John, Good question. The SMT screen aperture is shaped like baseball's home plate.
Steve At 11:28 AM 1/12/2006, you wrote: >Hate to ask, but what is homeplating? > >John Echols > > >-----Original Message----- >From: Brad Velander [mailto:[EMAIL PROTECTED] >Sent: Thursday, January 12, 2006 11:03 AM >To: Protel EDA Discussion List >Subject: Re: [PEDA] 0402 Land Pattern > >Steve, > My pads are similarly oriented. Typically my pad width matches >the chip width. > > We are homeplating because of excess solderball generation. It >is something that became more prevalent recently with current >formulations of no-clean (leaded) solder pastes that we were getting. >Our screens are anywhere from 5mil to 7 mil thickness depending on the >assemblies. We are homeplating all chip components that do not have some >form of relief (i.e. SMB or SMC devices, some molded devices have relief >areas, troughs, around the contact where the solderpaste is not squished >between the contact and the part body) around the pads/contacts. Our SMT >people tried a lot of other solutions and consulted with the paste >supplier extensively, the only workable solution we found was the >homeplating. Of course being a SMT production issue it could have >contributing factors from many sources during 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 10:45 AM >To: Protel EDA Discussion List >Subject: Re: [PEDA] 0402 Land Pattern > > >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 > > > > >____________________________________________________________ >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] ____________________________________________________________ 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]
