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.
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? Thanks, The Other Brian ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Steve O'Steen Sent: Friday, May 29, 2009 9:27 AM To: Michael Hopkins; Scott Douglas; [email protected] Subject: RE: [PSES] ESD testing I would suggest using a fine point Exacto knife, or equivalent, to breach the paint and access the metal for contact discharge. The point on the contact discharge tip can be damaged which could result in repeatability issues. Regards, Steve O'Steen Director, EMC Advanced Compliance Solutions, Inc. [email protected] 770-831-8048 ext. 210 www.acstestlab.com ****************CONFIDENTIAL**************** This e-mail and any attachments may contain information which is confidential, proprietary, privileged or otherwise protected by law. The information is solely intended for the named addressee (or a person responsible for delivering it to the addressee). If you are not the intended recipient of this message, you are not authorized to read, print, retain, copy or disseminate this message or any part of it. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete it from your computer. ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Michael Hopkins Sent: Friday, May 29, 2009 6:40 AM To: 'Scott Douglas'; [email protected] Subject: RE: [PSES] ESD testing Regarding ESD testing to painted surfaces, the following is from section 8.3.2 of the 2nd edition of 61000-4-2: “In the case of painted surfaces covering a conducting substrate, the following procedure shall be adopted: If the coating is not declared to be an insulating coating by the equipment manufacturer, then the pointed tip of the generator shall penetrate the coating so as to make contact with the conducting substrate. Coating declared as insulating by the manufacturer shall only be submitted to the air discharge. The contact discharge test shall not be applied to such surfaces. In the case of air discharges, the ESD generator shall approach the EUT as fast as possible until contact between the electrode and the EUT is made (without causing mechanical damage). After each discharge, the ESD generator (discharge electrode) shall be removed >from the EUT. The generator is then retriggered for a new single discharge. This procedure shall be repeated until the discharges are completed. In the case of an air discharge test, the discharge switch, which is used for contact discharge, shall be closed.” Best Regards, Mike Hopkins EM TEST USA [email protected] Office: +1 603 595 6420 Mobile: +1 603 765 3736 Fax: +1 603 577 9192 From: Scott Douglas [mailto:[email protected]] Sent: Friday, May 22, 2009 9:56 PM To: [email protected] Subject: Re: [PSES] ESD testing Yes, paints are usually (but not always insulative). But when doing ESD testing a guy at a lab once told me they dig the point in through the paint because in the real world there will be scratches through the paint and that is where ESD will get in. My own practice for the past (too many to recall) years has always been dig in the point on metal / conductive surfaces. We have also done contact discharge to plastic surfaces such as control panels and displays because that is where people will touch the product, though for that test we won't dig in the point. Then we do air discharge on plastic surfaces, but tend to have the approach start over plastic surfaces, then repeat with the approach over metal surfaces heading toward the plastic. Found lots of leakage at the interfaces between the two materials that way. With regard to painted surfaces, I have used epoxy-based paints that are virtually invulnerable to the ESD gun's point. Then I have used other paints that scratch just by looking at them, Scott Philo Beddo wrote: I've had customers state that painted surfaces are insluative. I generally disagree. But, there is a point buried in there. What is the dielectrict with-stand of the painted surface? AND how does the product's ESD immunity differ in either case? ASH From: Derek Walton <[email protected]> <mailto:[email protected]> To: "Grasso, Charles" <[email protected]> <mailto:[email protected]> Cc: John Woodgate <[email protected]> <mailto:[email protected]> ; [email protected] Sent: Friday, May 22, 2009 12:08:53 PM Subject: Re: [PSES] ESD testing Hi Chas, This is how I interpret the standard. Somewhere I recall if painted surfaces can be penetrated by the point, then Contact also applies. Cheers, Derek. Grasso, Charles wrote: The ESD standard is perfectly clear (at least to me) - The product is tested using contact discharge for conductive surfaces AND air discharge on insulating surfaces. I don't perceive an interpretation issue. If your product is a object constructed entirely of a conductive material - contact discharge only applies. Similarly if the product is an object constructed entirely of an insulator then only air discharge applies. If your product has combinations of both - then both types of discharges apply. Is this reasoning flawed?? -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of John Woodgate Sent: Friday, May 22, 2009 7:50 AM To: [email protected] Subject: Re: [PSES] ESD testing In message <[email protected]> <mailto:[email protected]> , dated Fri, 22 May 2009, Kate Savo <[email protected]> <mailto:[email protected]> writes: Safety/EMC Standards frequently omit the "and" in a list of items such as you excerpted here from 61000-4-2 - they only put an "or" in where they truly mean it to be interpreted as such. The "and" is implied and Contact ESD must be done on all conductive surfaces, and Air ESD on all insulating surfaces. If your product has both surface types, you should not omit either test scenario. Your local EMC/ESD lab should confirm this. I do not support that interpretation. If the list just said: - air discharge; - contact discharge to conductive surfaces, conducting planes and insulating surfaces. then 'and' might be inferred. But in fact, the inclusion of further words, defining the surfaces to which the two types of discharge shall be applied, excludes such an inference: a) contact discharge to the conductive surfaces and coupling planes; b) air discharge at insulating surfaces. - 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]> <mailto:[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]> <mailto:[email protected]> Mike Cantwell <[email protected]> <mailto:[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> <mailto:[email protected]> David Heald: <[email protected]> <mailto:[email protected]> - 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]> <mailto:[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]> <mailto:[email protected]> Mike Cantwell <[email protected]> <mailto:[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> <mailto:[email protected]> David Heald: <[email protected]> <mailto:[email protected]> - 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]> _________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - 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]> - 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]> - 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. 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