uC based reflow oven controller

Have a good idea for a new product for SFE or Olimex? Let us know!

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JimmyM
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Post by JimmyM » Tue Mar 24, 2009 1:41 pm

Really? 5 minutes? I've never seen that recommendation before.
Right now I ramp from 25C to 150C in about 1 minute.
I read about the lower pre-heat temperature to slow down the flux out-gassing (exploding), but 85C? Hmmm.
So you want the flux dry by the time the reflow portion of the cycle begins? I thought heating for too long burned off the flux activators.
Oh well. Can't hurt to try it on a test board.
So what would your parameters be?

ramp to 85C and hold for 5 minutes.
ramp to 150C for X seconds?
ramp to 220C and hold for Y seconds?

funnynypd
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Post by funnynypd » Tue Mar 24, 2009 2:14 pm

So you want the flux dry by the time the reflow portion of the cycle begins? I thought heating for too long burned off the flux activators.
It actually just dry the solutions (some water too, if the board stay in the air for too long or the environment humility is high) not the activators.

You can try some of the profile like these:
85C for 3~5 minutes,
100~110C for 2 minutes,
180C for 2 minutes,
220~230CC for 1 minutes,
Cool down for 5 minutes.

Temperature is oven and PCB size dependent, you can always try some different settings.

funnynypd
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Post by funnynypd » Tue Mar 24, 2009 2:18 pm

Right now I ramp from 25C to 150C in about 1 minute.
If the temp rise too quickly, it will burst and make a mess (the tiny solder balls will be everywhere just as you observed). So slow down the pre-heat phase may help solve the beading issue.

funnynypd
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Post by funnynypd » Tue Mar 24, 2009 2:20 pm

It also depends on the power rate of the heating element, oven size, Heat capacity of the whole oven, location of the hearing elements, etc.

JimmyM
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Post by JimmyM » Tue Mar 24, 2009 7:19 pm

My oven is a convection oven. About 0.9 Cu Ft. 2600W. So the heating is pretty even. but the temperatire of the circulating air can ramp pretty quickly. I can impose a ramp rate instead if just letting the elements heat the oven as fast as possible between steps.
The elements are 4 on top, 4 on bottom. All equally driven.

This is becoming very interesting with respect to the effect of ramp rate and paste melt result.

funnynypd
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Post by funnynypd » Tue Mar 24, 2009 9:49 pm

You got a powerful oven, so try to slow down the pre-heat curve and make sure there is no temperature over-shot into the reflow zone during the pre-heat period.

No temperature over-shot on your powerful oven is also important to prevent creating a mess due to solder paste burst.

corvette123
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Post by corvette123 » Wed Mar 25, 2009 10:31 am

hahaha this is the longest running thread in sparkfun history i think :D :D

yah Jim's oven is the oven that ate miami!!!
www.TheSiliconhorizon.com

reflow controllers, Xbee pic platform, PLC, UAV controllers.

corvette123
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Post by corvette123 » Fri May 01, 2009 4:38 pm

well for those of you wanting the new reflow controller,

its coming in abuot 2-3 weeks! (assuming the pcb's test out ok,... but they should i went over it like 3 times...)

its will be hardware version 3.0



lots of new features....


some last minute options in addition to the ones we posted:

-pcb will be done on high temp Tg=170 deg C
-optional high temp terminal blocks at order time (getting max temp of them from company....)
-normal term blocks rated to 100 deg C
-or order without term blocks...

small 1.5" x 1.5" reflow oven controller!

very excited to have this new version coming out!!

will drop a line when its out.

we will be redoing the software also, adding new features. until the software update, it will have the same great features as before and as always the open source code.

thanks

:)
www.TheSiliconhorizon.com

reflow controllers, Xbee pic platform, PLC, UAV controllers.

electron68
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Location: Boston, MA

Looking for a programmed PIC for the Reflow Toaster

Post by electron68 » Mon May 04, 2009 9:22 pm

Is there anyone here who'd like to sell me a pre-programmed 16F88 for the SparkFun Reflow Toaster? I'm not a PIC guy, so I'm not set up to do the programming myself. I tried the low-end Olimex dev board route, but something in my software/OS/serial port/cable/programmer lashup isn't right, and I'm exasperated enough that I'd rather spend some money than try to debug something that I'm not likely to use again.

Of course, it'd be even better if SparkFun included a programmed chip, or sold them separately, hint, hint.

Send me a PM if you want to help me out. Thanks!

corvette123
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Post by corvette123 » Tue May 05, 2009 6:39 pm

programming it is easy!

go on ebay and buy an ICD 2 clone and it comes with a DIP socket to slap the chip into if there isnt an ICSP header on the board...

cost: $35-40 bucks for the programmer.

then you will be able to program all pics with ICSP and DIPs just by slapping it in the socket.

look for the auction that comes with the socket programming board addon free of charge.
www.TheSiliconhorizon.com

reflow controllers, Xbee pic platform, PLC, UAV controllers.

Chr1s
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Post by Chr1s » Fri May 08, 2009 3:36 am

Those in Europe, who can't be bothered with making their own kit, may be interested in the following link:

http://www.reflow-kit.de/rkuk/index.html

Then again, it appears to use a low-cost convection oven (Severin TO2020 - not infra-red), and the controller doesn't look as useful as the one from Silicon Horizon.
It saves a bit of effort, at a cost, but I don't know how good the solder joints would be. IR toaster ovens don't seem to be available in Europe.

I have a controller all set up, using the Silicon Horizon board, waiting for my Infrawave oven. (I bought one on eBay in March, but it has disappeared in the postal system, with no tracking number - so after that was refunded I am now waiting for its replacement to be delivered, this time with a tracking number).

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leon_heller
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Post by leon_heller » Fri May 08, 2009 3:46 am

I bought a small IR toaster oven from Argos here in the UK - £19.99. it worked OK when I tested it with some solder paste on a scrap piece of PCB material. I was intending to make a controller for it, and got a suitable thermocouple, but haven't got round to it.

Leon
Leon Heller
G1HSM

corvette123
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Post by corvette123 » Fri May 08, 2009 5:36 am

reflow 3.0 pcb's are due back around may 18th...

so assuming they are not coasters :) then well be selling it a few days after!!

:D :D :D
www.TheSiliconhorizon.com

reflow controllers, Xbee pic platform, PLC, UAV controllers.

corvette123
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Post by corvette123 » Fri May 08, 2009 5:42 am

hey leon i see your using the DDS chip from analog...

did you know u can do ramps from them? yep. you do it by using 2 DDS chips. one feeds the phase of the other a square wave. then the 2nd one puts out the ramp.

pretty cool chips....

just letting u kow so you can make a "complete" signal generator hahahha.

that way youll have sin,square,ramp,triangle, everything.
in addition to FSK and PSK.

not a bad chip.

im using them in a design right now for a 400mhz to 3.5 ghz transmitter.
www.TheSiliconhorizon.com

reflow controllers, Xbee pic platform, PLC, UAV controllers.

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leon_heller
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Post by leon_heller » Fri May 08, 2009 5:47 am

I built a sine signal generator with one many years ago, when they first came out, it was useful for testing filters. I used one in a simple DC receiver controlled by my PC, as well.

Both my Yaesu transceivers have a DDS, as part of the PLL synthesiser.

Leon
Leon Heller
G1HSM

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