Author Topic: SMD Soldering Practice Boards  (Read 41882 times)

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Offline akis

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Re: SMD Soldering Practice Boards
« Reply #50 on: May 18, 2015, 09:57:22 pm »
Maybe use watch maker's tweezers which are guaranteed to be non magnetic.
 

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Re: SMD Soldering Practice Boards
« Reply #51 on: May 18, 2015, 10:13:12 pm »
Gentle baking required? Add chocolate icing when cool.  :-DD

Hold on ... I'm taking another picture. I think I discovered a new physics property.

Stand by -

 :wtf:
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Re: SMD Soldering Practice Boards
« Reply #52 on: May 18, 2015, 10:25:41 pm »
Behold - Magnetic wood.

I cut the end off a flat toothpick about the same size as the chip, and it sticks to the same part of the tweezers!

What the hell is going on?  :wtf:

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Offline pickle9000

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Re: SMD Soldering Practice Boards
« Reply #53 on: May 18, 2015, 10:32:43 pm »
Rosin on tweezers.
 

Offline Mr.B

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Re: SMD Soldering Practice Boards
« Reply #54 on: May 18, 2015, 10:47:17 pm »
Static?
I approach the thinking of all of my posts using AI in the first instance. (Awkward Irregularity)
 

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Re: SMD Soldering Practice Boards
« Reply #55 on: May 18, 2015, 11:06:23 pm »
Static?

Only on one side?  :-//

Rosin on tweezers.

pickle9000 -  I think you must be right, but it's hard to believe. I've cleaned and even filed the tips of the tweezers, it's hard to imagine any rosin is left, but I'm going to work on it with several other chemicals.
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Offline miguelvp

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Re: SMD Soldering Practice Boards
« Reply #56 on: May 18, 2015, 11:14:51 pm »
The rosin could be on the resistor and transfered back to the tweezers after cleaning.

 

Offline nanofrog

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Re: SMD Soldering Practice Boards
« Reply #57 on: May 19, 2015, 12:28:52 am »
If I understand it correctly to work with SMD you'd need

1) Properly fabricated PCBs so forget about making at home
2) Very very clean environment and pure white in colour so you can spot them little pieces
3) hot air machine and good quality soldering iron with special tip (shovel shaped)
4) PCB holder
5) Stereo microscope with long stem or head goggles
6) Flux and solder and braid something or other

Have I missed anything?
1. Nice but not necessary. Besides stripboard mentioned by rolycat, there are also SMD to DIP adapter boards for different package types. There are even some designed just for passives. Once soldered up, you can then insert them into a bread board or use solder to connect them as needed. It's also possible to dead bug with SMD's and some wire as well.

2. Good lighting is highly recommended (if not necessary, depending on eyesight), but clean, meh. Just enough of a spot to work on is all that's genuinely required.  >:D

3. Hot air is nice, but you can solder most packages just with an iron and appropriate tip, which in most cases, is a properly sized chisel/screwdriver shape for the pad. Drag tips have their place, as do the "shovel" types if I'm thinking of the same shape you are (rarely needed actually; meant for soldering a lot of pins simultaneously).

4. In most cases (i.e. single side), you don't actually need a PCB holder, as it will lay flat on your work surface. They do make working with components on both sides of a board far easier though.

5. Depends on the size packages you're working with and your eyesight. Magnifying head visor will be nice to use with larger packages for example, but may not be necessary. There will be a point however, that you will need magnification, and that will extend to a microscope if the package is small enough (say 0402 & smaller).

6. You'll want to use quality consumables, whether it be for SMD or thru-hole (solder, flux, and desolder braid/wick). Brands such as Multicore, Kester, Alpha (Cookson), AIM (American Iron & Metals), Indium, MG Chemicals (best wick/braid I've ever used), ITW/Techspray, and Stannol. There are some quality Japanese brands, but given the heavy counterfeiting, I'd just skip them. Simplest way to avoid getting garbage is to buy from distributors (eBay can be really risky IME).

As per flux, I'd recommend at least RMA, but RA would be better for a hobbyist IMHO, as it can work with both new and old work (heavy oxidation). In particular, MG Chemicals Rosin 835 is available in small bottles (hobbyist friendly sizes of 100ml & 1L). I believe Stannol does as well. Some prefer tacky/gel flux for drag soldering (doesn't spread as much as liquid). MG Chemicals 8341-10ml for example. Chipquik is another popular brand.

