DIYEFI.org Forum
http://forum.diyefi.org/

My own reflow controller
http://forum.diyefi.org/viewtopic.php?f=37&t=2520
Page 4 of 4

Author:  ivan141 [ Sun Jul 10, 2016 12:42 pm ]
Post subject:  Re: My own reflow controller

PID is not involved at the moment, still running fuzzy logic.
Also note: all ramps except ramp down are rate limited, the oven can go faster.
It also loses temperature faster than your extra-insulated toaster oven.
I have applied light insulation only (aluminum foil and tape), and reduced exposed volume
+ closer proximity to heater by putting the alufoil plated platform in there.

The behaviour of the heater is such, that as long as it is turned on, even at low power,
temps will almost always go up (maybe not at 220 deg C, but you get the picture).
That is the reason why I get on/off behaviour almost everywhere, if I didnt, temps would overshoot.

About the input filtering, still interested in a small schematic of your filter, but it was easier to implement
Kalman into my software than to redesign the board again.

Author:  ivan141 [ Mon Jul 11, 2016 9:16 pm ]
Post subject:  Re: My own reflow controller

Sound the horns! I actually finished a project far enough to see it perform it's intended purpose.

Baked my first VR board this evening, and it went pretty smoothly. I was worried my measured temps would
not be reached with some thermal mass in there, but lo and behold, around 170+ deg C the solder paste had
turned shiny.
Here's some pics of board in various stages of the process.

Paste applied with syringe. It looks much thicker then when it went on, must have spread out some afterwards.
Image

Baked! As you can see there are some solder bridges on the MAX9926 IC (too much paste or perhaps it could use
some added flux for this type of process. Or perhaps a smaller gauge needle, if I can squeeze the paste through it.
Image

Cleaned up with some solder wick:
Image

THT resistors added:
Image

That about wraps it up..
Image
Virtual La Reluctacion!

Author:  Fred [ Tue Jul 12, 2016 6:24 am ]
Post subject:  Re: My own reflow controller

ivan141 wrote:
Paste applied with syringe. It looks much thicker then when it went on, must have spread out some afterwards.

Yes, it'll slump a bit from the shape it comes out, it is just an emulsion after all.

ivan141 wrote:
As you can see there are some solder bridges on the MAX9926 IC (too much paste or perhaps it could use
some added flux for this type of process. Or perhaps a smaller gauge needle, if I can squeeze the paste through it.

If your syringe was easy to squeeze through, it was probably vastly too big. If it's nearly impossible to squeeze through, that's about right. The only real solution here is a stencil. You can get the IC in stencil from proto advantage (or could), do that first, then manually do the other parts that are less sensitive. This is what I did and it worked pretty well.

ivan141 wrote:
Virtual La Reluctacion!

ROFL :-D

Author:  ivan141 [ Tue Jul 12, 2016 7:41 am ]
Post subject:  Re: My own reflow controller

Hmm something wrong with that slogan.. it should be something with variable... but I had a beer to celebrate so I have an excuse :-P

Author:  ivan141 [ Tue Jul 12, 2016 7:49 am ]
Post subject:  Re: My own reflow controller

Not a bad idea for simple boards like these, those single-chip stencils.

Page 4 of 4 All times are UTC [ DST ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/