Author Topic: what do you use for reflow on quick, one off circuits? Space is at a premium.  (Read 7428 times)

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Offline cdevTopic starter

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 I kind of want to get some little electric skillet or similar for very fast one off PCbs just heat it up until it melts and then let it cool down. I have a little heatable thermometer which can go on it, it doesnt need to have a thermostat, adjustable heat would be nice.
"What the large print giveth, the small print taketh away."
 

Offline Falcon69

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I built a Reflow oven from a quad element $35 Black and Decker Toaster Oven.

All you need is a Thermocouple, PID, Relay, Heatsink, and a couple switches.  You can also get a data logger too for your laptop so you can see the Curve of the proper heating for the solder you are using.

I have a write up on the one I built over on the CNC Zone Forums.

http://www.cnczone.com/forums/general-cnc-machine-related-electronics/175422-manufacturing-software.html

I even have a wiring schematic there as well for it.

It works pretty good!
 

Offline radix

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I seriously need to try this once.
 

Offline chicken

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Here's my cheapskate stove top reflow rig:
- 1/4" aluminum slab
- 2 aluminum backing trays
- thermocouple

Heat aluminum slab to 160C - gently, it should be stable at 160C or only slowly increasing.
Add tray with PCB and temp probe inside, cover with 2nd tray, wait till PCB reaches 160C
Wait another minute or so, then turn up the heat to max.
Wait till PCB reaches 220, then take tray off the stove (don't bump it or you'll get SMD salad).
Let it sit to cool down, season to taste.

Propably not compatible with SWMBO  ::)
 

Offline Fat

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Rocketscream reflow board, I ordered the PCB and built it up. I think I'm abut $30 into the board and parts, salvage the K type temp sensor, and got a $6 SRS.  attached it to a homebrewed arduino uno and run it all to a $18 toaster oven.  Works great. Breaks down into components to store on my equipment shelf. it takes less than 5 minutes to set it all up.
 

Offline cdevTopic starter

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SRS = solid state relay? 

Actually, the oven sounds good.. I have an oster convection oven I can use, then I can make larger boards and get even heat. Just need to decide on the controller
"What the large print giveth, the small print taketh away."
 

Offline f5r5e5d

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if you're dealing with high pin count fine pitch or bga digital then reflow may be needed - but hand soldering is an option for many boards

even fine pitch can be flood and mop hand soldered if you are really talking just prototyping http://store.curiousinventor.com/guides/Surface_Mount_Soldering/QFP/

I wouldn't go below 0805 on passives

optics - magnifiers and bright lights make a world of difference
« Last Edit: March 30, 2015, 04:06:36 am by f5r5e5d »
 

Offline miguelvp

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SRS = solid state relay? 

Actually, the oven sounds good.. I have an oster convection oven I can use, then I can make larger boards and get even heat. Just need to decide on the controller

Just don't use it for food anymore
 

Offline nctnico

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I use a soldering iron with tips in several sizes and/or hot air. I just can't see the benefit of messing with stencils, solder paste and an oven. With a soldering iron and hot air I can also build & test a circuit in steps.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Fat

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SRS = solid state relay? 

Actually, the oven sounds good.. I have an oster convection oven I can use, then I can make larger boards and get even heat. Just need to decide on the controller

Yes, SSR=Solid State Relay.

I've read some accounts where people have just adjusted the oven manually to fit a profile, but building out the RocketScream board and doing some automation on it is part of the fun of my projects.

One thing to consider is that the stock RocketScream profile is set for lead free solder.  I modified mine to lower the temps and shorten the soak times for leaded solder. 

That little oven has been remarkable.

Fat
 

Offline Fat

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SRS = solid state relay? 

Actually, the oven sounds good.. I have an oster convection oven I can use, then I can make larger boards and get even heat. Just need to decide on the controller

Just don't use it for food anymore

Agreed. My kids have a tough enough life without being born with three eyes and no thumbs.

Fat
 

Offline Fat

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I use a soldering iron with tips in several sizes and/or hot air. I just can't see the benefit of messing with stencils, solder paste and an oven. With a soldering iron and hot air I can also build & test a circuit in steps.

It can be done.  We did hot air on the original two RocketScream boards we put together. It took us about 5 hours to put two together (drop solder, drop one part, reflow with hot air station, then move on, this time included the manual soldering of the not SMT components and headers).  I had a third board left over.  I place all the solder drops with a syringe, set the components, reflowed in the oven and then did the manual components and headers in less than 40 minutes.  I would have been faster if I had all the components organized. The time savings for me is significant.

Fat
 

Offline nctnico

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I don't use hot air for small components; I use the iron for that ofcourse. Just tack one side with solder and solder the components on one side. When a lot of components are done, solder the other sides. This works very quick. I only use hot air for really big components (like soldering a TO220 to a board).
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline georges80

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For single sided boards or ones with most of the components on one side, I often use a temp controller hot plate. Lots of them on Ebay (search for Fisher Scientific Isotemp), they seem to be more expensive now versus a couple of years ago. They come up to temp quickly and are quite stable once at temp.

Obviously you don't need the models with the stirrer :)

cheers,
george.
 

Online tggzzz

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I've documented my experiences here: https://entertaininghacks.wordpress.com/2015/03/25/assembling-pcbs-with-surface-mount-components/

"This outlines how I placed solder paste, placed components, saw small components, soldered and reworked small PCBs. I didn’t want to be constrained by the time it takes to apply solder paste, position components, and reflow in the HackSpace oven, so I looked for ways I could do the whole process at home. Summary: it does work and isn’t too painful. Naturally I’m evolving methods and techniques as my skill improves."
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online tggzzz

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I wouldn't go below 0805 on passives

Why not? I haven't had problems with 0603, yet.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline nctnico

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IMHO 0603 is doable by hand if you have good eye sight (or good glasses). Smaller parts are trickier to do.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 


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