In message <[email protected]>, dated Fri, 29 May 2009, "Kunde, Brian" <[email protected]> writes:
>Is that true? Has anyone done tests to see the difference of the ESD >pulse with a brand new sharp ESD Gun TIP vs a warn-out TIP that is no >longer sharp? I would think that as long as you make good contact with >the metal that the sharpness of the tip would have no or little affect >on repeatability. Yes, 'as long as'. It's not easy to be sure that a non-conducting layer has been fully penetrated, so a sufficiently dull tip may give optimistic results. > >One last question. The TIPs on our ESD gun are made out of Brass and >dull very quickly. They are very costly from the manufacturer so our >machine shop has been making us new ones out of the same base >material. However, because they dull so quickly I would like to have >them made out of a harder material, such as Stainless Steel. Has >anyone found that changing the tip material affects the repeatability >of the ESD test? Figure 3 of IEC 6000-4-2 does not specify the material of the tip. It doesn't even say that it must be conducting! (It actually says that there may be an insulating covering, but I guess it doesn't mean over the sharp point!) I can't see any reason why a hard metal tip should not be used. The hard (austenitic) variety of stainless steel, however, is naturally hard to work. Depending on the machining required, something else might be better. I can't see why the tip has to be 12 mm diameter. Since it is, the body could be a low-cost material, such as alumin(i)um, with a much smaller, interchangeable sharp point embedded. Has anyone got a store of phonograph/gramophone needles? No, not thorn ones, or diamond-tipped! -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
