holding through hold components in place before wave soldering/solder pot solder

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Rochey

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Hey folks,

I was scratching my head on the idea of using a simple adhesive (once without acid) to hold things like caps in place before they go through the soldering process.
I need something basically sticky, that i can put a little blob down on the corner of the part, that'll just hold it in place.

Hot glue makes such a big mess. I'm wondering if there' s a better solution?
 
TH or SMD? For TH the standard technique is to crimp over the leads.

I think SMD may have some dedicated adhesives to hold parts in place but nowadays with BGA and pads on the bottom, where would you put the glue?

JR
 
JohnRoberts said:
For TH the standard technique is to crimp over the leads.
I'm talking about TH.

I have never had much success crimping the leads. (you mean, bending them to the side a little on the solder side?).
Ideally, what I'd like to use is an adhesive that I can use on the corner of the cap (nowhere near the leads) that holds the part in place during assembly, without making a big stringy mess.

There's the red adhesive that most people use for SMD. That requires UV to cure. It's a pity, because it would have been excellent for this application too.

The other thought however, is, as it's for the modules side of expat audio, what would the customer perception be? a clean pcb, with a tiny blob in the corner is one side. A PCB covered in hot glue strings is another!
 
What about holding everything down to the PCB by using a "lid" of (some sort of heat-resistant, synthetic) foam rubber for the soldering frame?

Works well for hand-soldering...

Jakob E.
 
Rochey said:
JohnRoberts said:
For TH the standard technique is to crimp over the leads.
I'm talking about TH.

I have never had much success crimping the leads. (you mean, bending them to the side a little on the solder side?).
Ideally, what I'd like to use is an adhesive that I can use on the corner of the cap (nowhere near the leads) that holds the part in place during assembly, without making a big stringy mess.

There's the red adhesive that most people use for SMD. That requires UV to cure. It's a pity, because it would have been excellent for this application too.

The other thought however, is, as it's for the modules side of expat audio, what would the customer perception be? a clean pcb, with a tiny blob in the corner is one side. A PCB covered in hot glue strings is another!
Back a few decades ago I had a special pair of clippers that would cut and crimp over the TH component lead in one operation. Unless you crimp the leads the boards are difficult to handle pre solder.

Since those days PCB layouts have become so tight that automatic crimps may not always bend in the right direction.

JR
 
JohnRoberts said:
Rochey said:
JohnRoberts said:
For TH the standard technique is to crimp over the leads.
I'm talking about TH.

I have never had much success crimping the leads. (you mean, bending them to the side a little on the solder side?).
Ideally, what I'd like to use is an adhesive that I can use on the corner of the cap (nowhere near the leads) that holds the part in place during assembly, without making a big stringy mess.

There's the red adhesive that most people use for SMD. That requires UV to cure. It's a pity, because it would have been excellent for this application too.

The other thought however, is, as it's for the modules side of expat audio, what would the customer perception be? a clean pcb, with a tiny blob in the corner is one side. A PCB covered in hot glue strings is another!
Back a few decades ago I had a special pair of clippers that would cut and crimp over the TH component lead in one operation. Unless you crimp the leads the boards are difficult to handle pre solder.

Since those days PCB layouts have become so tight that automatic crimps may not always bend in the right direction.

JR

John - please please please, can you find a picture of those clippers?
 
something like this?
http://www.amazon.com/Hakko-TP-5000-15-D-Hardened-Construction-Dissipative/dp/B00FZPRHJ2/ref=sr_1_1?ie=UTF8&qid=1424372448&sr=8-1&keywords=cut+clinch

ordering it. just to see if it works. :)
 
I don't recall them looking like that, but yes that is the concept, cut and crimp over in one operation. As I recall cutting a large PCB full of TH parts was work, and I chucked my pair after they wore out from use. IIRC the jaws got loose so didn't crimp worth a flip anymore... but that was after years of use.

