Thanks to everyone that responded, and I'll take your suggestions and work on the process to better understand the causes of some of the problems. Ideally, a new oven would be in order, and I may be able to justify it. I agree that my challenge with this oven would be greater if we were required to use lead free solder, but we are not required to use it - yea!
Howard A. Watson
-----Original Message-----
From: Guy Ramsey [mailto:[log in to unmask]]
Sent: Wednesday, February 15, 2012 11:05 AM
To: 'TechNet E-Mail Forum'; Watson, Howard A
Subject: RE: [TN] IR Reflow Oven capability
Hi Howard,
I agree with Dave but you can characterize your oven with the DataPaq. And if you are on a tight budget you can verify your Datapaq, before you have it calibrated.
Put the thermal couple in a bead of solder. Then heat the solder with an air rework station or on a hot plate. Watch for the solder to change phase.
And verify that the thermal couple reads 183C or 361F. Put the thermal couple in boiling water for 100C or 212F. Compare the thermal couple reading at room temperature. If the instrument tacks well at these readings it should work okay for your needs.
Next, mount thermal couples across a large wide board and measure the top air and bottom air temps through the oven.
Then, mount thermal couples under a standard part (those QFPs for example) and place them across large wide board an measure the top and bottom side variation.
Finally, mount the loaded couples in a diagonal so you can monitor the response as the zones are loaded. Do the parts at the front get hotter than the parts at the back, compared to the results from the previous test.
This should give you confidence or reason to reject the oven for your applications.
Guy
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Watson, Howard A
Sent: Wednesday, February 15, 2012 10:44 AM
To: [log in to unmask]
Subject: [TN] IR Reflow Oven capability
Hello all,
Wow, after an 8 year hiatus from the electronics industry, and the Technet, I am surprised to see so many familiar names still active on the Technet. I see this as a testament to your wisdom and staying power, something I didn't have!
In my new job, in a very small shop of R&D quantity, I see that we have a very small IR reflow oven that is seldom used (most of our boards are entirely hand soldered or contracted out). The oven is a ~15 year old bench top oven with a heating tunnel that is 3 feet long - 4 heat zones. The reports I hear are of "hit-or-miss" quality output, which might not necessarily be the oven and could be the process. Our boards can be complex, multi-layer and with some large QFPs, big ground planes, etc. My question
is: does anyone have direct experience to share regarding these small bench top IR reflow ovens, and did/do you have a positive experience? For the record, the oven is a DIMA SMT Systems SMRO-0252. We use 63/37 solder, RMA flux. We do profile the boards, but since the datapaq has not been calibrated in 10+ years, I look at these profiles with some suspicion. Your feedback will help my decision process to keep the oven and work on the process, or work on getting a new oven. As always, I appreciate your insight!
Howard Watson
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