IMO, I don't feel that you are violating any "good design practices" by leaving the solder mask on these areas - I have done the same thing for many years. Sounds like you work with good board houses who are looking out for their customer! Jason Roetz, CID+ Master Designer Electrical Group, Industrial Controls Division 4201 North 27th Street Milwaukee, WI. 53216 Telephone: 414-449-6397 Fax: 414-449-7319 [log in to unmask] http://www.eaton.com/ -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Upton, Shawn Sent: Thursday, September 09, 2010 6:06 PM To: [log in to unmask] Subject: [TN] PCB Heatsink Pads I don't think I've seen this covered before. On a number of layouts that I've done, I've added some top or bottom layer metal round components that might dissapate some heat. However, I've always left the soldermask over these areas, since it's not a pad to solder to--it's just an attempt to spread some heat, just in case. [I generally use a "real" heatsink if I know it will make heat.] However, it seems that a good chunk of the time I get asked by board houses if this is a pad to solder to, and if I made a mistake. No biggie to correct this (they find plenty of real issues), but I'm wondering if this is somehow in violation of good design practice. Thanks. Shawn Upton ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 -----------------------------------------------------