Scott The PPT is formed with a mesh process ; leaving the checkered imprint on the surface ; supposedly keeping the flux in place . You still pay for the stencil ; only shift the process to bare board . The polished rollers process sounds intriguing . I've send a reply to this topic few moths back ; it'll be in files , incl. the contacts . From cost , no clean , double sided application , ( you do need a reflow with chiller of bottom side ), etc. , it is impractical for most of the assy spectrum . Very limiting and complex on the mix TH & SMD as well . There are better and cheaper ways how eliminate stencil process , pending the application . See you paul ; ResMed >---------- >From: Lolmaugh, Scott (AZ15)[SMTP:[log in to unmask]] >Sent: Thursday, 14 May 1998 0:15 >To: [log in to unmask] >Subject: Re: [TN] HASL alternatives > >All, >There was an interesting article in the February issue of SMT Magazine >(IHS Publishing Group) on page 56, entitled: "End Paste Defects with >Solid Solder Deposits". This is a technique where the PWB Manufacturer >applies solder to the board, then runs the boards through polished >rollers to flatten the solder coating into a flat surface roughly the >same height as the soldermask. Then a tacky flux is applied and finally >an easy peel cover sheet. They claim the boards retain solderability >well and the paste stencil process is eliminated. > >There have been similar / identical techniques touted in the past, known >as: >"Sipad" (R) Siemens AG, (solderpaste application method) >"Optipad" (R) Viele Circuits Inc. and Burkle USA, (liquid solder >application method) and >"Precision Pad Technology or PPT (R) Mask Technology Inc. (solderpaste >application w/ textured finish) > >If anyone knows of domestic (USA) Manufacturers offering this technology, >I'd like to hear who they are. >Thanks >Best Regards, >Scott Lolmaugh >SMT Production Engineering >Honeywell IAC, Inc. >602.313.3551 /FAX: 3402 (Please call first) > > > -----Original Message----- >From: [log in to unmask] >Sent: Wednesday, May 13, 1998 8:39 AM >To: [log in to unmask] >Subject: [TN] HASL alternatives > >To All, >We are now making a comparison between different alternatives to HASL. >The >chosen alternative will have to meet the following criterias criterias. > > - flat coating > - compatible with No-clean process and mixed technology > - resistant to 2-3 reflow (multiple heat cycle) > -and MINIMUM 1 year shelf life (storage before assembly) > >These are the alternatives we think can meet our needs: > >* OSP > - Benzimidazole (?) > >* IMMERSION > - Silver > - Bismuth > - Au-Ni > - Palladium > > >Q: Wich one do you think could be the best meet to our criterias ? > >Q: And what would be its advantage(s) compared to the others ? > >Q: OTHERS ? (is anyone using other coating alternative ) > > >Thanks for all for your help > > >Nicolas van der Heyden > >################################################################ >TechNet E-Mail Forum provided as a free service by IPC using LISTSERV >1.8c >################################################################ >To subscribe/unsubscribe, send a message to [log in to unmask] with >following > text in the body: >To subscribe: SUBSCRIBE TechNet <your full name> >To unsubscribe: SIGNOFF TechNet >################################################################ >Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional > information. >For the technical support contact Dmitriy Sklyar at [log in to unmask] or > 847-509-9700 ext.311 >################################################################ > >################################################################ >TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c >################################################################ >To subscribe/unsubscribe, send a message to [log in to unmask] with following >text in the body: >To subscribe: SUBSCRIBE TechNet <your full name> >To unsubscribe: SIGNOFF TechNet >################################################################ >Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional >information. >For the technical support contact Dmitriy Sklyar at [log in to unmask] or >847-509-9700 ext.311 >################################################################ > > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################