I love this use for 3D printing. It’s not that I’m a guy that builds custom cars. I just love the idea of using 3D printing in the real world, to replace broken parts in everyday objects or to create custom parts that extend the creative possibilities of whatever object it is you’re working with.
3D printing car parts is a perfect complement to what is a very creative hobby. Building custom cars is an extremely personal endeavor that balances the need for purely utilitarian parts, those needed to make a car work, with all of the decorative and form plus function parts used in creating the driver’s experience and making the car look really cool.
3D printing decorative objects are great, and I love it, but there’s something uniquely and viscerally satisfying about printing a component for a real-world machine, installing it in place and then watching the machine work.
Good Reasons to Print Car Parts
There are a lot of great reasons to include 3D printers in your arsenal of automotive tools. Cars are complex machines with thousands of little parts that lend themselves well to 3D printing. All of the brackets and clips, clamps and wire channels. All of these smaller parts can be created quickly in a 3D printer.
Creating custom parts is built into the DNA of the custom car builder. It’s a necessary part of the hobby, and part of what draws people to it.
3D printing makes the process so much easier than in the past, which helps longtime creators and also throws open the door to hobbyists that might not have had the necessary training or equipment previously.
3D printing custom parts cut down on the lengthy industrial process to create custom parts that were required previously.
Particularly when you’re restoring older cars you run into a lot of small to midsize components that are no longer manufactured and are really hard to find. 3D printing allows you to make these parts at home.
Hot rod builders can use 3D printing to craft custom decorative elements and create custom versions of older hardware with that signature hot rod flair.
Designers and hobbyists can use 3D printing to create custom looks with custom colors for standard auto parts, or they can take standard parts and make minor modifications to add a bit of custom style.
For most parts, stock FDM printers with the typical 0.4 mm nozzle should be absolutely fine. However, for parts that require additional strength, or to reduce print times on parts that require less detail, you may want to consider a larger nozzle.
Upgrading to a high flow hot end like the E3D Volcano would be a worthwhile upgrade for somebody looking to run a large volume of parts.
ASA is an ideal choice for printing car parts. It combines the strength and thermal resistance of ABS with increased UV resistance, high impact resistance and an even greater ability to weather large temperature fluctuations. This makes it the best choice for parts that need to stand up to the seasons, the elements and the harsh conditions under the hood.
However, ASA is expensive and harder to find. If ASA isn’t an option for you ABS is a decent second choice. It won’t weather as well as ASA but it’s still a strong, capable plastic. PETG is a decent compromise between ease of printing and durability.
I can’t recommend PLA, however. It lacks ABS’s toughness which makes it far more likely to snap in real-world applications. Also, it’s not nearly as temperature resistant, which makes it a poor choice for the harsher temperature ranges cars are subjected to.
If you’re adventurous and like a good 3D printing challenge, a hybrid material like nylon with carbon fiber will create extremely strong, durable parts with excellent wear and temperature range characteristics. However, these are not easy materials to work with and aren’t recommended for beginners.
For smaller, structurally insignificant parts, standard slicer settings will likely work. You can start with medium quality settings using a standard 0.4 mm nozzle.
This should work fine for parts that don’t require exacting specifications. For small parts that require slim tolerances, start with those print settings.
If you find that your printed parts aren’t quite accurate enough you can change your slicer settings to favor higher resolution by altering the extrusion width and the print speed and then print again. Then make note of the settings used for printing similar parts in the future.
A lot of auto parts are larger than what you’d normally print in standard hobby 3D printers. At the same time, unless they’re decorative they don’t require a lot of fine detail.
For these you should consider optimizing your settings for strength and speed, increasing your layer height, extrusion width, and print speed. Again, there can be some trial and error involved.
Time to Print
To give you a sense of how long car parts can take to print I ran the 4 wire version of the spark plug separator on my Prusa I3 Mk3 printer and it took 36 minutes to print.
