3D Printed Connectors and Housings

[winteriscoming]

I'm working on some wiring adapters so that my WMMT cabinets can wire into my MEGA JVS (Based on Sega Type 1 I/O connectors) and I ran into the need for random connectors/housings like I always do. It prompts me to spend way more than I need to on some housings and crimp pins. I have a ton of crimp pins and header pins for the connectors I use in pinball, and figured I would try my hand at designing and 3D printing some housings/adapters to work with what I have on hand.

It works!



I didn't search very hard, but is there already some kind of repository for connectors and housings? I'm even going so far as to make parametric designs, so that I can specify # positions and have Fusion 360 generate the correct housing:

So far I'm having good luck with a .4mm nozzle. I imagine some of these would do much better with a .2mm, but I'll have to wait until I get a chance to change nozzles and re-level to experiment with that.

 

[Derick2k]

Thats pretty cool, how do you think they will hold up to use? Also, what filament material are you using?

 

[winteriscoming]

Thats pretty cool, how do you think they will hold up to use? Also, what filament material are you using?

I've really only successfully printed PLA so far. I have spool of PETG and had no luck with it in my initial tests when I first started printing and haven't gone back to try anything else.

I don't know how well they'll hold up, but I'm not too concerned. I don't think they'll break down or anything. Certainly some connectors are subjected to heat and these have a lower melting point than some other plastics. I've encountered charred/melted housings in pinball machines. I'm not sure what those are made out of, but these would surely fail faster in that scenario. Other than high heat sources, I'm not too worried about it. I don't think any connectors on my I/O are approaching melting temps for PLA.

 

[twistedsymphony]

what size nozzle and resolution are you printing at where the internal geometry works to hold the pins in place?

I'll be honest I've wanted to be able to 3D print connectors since before I even bought my printer but it always seemed that the resolution wasn't high enough to make it viable.

I don't know of any online repository for connectors but if I do want to make them configurable SCAD seems to be the standard for that. Thingiverse even supports it so you can configure the design and download the compiled STL right on the thing page.

A good example is this: https://www.thingiverse.com/thing:1264391 click the "open in customizer" button to configure it and generate an STL.

 

[winteriscoming]

what size nozzle and resolution are you printing at where the internal geometry works to hold the pins in place?

So far I've just tested with a .4mm nozzle. I have some .2mm nozzles that worked quite well for me with some miniature figures I was printing. I've successfully printed at .04mm and .05mm heights with both nozzles, but there's an experimental feature in the latest version of Cura called Adaptive Layers that uses variable layer heights for the print according to the geometry and that's what I used on these housings, so I'm not sure what it ultimately decided for the various heights.

With the .4mm nozzle, I've had to make some of the inner walls a little thicker than what I measured so that they would print at .4mm width (or I'd have to indicate to Cura to print thin walls which seems less predictable).

I'm not sure if I'm slightly leveled too close to the bed, but I ended up making the holes larger for the side that's on the print bed because they were coming out too small.

So far I've been able to design and print these without the need for supports, which would get kind of inconvenient at this size.

The smallest pitch for connectors that I've needed is .100" (2.54mm), but I'm not sure if I could handle smaller. Maybe with the .2mm nozzle.

I don't know of any online repository for connectors but if I do want to make them configurable SCAD seems to be the standard for that. Thingiverse even supports it so you can configure the design and download the compiled STL right on the thing page.

A good example is this: thingiverse.com/thing:1264391 click the "open in customizer" button to configure it and generate an STL.

Ugh! I've got to learn yet another CAD software? I'm seriously on like 4 or 5 different programs trying to do the things I want to accomplish for 3D printing. Pile on the extra stuff I use for my CNC machine and it's crazy!

 

[twistedsymphony]

I'm not sure if I'm slightly leveled too close to the bed, but I ended up making the holes larger for the side that's on the print bed because they were coming out too small.

I press the nozzle right up against the bed for the first layer (I use a glass bed with spring mounts), this greatly helps with adhesion but I get some serious "elephants foot" on the first layer as a result. I typically compensate for this by adding a .4mm chamber along the parameter of everything that touches the bed, in effect this drops the outermost parameter from the bottom layer and the bottom edges come out perfect.

if you're running a brim for adhesion you could implement the chamfer on just the inside geometry (like the holes for the pins) and then use a deburr tool to trim off the brim.

Certainly some connectors are subjected to heat and these have a lower melting point than some other plastics. I've encountered charred/melted housings in pinball machines. I'm not sure what those are made out of

I believe most electrical connectors are a nylon/polyester blend. they usually withstand temps up to 150-250C depending on the blend. The charred/melted connectors usually come from components failing and shorting which then causes all of the traces/wires/connectors completing the short to act like a giant resistor and since it's not actually a resistor it heats up and causes traces to burn up as well as connectors and wire jackets to melt.. which ever happens to be the weakest link.

