I'm sorry. I tried to explain both as you've put it but I guess I kinda ran 'em together. But your right. DHH ______________________________ Reply Separator _________________________________ Subject: Re[2]: Burp Cycle! Author: [log in to unmask] at SMTPLINK-HADCO Date: 10/17/95 9:01 AM My interpretation of a 'Burp' cycle differs from a 'Kiss' cycle, in that with a 'Burp' the lamination press is momentarily opened and then closed prior to going to full pressure. Whereas with a 'Kiss', the pressure is shifted from low to high after a predetermined dwell, which remains our standard process even with vacuum assist. Dan Buxton _____ /____/\ _______|___ \/| /________ /_| |< Continental Circuits Corp. / ______||_ </| 3502 E.Roeser Rd. | / | /___| |/ Phoenix, AZ 85040 | | |___|_____/ Voice(602) 232-9133 Fax(602) 268-7386 | \/_____ /| E-Mail [log in to unmask] \_________|/ ______________________________ Reply Separator _________________________________ Subject: Re: Burp Cycle! Author: [log in to unmask] at INTERNET Date: 10/16/95 5:03 PM I think it's more commonly coined a "bump" cycle. I've ran into this when dealing with acrylic based adhesives such as flex circuitry. When the press initially closes, this cycle would help eliminate any air pockets trapped within the package. It's similar to "kiss" (or double stage) lam cycles for thermoset resin systems. The initial low pressure allowed the package to heat to melting temperatures before applying high pressure stage. This helps with high layer count PCBs that have very thin cores to manufacture them with. The thin cores can easily fracture and generally have very fine lines that can be stressed when high pressure is directly applied. (Vacuum assist lamination has virtually replaced all these various techniques) Hadco Printed Circuits Tech Center Two / Watsonville _/_/_/_/_/_/_/ _/_/_/_/ _/_/_/_/_/_/ _/_/_/_/_/_/ _/_/ _/ _/_/ _/_/ _/_/ _/ _/_/ _/_/ _/_/ _/_/_/_/ _/_/_/_/_/_/ _/_/_/_/_/_/ Dave Hoover (408) 728-6677 Senior Process Engineer (408) 728-1728 Fax [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: Burp Cycle! Author: [log in to unmask] at SMTPLINK-HADCO Date: 10/16/95 4:15 PM I recently heard reference to a lamination press cycle for multilayer PCB's as a burp cycle. This cycle is intended to help with air entrapment I believe. If anybody has any specifics on this cycle and or results of if it works or not I would appreciate any and all feedback. Thanx in advance. brian