New ICs are a nightmare

[BobW]

Could someone explain what is meant by "Drag" soldering?

(Do I need a dress, a wig, and false eyelashes?)

 

[Andrei_D12]

I think DerStrom refers to a smd soldering method, where soldering a 40pin or more ic is done by applying solder on all pins, then he drags the hot iron over all the pins, and the solder sticks to the pins, without creating bridges, because the excess remains on the tip. It's just an idea.

 

[KeepItSimpleStupid]

Could someone explain what is meant by "Drag" soldering?

(Do I need a dress, a wig, and false eyelashes?)

My experience is primarily with 63/37 solder with lead. the non-ROHS stuff. 63/37 has an identical solidus and liquidus temperature so it melts and solidify very suddenly.
My very first SMT removal/replace was a CPU. The pins were cut. the chip removed. The pads cleaned up. then the corners were tacked.

My friend suggested to have the pins face the floor and put the device above my head and drag the soldering iron across the pins.

It worked well. Bridges are very easy to remove using 63/37. Impossible when using 60/40 solder.

The hobbyist accepted technique is the stencil where solder paste is applied using a squeege, Parts placed and a toaster oven is used to set the parts.

There are lots of variations. BGA (Ball Grid Array) being a nearly impossible package to work with.

You just can't solder parts using an iron when all of the pads are under the IC.

 

[Andrei_D12]

If the BGA package is so much used, I can imagine what's next: after 30 years, the whole motherboard of a computer will be built on a large silicon chip and the other boards will be the same. Only capaciors and other big components will be separately...

 

[KeepItSimpleStupid]

Embedding components BETWEEN the layers can be done now.

Maybe the BIG components will be 3D printed?

 

[Andrei_D12]

3d printing generaly requires using the same material. However, it may be possible.
Today we are creating circuits with ICs. In the future, I imagine that the whole circuit will fit into a small PERSONALISED integrated circuit, instead of assemblying the circuit with separate components. Ok, I am talking about the industry's future, not about the hobbyist' future.

 

[MrAl]

Could someone explain what is meant by "Drag" soldering?

(Do I need a dress, a wig, and false eyelashes?)

Hi,

Ha ha. It's called "drag soldering" not "soldering in drag" ha ha ha

Another technique is similar, where you drag the iron across all the pins but letting the gaps between pins fill up with solder too so you end up with a solder bridge between all the pins on that side. Then, using solder wick, run the wick over the pins with the solder iron tip keeping the wick hot and that picks up all the excess solder thus removing the bridges. I have not tried this technique yet though, but have seen videos on the web. The wick has to be kept hot so it can absorb the extra solder.

 

[Andrei_D12]

Example of beautifully soldered QFPs and others.

 

[Andrei_D12]

Ah,I forgot. HAPPY WOMAN'S DAY!!!!(if there are women)

 

[granddad]

Andrei . interesting video, but lots of expensive stuff there for a hobbyist who just needs to get a chip on a board occasionally. I have had good results , with a standard 12W iron, .5mm tip, 22swg 40/60 solder , flux pen and solder mop , My last attack was on a 100 pin TQFP .4 mm , PIC24.
https://www.electro-tech-online.com/threads/diy-pic24fj1024gb610-breakout-board.147203/

 

[Andrei_D12]

I understand that John Gammel uses expensive tools, however, it's the technique that matters. In the video he showed some good ways of soldeing TQFP and SOIC. I am sure this can be done without that expensive soldering station. What I like the most in the video is the bevel tip he used. A flat contact surface means more heat transfered to the part being soldered, and if more heat is transfered, the lower is the soldering time.In my opinion, this makes a tip so eficient. While experimenting, I have seen that the best joints are created by using very fine solder, because you can control precisely the amount of solder for that joint. Too much is not good. Too little, you know... But a moderate amount is the best. Also fine solder melts faster than the thick solder. Ok, I don't mean I am a Jedi at soldering, but I tried these tricks and my joints were pretty nice on matrix board (one of the best ways of prototyping).

 

[djsfantasi]

I was surprised when I went to duplicate a circuit from almost two years ago - and couldn't find the in stock TH ICs I used on Digikey. Nothing exotic, just some CMOS logic gates, like a 4081 or 4082.

 

[schmitt trigger]

The problem is, as my eyesight becomes weaker and my pulse less steady, the components are becoming smaller and smaller.

Something that is also a must is a good bench magnifying glass, with an illuminator.
By good, I mean good optics. Some of the ebay offerings distort the image.

Something like this, is also very useful for inspecting your final work:

https://www.amazon.com/XCSOURCE-Mic...qid=1457446792&sr=8-4&keywords=usb+microscope

 

[MrAl]

Hi,

grandad:
I dont see any expensive stuff there, just a soldering iron with a chisel tip. But congrats on your 100 pin'er success! If you had a video that would be nice too.

All:
I used the technique shown in that video where the solder paste is placed across all pins at once, then soldered later.

I cant recommend using that one technique though, where he paints the tip with solder, then applies that to all dry pins. That's not a recommended technique in any kind of soldering and i am surprised to see it in that video. The common name for that is "lift and carry" which refers to that fact that the solder is placed on the tip first and then later carried to the job site (pins or leads). This is because the solder 'cooks' before it gets to the pin, and that's not good. At the very least, there should be flux on the pins first.

 

[Andrei_D12]

Indeed, that technique is a waste of solder.He said that he melts solder on the tip in order to protect it from corosion, then he removes the excess with the sponge, all that remains is a thin layer of solder.


The last soldering sequence is not right, however,the joints were beautiful. Quite weird.

 

[throbscottle]

drag soldering: https://www.instructables.com/id/How-to-Solder-SMD-ICs-the-easy-way/
a novel way of dealing with chips with a heatsink pad underneath: https://www.instructables.com/id/Soldering-underneath-chips/

 

[granddad]

I dont see any expensive stuff there, just a soldering iron with a chisel tip

Hakko FM-203 That's got to be >$500 ? my iron was < 20 GBP ..

 

[MrAl]

Hakko FM-203 That's got to be >$500 ? my iron was < 20 GBP ..

Hi,

Ohhhh, wowwww, sorry, i must have missed that

My whole soldering station cost just $80 if i remember right, and came with hot air gun plus temperature controlled iron. China of course but hey it works so i use it Soldering iron is over rated in the advertisement, but it's not too bad i guess. Works for this small stuff.

I find the 63/37 solder to work very well, and if you get a bridge, just press the small iron tip between the two pins and drag it away, in a direction parallel to the pins (which means away from the chip itself). That drags the excess solder away. I saw that on the web and it worked.

 

[mvs sarma]

I had bought few LMX2322 that has a special package
i was never able to manage to solder them.here is the package details
https://htmlimg2.alldatasheet.com/htmldatasheet/198776/NSC/LMX2322/774/13/LMX2322.png

 

[mvs sarma]

i had CSP package for National semi LMX2322. I could never use them as soldering was just impossible at home, as the pins are

underneath the chip and inaccessible.