You can print in Nylon, it's actually the best material for strength and temperature resistance, I've seen people print replacement gears for industrial applications using it. I've never tried but I hear it's an enormous pain in the ass to print with, you need really high temps (over 200C IIRC) and you tend to get a lot of warping and shrinkage that you need to accommodate for. I don't think you can get it colored either... just "natural" nylon.

I've done some printing with PETG, again you need some high temps for that (I think I'm using 145C nozzle temp, and no fan). it's got a rubbery feel to it and it's pretty strong, I'd argue its stronger than ABS in my experience, but when it fails it snaps like a kit-kat, at least when ABS fails it just bends and deforms and gets all chewy but it still holds together. I debated switching to PETG but I really don't like the surface finish, it's quite rough so for a lot of the stuff I'm making where the goal is to make it look nice, it really didn't work.

PLA is a lot stronger than most people give it credit for as long as you stay with a good brand, I've tested maybe a dozen brands of filament and a lot of them are straight garbage which is probably why PLA gets such a bad rap. For connectors though Nylon or PETG are probably your best bet and I say that not because of the strength but because they're going to need to flex and parts of them are going to be under pressure (when you consider the latches on the connectors use to mate), PLA doesn't like being under stress for long periods of time and it doesn't like flexing either, ABS is good to flex but again doesn't like being under stress. PETG and Nylon are both good with this though. I've printed fidget spinners and these little shark shaped clothes pins in ABS and after a few months all of them... 100% of them developed stress fractures. the shark pins because it uses the natural flexibility of the plastic as the "hinge" and developed the fractures on that area when it was left clamped to something for weeks, and the spinners had press-fit bearings and cracked from the stress of the bearing pushing outward. I had similar results with PLA, but it's expected with PLA.

I would guess that for those NH style connectors you're using, if printed in PLA or ABS the latching tab will eventually snap off on it's own accord if left plugged in for a few months, especially because this will stress right across the layer plane.

 

[winteriscoming]

I would guess that for those NH style connectors you're using, if printed in PLA or ABS the latching tab will eventually snap off on it's own accord if left plugged in for a few months, especially because this will stress right across the layer plane.

I guess we'll see. For now I'm sticking to PLA since that's what I mainly use and I can throw these connectors into my queue of other stuff I'm frequently printing. I designed these so they're thicker at the latch and there isn't really any pressure on it, unless it gets mounted such that the wires are causing it to be pulled in that direction. For the most part it's just hooking under the lip of the header to keep the connector from being pulled straight out easily, and not really making much contact. I think the friction of the pins is doing most of the work to keep the connector in place. If the latch gets broken off, it wouldn't be the end of the world, but would remove the safety aspect where the latch helps in making sure your plug is oriented onto the header correctly. Without the latch, it would be able to plug in the wrong way and reverse polarity on power connectors. I didn't even reference actual NH housings when designing it, so it's likely a lot looser at the latch than a real one would be.

My goal isn't to make connectors for high frequency of insertions and removals. I'm hoping to just get some adapters in place that will hopefully stay where they are indefinitely.

At any rate, crimp pins are a necessity, so if one has to order those already, then throwing in housings isn't going to break the bank. It's a scenario where you've got various crimp pins on hand and need specific housings that the 3D printed housings come into play. That, and it can sometimes be difficult to identify a connector. I think I've spent longer researching a specific connector in the past than I did designing any one of these.

Attached is the 4-pin JST NH style one of you wanted to experiment with printing it. Note that I did not design it for JST pins, and I'm not sure if it would work with them. It's designed for this kind of pin that's prevalent in pinball machines (These aren't the best kind of pins, either, since they only have 1-sided surface contact): https://www.digikey.com/products/en?keywords=08-50-0114

 

[twistedsymphony]

there isn't really any pressure on it

the original connectors have a small amount of pressure from the header against the latch on the connector, but if you designed yours so that when fully inserted there's no pressure then it shouldn't be an issue.

This is a really cool proof of concept but one of my philosophies for the Stuff I 3D print is "don't reinventing the wheel". so I tend to stick to parts that either don't exist or are very difficult to find and avoid designing replacements for readily available parts.

I think Where 3D printed connectors would really shine is in developing replacements for connectors that are no longer available. For instance the connectors for old Nintendo PCBs are completely unavailable so people resort to using connectors that just sort-of work on the headers. it'd be nice to design a proper fitting direct replacement.