Good People, FYI.
Had an interesting event in the lab last night, then remembered this PSTC thread. I had serialized some PCBs using a Sharpie marker. During a SFC test, molten ejecta carbonized several mm of the PCB surface where the serial was marked. Also, there were a small amount of contaminants in same area from re-work. The subsequent dielectric withstand failed at approx 1kV due to tracking in the marked area. Repeated test 2x with clean PCB -> no problems. Conclusion: (dirty PCB && sharpie marker) == bad Yes, I know that I did not normalize for contamination level and/or sharpie. R/S, Brian ====finddamnmail.py 1_1========== > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of > ted.eck...@apcc.com > Sent: Friday, October 20, 2006 6:30 PM > To: emc-p...@ieee.org > Subject: RE: Which inks are conductive? > > The second question is easier to answer. Sharpie® brand > markers are tested > to be nontoxic and are labeled according to ASTM D-4236. > They should be > RoHS compliant. I cannot state anything about the toxicity > or hazardous > materials for other brands of permanent markers. > > The first question is harder. Sharpie brand markers use an > alcohol as the > solvent. It should evaporate fairly quickly and would not likely > contribute to conductivity after the ink dries. However, it is quite > possible that there are other components that the ink could > be slightly > conductive. I would expect the resistance to be very high > and it is not > likely to cause a direct short circuit. The ink would not likely be > considered a risk of bridging basic or reinforced > insulation. The use of > the pens is so common that I would have expected at least > some failures to > be found and reported within the compliance community. > > However, it may be possible that the ink could provide > enough of a path for > copper or solder migration. Does anybody want to try an > experiment to see > if permanent ink can lead to dendrite growth? > > Ted Eckert > American Power Conversion Corporation > > The items contained in this e-mail reflect the personal > opinions of the > writer and are only provided for the assistance of the > reader. The writer > is not speaking in an official capacity for APC nor > representing APC's > official position on any matter. > > > > > "Jim Eichner" > > <Jim.eichner@Xant > > rex.com> > To > Sent by: <emc-p...@ieee.org> > > emc-p...@ieee.org > cc > > > > Subject > 10/20/2006 05:08 RE: Which inks are > conductive? > PM > > Good question, and if Doug doesn't mind I'd like to > piggy-back a question > on top of his. > > Does anyone know if the Sharpie or similar pens use RoHS > compliant ink? > > Jim Eichner, P.Eng. > Compliance Engineering Manager > Xantrex Technology Inc. > phone: (604) 422-2546 > fax: (604) 420-1591 > e-mail: jim.eich...@xantrex.com > > > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf > Of Powell, > Doug > Sent: Friday, October 20, 2006 2:42 PM > To: emc-p...@ieee.org > Subject: Which inks are conductive? > > Does anyone know if permanent markers conductive? Does > color matter? > > Right now I am referring to the Sharpie® pen in particular > but this applies > to others as well. > > This is all about violating creepage distances on insulating > surfaces. I > have had past experience office supply stamp pad inks that > cause arcing if > marks placed in keep out zones of high voltage circuit > boards. It also > occurs to me that those liquid ink silver and cold markers can be a > problem. Certainly graphite pencils can be a problem. > > Thanks, > > -doug > > Doug Powell > Advanced Energy Industries, Inc. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
