Do not buy ebay IR reflow ovens. (T-962 etc.) - Page 1
Forum section: electronics / general

author: Larry80
author_rank: Contributor
timestamp: July 18, 2019, 09:22:41 pm
content: Hi all,I just want to prevent anybody else from buying these garbage ovens, which are based on infrared heat and cost less than 1000$ on ebay. They seem to be some sort of kickstarter abortion gone wrong, copied and sold with fictional utility. Its sad that the form factor is quite robust and good for tabletop imaginative use, but that's about it. The only thing they are useful is to preheat the board material for manual heat-gun soldering afterwards.Tried to modify it heavily, different sensor placements, board placements etc. etc. but the infrared has inherent built in problem, which is unsolvable. It does not heat the air much, but the components and/or the base material. Ironically the reflective solder pads will absorb the least infrared, so the utility is inverted. The result varies from one place to the next and mostly the center of board will overheat (and all the ICs definitely). The edges stay reliably underheated, plus some chaotic factors too. Not good for even crudest prototyping, forget it.It can barely be used at all for leaded solders, but lead-free is impossible as the temperature ranges are much tighter. I get better results in kitchen oven using eyeball and nose as the thermistor.On another note,does anybody have any recommendations for relatively compact, very small production runs on smallish SMT boards? Does not have to be cheap, but i don't want to dedicate my shop floor to belt-fed reflow line so size is of the essence.

author: thm_w
author_rank: Super Contributor
timestamp: July 18, 2019, 09:56:22 pm
content: https://hackaday.com/2014/11/27/improving-the-t-962-reflow-oven/https://www.eevblog.com/forum/manufacture/current-state-of-the-art-in-budget-home-reflow/(see Keans post)https://www.eevblog.com/forum/manufacture/practical-diy-or-modest-cost-vapor-phase-does-it-exist-yet/

author: Larry80
author_rank: Contributor
timestamp: July 18, 2019, 10:10:16 pm
content: Toaster oven seems to be popular, it is very strange that this obvious reflow style is absent as a ready made product.Seems like only solution is to start hacking some ovens! I was also thinking about hot-plate method, i have flat aluminium slabs from 5-60mm thickness readily available and induction heating. That would create some super tight temperature profiles, is the only downside dangerous heated surface and no 2-sided SMT placements?

author: Peabody
author_rank: Super Contributor
timestamp: July 18, 2019, 10:44:24 pm
content: For boards with all the components on one side, a hot plate may be the answer. Here's a super-simple, super-cheap device I made for hobbyist use:For production you would probably need something more capable, but I think there are Ebay hot plates for $120 or so that might work very well. No IR issues with a hot plate.

author: thm_w
author_rank: Super Contributor
timestamp: July 18, 2019, 10:53:12 pm
content: Quote from: Larry80 on July 18, 2019, 10:10:16 pmYeah most people just sell the controller and expect you to buy the toaster oven, otherwise you move up to a few k for an "industrial sized" toaster oven.Downside of a hot plate is as you've said, and cool down is much slower from the large aluminum slab (which may or may not be an issue).Induction heating could work, but not many people here have tried (I recall someone doing induction and vapor phase?):https://www.eevblog.com/forum/reviews/_induction_-hot-plates-with-_digital-readout_-cheap-ok-for-reflow/The one issue is usually for a plug in induction cooktop, its usually not a simple on-off control: you have to plug it in, set power, then turn on, etc. So your control system would have to be more complicated than a SSR or relay like the toaster ovens. You also need to probe the slab temperature.

author: Larry80
author_rank: Contributor
timestamp: July 19, 2019, 06:41:01 am
content: Thanks for the tips, had not thought about the cooldown problem and inductions inherent electronic protections, saved me from another headache... Hot-plate without induction would require to move the liquid-phase board for cooldown, which might not be a good idea.Seems like there are tabletop ovens with integrated fans, combined with Controleo3 (https://www.whizoo.com/) this could be a workable solution. It has the software functions for baking parts too.Based on a small research, you need belt driven multi-segmented oven to truly approach the recommended reflow profiles, otherwise any convection oven will do..2k$ would not be that bad a deal, if it really works (therefore has to have belt) and size is compact. Seems like this feature combination is not available though, such a small market.