FWIW, I find no-clean formulations are harder to clean than rosin based flux as a general rule (purely synthetic; some is actually rosin or rosin based, which is easier, so read the datasheet if possible). I also opt for liquid in bottles as it's a lot less expensive than the disposable pens (you can dispense it with needle bottles, refillable felt or brush pens, or just dip an artist brush for example).

Gotta have some good tweezers to handle the parts too.
+1  :-+

Although the very specific shapes have their place, you can do a LOT with a couple of pair (say a #5 & #7 pattern in SA material, which is anti-magnetic & anti-acid). So look for 5SA (or 5.SA/5-SA) for example on the tweezers itself. Watchmakers tend to use models designated by an S which is magnetic and vulnerable to acids (these also tend to just have a number without any letter designation stamped or etched into the tweezers).  ;)

I'd suggest Pakistani made as a minimum if you can. Swiss is best, followed by Italian, Pakistani, and finally Chinese IME (there's also tweezers from Japan, Taiwan, and India). If money is really tight for example, VETUS is about the best of the Chinese brands from what I understand.

Given what I'm seeing for UK prices though, Swiss can be had for ~10GBP or less (8.66GBP for each pair linked) at Farnell under their Duratool brand  :o (5-SA & 7-SA). BTW, these particular Duratool pairs are rebranded Ideal-Tek, which is as good as it gets IME (example of their 5-SA). Same exact pair, but at more than 2x the cost. BTW, Ideal-Tek ODM's the tweezers for Lindstrom and Belzer for example.

Sorting through all of the Duratool tweezers (P/N's that start with D00* = Swiss made), they have a DURATOOL  D00349  TWEEZER SET, SA, 5PCS kit for 35.57GBP.  :o  So that makes these Duratool pairs one hell of a deal right now.  :-+
« Last Edit: May 19, 2015, 12:31:50 am by nanofrog »
 

Offline akis

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Re: SMD Soldering Practice Boards
« Reply #58 on: May 19, 2015, 06:53:20 am »
Say I have a home made PCB I have just etched. Do I apply the rosin "http://uk.farnell.com/multicore-loctite/pc21a/flux-pc21a-5l/dp/1115472"  over the whole PCB and wait 10 mins to dry? Or do I only apply it as I go along?

Currently I have been using SK10 on my PCBs. I let them dry overnight, http://www.rapidonline.com/tools-equipment/kontakt-chemie-flux-sk10-spray-200ml-87-0715 - is this more or less the same?
 

Offline tautech

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Re: SMD Soldering Practice Boards
« Reply #59 on: May 19, 2015, 07:59:13 am »
Say I have a home made PCB I have just etched. Do I apply the rosin "http://uk.farnell.com/multicore-loctite/pc21a/flux-pc21a-5l/dp/1115472"  over the whole PCB and wait 10 mins to dry? Or do I only apply it as I go along?

Currently I have been using SK10 on my PCBs. I let them dry overnight, http://www.rapidonline.com/tools-equipment/kontakt-chemie-flux-sk10-spray-200ml-87-0715 - is this more or less the same?
I'd just go with what you're using and flux core leaded solder.
This stuff is fine for me:
http://www.jaycar.co.nz/Service-Aids/Chemical-Aids/Aerosols/Circuit-Board-Lacquer-Spray-Can/p/NA1002
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Offline rolycat

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Re: SMD Soldering Practice Boards
« Reply #60 on: May 19, 2015, 11:26:25 am »
Given what I'm seeing for UK prices though, Swiss can be had for ~10GBP or less (8.66GBP for each pair linked) at Farnell under their Duratool brand  :o (5-SA & 7-SA). BTW, these particular Duratool pairs are rebranded Ideal-Tek, which is as good as it gets IME (example of their 5-SA). Same exact pair, but at more than 2x the cost. BTW, Ideal-Tek ODM's the tweezers for Lindstrom and Belzer for example.

Sorting through all of the Duratool tweezers (P/N's that start with D00* = Swiss made), they have a DURATOOL  D00349  TWEEZER SET, SA, 5PCS kit for 35.57GBP.  :o  So that makes these Duratool pairs one hell of a deal right now.  :-+

Very nice find.

