In a message dated 11/6/98 8:53:56 AM Pacific Standard Time, [log in to unmask] writes: << Hi Technetters, I have a curious question to ask, regarding the MPM auto-printer. If there is only 1 set of printer, however, has 10 stencils of the same kind of openings (Basically all the stencils are the same, used for only 1 type of PCB's pattern). If 1 of the 10 stencils is being used as reference for teaching, is there a requirement to re-teach every single stencil that is loaded into the printer to ensure the printing accuracy ? Regards, Poh>> Hi there Poh, If it were a perfect world, I would say no. But things being how they are, I would say that there could be a few reasons that you might need to teach every stencil: 1. Variations in the way the foil is mounted in each frame - The stencil vendors I've worked with are pretty accurate as far as being consistent and repeatable when mounting the foils, but that still is pretty much a completely manual operation... so there's going to be some human induced variation. The thickness of the epoxy that was applied to bond the mesh to the frame, and the foil to the mesh, is going to vary between stencils. The foil tension is going to be a little different between each stencil too, again due to the mostly manual operation. 2. Variations in the frames themselves - I've always reused many of the frames for my stencils...it's an easy way to save some money. But having foils in and out of them over and over again will cause each frame to develop it's own "personality" over time. Of course if we're talking about stencils that only have 1206 openings and a few 50-mil pitch IC's in it, then you might get by teaching one stencil and using the same parameters for the others. But when dealing with the pitches we all deal with nowdays, I'd teach every stencil if it were me....heck, it only takes 10-minutes, if that... -Steve Gregory- ################################################################ 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################