I agree with Bill. Nearly all of the "manufacturer's recommended stencil aperture layouts" for what we call belly pads on leadless castellated components are too large by half. An aperture size that provides about 1/2 of the solder paste area for a standard .006" thick stencil provides just about the right volume of solder to prevent the component from lifting so high that the perimeter terminations are open. A crosshatched pattern that provides 50% reduction for the belly pads seems to work quite well in filling the entire area with solder without lifting the part off the board. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bill Kunkle Sent: Thursday, December 28, 2006 10:45 AM To: [log in to unmask] Subject: Re: [TN] DRK package Jim, Although your attachment does not travel thru Technet, I found that this package is a QFN style component. I suggest a stencil opening design as follows: perimeter leads: 1 mil width reduction, 100% length, 2 mil corner radii center lug: print 50 - 60% of the the metallized area Use the area ratio calculation to insure good paste release. This scheme works well for most QFN/MLF components. Bill Kunkle Manager of Stencil Technology MET Assocs. 140 Mt Holly Bypass Unit 10 Lumberton, NJ 08048 www.metassocs.com Ph: 609 261 2670 Fx: 4007 -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of West, Jim Sent: Thursday, December 28, 2006 9:27 AM To: [log in to unmask] Subject: [TN] DRK package Hi, Looking for some help with the package shown within this email. The package virtually sits flush with the PCB, and the pads are directly under the body of the part. The pads are exposed on the side, but by a very small amount. I have a lot of questions regarding the processes from the beginning to the end, but wanted to see if anyone else runs this type of package and what your experiences have been like? Some questions would be stencil apertures design guideline, paste height, after reflow inspection method, and reworking. Best Regards, Jim West Engineering Manager Nexergy Inc. www.nexergy.com tel: (614) 351-6216 fax: (614) 324-1979 This email message and all attachments transmitted with it are intended solely for the use of the addressee(s) and may contain legally privileged, protected or confidential information. If you believe that you have received this message in error, please notify the sender immediately by email reply and please delete this message from your computer and destroy any copies. -------------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------