Hi Chris ( & the rest of us on this issues ) On one of my previous projects I've got just that requirement = almost flush base cut . Tried all sorts of tungsten blades , super thin grinding disks on hyper speeds with vacuum take off ; costly unsafe unrepeatable , you know it all . What we finished up with was in-house build rig consisting of a high speed diamond blade with >polished< top (Teflon coat if you feel extreme) gliding on geared time feed ( or lever if you have a girl with feel, don't give it to guy) below few chrome steel separating wires (.020 gauge in your case) on which the pcb is resting (in a nest ; unless you designed tool holes for top clamp fingers) . Both top touch clamp and bottom blade mounted with silicon foam suspension to ensure positive but gentle action If you design the top clamp on grid > you can change the fingers position according to your top geography ; say if you have 8 slits running from a center to glide & lock clamping fingers easy to a free spot on board . The wires we >tensioned< with cam lock lever ( piano wires & mechanics may do you ) Again, keep the cams sliding > so you can adjust wires in between the bottom topography on different boards . Check the status of separating wires periodically , the constant polishing kills them eventually If you have them on reels > just unlock the cams , pull fresh length in , lock again . Let me know if get stuck . See you Paul Klasek http://www.resmed.com > ---------- > From: Chris_Smith[SMTP:[log in to unmask]] > Sent: Friday, 17 July 1998 4:39 > To: [log in to unmask] > Subject: [TN] Lead Trimming Question ? > > All, > I have a lead trim operation that uses a Q-corporation LOM II > trimming system with a vacuum fixture. We are using the standard > cutting rings with a 30 degree angle. The Vacuum fixture being > used > is quite snug and there is very little vacuum loss in the > process. > The issue I have is the height requirement we're trying to > meet is > .020" max length. This strict requirement is resulting in pcbs > being > cut into and damaged, some flagging, and some solder fractures. > This > seems to be a very operator dependent operation and costly if not > done > correctly. I have tried varying the speed the cutter is moved > across > the board, having Q-corp sharpen the blades instead of us doing > it and > using a QB-1 PCB brusher which was purchased for this product. > Is there anyone out there with a similar trim height > requirement > and what types of things do you perform to insure a repeatable > process? Also anyone with suggestions please let me, I need to > get > this resolved if at all possible. > > Thanks > Chris Smith > Manufacturing Engineer > > ################################################################ > 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 > ################################################################ > ################################################################ 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 ################################################################