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Reflow at home


#1

It is time to try it at home for me.

Any advise on a good online source to order stencils?


#2

#3

I have seen them done with milar, cheap. I do not remember the link but they were made for $25 each or something similar.


#4

@ brightidea

Yep, looks like a good one! Thanks.

@ Gus

I think it is Pololu

[em]Laser-Cut Mylar SMT Stencil
Pricing: $25.00 for the first 4 square inches, $1 for each additional square inch. We round each dimension up to the next whole number, so a 2.1″ × 2.1″ design would be considered 9 square inches and cost $30.[/em]


#5

If you can afford it and find a good local supplier, go for a metal stencil.

You will not regret it, they are infinitely better than the plastic types.


#6

@ Architect - What type of oven setup are you planning to use?


#7

Agreed metal stencil is better.


#8

@ brightidea - I am still researching this. Any recommendations?

@ loveelectronics, @ Michael - Do you an online supplier in mind that provide these?

Thank you for your time!


#9

I am going to attempt reflow with a standard infrared oven in a few days. I can’t make any recommendations until then. I am currently in the same boat as you.

I have been researching the topic for quite sometime.


#10

Every time I pass the $25 toaster ovens in the local supermarket I think to myself, “self, you oughta have one of those, it’s cheap, and would be useful and fun to attempt a reflow oven”.


#11

Just dab solder paste on by hand, do it DIY style ! I am assuming you’re doing say under 10 boards at a time, not 100’s, so the cost payoff is pretty low for a stencil (even at $25 mylar). In most cases judicious application of paste from syringe nozzle will be fine. Where this becomes sensible to have a stencil is if this design is long lasting and you might need 100’s of them over the next year say, then you will get value from having the stencil… but you said reflow at home so I reckon give it a whirl and you’ll surprise yourself


#12

That is a very tiny chip (16LD MLPQ 4x4mm) and expensive. Do you think it is doable by hand? I don’t want to ruin it.


#13

its small, yep, but remember on a commercial board your solder mask will wick away the solder between pads (or even a home etched one, really, with the exposed fibreglass board area). See Dave’s episode 346 http://eevblog.org/video/EEVblog346-MLFpasteReflowSoldering-480x270.m4v


#14

Wikipedia says that the package “floating” on the central thermal pad is an issue, but I see no reason why that would be MORE of an issue at home. Just don’t get too excited with the paste under the chip, maybe?

This might be an easier link to the EEVblog: http://www.eevblog.com/2012/09/07/eevblog-346-mlfqfn-smd-reflow-soldering/


#15

Thanks guys! You’ve convinced me. I will try it without the stencil first.


#16

Should I try hot air reflow or oven? I am worried about plastic part - Gadgeteer socket.


#17

SMD sockets are made to be reflowed…you just need to use the correct temperature profile for the type of solder you are using and check to see if any of your components have their own heat profile requirements.


#18

Got it! What is the usual way to check/control temperature with hot air?


#19

Gadgeteer socket - personally, I haven’t tried a hot air reflow of that. When I did my MPR121 ( http://brettpound.wordpress.com/2012/05/25/the-wait-is-over/ )I only did the QFN with hot air, I manually soldered the socket on. When my next batch of PCBs arrive I will try a hot air reflow of that.

But if you’re doing a home reflow (skillet or toaster oven) then I think you could play it cautious, particularly if your toaster has a top element that might come into play - you don’t want your socket resembling toasted cheese open sandwich right ! :wink:


#20

Totally agree with you! :slight_smile: I like different kind of sandwiches.