RE: metallic coatings
Ken and John There are no requirements which are mandatory in Europe. Ilan Cohen Technical Director, Safety Telecom Divisions I.T.L (PRODUCT TESTING) Ltd. 26 Hacharoshet St, POB 211, Or Yehuda, Israel. Tel 972-3-5339022, Fax 972-3-5339019 ico...@itl.co.il, website: http://www.itl.co.il http://www.itl.co.il/ I-SPEC: The best place on the internet to learn about safety !! http://www.i-spec.com/ (I-Spec is provided free of charge as a service by ITL to the compliance community) From: Tyra, John [mailto:john_t...@bose.com] Sent: Monday, October 20, 2003 9:23 PM To: 'Ilan Cohen'; 'Ken Javor'; emc-p...@majordomo.ieee.org Subject: RE: metallic coatings Related to the question ...UL 746C sub-clause 47 specifies testing for adhesion of metallized coatings for EMC purposes. They reference test criteria in ASTMD 3359..If you are submitting to UL and you want to use an EMC metallized coating in a product, where if the coating was to flake spacings would be compromised, UL will require you pass these testsWhen I investigated this in the past Europe did not have any similar tests so an Engineer from TUV in Germany told me he would accept the UL results.Although this may have changed..Anyone know of any similar requirements for adhesion testing for Europe?? From: Ilan Cohen [mailto:ico...@itl.co.il] Sent: Monday, October 20, 2003 1:53 PM To: 'Ken Javor'; emc-p...@majordomo.ieee.org Subject: RE: metallic coatings Hi Ken From a safety point of view I typically recommend not to use coating on Plastics. The results can be destructive and dangerous. After some time you may end up with metallic coating parts falling on electronics and the results can be fire or electric hazard. UL has evaluated plastics and conductive coating for the plastics that matches and stays safe. Consult with UL people for the correct combination. Ilan -- Ilan Cohen Technical Director, Safety Telecom Divisions I.T.L (PRODUCT TESTING) Ltd. 26 Hacharoshet St, POB 211, Or Yehuda, Israel. Tel 972-3-5339022, Fax 972-3-5339019 ico...@itl.co.il, website: http://www.itl.co.il I-SPEC: The best place on the internet to learn about safety !! http://www.i-spec.com/ (I-Spec is provided free of charge as a service by ITL to the compliance community) - -Original Message- From: Ken Javor [ mailto:ken.ja...@emccompliance.com] Sent: Friday, October 17, 2003 4:03 AM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: metallic coatings
Related to the question ...UL 746C sub-clause 47 specifies testing for adhesion of metallized coatings for EMC purposes. They reference test criteria in ASTMD 3359..If you are submitting to UL and you want to use an EMC metallized coating in a product, where if the coating was to flake spacings would be compromised, UL will require you pass these testsWhen I investigated this in the past Europe did not have any similar tests so an Engineer from TUV in Germany told me he would accept the UL results.Although this may have changed..Anyone know of any similar requirements for adhesion testing for Europe?? From: Ilan Cohen [mailto:ico...@itl.co.il] Sent: Monday, October 20, 2003 1:53 PM To: 'Ken Javor'; emc-p...@majordomo.ieee.org Subject: RE: metallic coatings Hi Ken From a safety point of view I typically recommend not to use coating on Plastics. The results can be destructive and dangerous. After some time you may end up with metallic coating parts falling on electronics and the results can be fire or electric hazard. UL has evaluated plastics and conductive coating for the plastics that matches and stays safe. Consult with UL people for the correct combination. Ilan -- Ilan Cohen Technical Director, Safety Telecom Divisions I.T.L (PRODUCT TESTING) Ltd. 26 Hacharoshet St, POB 211, Or Yehuda, Israel. Tel 972-3-5339022, Fax 972-3-5339019 ico...@itl.co.il, website: http://www.itl.co.il I-SPEC: The best place on the internet to learn about safety !! http://www.i-spec.com/ (I-Spec is provided free of charge as a service by ITL to the compliance community) - -Original Message- From: Ken Javor [ mailto:ken.ja...@emccompliance.com] Sent: Friday, October 17, 2003 4:03 AM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: metallic coatings
Hi Ken From a safety point of view I typically recommend not to use coating on Plastics. The results can be destructive and dangerous. After some time you may end up with metallic coating parts falling on electronics and the results can be fire or electric hazard. UL has evaluated plastics and conductive coating for the plastics that matches and stays safe. Consult with UL people for the correct combination. Ilan -- Ilan Cohen Technical Director, Safety Telecom Divisions I.T.L (PRODUCT TESTING) Ltd. 26 Hacharoshet St, POB 211, Or Yehuda, Israel. Tel 972-3-5339022, Fax 972-3-5339019 ico...@itl.co.il, website: http://www.itl.co.il I-SPEC: The best place on the internet to learn about safety !! http://www.i-spec.com/ (I-Spec is provided free of charge as a service by ITL to the compliance community) - -Original Message- From: Ken Javor [ mailto:ken.ja...@emccompliance.com] Sent: Friday, October 17, 2003 4:03 AM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: metallic coatings