One thing that is often worth checking with kit from Farnell is whether their sister company CPC have it cheaper.

This is the case with these tweezers. The 5-SA and 7-SA can be had for £6 each, and the 5-piece set is only £28.45.

As with the Farnell prices, these are all ex VAT.

CPC also have free postage on all orders at the moment.
 

Offline GreyWoolfe

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Re: SMD Soldering Practice Boards
« Reply #61 on: May 19, 2015, 11:36:54 am »
Nanofrog states-I'd suggest Pakistani made as a minimum if you can. Swiss is best, followed by Italian, Pakistani, and finally Chinese IME (there's also tweezers from Japan, Taiwan, and India). If money is really tight for example, VETUS is about the best of the Chinese brands from what I understand.

I have a couple of the VETUS tweezers and I have been able to hold 0402 resistors to a practice board for soldering without any problem.  I got them for less than $6 USD each off of the internet.
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Re: SMD Soldering Practice Boards
« Reply #62 on: May 19, 2015, 12:30:17 pm »
I worked on the tweezers some more with 600 grit sandpaper, and they are working a lot better. Must be flux wicking up onto the metal. Hard to believe it's that hard to remove. Somebody refresh my memory - what's supposed to be a good flux remover?

Working on the 2nd board. The connections are OK but I still want to put too much solder on the tack pad. The second joint I usually do OK. It just looks so good when you are flowing solder it's hard to hold back.  :)

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Offline nanofrog

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Re: SMD Soldering Practice Boards
« Reply #63 on: May 19, 2015, 12:40:55 pm »
Very nice find.

One thing that is often worth checking with kit from Farnell is whether their sister company CPC have it cheaper.

This is the case with these tweezers. The 5-SA and 7-SA can be had for £6 each, and the 5-piece set is only £28.45.

As with the Farnell prices, these are all ex VAT.

CPC also have free postage on all orders at the moment.
Wasn't aware of CPC, so even better.  :-+

To make things easier, here's the search results for Duratool D003*;)

I have a couple of the VETUS tweezers and I have been able to hold 0402 resistors to a practice board for soldering without any problem.  I got them for less than $6 USD each off of the internet.
You can get Pakistani for around $6 if you're willing to hunt.  :-//

FWIW, there's a clearance sale going on here in the US on a number of styles as well at Newark. Even those still at regular prices aren't horrible. Oddly enough, I also checked MCM, and it seems they're not even listed.

I worked on the tweezers some more with 600 grit sandpaper, and they are working a lot better. Must be flux wicking up onto the metal. Hard to believe it's that hard to remove. Somebody refresh my memory - what's supposed to be a good flux remover?
Alcohol (isopropyl, ethanol, methanol, or denatured work well and are inexpensive). If it's particularly stubborn, you can also use or add acetone or xylene (i.e. a 80% alcohol + 20% xylene makes for a good flux cleaner for more stubborn deposits but won't soften/melt plastics or take inks). Be careful with acetone as it's even more aggressive (i.e. can soften/melt plastics and take the silk screen legend markings off).

FWIW, denatured alcohol, acetone, and xylene can be found in paint departments. The Kleen Strip brand from Home Depot does well IME for example (their denatured alcohol is a 50/50 mix of ethanol and methanol).
 

Offline technix

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Re: SMD Soldering Practice Boards
« Reply #64 on: May 19, 2015, 05:37:06 pm »
Tidy work is all part of a dancing act, will a few key things needed to do a good job.

CLEAN tip
Leaded solder
Tweezers
Magnification. Depends on how old your eyes are, dual lense heatset is all I need
Temp control.

Too finer tip can be a curse as it won't hold enough solder.
Needle tips are hard to use for other than very fine work when there is little thermal mass.
Chisel or hoof styles seem to be the most popular.

For SMD passives, I just wet a pad with solder, hold the device in place and re-heat, then solder the other pad. Too much solder on the tip or added will leave balling like yours, a concave fillet is whats required.
If it looks ugly, get the sucker out and do a pad again.

I'd add you job looks nice and clean.

