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Electronics => Beginners => Topic started by: Gala on August 17, 2015, 10:32:22 am

Title: Heat gun PWM control for SMD soldering
Post by: Gala on August 17, 2015, 10:32:22 am
So i plan on buying a cheap automotive heat gun and hacking it up to PWM the heater and the fan to control them, along with a LCD with a thermocouple sensor to show temperature. I've designed this simple circuit:

(http://i.imgur.com/LaMqkYB.png)


And i just wanted some feedback. Is it ok? Can it be improved? The ACX and GATEX to go STMicroelectronics 600V 40A TRIAC's.
Title: Re: Heat gun PWM control for SMD soldering
Post by: singapol on August 17, 2015, 10:47:52 am
Why go to all this trouble when you can buy a cheap hotair station like 858 but make sure the voltage is compatible to your country. Please don't say you want to experiment and learn.

http://www.amazon.com/Kohree%C2%AE-Digital-Rework-Station-Solder/dp/B00ITMPQS2/ref=pd_sim_sbs_469_2/175-3140822-1778067?ie=UTF8&refRID=1FKYDS3W6S77RYQFCXV7 (http://www.amazon.com/Kohree%C2%AE-Digital-Rework-Station-Solder/dp/B00ITMPQS2/ref=pd_sim_sbs_469_2/175-3140822-1778067?ie=UTF8&refRID=1FKYDS3W6S77RYQFCXV7)

Dave has a video on it.
Title: Re: Heat gun PWM control for SMD soldering
Post by: Gala on August 17, 2015, 10:53:05 am
Cost. The heat gun is 20 bucks and i have all the parts at my school, free :)
Title: Re: Heat gun PWM control for SMD soldering
Post by: GreyWoolfe on August 17, 2015, 11:32:35 am
What is truly the fascination about lowest cost.  You may very well end up with something almost but not quite good enough and that will be frustrating.  Look here:
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1312.R1.TR7.TRC2.A0.H0.Xyihua.TRS1&_nkw=yihua+858&_sacat=0 (http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1312.R1.TR7.TRC2.A0.H0.Xyihua.TRS1&_nkw=yihua+858&_sacat=0)

and it works quite well.  I have one and am happy with it.  And, as a side note, it is actually designed to do what you want it to.
Title: Re: Heat gun PWM control for SMD soldering
Post by: singapol on August 17, 2015, 04:54:51 pm
Cost. The heat gun is 20 bucks and i have all the parts at my school, free :)

Can you imagine holding a heat gun and trying to desolder a sot23 transistor or a smd resistor or cap? The nozzle is too big and more of surrounding components get heated up. 858 comes with 3
different sized nozzles for better heat distribution.It also has a magnetic switch which cuts off power when it is rested on it's cradle. Right tool for the right job as they say.And you look more pro using it... :D
Title: Re: Heat gun PWM control for SMD soldering
Post by: xenocide702 on August 17, 2015, 05:55:02 pm
Ordinarily I'd agree with the OP and say screw it, roll your own. You'll definitely learn a lot, regardless of how the project turns out. Even if it doesn't end up in a hot air station, that board could be very useful in other projects.

That said, I'd strongly encourage you to just buy a hot air station, if only for the nozzle adapters. Even the cheap knock offs are usually pretty decent. We're only talking 20 bucks difference, and your heat gun wouldn't come close to the fit and finish of even the worst knock off.
Title: Re: Heat gun PWM control for SMD soldering
Post by: wraper on August 17, 2015, 06:05:26 pm
You will blow off most of the parts from PCB with that thing. Also, without temperature control it will be pretty useless anyway. You'll end up burning the parts and PCBs.