author: asmi
author_rank: Super Contributor
timestamp: July 19, 2019, 01:48:54 pm
content: LOL. These are just a couple of boards I made in my trusty T-962:Both of those were assembled using lead-free paste. The only parts that ever overheated were Molex connectors - so I just use connectors from other brands (they don't have that problem). I do use community firmware and made some HW modifications as per instructions for that firmware. And for every new board design I do a "dry run" with thermocouple attached to a blank board and tune up the profile a bit as required. It's a small price to pay for great results from $200 oven. Would I want a true convection oven instead of my T-962? Sure! But they start atten timesthe price of T-962! Nope - that's not for me.Oh - and toaster ovens are even worse - they are IR too, but in addition require heavy modifications to bring them to the level of T-962 and at the end of the day will likely cost more.So until someone shows me a convection oven for a reasonable money, I'm sticking to my oven. Currently working on a board with big 676 ball BGA which costs as much as my ovenWill see how that goes.

author: Larry80
author_rank: Contributor
timestamp: July 19, 2019, 03:39:16 pm
content: Typical oven does work by convection. The grill heater works in IR and is visible. Normal heaters are behind the wall and best of them have even internal airflow. 200$ is quite a lot for device, that you need to totally gut and pray to get it working well. I know that any convection oven works quite well without any modifications, was just lured into thinking there were good ready solutions for this particular task available.I tried to calibrate with thermocouples to the board, but all constants have to be controller or it does not replicate. Ie. how heated the interior is from previous runs, how long the tubes stay lit at various phases, at what angle/position the board might end up in etc. Any of those change and the result can be random.This is just the nature of IR. Sensors measure the air and the board is baking in varying IR light, absorbing at various levels on each surface millimeter. By design even best case, edges do stay cooler as they are not surrounded by absorbing material on all sides. Possibly on good equipment the IR is uniform and seems like the boards on them require jigs for repeated placement.By looking at your design it seems to have low component count on it. This might improve the results, because more absorbing material is exposed (metal pads are not absorbing practically anything). I had metal cased board directly connected on mainboard and it did not solder at all, presumably because of the reflecting enclosure, just one of the natural infrared shortcomings.

author: asmi
author_rank: Super Contributor
timestamp: July 19, 2019, 04:07:31 pm
content: Quote from: Larry80 on July 19, 2019, 03:39:16 pmCan you show some examples of convection ovens that work out of box and are comparable in price to T-962? All modifications took just a couple of hours to implement for me, so not a big deal at all since this is a one time affair.Quote from: Larry80 on July 19, 2019, 03:39:16 pmWell it works for me, so I must be doing something right... I only do pre-tuning for critical boards with BGAs and stuff, for simpler boards with cheaper parts I don't bother, and again, results were very good.Quote from: Larry80 on July 19, 2019, 03:39:16 pmEach of those board have 200+ components on both sides, so I wouldn't say it's a "low count". Among them are big BGAs with full grids, and since they reflowed just fine, I can only conclude that air got hot enough for lead-free solder balls to melt, while the rest wasn't too hot at the same time since it still works. I also have several metal-shell connectors (HDMI, USB 3 micro) on those boards, and these reflowed as well despite your claim that they are "not absorbing practically anything" (which is demonstrably false as you can see).Like I said, I use community firmware which among other things spins the fan slowly during ramp up and thus provides some air circulation, which could be why my results are eons better than your claims of what they should be.I will need a larger oven soon, so I'm on the lookout at the moment. And so far the T-962A is very high on my shortlist because of my positive experience with the smaller one that I've been using. But if you know anything better I would love to hear about those options!

author: MT
author_rank: Super Contributor
timestamp: July 20, 2019, 01:52:42 am
content: SMT Toaster oven! I'll have to try that one!http://www.electricstuff.co.uk/smtoast.html

author: IanJ
author_rank: Unknown
timestamp: July 20, 2019, 08:09:02 am
content: I have been using a T-962A from EBay for a couple of years now and have put through a few hundred boards, sometimes just 1 board at a time, sometimes filling the entire tray all with zero problems. My hints/tips to get there as follows.1. Ditch the stock control board for one fromhttps://www.estechnical.co.uk/products/reflow-oven-controllers, I did this from day 1 without even powering up the stock T-962A. The new board comes as part of a kit of parts to add/replace.2. Spend some time to adjust/tweak the profile for your setup.......then leave it alone.Ian.

