In a past life we used CEM-3 material and had problems with it's expansion rate. What we saw was that as the board was manufactured it would grow/shrink ~.001/linear inch. This gave our assy people quite a bit of frustration not to mention our incoming inspection department went mad trying to inspect the boards. Personally I would stick to the FR-4 material since the cost difference between the material is close but the assy & manufaturability of the material causes some problems. Steve Collins ---------- > From: Christopher Jorgensen <[log in to unmask]> > To: [log in to unmask] > Subject: [TN] Specification for Laminate Based on End Usage > Date: Tuesday, March 02, 1999 10:29 AM > > TechNetters, > > Can anyone out there give Tim some recommendations based on your experiences? > > +++++++++++++++++++++++++++++ > > Name: Tim Bowe > Company: Diebold, Inc > E-Mail: [log in to unmask] > > Comments: > > I am looking for some direction on what type of laminate base material should be > specified for rigid printed circuit boards used in Diebold products. After reviewing > numerous IPC and UL documents, I do not clearly understand the pros and cons of > various laminate grades and their specific applications and am asking you, who use > these materials on a daily basis, for assistance and recommendation. > > We have qualified a new color monitor for our ATM machines from a domestic and > off-shore supplier. Monitor performance is categorized as Class 2 Dedicated Service > Electronics Products classification listed in IPC-6011 where high performance and > extended life is required and for which uninterrupted service is desired but not > critical. > > The monitor PWB is single-sided, approximately eight-inches square, supported by > corner stand-offs in a metal chassis. Components are all thru-hole connection. Some > of the power transistors require free-standing heat sinks. Other bulky components > include coils and transformers. This AC operated device incorporates an internal > universal switching type power supply integrated onto the PWB. AC input voltage > range is: 100-vac to 240-vac. There is also several hundred volts present on other > circuit traces required by the CRT (cathode ray tube). > > To meet our reliability requirements, the domestic supplier plans on using FR-4 > laminate with plated-thru-holes; the off-shore supplier contends equivalent > reliability with their CEM-3 laminate material without plated-thru-holes. The > following Diebold requirements need to be considered in making this supplier > selection: > > 1) Operating Temperature: 0C to 60C @ 95% RH (max). For reliability predictions, the > operating temperature is 30C, 90% of the time and at the extremes 5% of the time. > > 2) Shipping/Storage Temperature: -40C to +70C. Absolute humidity content not to > exceed 100% at 32C. The off-shore supplier will probably ship product by boat to a > domestic warehouse facility until required by Diebold for "just in time" delivery. > Is laminate moisture absorption of CEM-3 vs. FR-4 a product reliability concern > during this transit process? Specifically, storage in possibly hot/humid shipping > holds for a number of weeks. > > 3) Transit Vibration: This product is shipped from Diebold either installed in an ATM > or individually boxed for field service replacement. In either case, this product > may ship anywhere internationally. How does the laminate flexural strength > characteristics of CEM-3 vs. FR-4 affect product reliability due to transit vibration > effects? What about product reliability during various "handling processes" of the > individually boxed version? > > 4) Flame Retardency: What is the difference between the NEMA FR-4 and CEM-3 ratings > for these laminate materials? Which is best suited for Diebold's needs? > > Our annual volume requirement is 10K - 12K. If the off-shore supplier is selected, > there is an additional annual cost savings of a couple hundred thousand dollars. > Although cost is an issue, Diebold's primary mission is delivering defect-free > competitive products and services on time to our customers. What is your > recommendation on the PWB laminate material type we should specify? > > Your assistance in this matter is greatly appreciated. > > Sincerely, > Diebold, Inc. > > Tim Bowe > Module and System Development > Diebold, Inc. > > Voice: 330.490.4668 > FAX: 330.490.4508 > em@il: [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 > ################################################################ ################################################################ 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 ################################################################