / bare board plating? Do you only use homeplate with 0402's? What's your stencil thickness? Ours is 0.006in thick and paste is applied with with a single blade steel squeege. Thanks again, Steve At 10:23 AM 1/12/2006, you wrote: >Steve, > Your pattern is very close to what I use for regular 0402 > chip resistors. If I convert mine to metric I get, 0.51mm x 0.63mm > pads on 1.14 centers. Carried the precision one more place just so > that you would see the slight differences. > However I have a second 0402 land pattern for 0402 > capacitors or inductors, typically they are a little thicker part > and have more metalization on the end caps. My 0402C land pattern > is 0.51mm x 0.71mm pads on 1.07mm centers. > From my experience the sizing you are using should not be a > problem. If they were talking about keeping your pads precisely the > same size and just moving them closer together then you may see an > issue with solderballs as the solder is moved more under the > non-metalized portion of the body. However, that is highly > dependant on solder paste and other issues. Currently we homeplate > all of our chip components for solderpaste because this has become > a significant problem with our current solderpastes and processing. > >Sincerely, >Brad Velander >Senior PCB Designer >Northern Airborne Technology >#14 - 1925 Kirschner Road, >Kelowna, BC, V1Y 4N7. >tel (250) 763-2329 ext. 225 >fax (250) 762-3374 > > >-----Original Message----- >From: Steve Allen [mailto:[EMAIL PROTECTED] >Sent: Thursday, January 12, 2006 9:49 AM >To: Protel EDA Discussion List >Subject: [PEDA] 0402 Land Pattern > >Hi, >I'd like to hear some recommendations for 0402 land patterns. I've >had good success with >0.6 MM X 0.55MM with 1.1MM centers. Below is a crude drawing: >______ ______ >| | | | 0.55MM >|_____ | |_____ | >0.6MM > > |------1.1MM ------| > >One board assembly shop wants pads closer together to prevent tomb >stoning. Another shop vehemently advises against having pads closer together. > >So what should I do? What are your experiences and recommendations? > >Thanks, >Steve Allen > > >____________________________________________________________ >You are subscribed to the PEDA discussion forum > >To Post messages: >mailto:[email protected] > >Unsubscribe and Other Options: >http://techservinc.com/mailman/listinfo/peda_techservinc.com > >Browse or Search Old Archives (2001-2004): >http://www.mail-archive.com/[email protected] > >Browse or Search Current Archives (2004-Current): >http://www.mail-archive.com/[email protected] ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