author: mrpackethead
author_rank: Super Contributor
timestamp: July 20, 2019, 08:47:42 am
content: Having great results with the Vapour Phase Frying pan. Another coupel of weeks, and we might have some thing to show off.

author: Neganur
author_rank: Unknown
timestamp: July 20, 2019, 11:50:42 am
content: EDIT: soldI have a reflow oven surplus to my needs if you want, it comes with a controller from the German company Beta Layout:https://de.beta-layout.com/elektronik-shop/reflow-loeten/10703-reflow-kit-v3-basic/Controller:reflow controller V3 PROOven:Severin TO 2045Dave reviewed the cheaper version of the controller120 EUR for both, can deliver in person if you're in the greater Helsinki area

author: arvidj
author_rank: Contributor
timestamp: July 20, 2019, 12:43:40 pm
content: Quote from: asmi on July 19, 2019, 04:07:31 pmasmi,Care to share what community software and changes you have made to be successful?Thanks,Arvid

author: asmi
author_rank: Super Contributor
timestamp: July 20, 2019, 05:30:35 pm
content: Quote from: arvidj on July 20, 2019, 12:43:40 pmThe firmware was taken from here:https://github.com/UnifiedEngineering/T-962-improvements/wikiAs for HW modifications - I honestly can't remember them all now as it was like 3 years ago, but I remember I was following someone's video on YT. I couldn't find the exact video I was following after a quick search, but there are plenty of others. Also some mods (like system fan control, or cold junction compensation) are described in the firmware's wiki.One thing I noticed is just how many idiots out there on YT put boards right on a drawer, run a profile and then immediately proceed to complain about it not working without even thinking for a minute why! It never crossed their mind that the metal drawer is a huuuuuge heatsink that's going to soak up a TON of heat off your PCB! But if you raise the board above the drawer (I use standoffs made from small M3 screws, or just some old PCBs as spacers if the board I'm reflowing doesn't have mounting holes), the results improve dramatically!

author: GerardG
author_rank: Regular Contributor
timestamp: July 22, 2019, 07:12:50 am
content: Hello,Drawer type ovens and home made toaster ovens will work for some boards. Per design they have a hotspot on the board.I prefer a conveyor reflow oven like the Neoden IN6. Conveyor ovens will give a more uniform heating of the PCB.Best regards,Gerard

author: CoolNamesAllTaken
author_rank: Contributor
timestamp: July 30, 2019, 08:02:18 pm
content: I have modified a T-962A and have also built a Controleo3 kit--the Controleo3 knocks the T-962A out of the park, even with the thermocouple mod and Unified Engineering firmware on the T-962A. For a few bucks more, the Controleo3 provides much better temperature control, non-IR heating (components heat evenly), and much less hassle overall (reflow profiles worked great out of the box--I had to build a custom profile for the T-962A because it wasn't able to heat up fast enough to match the stock Unified Engineering profiles).

author: Larry80
author_rank: Contributor
timestamp: August 03, 2019, 06:18:32 pm
content: I got now a basic toaster oven with controller, insulated it all around (quite easy if you have correct wool for the job), works like a charm. These cheap toaster ovens have partial IR effect as the heaters are visible, but they do not even get to glowing. More expensive household oven with air circulation could probably work out of the box (combined with controller of course).By tampering with the heating profiles, this setup gets to very repeatable profiles. Door has to be opened when the reflow is done, but otherwise its automated and reliable. Best is to pre-heat for a long duration (80C), to get everything stable and repeat for the 175C soak step. They take much longer than the recommendations, otherwise profiles will overshoot dramatically, but i consider those 2 step timings to be for maximum throughput only. After letting everything stabilize in 175C, the jump to 245C can be plateaued reasonably fast.

author: JohnG
author_rank: Frequent Contributor
timestamp: August 17, 2019, 02:18:45 pm
content: Another vote for the Controleo. I had version 2 and moved to version 3 when it came out. I do mostly prototyping work and rework, but I have probably run a couple hundred boards through it with no issues, including 2-3 reflows on boards for staged assembly and/or repair.John