Okay I am dancing extra hard here:

* 0603 size is my standard go-to size
* Old through-hole era 35W iron, NO temperature control
* RoHS solder (tin-silver type)
* Almost no tolerance on board (was intended to reflow but stencil got too expensive)
* No magnification, bare eyes only (I do have 20/20 vision)
 

Offline tautech

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Re: SMD Soldering Practice Boards
« Reply #65 on: May 19, 2015, 08:31:33 pm »
Working on the 2nd board. The connections are OK but I still want to put too much solder on the tack pad. The second joint I usually do OK. It just looks so good when you are flowing solder it's hard to hold back.  :)
Just a light tinning of the tack pad is generally enough., hold the passive down and reheat that pad.
OR different technique: load tip, place and hold component, touch conponent terminal and pad together while watching for fillet to form or solder to wick across the joint.

Be prepared to cleanup any pad with a sucker.
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Offline tautech

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Re: SMD Soldering Practice Boards
« Reply #66 on: May 19, 2015, 08:40:41 pm »
Tidy work is all part of a dancing act, will a few key things needed to do a good job.

CLEAN tip
Leaded solder
Tweezers
Magnification. Depends on how old your eyes are, dual lense heatset is all I need
Temp control.

Too finer tip can be a curse as it won't hold enough solder.
Needle tips are hard to use for other than very fine work when there is little thermal mass.
Chisel or hoof styles seem to be the most popular.

For SMD passives, I just wet a pad with solder, hold the device in place and re-heat, then solder the other pad. Too much solder on the tip or added will leave balling like yours, a concave fillet is whats required.
If it looks ugly, get the sucker out and do a pad again.

I'd add you job looks nice and clean.

Okay I am dancing extra hard here:

* 0603 size is my standard go-to size
* Old through-hole era 35W iron, NO temperature control
* RoHS solder (tin-silver type)
* Almost no tolerance on board (was intended to reflow but stencil got too expensive)
* No magnification, bare eyes only (I do have 20/20 vision)
IMO doable but without temp control the flux will be baked off too quickly, see if you can get a light dimmer and put it in series with your iron to tame the heat.
For inspection, you should have a headset at least, without it you can't see the inperfections or tiny whisker like bridges no matter how good your eyesight is. High density PCB's more so.  ;)
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Offline technix

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Re: SMD Soldering Practice Boards
« Reply #67 on: May 20, 2015, 06:55:36 am »
Tidy work is all part of a dancing act, will a few key things needed to do a good job.

CLEAN tip
Leaded solder
Tweezers
Magnification. Depends on how old your eyes are, dual lense heatset is all I need
Temp control.

Too finer tip can be a curse as it won't hold enough solder.
Needle tips are hard to use for other than very fine work when there is little thermal mass.
Chisel or hoof styles seem to be the most popular.

For SMD passives, I just wet a pad with solder, hold the device in place and re-heat, then solder the other pad. Too much solder on the tip or added will leave balling like yours, a concave fillet is whats required.
If it looks ugly, get the sucker out and do a pad again.

I'd add you job looks nice and clean.

Okay I am dancing extra hard here:

* 0603 size is my standard go-to size
* Old through-hole era 35W iron, NO temperature control
* RoHS solder (tin-silver type)
* Almost no tolerance on board (was intended to reflow but stencil got too expensive)
* No magnification, bare eyes only (I do have 20/20 vision)
IMO doable but without temp control the flux will be baked off too quickly, see if you can get a light dimmer and put it in series with your iron to tame the heat.
For inspection, you should have a headset at least, without it you can't see the inperfections or tiny whisker like bridges no matter how good your eyesight is. High density PCB's more so.  ;)

I have soldered several TQFP-100 packages (Altera EPM240/EPM570 CPLD eval kits) and flux boiling away too quickly does pose a problem. However since I do inspection with my multimeter, coupled with my 20/20 vision, magnification didn't came to me as a need really.

About the iron, I think I will take one of my earlier IoT dimmer project board and make a digitally-controlled dimmer out of it, probably with temperature probe feedback.
 

Offline savril

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Re: SMD Soldering Practice Boards
« Reply #68 on: May 21, 2015, 08:16:34 pm »
I've done the same board as you. Did the same mistakes ;D (too much solder) plus 2 pad lift and repaired. This board is inexpensive enough not to fear loosing the components or the board. It made me feel secure enough to get into SMD.

