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Topic: SMD soldering ... (Read 2 times) previous topic - next topic

eddiea6987

Oct 01, 2011, 04:20 pm Last Edit: Oct 01, 2011, 04:22 pm by eddiea6987 Reason: 1
anyone know of any cheap IC that come in a LQFP package or something of similar pitch / spacing , i just need to practice soldering  something  in that range for a project but i do not want to damage the actual chip i am going to use because its not cheap...
and most suppliers do have filters but first you have to indicate what your looking for and then further down the line the package type... so i do not know what comes in such a package and still be cheap enough to burn the helll out of.
here is a link to LQFP package outlines... and an image


any tips on shaking??? i shake a lot when soldering its probably my nerves, i figure ill load up on sugar to stop the shaking :/
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

RuggedCircuits

Here's one for $0.90:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=544-2717-ND

I can't think of anything cheaper.

--
The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected

madworm

#2
Oct 01, 2011, 08:40 pm Last Edit: Oct 01, 2011, 08:47 pm by madworm Reason: 1
If you open up your computer, you'll find a PCB with lots of those chips  ]:)

Regarding steady hands: if the size of your soldering iron allows it, make sure you hand rests on something comfy. Maybe some sort of rice-filled pillow.

Regarding LQFP: this stuff is easy. You don't have to do it pin-by-pin. Just get a good quality paste flux (EDSYN FL-22 is good, will last quite a while so the price isn't really that bad) and don't worry about it. Got a bridge? Clean your tip, add flux and wipe it away (maybe use braid as well).

But you're right to practice and build up confidence.
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Osgeld

using an old dead board with a similar package chip is a good way to start without spending money, this lets you get a feel for how you want to do things, and how to correct bridges
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

eddiea6987

yeah i have to get a feel for it and learn some do's and dont's, i made a pcb design with two smd caps and the pads where horizontal  like this - -  and i placed 2 of those caps extremely close together -- --  and well once i had one cap fully soldered on then the other ones was impossible to solder because i had no room to squeeze my tip in there , i also need to stock up on varying tips.
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

Udo Klein

There are lots of SMD soldering tutorials on the internet. You need to decide if you go for a solder paste + oven approach or if you want to solder by hand.

If you solder by hand: flux is your friend. Buy a flux pen.
Check out my experiments http://blog.blinkenlight.net

madworm

AND paste flux, at least if you'll do more than just 1 chip per year. The liquid flux evaporates far too quickly for relaxed smd jobs.
• Upload doesn't work? Do a loop-back test.
• There's absolutely NO excuse for not having an ISP!
• Your AVR needs a brain surgery? Use the online FUSE calculator.
My projects: RGB LED matrix, RGB LED ring, various ATtiny gadgets...
• Microsoft is not the answer. It is the question, and the answer is NO!

Graynomad

You can get a hot-air rework station for $120, they make it real easy.

Also go to your local computer shop, they'll have dead mother boards you can practice on.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

eddiea6987

yeah i am getting a hot air rework station in the next week or two , and i have seen plenty of videos it does not seem all that challenging but just a matter of technique and practice , flux , desoldering wick , a good lamp or loupe and im goood to go .
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

Boz

I ran into the cap issue early on also, the best answer if you arent ready to go into full reflow oven or air, is to get a cheap 20 dollar(us) electric skillet, I got mine at target.

Do solder paste on the surface mounts that you dont want to or cant do due to positioning, heat the skillet place the board close to the element ring and watch for the reflow to take place, usually in a minute or two kill heat, wait a minute remove board, then continue on with any hand soldering you have to do.

I place all my components this way, and leave the chips, like ftdi chips, and connectors and things for hand soldering.

I could do the chips this way also, but I dont use stencils for the board, just not there yet, and fine pitch can get too much paste, causing more bridges then if I use the flux paste and hand solder method for them.

So I have a sort of two step SMD process but as they say it works for me, and it was a cheap entry level answer to the challenge.

eddiea6987

I already did some small smd soldering with some boards i got from CrossRoads that use the 328p-Au , and  i wish i had a camera because those babies came out implacable, or very close to. I was ever so proud. Now i have to order some SM  resistors and leds , im thinking about 0805 sizes since they are on the realist side of humanly possible, at least  for me .
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

CrossRoads

I am stil trying to get rid of short between power/gnd on the first board I assembled. I think it is behind pins 3-4-5-6, can't get it to wick out.
Gonna try hot air station one of these nights, take the chip off & start over I think.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

madworm

Yes 0805 and larger are quite nice to handle without wearing magnifier glasses.

For my last project I felt pushed to go down to 0603 for the resistors that are scattered around an ATtiny2313. The LEDs are 0805, the capacitors are 0805 and 1206.



I'm still able to do it (but barely) without a magnifier, but that will probably change in a few years. I'll probably get me one of those 'head-mounted' magnifiers pretty soon and keep on dreaming of a microscope with top illumination.

Some time ago I ordered a couple of 0402 LEDs just to "see" how tiny they really are and I basically see that I don't see them... They're the size of tiny salt crystals. Totally unusable for me.
• Upload doesn't work? Do a loop-back test.
• There's absolutely NO excuse for not having an ISP!
• Your AVR needs a brain surgery? Use the online FUSE calculator.
My projects: RGB LED matrix, RGB LED ring, various ATtiny gadgets...
• Microsoft is not the answer. It is the question, and the answer is NO!

Msquare


I'm still able to do it (but barely) without a magnifier, but that will probably change in a few years.


any tips on shaking??? i shake a lot when soldering its probably my nerves, i figure ill load up on sugar to stop the shaking :/
Oh, you both have so much to look forward to in comming years  ]:)
A good beer (just one) is better than sugar.

eddiea6987

Quote
A good beer (just one) is better than sugar.


is that after every joint?  ]:D
I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"

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