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Topic: technique for neat smd components? (Read 1 time) previous topic - next topic

KirAsh4

Quote
01005 (0402 metric): 0.016 × 0.008 in (0.41 × 0.20 mm) Typical power rating for resistors 1/32 watt
   0201 (0603 metric): 0.024 × 0.012 in (0.61 × 0.30 mm) Typical power rating for resistors 1/20 watt
   0402 (1005 metric): 0.04 × 0.02 in (1.0 × 0.51 mm) Typical power rating for resistors 1/16 watt
   0603 (1608 metric): 0.063 × 0.031 in (1.6 × 0.79 mm) Typical power rating for resistors 1/16 watt
   0805 (2012 metric): 0.08 × 0.05 in (2.0 × 1.3 mm) Typical power rating for resistors 1/10 watt
   1008 (2520 metric): 0.1 × 0.08 in (2.5 × 2.0 mm)
   1206 (3216 metric): 0.126 × 0.063 in (3.2 × 1.6 mm) Typical power rating for resistors 1/8 watt
   1210 (3225 metric): 0.126 × 0.1 in (3.2 × 2.5 mm) Typical power rating for resistors 1/4 watt
   1806 (4516 metric): 0.177 × 0.063 in (4.5 × 1.6 mm)
   1812 (4532 metric): 0.18 × 0.12 in (4.6 × 3.0 mm) Typical power rating for resistors 1/2 watt
   2010 (5025 metric): 0.2 × 0.1 in (5.1 × 2.5 mm) Typical power rating for resistors 1/2 watt
   2512 (6432 metric): 0.25 × 0.12 in (6.3 × 3.0 mm) Typical power rating for resistors 1 watt
   2920 (7450 metric): 0.29 × 0.20 in (7.4 × 5.1 mm)


* source: Wikipedia

I have personally worked with sizes down to 0402, but not smaller.

jfhaugh


I have personally worked with sizes down to 0402, but not smaller.


I've worked down to 0603, but I'm almost 50, wear bifocals, have minor arthritis (do NOT spend decades learning to type ever faster -- it wrecks havoc on the joints.

I've since given up on 0603's until I get someone else to do pick-and-place and reflow soldering.  Which means, when I change the layout from 1206's to 0603's, I'm gonna have a TON of free space!

Osgeld

#17
Feb 24, 2012, 04:20 am Last Edit: Feb 24, 2012, 04:22 am by Osgeld Reason: 1
I can do a 402 by hand (though I really really rather not) and check it under a microscope lol, and I did a few SOT23 6 terminal flip flops today, which is a little bit bigger than a 1008 ... but its got 6 pins
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

jfhaugh


I can do a 402 by hand (though I really really rather not) and check it under a microscope lol, and I did a few SOT23 6 terminal flip flops today, which is a little bit bigger than a 1008 ... but its got 6 pins


I can solder tiny pins.  It's moving around the tiny parts.

For tweezers, I use a pair I picked up at Fry's that have tips sharp enough to kill.  The fine point also seems to prevent heat conduction, so the part and solder get hot, and the heat stays there and doesn't conduct to the tweezers (and make the part cold).

Solder =wants= to fill in any gaps it can find, thanks to the miracle that is surface tension.  Stay away from the coffee and lots of tiny pins shouldn't be too hard.  Though I think I'm gonna buy me a hot air soldering thingy soon.

winner10920

The hot air thing is a substitute for the oven I guess?

jfhaugh


The hot air thing is a substitute for the oven I guess?


Yes and no.  A hot air soldering pen can be used on small areas.  Whereas an oven can't be used on small areas :)

Here's a demo.  Note how huge his finger is and how small the QFN is --

http://www.youtube.com/embed/c_Qt5CtUlqY

Constantin

Correct, hot air systems are great for replacing components or working small sections at a time. But if you have any interest in getting things done quickly, the stencil approach is hard to beat. Plus, there is usually little to no rework after the fact because the solder paste amount is always right (ie no bridges to be removed). I guess it comes down to how much you value your time.

winner10920

I value my money more than my free time lol

KirAsh4

Heh, I used to think that way too, money before free time.  The problem is, I call that penny wise, pound foolish.  At least for me it was.  I used to think I could do it all by hand and save money, but it was taking forever and on parts that small, I was having more misses than hits.  So, I invested in a cheap electric skillet and now I do everything by reflow.  I do still cut my stencils by hand, but most of what I have done so far wasn't too crazy.  The most pads I had to cut were 288 on one PCB, of which 168 of them were 0.5mm pitch.  THAT was fun to cut by hand.  Took about an hour.  But, the reflow of all 20 boards took about 20 minutes.

Now I'm working on a project where there will be several different PCBs and this time I'm just going to get stencils made.  Especially since I have a QFN32 and a MLF32 on one of them.

winner10920

Well that and I don't think my parents would let me get anything like that, they'd kill me if they knew I soldered in the house as often as I do

Constantin


Well that and I don't think my parents would let me get anything like that, they'd kill me if they knew I soldered in the house as often as I do

Why? Fire risk? The only truly dangerous part IMO is the potential for lead and acid fumes to do their thing unless you use a fume hood to collect that stuff.

winner10920

That's the silly part, my parents don't know or understand what I do, all they know is soldering is dangerous apparently and my parents are not very open to debate or learning something new

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