I also vaguely recall having to be careful about damaging some PCB traces if held too close to the board. But my old clipper's jaws did not look exactly like that, so hopefully that is an improved design.

JR
 
I ordered it nonetheless. It's for use with Eden builds and the new VU meter boards.
I've also ordered a "detailed hot glue" gun, just to help with some headers. I'm also using offset header holes to help hold the pin headers:

https://www.sparkfun.com/tutorials/114

mod1.005.jpg
 
It is a meticulous process but possible I can try to snag photos of the jigs used for trimming/crimping TH components for a fairly large controller board. 

Basically cut and crimp the leads PRIOR to populating...

The shape of the lead now causes the TH component to "stand".

The only pain in the ass after you were done was if you sneezed or tripped on the way to the wave solder, you'd have to spend another hour re-populating the whole thing...

aha
http://www.cutbend.com/
 
I avoid hot glue "strings" by cutting little chunks of the gluestick and place where I want them and use hot air to melt. If the board is pre-heated the glue chunks stick and don't blow away from the hot air pressure. I do this for strain relief on test wires, but it could work for your application.
 
Rochey said:
I ordered it nonetheless. It's for use with Eden builds and the new VU meter boards.
I've also ordered a "detailed hot glue" gun, just to help with some headers. I'm also using offset header holes to help hold the pin headers:

https://www.sparkfun.com/tutorials/114

mod1.005.jpg

What is the offset on those vias from center?
 
Matador said:
Rochey said:
I ordered it nonetheless. It's for use with Eden builds and the new VU meter boards.
I've also ordered a "detailed hot glue" gun, just to help with some headers. I'm also using offset header holes to help hold the pin headers:

https://www.sparkfun.com/tutorials/114

mod1.005.jpg

What is the offset on those vias from center?

thats a good question. I just reused them as is, and they are perfect with all the headers I've used.
 
Hi, I use peelable solder resist such as multicore spot on. apply a bead across the centre of components being careful not to block any holes requiring soldering.

works great!!
 
For 1990's mass production of amps with thru' hole parts, it was common not to crimp but guillotine all the leads straight (no crimping) in one go immediately after stuffing.  This was to facilitate removal of parts in service.

The stuffed boards went straight from stuffer to guillotine to wave solderer.

Wave soldering sometimes pushed the components up but this happened far less often than you'd expect and was easily sorted out on post solder visual inspection.

We weren't the only ones who did this.  IIRC, so did QUAD and Mission.

Stuff which had to be glued down were usually bigger parts which had to be inserted manually instead of by the pick & place stuffer.
______________________

Today, for small production, if you MUST glue, a drop of cyano is expensive but quick & easy.
 
It would help to know your soldering process... Ricardo describes the typical production wave soldering process and machine insertion to TH parts typically clip the excess leads while inserted. In a machine inserted production line the boards don't get handles so parts generally stay put.

I recall back in the early '80s when my small company was hand soldering TH parts, IIRC they used some board holders that used soft foam above the boards to clamp the parts in place, The whole assembly rotated on an axis so you could flip the board over for soldering, that flip it around again to make and parts adjustments.

I have also seen high volume boards use cardboard with cut outs for the tall parts to sit on top of the loose parts to hold them down.

JR 
 
If you can, try to make sure that whatever you use to tack components on a PCB is safe for use on electronics.  There are some types of RTV, for example, that outgas in a manner that can be corrosive or damaging to boards.  I'm not real sure of the exact mechanism, but I know it's a consideration I've come across in production work for RTVs used for mechanical tacking down of heavy components.

In my current industry, we seem to use epoxies more than RTV for mechanical support of all the components with some mass to them, and I don't know much at all about the types or considerations for that.
 
I'm glad to see this thread come to life again.

is there an epoxy that has a similar drying time to hot glue (or even a few minutes), that dispenses in a cleaner way than hot glue?

HG is awesome in that you can hold the part, squirt the glue and it's done... but the stringing kills me.
 

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