Manual soldering of TQFP 100 pin chips

[BlackOps]

Hello im going to use PIC32, with 100 pin TQFP package, pitch = 0.4mm

any tips on soldering such a chip?

i saw a lot of videos online..the one which i liked most of all was like that:

they put solder on the pins...melt it...and while melting move it along the pins...and solder melts directly on the pins, without shorting them...

do u think that would be fine?

and i have a 25W simple RadioShack soldering iron... would that be possible to do it with that?

thanks!

 

[karesz]

Hi,
No, it would practically not function!
You need a fine solder iron, maybe at 0.3-0.4mm on the tip and a good flux & PLANAR PCB!!
If you have experience in "typical" soldering, you have chance with good solder tip/very good flux and FEINST TINN (i.e. 0.3mm in diameter!)-or better solder paste & heath gun, but it (booth) needs experience!...
K.

 

[BlackOps]

ok which soldering iron would u guys recommend for TQFP soldering?

i saw many ones online...but kinda dont know whats better to choose?

take a look please at this tip... its 0.3mm
https://www.alliedelec.com/search/productdetail.aspx?SKU=8730043#tab=Specs

but the thing is i dont know to which soldering iron would that tip fit? Cuz that company seems not to produce soldering irons...

any ideas?

 

[FvM]

Individual soldering of pins is one option. I prefer a 0.2 mm tip for this purpose, which is available from most
manufacturers. Unfortunately I don't know, what's in your reach.

Some manufacturers are proving a "micro well" with a concave tip. Ersa has invented it about 10 years ago, others followed.
It's a larger tip with a solder reservoir and works with a lot of flux applied to the part. I guess, that's what you mean with "moving
the solder along the pins". In my opinion, it works quite good, after removing the flux (not absoltely necessary), the solder joints
look like reflow processed. But it's mainly a matter of taste. I notice, that the prototype producing staff mostly prefers
individual pin soldering.

Personally I prefer hot plate soldering with solder paste, either applied through a stencil or a dispenser. With a dispenser, you can
hardly avoid to apply surplus solder paste on fine pads. For prototyping, it's most easy to remove it with desoldering wick after reflow.

Assuming you have only a (relative) coarse tip and thick solder wire, it should be still possible to solder a 0.4mm pitch part. By
applying sufficient flux, you have a good chance to get only few initial shorts, and you can remove them with a good quality
desoldering wick.

 

[pranam77]

Manual Soldering of SMD devices requires practical skills with experience. You may see than manual soldering Video on this link.

 

[BlackOps]

pranam77: i never soldered TQFP chips (used to do regular soldering alot though), but even i notice that the video link u show is horrible... it is very bad technique and i wonder is that chip working after such a soldering.

FvM, thanks alot for reply, could you please tell me the exact Model/Name of your soldering iron with which u are using 0.2mm tip?

if anyone else would share which Model of Soldering iron he uses i would appreciate it!

i really searched alot but cannot find any soldering iron for which i could separately buy 0.2mm tip!! any suggestions?

 

[IanP]

My 0.02 is this: realistically speaking it can’t be done manually, and it is not designed to be done that way ..
Try to get the same (or similar) chip in a different housing that, although not specifically designed to be handled manually, can be handled manually ..

After all, 0.2mm tip has practically no heat capacity to do anything ..

Rgds,
IanP

PS. Don’t think I’m always that sceptical about things ..

 

[BlackOps]

IanP...but people are doing it with 0.2mm as i see...how come? and there is no another package...and TQFP is not so bad... its just ME personally never did that... but many people succeed with this... that is why i want to know the soldering Iron they are using with 0.2mm tip...


oh one more quick question is it really easier/possible to solder 100pin TQFP with HEAT GUN?

what you think?

 

[pranam77]

pranam77: i never soldered TQFP chips (used to do regular soldering alot though), but even i notice that the video link u show is horrible... it is very bad technique and i wonder is that chip working after such a soldering.?

It may be a bad technique but as i have mentioned in my last post, its skilly job to work with. And too you need to ground the Soldering IRON tip before soldering such delicate IC's. Practically speaking I can do the said job and i can prove the IC will work fine. Anyways, soldering the said device with Hot air Gun will be the perfect prociedure.

if anyone else would share which Model of Soldering iron he uses i would appreciate it!?

All micro soldering irons shown on **broken link removed** page, have very fine, needle sharp tips to work with smd components. I am using it since more than 6-7 years.

 

[karesz]

...After all, 0.2mm tip has practically no heat capacity to do anything ...

I cannot agree!
Good, I have self only 03 mm tip from JBC, on the hand piece of 50W, https://www.jbctools.com heath capacity is a very firm depend value!
As I wrote in a similar topic here, With JBC stations, 0.3mm tips, and 0.3mm tins & GOOD flux its realistic_clear these isnt a holiday job, but in small quantities is to make!...
I have my third such solder station in the past teen years at all my 3 firms one-or more, and in allday usage...
K.