However it didn't not light up the LED when I plugged it :(. I checked all the connections, diode orientation, that the LED was not fried, ... Only to discover that the total resistance was 12k and that I would have to plug it to mains voltage to get it to light up :palm:.
So resistors values are random.
 

Online xrunnerTopic starter

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Re: SMD Soldering Practice Boards
« Reply #69 on: May 21, 2015, 10:36:34 pm »
Finished the second board. It simply flashes 10 LEDs in sequence using a 555 timer and a CD4017 decade counter. The hardest part was the tiny 0603 resistor packs with 4 10k resistors in each one. They are all just wired in series for a total of 200k, but when I tested the series total I got some reading in the 4 Megohm range. The second row had a bad connection to a pad, after touching them up it fixed it. Also had solder bridges on these when installing. Tough and tiny little buggers.

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Offline GreyWoolfe

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Re: SMD Soldering Practice Boards
« Reply #70 on: May 22, 2015, 11:58:26 am »
That looks like a fun build for practice.  At $5.25 USD a bargain even.  No 0402 soldering though.  I am ordering one.
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Re: SMD Soldering Practice Boards
« Reply #71 on: May 22, 2015, 12:21:07 pm »
That looks like a fun build for practice.  At $5.25 USD a bargain even.  No 0402 soldering though.  I am ordering one.

Yea it's a pretty good idea if you just want to practice. The next board I think does the same sort of thing once it's done - flash 10 LEDs except they are in a circle on this one. Oh and another thing - it's got 0402's to solder. man, those things are TINY!  :palm:

After that I have a "real" kit to make. It's a clock kit that looked rather unique so I got one.

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Offline technix

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Re: SMD Soldering Practice Boards
« Reply #72 on: May 22, 2015, 04:16:46 pm »
So this is what I treat as SMD soldering practise kit.

The chip in the middle is Altera MAX II CPLD in 100-pin TQFP package, pictured EPM570T100C5N and I also have a couple of such boards populated with EPM240T100C5N. Supporting the CPLD is AMS1117 in SOT-223, a bunch of R and C's (1206 and 0805 footprints, and I populated all footprints with parts one size smaller - 0603 parts in 0805 footprints, 0805 parts in 1206 footprints) and a few LEDs (0805)
 

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Re: SMD Soldering Practice Boards
« Reply #73 on: May 24, 2015, 12:51:57 am »
I had better results with the Mastech  ms8910 ($18.05 on amazon) than this one. The tips of this one are very poor.

YMMV :)

You are correct ^^^  :(

Those El Cheapo SDM test clips for DMMs ... suck. I just got them the other day and I am disappointed.

The tips are just not pointed enough to penetrate any surface contamination. They work OK, for the most part (although not all the time) on clean SMD parts. But anything already soldered - fuggetboutit.

Lessons learned.  ???
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Offline Electro Fan

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« Reply #74 on: June 01, 2015, 02:05:35 am »
Finished the second board. It simply flashes 10 LEDs in sequence using a 555 timer and a CD4017 decade counter. The hardest part was the tiny 0603 resistor packs with 4 10k resistors in each one. They are all just wired in series for a total of 200k, but when I tested the series total I got some reading in the 4 Megohm range. The second row had a bad connection to a pad, after touching them up it fixed it. Also had solder bridges on these when installing. Tough and tiny little buggers.



Not sure if I purchased from the same seller as you did - I purchased on eBay from asp_ezpone.  The price was $4.25 plus $1.00 for shipping to the U.S.

http://www.ebay.com/itm/351311595209?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

I ordered the kit and about 8 days later I received a package from asp_ezone saying sorry for the delay but the moment you bought this product it was out of stock.  To show their concern for customer happiness they included 10 pieces of "Dupont" breadboard jumper cables which look nice enough.

About 2 days later the original order for the SMD kit showed up.

So that's about 10 days for delivery of a PC board with about 100 components from China for $4.25 plus $1.00 shipping and a free shipment of 10 breadboard jumper cables within the first 8 days just to maintain customer satisfaction.

Amazing customer service!  :-+ :-+
« Last Edit: June 01, 2015, 02:11:02 am by Electro Fan »
 


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