-Original Message- From: Ken Javor [ mailto:ken.ja...@emccompliance.com] Sent: Thursday, October 16, 2003 7:03 PM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. Ken: Some of our recent products for the Army Marines used plastic and composite materials for cases. We used electroless nickel, and had no problems. Of course, the need for shielding was known from the start, so the mechanical guys were able to design the cases without difficult internal corners and problematic sealing surfaces. Mating the MIL connectors to the shielding was a bit more difficult, but we used a combination of clamped surfaces, conductive elastomer gaskets and conductive epoxy. Ed Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty
RE: metallic coatings
I've heard of these polymer matrices before and wondered how they would perform, not only for EMC, but for safety as well. It's important to remember that using such a polymer may have consequences in the safety arena: * may require a connection to protective earth, if there is a risk of electric shock inside the box under normal or fault conditions * may lead to excessive earth leakage currents, if care is not taken in the overall design, if mains voltages enter the box * may require ball pressure testing, if the polymer is in compression by a required earthing connection (assuming the end-product standard calls for it) * since the material is 'nonstandard' in terms of CSA 0.4, how it might perform under the fault testing (briefly described in the 60950-1 standards) It would be good the group to hear from anyone who has successfully used one of these conductive structural resins in their designs (within the limits of IP consideration). Regards, Peter L. Tarver, PE Product Safety Manager Homologation Services Sanmina-SCI Corp. San Jose, CA peter.tar...@sanmina-sci.com From: Wani, Vijay (V) Sent: Friday, October 17, 2003 10:25 AM Ken: You might try to make the plastic housing/box itself out of a conductive composite. We have some polymer composites which can be injection molded, and which shield to high levels. This would get around having to redesign the circuit and also some of the problems you cite with coatings (peeling, etc). Any interest in this? Vijay Wani The Dow Chemical Company Office (989) 636-0473 Fax (989)638-9289 vw...@dow.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: metallic coatings
I agree with Joe and want to point out one other process for adding metal to plastic. I believe the coating is probably cheaper than the inner metallic housing, but I think you'll get better performance with the inner shield, in particular if you haven't designed the plastic enclosure to work with the metalization. The coating won't get into small and/or sharp radius for example, leaving unwanted seams. The contact pressure between halves has to be addressed as does the mating of any connectors that leave the box, etc. It can be done but it has to be part of the design process not afterwards. The coatings shouldn't flake if you use a NRTL recognized coating and plastic combination, along with an approved applicator - at least for commercial stuff. They learned early on about the metal flaking problem and have added aging tests. (Does that fully address the problem? I'm not sure) For a military application the environment - salt fog etc may defeat the whole process. There is one other form of metallization - injecting fibers inside the plastic. But it has its own problems, How to make contact with the metallic fibers, the more metallization you have the quicker the mold parts wear out, layers of high metallization and low metallization layers inside the plastic. Again doable - but it takes design and money and isn't really suitable as an after the fact design add in. Gary - Original Message - From: Joseph Randolph mailto:j...@randolph-telecom.com To: 'Ken Javor' mailto:ken.ja...@emccompliance.com ; emc-p...