Carpokes

In a previous post I described making a CAD model of the base of the turn signal stalk. What I lacked at the time was a 3D printer to, you know, make the part.

Now, I have one. It's an entry level FDM/FFF (filament) printer made by Anycubic. I've been thinking about getting one for ages, and I finally did. One of the things that slowed me down with getting one was all the jargon. The different printing technologies (filament vs resin), the different kinds of filament, etc - they all have a three-or-four letter acronyms that mean a lot when a person has a frame of reference. It's quite daunting otherwise.

Below is my first prototype of the turn signal stalk base. Made with PLA (polylactic acid) filament. This standard type of filament would NOT be suitable for use inside a car given the temps it must endure. It's good enough for prototyping though.

I'm still learning how to generate supports in the slicer software (PrusaSlicer). The slicer takes something a CAD program can output (a *.stl file) and turns it into something a 3D printer can use (g-code), taking into account the characteristics of the particular printer (nozzle diameter, layer heights, material feeds and speeds, etc).


The upward-facing surface came out decent enough. The downward-facing surface - the one against the supports - did not. Though the main spring fits great against the little side wings

I got the overall dimensions pretty right. The holes where springs rest and the separate original nylon and copper parts insert are a little tight, though. The turn signal stalk does fit into the main opening with a satisfying snugness.
The next prototype I'll try to print standing on its end.

This is awesome! Congrats. I really do believe that 3D printers (and CNC routers) are becoming must-have tools for home mechanics and hot-rodders. What CAD did you use to model the part? It's quite complex for a first print!! I've torture-tested ABS inside my daily driver, and even on 100+ degree days sitting in the sun, I have not had ABS melt yet. If I can help with your 3D printing efforts, just say the word. Hoping you get the model just right and end up posting it here!!

Tom wrote: Fri Sep 08, 2023 8:11 pm This is awesome! Congrats. I really do believe that 3D printers (and CNC routers) are becoming must-have tools for home mechanics and hot-rodders. What CAD did you use to model the part? It's quite complex for a first print!!

Thank you Tom! I think you're totally right about home mechanics and hobbyists needing a 3D printer. I can think of about two dozen things I can do with it right now. When I have more space, a mini CNC router setup would be superb. And a laser cutter.

My first prints have been simple trays to line the bottom of storage cabinet drawers - the Gridfinity system. Those have allowed me to adjust print settings and experiment with the results while also producing usable things that don't need to be visually perfect, or even good.

Only today did I decide to try the complex turn signal part. It will provide me with many more iterations of how the settings affect the part. I'll definitely post it here when I've got the clearances dialed in.

As for CAD, I'm using FreeCAD. I'm a long-time Linux user, and I wanted to run something natively. It's still at version 0.21, so it's not exactly mature yet. I does most of the things a person would want a CAD program to do though, with one significant hurdle - the "Topological Naming Problem". Without deliberate attention to setting up sketches, edits to previous geometry that change the number of faces or edges will break any sketches based upon that geometry ("breaking" the part and forcing me to manually reassign the sketch to the appropriate face in order to un-break it). There are ways to work around it, though it's super uncool to need to.

I'm planning to print my "production prototype" (ie, the one going in my car) turn signal part in ASA (acrylonitrile styrene acrylate), unless of course your experience would lead to different advice.

ASA is chemically similar to ABS (acrylonitrile butadiene styrene) with similar performance and heat tolerance, but not quite as stinky to print (allegedly). At least the YouTubers I like swear by it, basically saying "skip ABS and go straight to ASA". I mainly say all that, and the long-form names, for other on-the-fence-about-3D-printing folks to demystify some of the jargon. There's so much jargon.

It is really fun, though. Way more fun than I was anticipating. And I'm already predisposed to liking nerdy tech fun things. It's version 0.x of Star Trek matter synthesizers, which then lead to replicators!

I spent a little more time refining my CAD model - now fully parametric - adjusting hole sizes and clearances and depths. These photos are from a sliced-in-half print for assessing clearances, etc.

