joe_prince
Well-known member
Does anyone have a good reflow oven they can recommend? Looking to get one for small quantity, small board size, personal use. Would like to spend no more than $400 (if that's possible).
Does anyone have a good reflow oven they can recommend? Looking to get one for small quantity, small board size, personal use. Would like to spend no more than $400 (if that's possible).
The actual toaster oven I bought was a Hamilton Beach because (A) it had convection fans and (B) it was on sale.
The oven controls are set to 'broil' and 'always on' and the 328 runs a pretty simple cycle of:
1. Oven on till 150C or 3 minutes (preheat)
2. Oven off for 30 seconds (soak)
3. Oven on till 225C or 2 minutes (flow)
4. Oven off till cooled to 200C
5. Beep to signal to open door
6. Beep when temp has dropped to 50C
See here for some pics and a description. Probably cost about $150 in materials and works.
I hear the $285 eBay jobs require modifications to work well.
Efficient 'printer' to bring solder paste onto boards is very useful.
This sounds like it might be the oven potatotron used:
http://www.amazon.com/Hamilton-Beach-31333-Convection-Toaster/dp/B008J8MLHA/
joe_prince said:Thanks for bringing this to my attention. Most of the boards I'm doing are for personal use, so stencils should be fine for now but I'll keep this in mind.
the device ('printer') I'm using is a heavier (stable) plate where you can position a stencil in place by means of two magnets, but in such a way that you can flip the stencil away without smearing the solder mask. I used this for putting solder paste on multiple but identical boards. So the term printer is really a misnamed term, but that is what they call it.
I saw that model as well, but I didn't see the convection fans potatotron was mentioning. It might be an older model that isn't around anymore since it was back in 2012.
There is a kickstarter right now for a PCB printing machine... i.e. put in some bare FRP and then the traces are printed, along with balls of extra solder for device connections. The whole enchilada is then heated from below and voila... finished PCB. If I were to do this again, I would look into redoing the control scheme, i.e. heat primarily from below with short bursts from above for only the critical reflow phase. But I don't have time and the current system works well enough. Also, wonder if the quartz tubes can handle a triac vs. being current limited by using a SCR.
I see one review complaining that the convection fan stopped working, so I think it does.
I'm guessing it's behind that grill on the lower right.
No, it's not prometheus. The fab I'm aware of prints solder paste directly onto FRP vs. milling a copper layer off. OK, found it... it's the voltera, see it on Hackaday. This is not an endorsement, BTW! I have no idea if it works. For example, the prometheus can handle some very tiny spacings/pads, etc. It's unlikely the Voltera can...
I just read through that SparkFun post (good stuff there) and had a few questions about the oven itself. For the burners in the oven, do I need top and bottom burners?
I didn't see many ovens with the fans you're talking about...do you feel that heat distribution would be uniform enough without the fan?
And for the thermocouple, are you using type K as well?
Was thinking about possibly having multiple thermocouples and averaging their values to get a better idea of the heat distribution.
When I started making these a few years ago I did not want another project, I wanted a low cost functioning solution with "some assembly required"
I purchased the Arduino Reflow Oven Controller Shield and paired it with this Panasoic IR Toaster oven.
I actually charted out the reflow curve. The problem with many of these solutions is not necessarily the heating, but the cooling. In order to follow the recommended cooling profile I have to open the door of my toaster oven right after the reflow process is completed. Only then it cools down fast enough. The proper cooling BTW is easily as important as the proper soak and reflow time/curve because it is then when the solder metal(s) re-crystallize. Sounds complicated, but the solution - opening the door - was easy ;-)
I purchased the Arduino Reflow Oven Controller Shield and paired it with this Panasoic IR Toaster oven.
My oven was a $30 black and decker special from Amazon. Two quartz Tubes below, two above. I modded the living daylights out of that thing. I especially recommend reducing the thermal mass of the thing by adding high-temp insulation inside the cavity. That makes it much easier for the control system to actually run the whole process in the 3 minutes it is supposed to.
(DO NOT even think about using house fiberglass!!! The stuff will go exothermic around 475*F since they use sugar as a binder)
The Dual SCR doesn't get very warm thanks to the massive heat sink I fitted the thing with. If I had to do this again, I'd put the lower elements on one SCR, the upper ones on the other. Then re-write the Arduino code to reflect the desired curve, with the heavy lifting being done from below and only the occasional flash from above.
As for cooling, this is something I want to address in a future iteration of my oven. Opening the door (and there are cams out there to do that for you) certainly helps but you want to be cautious initially until the solder has solidified. A member over at Arduino forums mentioned that cooling ceramic capacitors too quickly leads to naughty failures, i.e. invisible cracks that randomnly cause issues.