Forgive me just to express my opinion, it may be of no use in technical point of view, I would like to introduce the situation concerning UL testing/approval in Japan. The "rally" for the subject of UL testing/approval caught my interest and I was impressed with your very clear comment and am agree with it. I also remember a part of the comment by Mr. Ed Cosper in which he stated that the OEMs should pay close attention. Some OEMs often require all 94-V0 combination of materials for us PWB manufactures. I think it is one reason we tend to regard "lower flame level" as "everything is inferior" one. For OEMs, it may be easiest way to request all 94-V0 materials for each parts to apply for their final set approval for UL, but I guess it sometimes cause waste of cost because we PWB manufactures have to select the materials from limited list intended for 94-V0 even though it cost much. I understand the requirement of UL is mainly focused on the final set or products of OEMs and UL recommend appropriate, not always high end, material for every portion of these products. In our PWB design viewpoint, we would like to propose the best, or at least better, material combination that can realize best function and safety properties at once in lowest cost. I am wondering how the US industry is facing for this subject. Thank you for your time for my opinion and I would be very much appreciated if I could know any input from US industry's viewpoint. I am here in Tokyo and have no chance to visit US company(who is in the same business) in order to exchange my idea. But except by TechNet! Toru Koizumi Fujikura Ltd. [log in to unmask] >Ed, > >UL approvals of materials is different than UL approval given to fabricators. >The materials usually undergo seperate material testing. The fabricators >qualification is after processing of several materials together. An example >would be a particular soldermask on a laminate material. The type soldermask, >it's thickness, the type laminate material and it's thickness will have an >affect on the final flamability rating given to a fabricator. > >It is not unusual for a different flame rating to be given for the combination >than that given to the individual material. A case in point would be the use >of polyimide laminate and soldermask. Many thin polyimide materials do not >carry a 94-V0 rating. Especially once a soldermask is applied to it. But given >the correct combination of soldermask and polyimide thickness, it is possible >to receive a 94-V0 rating. > >I don't believe that the fabricator actually "fails" to receive a rating, but >would receive a lower rating than he was seeking to achieve. Most fabricators >will submit maerial combinations so as to receive several ratings for a given >set of tests. As another example. They may submit samples of different >laminate thicknesses with a specific soldermask apllied to it. The result >would be a 94-HB on the thinner materials and a 94-V0 on the thicker >materials. > >Regards, > >Gary Ferrari >Executive Director >IPC Designers Council > >################################################################ >TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c >################################################################ >To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: >To subscribe: SUBSCRIBE TechNet <your full name> >To unsubscribe: SIGNOFF TechNet >################################################################ >Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. >For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 >################################################################ > > ---- Fujikura Ltd. [log in to unmask] ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################