Lead forming tools for LEDs - Page 1
Forum section: electronics / general

author: dkonigs
author_rank: Regular Contributor
timestamp: November 12, 2023, 04:50:05 pm
content: There's a particular key switch assembly that I'd like to be able to use on a project, where the manufacturer has a spot for an embedded LED in the corner of the switch cap. (Its a Marquardt 6425.1101 switch, with a 190.059.023 parallel guide, and a 842.500.011 cap.)Of course while they sell key switch assemblies with embedded LEDs for the smaller key cap setups, they don't sell this for the wider ones where you use that parallel guide bit to get a longer button.In any case, what I'm looking for is a tool that can lead-form an LED like shown in the attached diagram. Its a ~3mm diameter LED, and the particular bend kinda offsets the LED from the spot where the leads go through the switch guide into the PCB.I know there are big fancy machines that could probably be combined with some sort of custom die to handle this, but I'd really prefer a much simpler low-volume solution. I've also found a lot of lead-forming pliers out there, but there are so many options that I really don't even know what I'm looking for from just the product description.Is this is a standard shape? Is there a particular brand/model/spec of pliers I should be looking for to solve this problem?I hope I'm making sense, so thanks for any help you all can offer.

author: Infraviolet
author_rank: Super Contributor
timestamp: November 12, 2023, 06:12:11 pm
content: The best choice is probably to 3d print some sort of lead forming jig for the LED. It would take the form of several parts with appropriate grooves for the normally straight legs to slot in to, then you'd apply a force in the right direction which would move some of the parts of this jig to do the bending. Given how bendy these sort of long component legs typically are a printed plastic jig should have no trouble applying the necesary forces, I would NOT expect a metal jig to be needed for this the way that metal parts are needed for the teeth of crimper tools.An image search for "led leg bending jig 3d print" should give some images to give you ideas, though as you want a double bend the mechanism you'll need will be a bit different. You'll probably be able to do it all with some sliding pieces rather than with rotations about hinges.

author: dkonigs
author_rank: Regular Contributor
timestamp: November 13, 2023, 10:08:20 pm
content: So I think I might have a solution, but this also might end up being a moot need as well.I don't really want to use a plastic jig for this, because I want sharp and stiff bends. Its a shape the LED needs to hold firmly. Of course plenty of DIY'ish options still exist.As far as solutions, I stumbled across the PTR-30-L-D series of lead-forming pliers. Its hard to tell if they'd make the exact shape I need, but I think they might. The pliers specs and the application datasheet seem to differ in whether the diameter of the leads themselves is included in the dimensions of bent form. The only problem is that the pliers cut off the end of the leads at only 5mm, which isn't long enough. So one idea would be to try these pliers, but modify them with a Dremel so they don't actually cut off the ends of the leads.However, there is another issue that may make this whole idea moot. I can only find the version of this button cap with the LED window in the corner, in black. However, I'm using the light gray version of these button caps everywhere else, and don't want to change that. There doesn't seem to be a light gray version of the button cap with an LED window.

author: coppercone2
author_rank: Super Contributor
timestamp: November 14, 2023, 05:36:08 am
content: those tools are good. I feel like a fool not having one ten years ago.Keep in mind there is a few versions for bending or cutting and bending. I only have the cutting bending one, but I can assure you even if it does not work for that, its extremely handy for through hole parts.that one you found should workhttps://hakkousa.com/chp-lead-forming-ptr-30-l-d.htmlscroll down to diagram of bent part (specifications tab)

author: ajb
author_rank: Super Contributor
timestamp: November 14, 2023, 09:20:14 pm
content: Lindström offer customizable forming pliers, eg:https://www.lindstromtools.com/int_en/ergotm-specials--cut---form-----up-to-16-awg-rx331a.htmlNo idea how much that would cost -- their standard pliers are 2-4x as expensive as the Hakko/Piergiacomi stuff so certainly won't be cheap -- but depending on your volume it might be worthwhile to just send them a drawing and be done with it.Quote from: dkonigs on November 13, 2023, 10:08:20 pmThe centerline-to-centerline offset of the finished form is directly set by the offset between the two parallel forming surfaces regardless of the lead diameter. So the only sensible way to specify the pliers is by that offset value, although the drawings may be unclear about that or just plain wrong.