Colecago’s Blog » Arduino, Ben Heck, Tools

Ben Heck Reflow Oven

Many months ago I worked on a reflow oven at Ben Heck’s shop over a couple of weekends.  It worked out pretty well and he included it in an episode

I used a toaster oven, two thermocouples and readers, one of Ben’s homemade Arduino boards, an LCD screen, and a solid state relay.

Many of the parts can be found from the distributor Newark http://www.newark.com/ or http://canada.newark.com/

SSR –  http://www.newark.com/opto-22/240d10/ssr-panel-mount-280vac-32vdc-10a/dp/96F1061
Thermocouple reader –  http://www.adafruit.com/products/269
Thermocouples  – http://www.omega.com/pptst/5TC.html
Arduino – http://www.newark.com/arduino/a000073/dev-brd-atmega328-arduino-uno/dp/63W3545
LCD – http://www.newark.com/powertip/pc1602ars-cwa-a-q/display-alphanumeric-16-x-2/dp/05M0978

For the toaster oven, look at rummage sales or resale stores. The dumber the interface the easier it is to take over with a solid state relay instead, and you definitely want a top and bottom element for more even circuit board heating. I’ve heard of issues with reflow ovens with only one.

For modifying the profiles-

int profile[4][6] = {
{
75,140,45,125,205,20 }
,
{
75,140,45,125,205,20 }
,
{
75,140,45,125,205,20 }
,
{
75,140,45,125,205,20 }
};
String profileNames[4] = {
“Ol’ Fashioned Pb”, “New Fangled RoHS”, “Profile 3 “, “Profile 4 ”
};

The format of the profiles is:

{Ramp 1 0-255, 1st target temp, hold seconds at 1st target, Ramp 2, 2nd target temp, hold seconds at 2nd target}

Ramp rate is kind of a misnomer, its just the analog write value but because our relay is a zero cross and we aren’t accounting for the cross, it doesn’t exactly work as good as a PWM value would.

 

The ROHS profile definitely needs changing, probably a 220 target. Your results may vary but you will definitely have to tweak for your own oven and possibly it could change depending on your board as well.

 

Attached at the end of the post is the code.  For more discussion on the project or for links to Ben’s wooden cut panel, go to the thread on the Element14 forums

http://www.element14.com/community/docs/DOC-65496/l/episode-116-bens-home-brew-solder-reflow-oven-20-episode

 

Arduino code:

Reflow Oven Code

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