Overhauling a 3-Zone Reflow Oven

[Ed] owns a 3-zone reflow oven (which he coincidently uses to manufacture reflow oven controllers), but its performance has gotten worse and worse over time. The speed of the conveyer belt became so inconsistent that most boards run through the oven weren’t completely reflowed. [Ed] decided to rip out the guts of the oven and replace it with an Arduino, solving the belt problem and replacing the oven’s user-unfriendly interface

When [Ed] was looking into his belt speed problem, he discovered that the belt motor was controlled by an adjustable linear regulator with no feedback. Although this seems a bit sketchy by itself, the motor also had some mechanical issues and [Ed] ended up replacing it entirely. After realizing that closed-loop speed control would really help make the oven more consistent, [Ed] decided to overhaul all of the electronics in the oven.

[Ed] wanted to make as little custom hardware as possible, so he started out with an Arduino Mega and some MAX31855’s that measure multiple thermocouples in the oven. The Arduino controls the belt speed and runs PID loops which control heating elements in each of the oven’s 3 zones. The Arduino can be programmed with different profiles (stored in EEPROM) which are made up of 3 zone temperatures and a conveyor speed. Don’t have a 3-zone oven of your own to hack? Check out some DIY reflow oven builds we’ve featured before.

Improving the T-962 Reflow Oven

The T-962A is a very popular reflow oven available through the usual kinda-shady retail channels. It’s pretty cheap, and therefore popular, and the construction actually isn’t abysmal. The controller for this oven is downright terrible, and [wj] has been working on a replacement firmware for the horribly broken one provided with this oven. It’s open source, and the only thing you need to update your oven is a TTL/UART interface.

[WJ] bought his T-962A even after seeing some of the negative reviews that suggested replacing the existing controller and display. This is not in true hacker fashion – there’s already a microcontroller and display on the board.

The new firmware uses the existing hardware and adds a very necessary modification: stock, the oven makes the assumption that the cold-junction of the thermocouples is at 20°C. The controller sits on top of an oven with two TRIACs nearby, so this isn’t the case, making the temperature calibration of the oven slightly terrible.

After poking around the board, [WJ] found an LPC2000-series microcontroller and a spare GPIO pin for a 1-wire temperature sensor. The temperature sensor is placed right next to the terminal block for the thermocouples for proper temperature sensing.

All the details of updating the firmware appear on a wiki, and the only thing required to update the firmware is a serial/USB/UART converter. A much better solution than ripping out the controller and replacing it with a custom one.

Toaster Oven Reflow Controllers

With a lot of people who are suddenly too cool for through hole and of course the a few generations of components that are only available in SMD packages, it’s no surprise the humble toaster oven has become one of the mainstays of electronic prototyping. You’re gonna need a controller to ramp up those temperatures, so here are two that do the job quite nicely.

[Nathan]’s Zallus Oven Controller is a bit different than other reflow controllers we’ve seen on Kickstarter. He’s offering three versions, two with different sized touch screen displays, and one that is controlled with a PC and push buttons. The display for these is beautiful, and of course you can program your own temperature profiles.

If Kickstarter isn’t your thing, [Dirk] created his own reflow controller. Like the Zallus, this has a graphical display, but its homebrew lineage means it should be simpler to maintain. It uses a K-type thermocouple, and unlike every other reflow controller we’ve ever seen, [Dirk] is actually checking the accuracy of his temperature probe.

No, reflow oven controllers aren’t new, and they aren’t very exciting. They are, however, tools to build much cooler stuff, and a great addition to any lab.

Reflow Oven Controller with Graphic LCD

Reflow Controller

A reflow oven is one of the most useful tools you will ever have, and if you haven’t built one yet, now is as good a time as any. [0xPIT’s] Arduino based reflow oven controller with a graphic LCD is one of the nicest reflow controllers we’ve seen.

Having a reflow oven opens up a world of possibilities. All of those impossible to solder surface mount devices are now easier than ever. Built around the Arduino Pro Micro and an Adafruit TFT color LCD, this project is very straight forward. You can either make your own controller PCB, or use [0xPIT’s] design. His design is built around two solid state relays, one for the heating elements and one for the convection fan. “The software uses PID control of the heater and fan output for improved temperature stability.” The project write-up is also on github, so be sure to scroll down and take a look at the README.

All you need to do is build any of the laser cutters and pick and place machines that we have featured over the years, and you too can have a complete surface mount assembly line!

An Open Source Cortex-M0 Halogen Reflow Oven Controller With LCD

reflow oven controller

Homemade reflow ovens are a great inexpensive way to quickly solder multiple prototypes at once. [Andy] may just have built one of the best ones we’ve featured so far on Hackaday. For his project a £25 1300W 12litre halogen oven was chosen because of its low cost and fast heating time, the latter being required to follow typical reflow profile ramp-up stages.

To control the AC power [Andy] first bought a chinese Fotek Solid State Relay (SSR) on ebay, which was quickly replaced by an american one after reading concerning reports on the internet. He then made the same ‘mistake’ by buying the typical MAX6675 thermocouple-to-digital converter from the same website, as he spent much time understanding why the measurements were wrong when the IC was just defective. His final build is based around a 640×360 TFT LCD that he previously reverse engineered, the cortex-M0 STM32F051C8T7, a SPI flash, some power regulators and buttons. The firmware was written in C++ and we’ll let our readers visit [Andy]’s page to see how well  his oven performs.

Reflowing With A Hair Straightener

final

Around here, reflow ovens usually mean a toaster oven, and if you’re exceptionally cool, a thermistor and PID controller. There are, of course, a thousand ways to turn solder paste into a solid connection and [Saar] might have found the cheapest way yet: a hair straightener with a street value of just £15.

We don’t expect the majority of the Hackaday demographic to know much about hair straighteners, but [Saar] has done all the work and came up with a list of what makes a good one. Floating plates are a must to keep the PCB in contact with the heating element at all times, and temperature control is essential. [Saar] ended up with a Remington S3500 Ceramic Straight 230 Hair Straightener, although a trip to any big box store should yield a straightener that would work just as well.

One modification [Saar] added was a strip of Kapton tape to one of the ceramic heating elements. It’s not a replacement for a toaster oven or real reflow oven, but for small boards it works just as well.

Video below.

Continue reading “Reflowing With A Hair Straightener”

A Pair of Toaster Reflow Oven Builds

heater

For some reason or another, the Hackaday tip line sometimes sees a short burst of submissions for the same project. The latest one of these was for toaster oven reflow stations. They’re both great builds and different approaches to making a useful tool out of home appliances.

First up is [Richard]’s build. he ended up with a fairly high-end build using a Rocket Scream Reflow Oven Controller Arduino shield. This shield accepts a normal K-type thermocouple and controls an external solid state relay with the Arduino’s PID library. [Richard]’s build has a few neat additions – a properly dremeled enclosure, computer fan, and a welding blanket for insulation. Now that we think about it, it’s odd we’ve rarely seen any sort of insulation in these reflow oven builds.

Next up is [Ray]’s version of a Black & Decker reflow oven. While not as fancy as [Richard]’s build, this one does have a few features that make it very interesting. Instead of messing around with thermocouples, [Ray] simply took a digital kitchen thermometer – a neat tool that already a thermistor in a compact metal probe – and read the analog value with an Arduino. To control the power, [Ray] is using a cheap 433 MHz radio transmitter to control a few remotely operated power sockets. It’s a very clever and inexpensive replacement for a SSR, especially since [Ray] had these power sockets just lying around.

So there you go. The same tool, built two different ways. A great demonstration of how you can not only build anything, but you can build anything any way you want.