Surface Mounted Components

4 views
Skip to first unread message

Dana Kelley

unread,
May 31, 2020, 5:25:39 PM5/31/20
to Nashua Robot Builders
I've a basic question regarding hand soldering basic components like resistors, caps, SOIC with 0.050" spacing, and maybe even tighter spacing in future.

Soldering size 1206 resistors and caps was fairly easy. The hardest part is getting them to stay put during heat and solder application. That any slight jarring of the PCB moves them.

Is there a solder paste or something that would help keep the part stable and not interfere with soldering.

It seemed best to first put a dab of hot solder on one pad, then reheat and move device into the puddle and then hold in place. After which solder the other connection. I used small tweezers from a child's stem kit to hold in place.

All feedback is appreciated.

Project Update..... I expect to be debugging the first PCB w/ FPGA and motor drivers by weeks end. Waiting on parts ordered too late! The first step for debug is to write the Arduino end of the Serial Interface. Very simple SI running at about 100KHz, maybe 200KHz. I've used the fast write/ read IO instructions before. This interface design can suffer interrupts without issue.






Jay Francis

unread,
May 31, 2020, 5:32:43 PM5/31/20
to nashuarob...@googlegroups.com
This is the way...


It seemed best to first put a dab of hot solder on one pad, then reheat and move device into the puddle and then hold in place. After which solder the other connection. I used small tweezers from a child's stem kit to hold in place.


Same thing with multi-pin parts.  Put solder on one pad, solder one pin while adjusting position.  Once happy, solder the opposite pin (if it makes sense), then solder the rest.

Get some good tweezers and keep the ends clean and free of any flux (isopropyl alcohol works well).

For even finer pitch multi-pin parts, you can use the "flow solder over everything and solder wick out the excess" approach.  Works surprisingly well.  I bet there are YouTube videos out there showing techniques...

And, yes, for larger projects you'll eventually just switch over to getting stencils made, using solder paste, and some kind of reflow.

Some kind of hot air tool makes the inevitable part removal a lot easier too. https://www.sparkfun.com/products/14557

--Jay


May 31, 2020 at 5:25 PM
--
You received this message because you are subscribed to the Google Groups "Nashua Robot Builders" group.
To unsubscribe from this group and stop receiving emails from it, send an email to nashuarobotbuil...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/nashuarobotbuilders/321034bd-a01e-4c4f-bcb2-6611a007b63d%40googlegroups.com.

Jay Francis (Reactive Technologies)

unread,
May 31, 2020, 5:39:15 PM5/31/20
to nashuarob...@googlegroups.com
Oh, and I ignored the part about actually being able to see what you're doing...  that kinda helps.

Lots of ways to do that based on budget and personal preference.  My preference is an optical stereo microscope (not any kind of camera based one - tried that - didn't like it...).  I also have a magnifying visor and eye loupe... although you have to get pretty close to the soldering iron when using the eye loupe ;-)

--Jay


May 31, 2020 at 5:32 PM

Dana Kelley

unread,
May 31, 2020, 6:36:43 PM5/31/20
to Nashua Robot Builders
When the time comes I'll op for the optical stereo microscope. I have magnifying lenses which are good for the current level. I was thinking about what dentists use. They are pretty pricey. A microscope would be better. The heating removal tool will be needed at some point for sure.

On Sunday, May 31, 2020 at 5:39:15 PM UTC-4, Jay Francis (Reactive Technologies) wrote:
Oh, and I ignored the part about actually being able to see what you're doing...  that kinda helps.

Lots of ways to do that based on budget and personal preference.  My preference is an optical stereo microscope (not any kind of camera based one - tried that - didn't like it...).  I also have a magnifying visor and eye loupe... although you have to get pretty close to the soldering iron when using the eye loupe ;-)

--Jay


May 31, 2020 at 5:32 PM
This is the way...

It seemed best to first put a dab of hot solder on one pad, then reheat and move device into the puddle and then hold in place. After which solder the other connection. I used small tweezers from a child's stem kit to hold in place.


Same thing with multi-pin parts.  Put solder on one pad, solder one pin while adjusting position.  Once happy, solder the opposite pin (if it makes sense), then solder the rest.

