Does anybody have experience in using 3D printing for housings of automotive ECUs? I am not talking about prototypes or passsenger car series production, but small series for commercial vehicles.
Thanks
Torsten
Certainly not FDM or other methods that use thermoplastics.
It’s just too hot either in the engine compartment or after a week of desert sunlight.
Just get some 16 gauge steel sheet, a few nibblers, steel sheet clamp, a propane torch and some metal working solder.
The housings will be tough, and relatively easy to fabricate, and you can rest assured that even if the engine overheats (anything short of an engine fire) the ecu housing won’t be falling apart.
I don’t like electronics enclosures made of conductive material
You mean like the enclosures for iPad, iPhone, your desktop PC, and pretty much every server in production?
There’s nothing wrong with using steel for an electronics enclosure. Obviously one must, prime and then paint the enclosure with a suitable enamel to prevent rust and shorting hazards.
But if you really hate the idea of using steel/aluminum/magnesium or other metals, then you could always go composite.
2" fiberglass woven tape + system three/west system epoxy + 1mm thick solid cardboard for making the forms.
Either way, both beat 3D printed plastic for durability.
Polyurethane sounds easier.
Can easily mold the clips to close it up, the spacers for the PCB(s) and form-fitting recesses for any connectors.
My Desktop isn’t inside a machine that my life depends on that shakes and rattles heavily for hours on end in extreme heat and sometimes gets sprayed with salt water from below.
I can see 3d printing a prototype, but it wouldn’t trust it in severe-duty real world service. Are you looking a a production run of 1, 100, or 10,000?
If you’re not afraid to mix some epoxy, woven fiberglass tape wetted out with a solid marine-grade epoxy draped over the FDM prototypes for reinforcement in real world use cases is relatively easy to get going. This works decently for one-off and other isolated cases.
These are the tapes I’m referring to (not the “fiberglass tape” found at Home Depot or other consumer outlets):
And here are the types of epoxy I’m referring to:
https://www.fiberglasswarehouse.com/MainPage.php?Nav=Fiberglass%20Resin&Category=Epoxy%20Resin
Tying this back to 3D printing:
Lose the cardboard forms, print positive versions of the enclosures in ABS then coat the ABS surface with aluminum tape as seamlessly as possible.
Set up a vacuum bagging rig and spray mold release onto the 3D printed ‘positive’ of the enclosure, once mold release has set, spray and apply about 3 layers of a light fiberglass cloth (8 oz e-glass twill works well for detail retention), bag it and let the assembly cure for a day. This is labor intensive and requires skilled laborers.
Alternatively, one could print the enclosures via FDM, then reinforce the exterior structure of the enclosures by spraying them with chopped strand fiberglass (how composite shower booths/bathtubs are fabricated).
This is the least laborious process, but cannot retain details well.
Frankly, depending on volume, I’d say use the prototypes to have steel stamping dies made. Production with stamped steel sheet (16 gauge works well generally, for extreme environments 14 to 12 gauge works too) is fast. If the pcb is designed well, electrical shorts wouldn’t be an issue.
I use 22 to 16 gauge steel sheet in one-off fabrication of all kinds of electronics enclosures. It’s the fastest way to go from idea to a tough prototype with a spartan capital outlay. If spot welding is used, it gets even cheaper.
Carefull, Epoxy shrinks by up to 5% and is not very flexible.
Indeed all composite fabrication involves taking curing into account with regards to dimensional contraction, this is nothing new.
Apparently polyurethane filament is available for use in 3-D printers, I’m just not sure how appropriate the material would be inside of an engine bay exposed to temperatures above 150°F (in the summertime). With vehicle electronics enclosures flexibility usually isn’t a huge design constraint.
@Marcus_Wolschon , were you referring to injection molded polyurethane?
Wonder how Nylon 66 would extrude? Its what modern engine intakes are made out of…and by modern, I mean 17 year old Corvettes. 