I would say that temporary masking would be needed mostly through the wave and not through the reflow, since the paste is placed in places where solder is needed with exceptions such is via in pad. Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer Sent: Wednesday, January 03, 2007 11:18 AM To: [log in to unmask] Subject: Re: [TN] Temporary peelable solder masks Printed peelable mask is generally incompatible with SMT because it interferes with the solder stencil if it's thick, and if it's thin it can be very difficult to remove. Probably less printed peelable in the US reflects a higher proportion of SMT boards built here. Wayne Thayer >>> [log in to unmask] 1/3/2007 10:43:45 am >>> Peter, I guess in part that is what I am asking. Do US assemblers more commonly use the in-house/DIY approach rather than have the PCBs supplied with the masking pre-applied to a supplied (gerber layer?) pattern. Alternatively I know that some use masking that is removed by a post-wave-solder cleaning process rather than peelable. Just surprised that what our suppliers seem to think is not a big problem to provide as a normal service is apparently not so readily available in USA... Or maybe it just depends who you ask! Cheers Nigel Burtt Production Engineering Manager Dolby Laboratories, Inc. - European HQ Email: mailto:[log in to unmask] Tel: +44 (0)1793 842132 [direct line with voicemail] Fax: +44 (0)1793 842101 -----Original Message----- From: Peter Swanson [mailto:[log in to unmask]] Sent: 03 January 2007 15:37 To: TechNet E-Mail Forum; Burtt, Nigel Subject: RE: [TN] Temporary peelable solder masks Nigel, You rightly draw the distinction between a) the types of temporary masks which are pre-applied by screen printing, usually by the pcb fabricator and b) the temporary masks which are dispensed on by the guys doing the assembly. They are different. Whilst it is obviously desirable to have this job done by your fab guy, as you pointed out, it isn't always straightforward. In particular, I remember a few years back when the process window on the screenable materials wasn't very wide, resulting in problems from under/over cure, removal, etc. Maybe the formulations are more robust today. It is possible to make the "in-house" dispensable types more appealing. Dispensing can be by fairly inexpensive robotics. Curing can be quick by heat or UV. Is this approach an option? Regards, Peter -------------------------------------------------------- Peter Swanson [log in to unmask] INTERTRONICS http://www.intertronics.co.uk Tel: +44 1865 842842 Oxfordshire, England INTERTRONICS is dedicated to providing quality material, consumable and equipment solutions to the high technology, high performance assembly industries, incorporating outstanding levels of technical support and customer service. Read our blog! http://www.intertronics.co.uk/blog/blog.htm -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of N Burtt Sent: 03 January 2007 09:27 To: [log in to unmask] Subject: [TN] Temporary peelable solder masks I'm being told that these are not widely used in USA, the common types used here in the UK (Peters and Electramask) not readily available, and they create packaging and shipping problems... thus US PCB suppliers reluctant to supply PCBs with peelable masking applied. Is this true? Now they are by no means a perfect solution to protecting holes on a PCB during wavesolder, but am not aware of another way of doing so in a no-clean RoHS process if fixturing can't do it. What do US PCB assemblers do if pre- applied peelable masking is really not viable? 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If you are not the intended recipient, disclosing, copying, distributing, or taking any action based on this message is strictly prohibited. --------------------------------------------------- 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 -----------------------------------------------------