The other thing is that unbeknownst to you something could have changed in the oven.Īnd getting back to my brother's comment, three-zone ovens tend not to be of the highest sophistication and quality, so there may have been a degradation in the oven, fan degradation, heaters, temperature sensors getting off balance. the same recipe on your reflow oven, which could obviously be a source of the problem where a reflow recipe was adequate for one board and along comes a heavier board and you have to change the process to achieve acceptable soldering.

Is this warping on an assembly that you have been building with this big PoP component for all this time, or is this assembly a new one that you're trying to run in the same 'process', i.e. You say the process hasn't changed but all of a sudden you're getting warping. The idea of something changes though that you said, Phil, in your infinite wisdom is true. So most people use at least four or five zones for tin-lead, and preferably six or seven if you're doing lead-free. I agree, a three-zone reflow, assuming they are three equally sized zones, is really not very flexible in controlling the time temperature profile. To basically be using process equipment you bought at a restaurant supply place is not a good idea. If it's not your process, it's probably your application because that's a pretty sophisticated application. Second, last time I saw a three-zone oven used was when it was to make toast at the hotel buffet. Yet our process has remained the same and there have been no changes.įirst you have to take your dish of derision - a three-zone oven! Obviously you bought it out of a catalog. The problem with boards bowing or curving upwards towards the middle of the board has just started recently. The profile worked without issue for at least six months. The assembly has a 40 millimeter package-on-package BGA component. Well, we, the Assembly Brothers, Pick and Place are going to answer a question sent to us by A.M.īoard flexing has recently started to occur on one of our circuit board assemblies. And we're here to work on and solve and comment on process, problems, situations, methodologies and all things electronic assembly.

By day ITM Consulting, but with you now is Board Talk. He is a pioneer in the science of reflow.

He has vast experience in SMT equipment, materials and processes.Ī Lean Six-Sigma Master Blackbelt, Jim has a wealth of knowledge in soldering, thermal technology, equipment and process basics. With over 35 years experience in PCB assembly, Phil is one of the leading experts in SMT process failure analysis. Process Troubleshooting, Failure Analysis, Process Audits, Process Set-upĬEM Selection/Qualification, SMT Training/Seminars, Legal Disputes We are using a three-zone reflow oven.īoard Talk Board Talk is presented by Phil Zarrow and Jim Hall of ITM Consulting. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video.īoard flexing has started to occur on one of our circuit board assemblies, yet our process has remained the same.

Reflow pcb