This one was printed with 0.1mm layer height and "automatic" extrusion width, two inner/outer perimeter walls, and 10% rectilinear infill - still prototyping. The original part is in black. The prototype is in gray. The depth of the "pad" isn't right in the first pic (due to a mis-keyed value on my part). It's getting there.

After the adjustments following this recent print, I suspect the model would print great on a resin printer right now, oriented to print standing on it's rectangular end or at some angle that resin printer owners understand. On a filament printer, getting the supports right for a nice-enough surface finish on whatever ends up being the underside is challenging.



My prototypes so far have been printed "flat", either as a complete unit with lots of underside support, or as a sliced-in-half version for confirming some aspect of the model. I'm gonna print one standing on it's tail to see how it turns out.

Looking great! Happy to throw it on my resin printer if you want to see it printed that way Keep up the great work. For the 'stringing' in that last picture you might want to check your retraction settings and print temps.

WOW! The last several posts here just turned the day from a loss to a winner.
I clearly need to investigate 3D printing more!
Thank you gentlemen!

Tom wrote: Wed Sep 20, 2023 1:10 pm Looking great! Happy to throw it on my resin printer if you want to see it printed that way Keep up the great work. For the 'stringing' in that last picture you might want to check your retraction settings and print temps.

Thank you for the compliment!

I definitely need to solve the 'stringing'. It was more obnoxious with the vertically-oriented print (update to follow).

ROB III wrote: Wed Sep 20, 2023 6:21 pm WOW! The last several posts here just turned the day from a loss to a winner.
I clearly need to investigate 3D printing more!
Thank you gentlemen!

It's really pretty fun, too. So much to learn. So many things to figure out. Still fun. Satisfying.

The printer I bought is an "Anycubic Kobra Neo". It's from a decently well-regarded manufacturer of 3D printers. It was $150 a month ago (with a free spool of filament). It's now $130 (w/o the filament bundle deal). For that price I kinda want a second one already.
https://a.co/d/eFLjjEE

It was easy to set up, though a person does need to be precise about "tramming" it in (like a milling machine). It has an auto-leveling feature, but that only goes so far. My X/Z axis was 3mm off from left to right in relation to the print bed surface. That was WAY too much for the auto-leveling to handle properly.

I think their "Kobra 2" line is out, so I imagine other printers in the "Kobra" (sans 2) lineup are also on sale.

Not an affiliate and not sponsored. Just pretty pleased with my choice.

Today's prototype is blue. I printed it standing on end with 0.08mm layer height and automatic "organic" supports (for the features that would otherwise have to print in midair). I still have a stringing problem to solve, which makes post-processing way more tedious. The front left support column was trying to move, so there is a blob of glue stick adhesive at the base of it to hold it in place.
This is the closest one yet, so I installed the stalk and all the factory components into this part. The spring-loaded square-shaped front protrusion has a tiny little "tooth" that engages with the mostly blind rectangular slot in my model. However, my "tooth" is so worn it doesn't stay retained in its opening and likes to launch itself. Still, when the stalk is seated in the switch housing, it works just fine.

That protrusion locks in your left/right turn.

Everything else fits, too! I hadn't fully driven the dowel pin that retains the turn signal stalk to this blue part at the time I took these pics.

Today's prototype is yellow - it's pretty good. So good I installed it in the switch to test it out. It's still PLA, and there are still some tweaks I want to make, but it works! The factory nylon parts and springs and copper contacts all fit with good tight clearances. Same story with the stalk.


edit: I got the video to play in this post (by uploading it to YouTube).

https://photos.app.goo.gl/NxAS7MR4oGPF4g987
I can't seem to upload a video (to the forums), but that's a link to a google photos album with a single video in it.

I added some "ramps" to my model for print-ability (ramps shown in bright green on these CAD images). It makes the most sense (to me) to print it standing on its rectangular end with minimal supports. The ramps don't interfere with functionality, but they do mean those areas don't require support (or the slicer doesn't want to put automatic supports there any more).


I still need to test the electrical connections to make sure there aren't any surprises. I'm feelin' pretty good about this though.