>>> David Ricketts <[log in to unmask]> 07/09/97 04:45pm >>> Thomas Kropski wrote: > > What is the smallest reasonable text size for silkscreen text. Text > height, width, and thickness. With design density increasing, we would > still like to have as many ref des possible. From a PCB designer, > what tooling parameters are acceptable for good resolution on the > finished products. The only real limitation to silkcreen is your PCB fabricator. We have successfully used 40 mil high by 6 mil stoke width with the right vendor. Older eyes may require help, but the text is completely readable and clear. Our typical text size is 60 x 10 and 50 x 8. Our software does not control the width. As to the suggestion of eliminating silkscreen altogether by Tom Coyle, that is a tempting but limited view. Every company will have different products and priorities. Saving $1 per panel could cost $thousands in assembly and rework errors. If your engineers get everything right every time, and you use pick and place machines for assembly with every single part, including through-hole parts on both sides of the PCB, and do not add discrete wiring at a later assembly, who needs silscreen? :) David ----------------------------------------------------------------------------- To all: Why not consider getting rid of the solder-masks as well as the silk-screen. Add two layers (just pads or smt lands and fanout pattern) for the outer layers and get on with life utilizing the less expensive boards. Also, when utilizing this technique, why not just etch your reference disignators. From what I have been led to believe, the cost advantage is seen when having to utilize over 6 or so layers. You would just make a 6 layer board into an 8 layer. It would be interesting to get some feed-back on this. I used to work for a military contractor that initially was doing pcbs masked with dry-film. The thinking then was to avoid the masks using this technique. The extra "pads-only" layers allowed for etched-in reference designators. Any thoughts regarding costs/trade-offs would be appreciated. John Swinehart BFGoodrich Avionics Systems, Inc. *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************