Hi Group,
Much thanks to Ken Wyatt, Peter Merguerian, Kevin Robinson, Brian O'Connell, Ron Pickard and Bill Owsley for your good advice. I have since learned that the material is High Impact Poly Styrene HIPS, I don’t have details on the shielding material other than it is 99.96 pure aluminium, Resistance is approx 2 ohms/square, Deposition is approx 150 angstroms. I performed some rudimentary radiated emission testing by cutting out a large square of the existing metal cover and attached the sample metalized material using copper tape. The results were inconclusive as I was using a NON-semi-anechoic, shielded room, some frequencies went up while others were about the same or slightly lower. I will re-test in an anechoic room. Peter’s point on the ensuring the metalized coating material does not peel and short out electrical circuitry is a point well taken as well as Kevin’s advice on avoiding this material like the plague. Ken’s comment on recycling issues was also very valuable as well as other comment on EMI/EMC. There is a UL class on this subject towards the end of the month in Brea CA which I will be sure to attend. Thank you all again, Ryan Jazz Jayasinghe Compliance Engineer x1198 Canoga Perkins Direct:(818) 678-3898 20600 Prairie Street Company:(818) 718-6300 Chatsworth, CA 91311-6008 e-mail: [email protected] www.canoga.com <http://www.canoga.com/> FAX:(818) 678-3798 ________________________________ From: Bill Owsley [mailto:[email protected]] Sent: Thursday, August 12, 2010 6:15 PM To: Jayasinghe, Ryan; Ken Wyatt Cc: [email protected] Subject: Re: [PSES] Polycarbonate Chassis A double amen to this! And cost saving be damned, we're going to have plastic no matter what! - Bill In the event of a national emergency, click on the following links to provide directions to your duly elected mis-representatives. http://www.usa.gov/Contact/Elected.shtml or... https://writerep.house.gov/writerep/welcome.shtml http://www.senate.gov/general/contact_information/senators_cfm.cfm if really desperate... http://www.usa.gov/Contact/Elected.shtml --- On Thu, 8/12/10, Ken Wyatt <[email protected]> wrote: From: Ken Wyatt <[email protected]> Subject: Re: [PSES] Polycarbonate Chassis To: "Jayasinghe, Ryan" <[email protected]> Cc: [email protected] List-Post: [email protected] List-Post: [email protected] List-Post: [email protected] Date: Thursday, August 12, 2010, 3:56 PM Hi Jason, I don't recall any detailed answers to your questions, so I'll offer a few points. First, plated plastics are not nearly as recyclable as your steel enclosure, so that may be a consideration. I've done a lot of shielding tests on plated and impregnated plastic enclosures. Some points to be aware of would include the fact that thin plated or vapor-deposited shields are generally not as good as thicker all-metal shields, you need to be careful about overlapping (with a tight fit) any access plates (i.e., make sure the plating makes a continuous seal across any joints) and finally...and maybe most important...make sure any connectors (USB, LAN and the like) are well-connected to the enclosure plating prior to exiting the enclosure to reduce CM currents flowing on I/O cables. This may be easier said than done. Shielded plastic enclosures can be made to work, but you'll really need to help your MEs ensure proper EMC design priciples are incorporated. Cheers, Ken ___________________ Kenneth Wyatt Wyatt Technical Services LLC Woodland Park, CO [email protected] www.emc-seminars.com On Aug 5, 2010, at 1:51 PM, Jayasinghe, Ryan wrote: Hello Group, I have been asked to investigate the possibility of changing one of our chassis’ material from Steel to some type of polycarbonate, the motivation is strictly cost. There will be some metalized shielding on the inside. I don’t have all the specification on the shielding properties at this time. The product is roughly a 1Ux12”x 12” ITE product AC or 48VDC ~35W power two port RJ45 Ethernet for UTP. FCC, UL, NEBS Type 2 and 4. I am concerned about the ESD and EMI aspects as well as other issues such as grounding. I will be interested in hearing any horror stories or outright restriction or test hurdles that maybe encountered. Cordially, Ryan Jazz Jayasinghe Compliance Engineer x1198 Canoga Perkins Direct:(818) 678-3898 20600 Prairie Street Company:(818) 718-6300 Chatsworth, CA 91311-6008 e-mail: [email protected] www.canoga.com <http://www.canoga.com/> FAX:(818) 678-3798 - 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. 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]>
