SMD soldering

Other Hardware General Electronics
1

Hi,

I want to create a small PCB using only smd components, smd atmega, smd regulator everything smd, just a simple example to master my skills in smd soldering and making pcb, i had this question for many months maybe years, how exactly to solder smd components and how hard is it.
I've seen many youtube videos and there is many tehnics how to solder smd components but for that it require many different tools (hotgun, oven, solder paste..etc), as a beginner i got only the basic soldering tools.

Any advice as a beginner in smd soldering? I want to master my skills and create more complex
smd PCB's in the future making my projects small as possible as well saving as much as possible space
while creating a device.

D.60

2

Have you seen these?

.

3

Thanks for the links, i skipped the 1st 2 links because I'm not a beginner in soldering but a beginner
in smd soldering, need some advice/tricks. I'm watching the 3rd video now.

4

Do it right. Get a laser cut mylar stencil from pololu.com for applying solder paste.
Get an old 4 element toaster oven (basement or a yard sale) - want 1500 watts.
Get a multimeter with thermocouple probe.
Use the stencil and plastic putty knife to apply paste. Place the parts.
Put in toaster oven, crank heat to 125C, hold there for 90 seconds, crank heat to 195-200C, hold there for 90 seconds, let it cool down. Try a few runs to see where you need to turn your heat dial to for the temps. May have to dial it back & forth a little while holding to keep it near the desired temp.
This solder works well CML Supply
and I haven't seen a better price. I have a 500g tub and I have been refilling my syringes with it.

5

Do it right. Get a laser cut mylar stencil from pololu.com for applying solder paste.
Get an old 4 element toaster oven (basement or a yard sale) - want 1500 watts.
Get a multimeter with thermocouple probe.
Use the stencil and plastic putty knife to apply paste. Place the parts.

I had the same idea but wasting a lot of money ordering each time mylar stencil.
I need to buy solder paste and used small oven and ofc homemade temp. reader :smiley: no need to buy
one when you can build one.

6

For stencils you really want a frame to hold the stencil taut and be able to position the board relative
to it - I built one with strong magnets and a steel base to allow fine adjustment. For fine pitch parts
you cannot tolerate the stencil moving w.r.t. the board at all.

stainless steel stencils are a lot more reliable if you can afford it. They also make great squeegees for
applying paste to another stencil.

Get "no clean" solder paste if you can, and don't be tempted to buy a large amount, it rapidly dries
out once opened, getting less usable over a few months.

7

I'm using a craft-cutter to make mylar stencils at home. You can see more at Peter Monta's site: http://pmonta.com/blog/2012/12/25/smt-stencil-cutting/, or github.

Jimmy

8

I tape my stencils in place when I squeegee the paste on. I don't do any parts with finer pitch than a 328P or a 1284P. Can't apply the paste steadily enough, can't place the parts steadily enough. Repeat thru gritted teeth: "A man's got to know his limitations."

9

http://www.silhouetteamerica.com/shop/machines/portrait
mixographer, do you suppose the smaller sihuouette cutter would work also?
Not many of us making 8x10 SMD PCBs where the bigger machine would be needed.

10

For making just a couple of boards, drag soldering really isn't that bad.....

Tack the parts in place by one pin, no clean gel flux along the other pins, drag solder... it's faster than soldering a DIP with as many pins ime.

11

Does everyone use cut stencils these days ?

For diy i still favour the old silk screen method as they are relatively easy to make myself.

12

@Crossroads, the Silhouette Portrait works great. Most of my boards are under 80x80 mm, so the 8x10 in stencil area is fine.

jimmy

13

Thanks for sharing the youtube video link. This may really help to the beginner in the electronic world.

14

DrAzzy,
Drag soldering is not going to work for me. MrsCrossroads & I usually set up a little assembly line. I prep the cards (clean), make up a little frame to hold one snugly in place (using old cards taped in place as the border), get the stencil taped in place, squeegee on the paste, and hand it to her for parts placement. We'll do 5 or 10 at a time depending on size & number of components. That fills up our toaster oven tray. Walk that downstairs, about a 5 minute cycle for the reflow, have a little snackbreak while the tray cools, then start the next batch. Soldering TQFPs one by one is too time consuming.

Boardburner,
What's "the old silk screen method"? I have been getting laser cut stencils from Pololu, I'm gonna take mixographer or xl97 up on their offer and try a knife cut stencil for the next board I assemble, if that works well maybe pick up a $180 machine, which will pay for itself in about 6 boards.
http://www.silhouetteamerica.com/shop/machines/portrait

15

if that works well maybe pick up a $180 machine,

Or maybe a CNC for $1,800 to go with your 3D printer :wink:

16

Why a CNC? That's not much help in making double sided, via'd, solder-masked, and stenciled boards. Need a board shop for that. I'm plenty happy buying boards from iteadstudio.

17

Why a CNC?

2016-01-28_13-38-53.png
2016-01-28_13-38-53.png506×502 222 KB

To make stencils, you did mention Silhouette

.

18

Yes, Silhouette to make the stencil.

19

Or an expensive CNC (and carbide bits as shown) to make your stencils (amongst other things). :wink:

20

CrossRoads:
DrAzzy,

Boardburner,
What's "the old silk screen method"? I have been getting laser cut stencils from Pololu, I'm gonna take achines/portrait[/url]

Standard silk screen printing with a coarse screen mesh & photo stencil.
Some have experimented with using negative working laminate resist as the stencil material.

I have had no luck though.
Solder keeps lifting off.