Dear Technetters, In the good old days we used to thermally shock boards - literally move from a hot oven to a freezer via a conveyor belt with no real control of the ramp rate. We then improved the process and carried out extensive (and expensive) environmental stress screening of our boards. This has involved temperature stressing at about 20 degrees per second to about 70C with functional testing during the temperature ramp. This was followed by an hours soak with more testing and then ramping to about -30C with yet more testing. We are now investigating the use of HARASS, Highly Accelerated Rapid Air Stress Screening, which gives rates of 60 C/sec and very controlled top and bottom temperatures. This technique is supposed to make weak joints apparent so that testing can be carried out after the test. Has anyone any experience of this technique? There is a concern that it may damage components but we have found no evidence. Thanks for any information, Richard Philp Matra BAe Dynamics, Stevenage, UK ################################################################ 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 ################################################################