EEVblog #558 - Beta Layout DIY SMD Thermal Reflow Oven

Dave plays around with converting a toaster oven into a surface mount SMD reflow oven with a beginner kit and controller from Beta Layout.
Includes basic calibration and thermal profiling of the oven.
Also a look at an example PCB from PCB-Pool, and reflow of an example board with lead-free solder paste.
And using an Agilent bluetooth multimeter to remote log the temperature.
Guest appearance by Sagan!

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[codetech]

After watching this, I went to WalMart and got a brand new $22 Hamilton Beach toaster oven, used a SSR, China clone Mini Pro Arduino, a $9 China thermocouple with MAX6675 breakout, and used one of the Arduino PID libraries. A 1602 display fits on the front and shows time and temp, and it's designed to allow you to create your own curves (list of x seconds at y temp, 0=done).
It worked first time, and every time I tested, and as a bonus the wires on the wire rack of the super cheap toaster oven were so thin that they don't seem to be soaking heat away. I even "fixed" (by reflowing) a CAN board that had never worked properly since I got it.
Gotta love when something is this easy!

[JimGriffOne]

At 38:10 the metal underneath is acting as a heatsink. Those three components are directly above it. It's also casting a shadow on the board, preventing as much infra-red from reaching the board at that location.

[CarstenGroen]

"Stevie Wonder can solder 1206" :D
Love your videos and the way you teach all the different stuff Dave !

[EvelienSnel]

Wonderful to see how well the reflowing worked on the 0805s on the left. You could really see them center themselves one after the other. This video was a lot more instructive than a 100% success would have been!

[GerelchuluunB]

Try put gap between that iron bar tray and the board. Do not put the board directly on that bar, that is causing odd temperature, parts on steel bars are not going hot enough to melt the tin. See it from 38:10 (Pause) Please try to understand my poor English. :)

[ultrastoat]

First class video. Really like the close ups. Really interesting to see the reflow wave move from left to right across the board. Great video.

[jgmrequel]

Regarding the stencil, you can trim the right and bottom edges to board size, and work bottom up, right to left, so you never overlap a board with solder applied. Add a bit of a 'tape handle' to one of the trimmed sides to give you the ability to lever it up after application.

[ZlayaCoaka]

FYI: The AC mains and service in the USA are "220" Volts (center-tapped) -- typically 234 Volts; mine is at the moment 241 Volts. SO, us Yanks are actually not SOL.

[DemetryRomanowski]

I used an old conveyor style pizza oven for my SMD reflow, worked a treat!

[KOTR]

It won't help for the top elements, but you can put the crumb tray in the bottom slot (above the heating elements) to avoid there being a hotspot and better distribute the heat from the bottom elements. This will allow you to keep the rack in the same position you have it in the video perhaps.

[Jim-eiiv]

I designed and prototyped a board with about 120 components, including fine pitch ICs, SD card sockets and so on. I learned a few things as I prototyped many versions of this. Oh, I was using a much less expensive controller from SparkFun that worked extremely well and has a digital display to show you what the temp is and where in the profile it is. Cheaper too.

First, older toaster ovens get hotter quicker than brand new ones. An old Black & Decker was about the best I found, so an old toaster oven from a yard sale is better than a new one from your local department store. That said, toaster ovens don't really have enough power to ramp up the heat quickly enough to match the paste profile. They heat too slowly.

Next issue is, they cool too slowly. You really have to manually open the door an inch and close it, watching the temp a you go. The rate of cooling is as important as the rate of heating.

That all said, I was able to get the oven to come pretty close to the paste profile and by manually opening and closing the door I could hit the cooling profile pretty close. The reflow was nice and the boards worked well.

My oven was not a convection oven, but there is a valid concern about how much air those move. You really need to move the air slowly because the parts can in fact be blown off the board easily.

I'm beginning a new project and I think I'll be modifying my oven by adding an additional heating element or two from another oven. At that point I'll need a dedicated 20A power circuit, which is fine. I keep thinking I'll add some motorized vents to control cooling. That would be nifty.

Finally, Dave never showed us how he cured the problem where components didn't reflow if they were sitting on the oven grill (and the grill sinking the heat away). I never encountered that problem, so I have no suggestion to offer. The best trick I learned is wrapping another in the thermocouple to get a read of board temp as opposed to air temp. I like that, so a thumbs up!

[bugs]

I also recommend going with a Black and Decker Oven with the ControLeo2. I'm very pleased with my build.

[CookieManCookies]

When I used to work on reflow ovens, we used klapton heat resistant tape with thermocouples. Typically smaller sized thermocouples give better accuracy, but are higher variation in temperature.

[FantaFuture]

i just discovered this channel and man i love ur passion for this stuff!

[mondotv]

Good work Dave as usual. Small point - that is a convection oven you have there - convection refers to the process of air moving naturally because of heat. Hot air rises so a convection oven is traditionally hotter at the top and cooler at the bottom. An oven with a fan is a fan-forced oven - meaning of course that the fan moves the air around and spreads the heat more evenly.

[gerardcallaghan]

What a pity we didn't get to see the reflow result AFTER the recalibration. Still, a good video; well done Dave.

[msylvain]

Severin is one of the dirt cheap household stuff brands you find in hard discounters, here in old Europa.

[MrJustwatchandlisten]

It is most likely using a standard PID tuning method such as Ziegler-Nichols to learn the best P, I and D values. Most tuning methods involve impulsing (basically turn the system fully on) and getting the frequency response.

[theinsanityunleashed]

I started to sweat when it looked like it wasn't working, glad you noticed the problem. Not sure I'd have much use for one but it looks like it worked pretty well in the end.

[TimeWasted]

Cute junior engineer at 23:03. When will he start doing his own videos Dave ? I really appreciate some of the "fails" you experience as I learn lots more from that than from fully successful tries. Glad you don't edit that out, it is very informative.