Shaping/cutting leads of radial components for surface mount ?

[Externet]

Hi.
Is there a preferred method to surface mount radial components by shaping the leads on a way that will somewhat keep them upright for reflow soldering ?

Say a 5mm electrolytic, or a led, meant for trough hole... how to 'convert' them into useable for automated placement surface mounting ?
Do you know of examples, pictures, lead cutting/bending machinery ?

Perhaps something like this :

Better suggestions, please ?

 

[ericgibbs]

hi ex,
Look at this link... the PNG500 https://www.olamefusa.com/e_forming_handtools.htm

Eric

 

[dougy83]

Externet, something like what you've shown can be used for radial caps as well. Because of the bulk of the component, the solder paste won't be able to hold it in place if the board is bumped before reflow; you can use a small amount of glue under the device to accomplish this.

 

[kubeek]

Hi.
Is there a preferred method to surface mount radial components by shaping the leads on a way that will somewhat keep them upright for reflow soldering ?

I have to say that the preferred method to mount radial through hole components is to mount them through hole, radially. I don´t know what kind of device you´re making, but be prepared that if you surface mount some big-ass component, there will come a time when said component will just vibrate off the board, either braking the leads or taking the pad along.
And since you´re talking reflow soldering, which implies mass production, I´d rather find components which fit all the aspects of production.
(unless said product will be kept inside a distribution board securely mounted on a wall or something similar, plus no significant thermal contraction/expansion, aka home automation system mounted in 23°C controlled environment)

 

[jpanhalt]

Something to consider is to solder through-hole components on the top side. If you want reinforcement, you can etch a small pad on the reverse side.

Here is an example I made several years ago. The large bridge rectifiers on the left are though hole; the rest of the components are surface mount.


On a single sided board, just solder the top side as close to the board as practical. Be sure there is a little extra solder. Then heat the lead from below and push the top-mounted TH component into place.

John

 

[MrAl]

Hello,

I have hand soldered through hole components to surface mount pads in the past, but this is hand soldering. I have been the leads 90 degrees from the body, then bent another 90 degrees a ways down the lead length until they were parallel with the body. This gave me a way to solder them to the top of the board and get a good solder joint with no problems.

Again though, this was hand soldering. Flow soldering would be different because the parts have to be held in place and in the case of something like resistors, they have to be held upright too. If the leads are bent slightly outward like your picture shows, they might stay upright but they are still too vulnerable to movement by the slightest vibration or even the solder itself as it passes over.

What might help is to have small holders made for each type of component. The component would be matched to it's holder and then placed on the board. The holder then disintegrates as the heat hits it, or it has to be removed in another process step.
There are plastics made for this purpose for IC sockets, but i've never actually tried any of them so i cant say for sure how well they work.

As mentioned in one of the previous posts, glue might help as long as it can stand up to the heat. The part would be simply glued down in the right position and orientation.
I have actually used glue in the past but again this was for hand soldering. I used Elmer's Glue (chuckle) because that was all that was needed for temporary hold down while i soldered a couple leads on the surface mount IC package. The glue stays wet long enough for me to position the part perfectly on the pads, then let dry, then solder. Im sure there are better glues however for automated soldering. There is a high temp silicone that would be ideal but it does take time to dry, roughly 12 hours, so that would take an additional lengthy processing step just to glue them down and wait 12 hours.