I also ran the BRZ Gauge Pod Holder which took 2 hours and 16 minutes to complete.
Remember that these are just estimates. Every printer model has its own print speed, so use my examples as a baseline.
If you’re using an FDM printer you may need to give your prints a quick sanding and/or filing to clean off any burrs. You may also want to bond the outer faces to smooth out print striations or any low polygon angularity, particularly if the parts are decorative or are used in places where they’re visible.
Painting is also recommended if you’re trying for an attractive, finished look.
It may go without saying, but I’ll say it anyway if the part you’re printing is going under the hood or otherwise out of sight there’s no reason to do any post-processing at all unless it’s necessary to be certain the part performs as needed.
If you’re printing parts with an SLA printer you’ll need to do the standard alcohol cleaning to remove the sticky post-print film that adheres to your model after it comes out of the resin bath.
What are the Biggest Challenges You’ll Face?
ABS and ASA both are prone to warping, particularly in larger parts. This can be a problem for automotive applications, where warping can interfere with proper function.
It’s important to keep the application in mind for the specific part you’re printing. If warping is going to be an issue then you may need to consider adding structural elements into your design to help the part maintain its shape, or use materials that don’t suffer from the same problem, like PETG.
Larger pieces are also slow to print and can be expensive, particularly if ASA or other expensive materials are used. If the part you’re printing can be purchased for significantly less, that may be a better option unless there’s a necessary custom element you’re including that can’t be added any other way.
Also, 3D printed objects are limited in size and strength. Injection molded plastics are always stronger and more resilient. Be certain to consider, on a part by part basis, whether 3D printing is the best choice for the specific application. You don’t want to take chances on parts where failure could lead to catastrophic or damaging results.
Plus, if you want to create custom parts you’ll need to learn a CAD program, like SolidWorks, Fusion 360, OpenSCAD or Tinkercad.
This isn’t a challenge unique to printing car parts, but it is something you’ll eventually need to learn, and there is certainly a learning curve if you ever want to print well-made, custom parts.
Remember that automotive parts often require exacting specifications, so make certain your measurements are accurate before printing, or you may find yourself wasting a lot of expensive print material.
Needed Extra Materials
Besides your extrusion materials, you’ll likely need sanding and/or filing supplies, Bondo, and surface/application appropriate paints for a finished look. You may also want to consider metal inserts for threaded applications that require additional strength.
Car Part Resources
There’s a wide variety of custom automotive part models available online. Searching on Thingiverse, Grabcad, or YouMagine will return a host of fun, interesting and useful items to print for your car.
And there are very good CAD software packages, like those we mentioned earlier, that will help you design your own parts for all of your custom automotive needs.
Here are a few select models, curated to give you an idea of what’s available to you.
Spark Plug Wire Separator
This wire separator is designed for 8 mm spark plug wires, and there are versions available that handle anywhere between two and six wires. You’ll notice in the write up the author explicitly states that ABS (or ASA) must be used because of the high temperatures the part is likely to be subjected to.
SwitchRest: Nintendo Switch Headrest
This fun piece of hardware converts the back of your car’s headrest into a holder for a Nintendo Switch. Great for kids that want to watch the device while sitting in the back seat.
Air Vent Gauge Pod
This custom part fits standard 52 mm gauges and allows one to be installed in the driver’s side air vent in a Subaru BRZ or Scion FR-S. It has air vent spaces around the outside of the gauge holder to allow the air vent to continue functioning normally.
Jeep JK Switch Panel
This is a custom switch panel made to fit the bezel curve of the dash in a Jeep JK Wrangler. It houses custom switches which can be used for a variety of purposes.
It should be clear now how useful 3D printing can be to both custom car enthusiasts and 3D printing fans looking for new and interesting projects to tackle.
Even if you aren’t creating custom parts for inclusion in your own builds, there are plenty of fun printing projects intended to extend the use of your vehicle and make life more interesting.