@majordomo.ieee.org Sent: Thursday, October 16, 2003 8:37 PM Subject: RE: metallic coatings Hi Ken: Conductive coatings are tricky, and I generally try to avoid them. It can be difficult to get good electrical connections at the separations where different parts of the box meet, unless the mating surfaces have been specifically designed for the purpose. Even so, the contact quality can deteriorate over time with some materials. Worse yet, some coatings have a tendency to peel as they age. I would think these limitations would be even more of an issue for military environmental conditions. I don't know the background of your request, but if this is being contemplated as a band-aid for an EMC problem, you may want to pursue other fixes such as circuit board revisions. If you really do need some shielding but want to avoid the coatings, you might consider a stamped steel insert made out of thin sheet metal that conforms to the inside contours of the plastic box. There are also some shielding constructions where a conductive film is bonded to a non-conductive substrate that can be die stamped and then folded to fit around the circuit board inside the plastic housing. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) j...@randolph-telecom.com http://www.randolph-telecom.com -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Ken Javor Sent: Thursday, October 16, 2003 10:03 PM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: metallic coatings
Ken: You might try to make the plastic housing/box itself out of a conductive composite. We have some polymer composites which can be injection molded, and which shield to high levels. This would get around having to redesign the circuit and also some of the problems you cite with coatings (peeling, etc). Any interest in this? Vijay Wani The Dow Chemical Company Office (989) 636-0473 Fax (989)638-9289 vw...@dow.com From: Joseph Randolph [mailto:j...@randolph-telecom.com] Sent: Thursday, October 16, 2003 11:37 PM To: 'Ken Javor'; emc-p...@majordomo.ieee.org Subject: RE: metallic coatings Hi Ken: Conductive coatings are tricky, and I generally try to avoid them. It can be difficult to get good electrical connections at the separations where different parts of the box meet, unless the mating surfaces have been specifically designed for the purpose. Even so, the contact quality can deteriorate over time with some materials. Worse yet, some coatings have a tendency to peel as they age. I would think these limitations would be even more of an issue for military environmental conditions. I don't know the background of your request, but if this is being contemplated as a band-aid for an EMC problem, you may want to pursue other fixes such as circuit board revisions. If you really do need some shielding but want to avoid the coatings, you might consider a stamped steel insert made out of thin sheet metal that conforms to the inside contours of the plastic box. There are also some shielding constructions where a conductive film is bonded to a non-conductive substrate that can be die stamped and then folded to fit around the circuit board inside the plastic housing. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) j...@randolph-telecom.com http://www.randolph-telecom.com -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Ken Javor Sent: Thursday, October 16, 2003 10:03 PM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: metallic coatings
Hi Ken: Conductive coatings are tricky, and I generally try to avoid them. It can be difficult to get good electrical connections at the separations where different parts of the box meet, unless the mating surfaces have been specifically designed for the purpose. Even so, the contact quality can deteriorate over time with some materials. Worse yet, some coatings have a tendency to peel as they age. I would think these limitations would be even more of an issue for military environmental conditions. I don't know the background of your request, but if this is being contemplated as a band-aid for an EMC problem, you may want to pursue other fixes such as circuit board revisions. If you really do need some shielding but want to avoid the coatings, you might consider a stamped steel insert made out of thin sheet metal that conforms to the inside contours of the plastic box. There are also some shielding constructions where a conductive film is bonded to a non-conductive substrate that can be die stamped and then folded to fit around the circuit board inside the plastic housing. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) j...@randolph-telecom.com http://www.randolph-telecom.com -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Ken Javor Sent: Thursday, October 16, 2003 10:03 PM To: emc-p...@majordomo.ieee.org Subject: metallic coatings Does anyone have any suggestions for a metallic coating that can be deposited on the interior of a plastic box that would need to meet military environmental conditions? Suggestions for other metallization techniques are also welcome. Thank you. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