Get some good tweezers and keep the ends clean and free of any flux (isopropyl alcohol works well).

For even finer pitch multi-pin parts, you can use the "flow solder over everything and solder wick out the excess" approach.  Works surprisingly well.  I bet there are YouTube videos out there showing techniques...

And, yes, for larger projects you'll eventually just switch over to getting stencils made, using solder paste, and some kind of reflow.

Some kind of hot air tool makes the inevitable part removal a lot easier too. https://www.sparkfun.com/products/14557

--Jay


May 31, 2020 at 5:25 PM
I've a basic question regarding hand soldering basic components like resistors, caps, SOIC with 0.050" spacing, and maybe even tighter spacing in future.

Soldering size 1206 resistors and caps was fairly easy. The hardest part is getting them to stay put during heat and solder application. That any slight jarring of the PCB moves them.

Is there a solder paste or something that would help keep the part stable and not interfere with soldering.

It seemed best to first put a dab of hot solder on one pad, then reheat and move device into the puddle and then hold in place. After which solder the other connection. I used small tweezers from a child's stem kit to hold in place.

All feedback is appreciated.

Project Update..... I expect to be debugging the first PCB w/ FPGA and motor drivers by weeks end. Waiting on parts ordered too late! The first step for debug is to write the Arduino end of the Serial Interface. Very simple SI running at about 100KHz, maybe 200KHz. I've used the fast write/ read IO instructions before. This interface design can suffer interrupts without issue.






--
You received this message because you are subscribed to the Google Groups "Nashua Robot Builders" group.
To unsubscribe from this group and stop receiving emails from it, send an email to nashuarobotbuilders+unsub...@googlegroups.com.

--
You received this message because you are subscribed to the Google Groups "Nashua Robot Builders" group.
To unsubscribe from this group and stop receiving emails from it, send an email to nashuarobotbuilders+unsub...@googlegroups.com.
May 31, 2020 at 5:25 PM
I've a basic question regarding hand soldering basic components like resistors, caps, SOIC with 0.050" spacing, and maybe even tighter spacing in future.

Soldering size 1206 resistors and caps was fairly easy. The hardest part is getting them to stay put during heat and solder application. That any slight jarring of the PCB moves them.

Is there a solder paste or something that would help keep the part stable and not interfere with soldering.

It seemed best to first put a dab of hot solder on one pad, then reheat and move device into the puddle and then hold in place. After which solder the other connection. I used small tweezers from a child's stem kit to hold in place.

All feedback is appreciated.

Project Update..... I expect to be debugging the first PCB w/ FPGA and motor drivers by weeks end. Waiting on parts ordered too late! The first step for debug is to write the Arduino end of the Serial Interface. Very simple SI running at about 100KHz, maybe 200KHz. I've used the fast write/ read IO instructions before. This interface design can suffer interrupts without issue.






--
You received this message because you are subscribed to the Google Groups "Nashua Robot Builders" group.
To unsubscribe from this group and stop receiving emails from it, send an email to nashuarobotbuilders+unsub...@googlegroups.com.

Skye Sweeney

unread,
Jun 1, 2020, 7:48:43 AM6/1/20
to nashuarob...@googlegroups.com
I can't recommend the stereo microscope enough. With a 1/2X barlow lens you get good magnification with a good standoff distance.
Last night I had to solder 8 wires to solder cup pins. Under the scope the job was painless and accurate as you actually see what you are doing. 
 You can get them for ridiculous amounts of money (like the Mantis for $3K) or for still non trivial but reasonable money (300-400) for an AmScope.
As my eyes have gotten older, I tend to do everything but tie my shoes under the microscope. They are very good for removing splinters!

I investigated the glasses dentists and surgeons use. They are very expensive and you need new glasses if your basic prescription changes. 
I get new glasses every year or two with a stronger prescription. I would be buying 1K glasses every couple of years. 

To view this discussion on the web visit https://groups.google.com/d/msgid/nashuarobotbuilders/5ED42400.8040305%40ReactiveTechnologies.com.


--
-Skye Sweeney
Reply all
Reply to author
Forward
0 new messages