 

[BlackOps]

Ok im stil researching adn deciding about this...

and now, it seems to me that soldering with hot air gun would be actually easier! isnt it?

now...the thing is these hot air guns are pretty expencive, but i found some of these:
CSI899A+, CSI825A+

anyone knows anything about these hot air soldering stations? Do u think its worth it to pay around 150$ to get something like that?

 

[karesz]

Hi Azeri,
Den-On`SC-7000Z,http://www.denondic.co.jp/en/, is a good vacuum desolderer, you can switch it to hot air gun_maybe its OK, exactly I have a coworker-hes formerly firm did applyed it_he told me it was true good as hot gun too.
It costs in EU ca. € 400, but you can find surly similars from China /HongKong...
A good hot air gun is surly a practical tool for soldering-desoldering finpitch ICs, but you must learn to work with: need some practice, as so much things too...
I have in the firm that, I used it up to day only as desolderer: I like it...
K.

 

[electronicus]

Look the video demonstration : https://www.youtube.com/watch?v=vZ1qisX52rI&feature=related

 

[karesz]

Salute Electronicus,
Tnx_good video.
I makes very similar too, but with the same,horisontal holded,(fein) tip_needs more practicum, but only one tip.
The videos double tip methode is clear better, but you buys the special tip for that._that is life...
K.

 

[TA37]

That was a great video. Not sure what other posters are complaining about with damaging the part and using a fine tip. Damage occurs with too much heat applied, which won't happen if you are steady with the larger tip and don't hold it down forever.

Also, note that with the proper pad cleaning (and pre tinning) and with proper use of liquid flux, bridging should not be a problem. The solder will want to wet to the individual pads and pins. If you don't use enough flux, or get too much gunk on your tip, a solder bridge is easy enough to remove (see follow-on video https://www.youtube.com/watch?v=eg2hxpy--gg&NR=1 )

Always use a clean tip, enough flux, and a clean and tinned board. Always clean the board afterward too. "No clean" flux does not live up to its name. And practice.

 

[VSMVDD]

buy a cheep kada unit like the rest of us
or use ir

or you can use an old toaster from the kitchen

there is some video on utube how to 'blank out' area's on the elements
and also re wrap them
to avoid issues or chip die over heat

liquid flux dress the area and heat it first
you can apply solder paste also to inrush the pads with a good amount of wetting

heatshield chip dies using old cut up sanding wheels
i find they are good when cut to a small block and disapate even like a space shuttle heatshield
you get a box of 1000 cheep as chips

and saves the chip center from overheating under harsh air etc ir flow...too pin

i use a kada 852 and i have 50 nozzles so far in my collection
and i got spare parts while there there and cheep
{can supply links via pm }

i also have a reflow table i/r from ebay... good for any ic with tweezers and a steady hand

the kada also comes with .2mm iron tip
you can get a pak of 10 tips for it on ebay for e10 inc post to eu

.1 to 10mm
variour types

and use an eye loop
**broken link removed**

 

[Rob B]

I don't have any pictures to illustrate but I have removed (with hot-air) and refitted *many* small-pitch surface mount devices including TSOP48 and QFP208 packages with just a basic iron.

I found the best method to be that of what I call subtractive soldering (you remove the solder you don't want).

I ensure the part and pads are clean and then align the part manually. Pushing it into place with tweezers or other fine tools (now is a good time to check the orientation!).

I then carefully place a blob of solder in one or two places around the device to secure it (only touch the pins with the solder ball, not the iron tip!). I then apply a larger amount of solder and draw it along the edge of the component (shorting pins as mentioned in a reply above, it doesn't matter if you clean it up well).

Keep the solder wetted by adding a little more, with practice you can draw the bead of solder to one corner leaving the majority of the pins correctly and neatly soldered.

Remove the rest of the solder using desolder wick (braid), apply a little flux if the solder is de-wetted. you can remove small solder-bridges by touching the tip of your iron to the ends of the component leads. I find it worthwile to reheat all of the pins by tapping the ends (the toe) of the legs with the iron tip.

I have tried this with many different types of iron and wick etc. Unless you have a solder stencil this is the easiest method. Reflowing a component on with hot air usually requires rework with an iron.

It takes practice to do this efficiently, at first you may find it difficult to leave a good ammount of solder on the pins and pads (correct fillet).

I think the Hitachi/Renesas SH3 is the largest IC I have fitted like this .

 

[BlackOps]

i have the Hot-air soldering station now... i tried reinstall few chips... it was ok for practice... now im planning to install PIC32 on some board... but the thing is... i cant find what is the maximum allowable temperature for soldering TQFP100 PIC32 ? any ideas?

 

[karesz]

Hi,
try to general "family specs of TQF xxxyyyy" of microchip_if dont exist/find from some other firm.
Usually you must not need more as 250/300Celsius in 10-15 second, but to chek it by a target firm is better...
K.

 

[BlackOps]

ok, thanks, i did find it... now the question is like that: With my hot air-gun i have a few rounded tips of different radius..

So, do i have to place PIC32 and point air gun with short radius tip along its pins around the chip OR should i choose a bigger radius tip and point it to the center of the chip?

which strategy u think is better? (i have succesfully resoldered some chips on old boards...but before beginning it with PIC32 want to make sure im doing fine)