This is not uncommon. The solution, as you have found out, is to insure every card's panel makes contact with a neighbor, or the adjacent side card cage wall. And as you see, demonstrating the need is not all that difficult. However, actually getting people to add it is another matter.
Expenses associated with even a small tooling change may make it undesirable to modify cheaper, lower-profit cards. Also, legacy cards made to looser tolerances may not fit into assemblies of later, better grounded and shielded cards. On top of this, other practical issues must be considered: Will fingerstock survive manufacturing and shipping? Will it fit into shipping containers? Might fingerstock cut or scratch people adding it or packing cards, or even end-users on whose cards it is mounted? Will it stay put and not fall off? Does it compromise ventilation, fire containment or sealing? Lately, is it properly recyclable? Right-angle, clip-on contact fingerstock may be had. Installed opposite each other, it might work. Fingers tend to fall off easily, can prevent use of existing shipping boxes, are time consuming to add, if installed singly must be tightly controlled as to location, are either easily damaged or prone to scratch users, and may be suspect for disposal. The final cost may be more than you want to spend. These materials are best used along the whole edge of cards, with panels designed to accept and mate with them. My experience suggests that adding card-edge grounding is therefore most easily done for a *new* product -- and that companies who don't have this problem already use it. Cortland Richmond Ian McBurney asked: >> My question is does anyone know of a component (like a short finger strip) that can be mounted onto the front panels or circuit boards that will bond the panels together. The bonding only needs to be in one or two positions to half the wavelength of the emissions. However the cards must be able to be removed and replaced. This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Mcantwell mcantw...@ieee.org For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
