Improving a T-962A Reflow Oven Part1

[@Chingonazo1]

Very interesting. I had this conditions in other reflow tools that characterized. I compensated using lower melting point solder paste, and it worked fine. Thank you for sharing.

[@m1geo]

Interesting. I had no idea about the flicker and harmonics standard, despite being a ham radio operator, who cares greatly about mains born EMC. Thanks!

[@zbubby1202]

I think it is important to note in something as relatively simple as an IR reflow oven why the distinction between "industrial grade" and "hobby grade" shouldn't matter to most people. "Professional" results are going to be able to be achieved with either if you put in the requisite time to understand the machines and their eccentricities. The primary difference between "industrial" and "hobby" in these units is not quality of output per se but throughput. The industrial equivalent will have a conveyor belt that can interface with placement machines and basically is pre-configured for pumping out ungodly numbers of pcbs in as little time as possible. You will obviously never do that with the "hobby" units, but for anyone that is not producing pcbs on the scale of thousands per day, it really isn't going to be any different for you.

[@Dr.Bigglesworth]

Do you have any info on how you attached your thermocouples to your test board? Does covering the probe with Kapton tape affect the heating of the metal under the Kapton tape?

[@chrismr3972]

Looking forward to see where you get to. It is possible to change the power using variable voltage PFC drive on each lamp, though it's over the top if you have a simple solution.

[@JerryWalker001]

I was initially going to redesign the 'system' but as this is not my primary reflow oven I wanted to find a solution that anyone could apply with minimal cost and effort. The video currently uploading shows a good step towards this. Let me know what you think.

[@chrismr3972]

@@JerryWalker001 I saw the improvement - nice! Then I wondered how about rotating the baffles, so you get even more heat spreading and move some air at the same time. Of course, it's complicated to make things rotate in a hot environment, but just a thought. Maybe this is part of the reason a conveyor line is so good - each board passes through the same profile even if some heaters are 'off'. I'm interested because I have one and would also like to get it to 'perform' better. I bet there are lots of people in the same boat so well done for tackling it.

[@JerryWalker001]

Chris Mr, You should find the next video very interesting (posted tomorrow). You are absolutely correct that the professional machines have the advantage of moving the boards so do not have the same problems of hot and cold spots because the baords sweep past the heaters. The improvement using just baffels is quite good and probably makes the machine much more useable (I will show some run results). The original goal was a non intrusive upgrade and the baffels possibly acheive that but I was not really satisfied with the results and as I had my machine apart I thought I would try some other things. Most likely many people would be willing to make other changes if the results were worth it (and the cost not too high). I have tried fitting a circulation fan to re-circulate the hot air instead of blowing cold air into the chamber. The results so far are very good (again I will show some results). I have other things to try and one of them is to fit a 'shifter' to the drawer which will simply move the board tray back and forward approx 25mm during the run to simulate a conveyor. I will post results as I proceed so anyone can decide if they want to make the changes based on results. The fan has transformed my machine as you will see in the next video with a temp spread at peak of only 6C and peak times spread by only 2 seconds compared to 40C and 60 seconds in the original configuration and peak within 2C of the set profile temp compared to 20C.

[@dougruisaard8054]

Great set of videos... I assume you're in a bind with all of the COVID issues but I am VERY MUCH looking forward to some sort of "wrap-up" video giving the details of the final fan config, the thermal lamp baffle measurement and the very "mysterious" simulated conveyor system... I suspect it will be some sort of microwave oven-like turn table but I'm very much intrigued. Any idea of WHEN your next youtube on this subject may be available?

[@ubairsofi7568]

My NXP lpc2134 micro controller is faulty. Unable to get the same chip.I found a NXP LPC2138 micro controller ..Can i replace it with the original one?

[@gbowne1]

how about some interal sort of waveguides and a better control... more sensors

[@JerryWalker001]

Todays video shows some improvement. Unfortunately a better controller and more sensors alone will not help much because there is a fundamental issue which I cover in the next video. A better controller may then help although what I am hoping to acheive is a very simple modification that anyone can apply with minimal cost and work.

[@jontscott]

Should be fun, I have a very similar machine to that. My solution was to adjust the top temperature higher until it soldered everything. Bad for the parts and all but it mostly works, should be interesting if you find a better solution!

[@Conservator.]

I’m Dutch and I know nothing about the flicker standard. With that out of the way I have to say that I don’t understand why you shouldn’t be allowed to use PWM provided that you install decent filter as well.

[@JerryWalker001]

Because the standard does not allow it, it makes no difference if you understand it. In the UK (and all harmonized standard countries) the standard applies to any commercial product and a filter would make no difference as it relates to mains voltage stability and Not 'noise'. Having said that I am talking about low frequency switched control and not high frequency control although the standard would still apply if it causes the mains voltage to be 'switched' in such a way that step changes in voltage beyond certain limits are caused. Suggested site to review www.newtons4th.com/electromagnetic-compatibility-iec61000-3-32013-flicker-analysis/

[@Conservator.]

Jerry Walker Hi, Thank you very much! You are absolutely right that it doesn’t matter whether I understand it or not. 😁 I’ve looked at the suggested pages and the standard makes much more sense to me now. It’s to prevent excessive voltage fluctuations mainly caused by appliances with large motors or resistive heating elements. I was thinking about SMPS but they switch at high (>50kHz) frequencies and are off the chart (Pst curve of fig 2). The noise they induce could and should be filtered of course. Using transistors for switching or otherwise regulating the heating elements would probably be too expensive for this oven. More importantly, having watched your other video’s now, regulation isn’t even the issue. I do appreciate your robust methodical approach. Thanks again, Eduard

[@JerryWalker001]

Thanks, Yes absolutely correct and as you see in the later videos the problem turns out to be one of energy distribution rather than temperature control.

[@AmauryJacquot]

you could PWM the 1500 or so Watts, as long as you're doing it with DC...

[@gbowne1]

that looks a lot like a S100 buss board card

[@JerryWalker001]

Its a card from the transistor processor kit. It is identical in width and connector to an S100 but it is 20mm taller.