When you’re working on a project, especially one that doesn’t have many readily available parts, chances are you’re going to have to do some fabrication. We all know about the basic fabrication tools that are out there, but have you ever thought about using 3D-printing technology in your shop? Well, we’re going to look at how you can use a 3D printer in your shop and on an automotive project.

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The progression of 3D printing technology has allowed it to become something you can do at home.

Right now, we’ve got a few projects that we’re working on that will need some custom parts, and using a 3D-printer to create them makes sense. We reached out to the team at ELEGOO, a leading 3D printer company, to get a printer for our shop. They recommended we try the ELEGOO Neptune 3 Max FDM printer. This particular FDM printer has a massive 16.53×16.53×19.68-inch build volume, so that will allow us to print some pretty large parts.

The Neptune 3 Max is a feature-rich printer that’s actually very easy to learn how to use. One of the features we like about this printer is its ability to run different types of printer filament, which is important when you’re printing car parts. If you’re interested in getting a 3D printer for your shop, this printer should be at the top of your list.

FDM 3D Printing Basics

Let’s talk about what FDM printing is and how it works. The FDM in FDM printing stands for Fused Deposition Modeling. This type of printing uses a polymer-based filament that’s melted and laid down in 2D layers on top of each other. As these layers are stacked up, they create a three-dimensional object. So, think of it as a reverse CNC machine, instead of removing material to create an object, it uses the polymer filament to build an object.

FDM printers work by taking the filament and running it through a heating block via some type of motorized system. As the filament is pushed through the heating block, it melts and runs through a nozzle that lays the material down on the print bed. While this is happening, cooling fans are running to help cool the filament so the layers will fuse together and stack up properly. This all happens as the print head moves along the X, Y, and Z axis of the print bed.

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Filament is fed through the hot end where it is melted and laid down on the print bed. The stepper motors are in charge of moving the print bed, print head, and print head gantry during the printing process.

The print head is typically moved by a belt system that’s controlled by stepper motors. These motors move the print head along its tool path based on the G-code that’s uploaded to the printer’s operating system. This G-code is created in CAD/CAM software and can be used to design literally anything that you can dream up, you’re just limited by the printer’s abilities.

The filament that the printer uses to create objects is an amazing material. There are all kinds of different filaments out there that have different properties and abilities. The price for most rolls of filament is less than $60, and depending on what you’re making, can make lots of different items. Since the filament is so versatile, it can be used in the automotive world for prototyping parts, as well as creating useable parts.

Most 3D printers read .STL format files that are created in CAD/CAM programs. You import the .STL file into slicing software that will convert the file into printing instructions for your 3D printer. This information is used to generate a G-code file that the printer can read and follow to create the object you’re printing. You can go to websites like Thingiverse, Cults, and GrabCAD to find .STL files for your printer.

If you want to learn in more detail how FDM 3D printers work, you can watch this video.

Filament: The Building Blocks Of 3D Printed Parts

Let’s take a deeper dive into FDM filament and how you can use it in an automotive application. You’ll see common filaments like PLA, PETG, and ABS used the most for 3D printing. When you’re selecting filament for 3D printing car parts, you need to take into consideration things like engine heat, vibrations, how UV rays will interact with the parts, and how much stress the part will be put under.

Tyler McCormack owns Reversion Raceworks, a company that specializes in making 3D-printed parts for automotive applications. He explains why you should use PLA filament when you’re making prototype parts for a project.

“PLA is one of the most common materials in the 3D printing industry. This material is extremely cost-effective and exceptionally easy to print. Due to its material properties, this is a poorly suited material for long term use, since it is not very stable at high temperatures, and will degrade over time. However, for test parts or mockup, it is hard to beat the price vs. performance of PLA.”

Let’s say you’re making a custom gauge pod for your project vehicle. After making some test prints using PLA and dialing in the design, you have something that works. What material should you use to print it? You’ll want to use a filament with good thermal stability since it will be exposed to different and elevated temperatures.

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A part that will be exposed to the elements will use a totally different filament than something that will only see the inside of the vehicle.

“You want to make sure the material you select will be stable to ambient temperatures that will reach at least 170 degrees Fahrenheit. Common materials we use for projects and parts are PETG, ABS, and various grades of Nylon. For increased toughness, PETG, ABS, and Nylon can be supplemented with glass fiber or carbon fiber fill. If you’re looking to 3D print a part but don’t intend to paint it, ASA is also a great choice. ASA is extremely similar to ABS, but has built-in UV modifiers that prevent color fade and deterioration, making it exceptionally well suited to outdoor use. Overall, Nylon is one of our favorite materials to use since it is extremely durable and stable, but it’s more expensive than other materials,” McCormack says.

If you’re going to print something that’s being used under the hood of a vehicle ambient temperatures really become a factor. PLA won’t do well as the filament of choice for parts that are used in the engine bay. McCormack recommends using filaments that are made of a Nylon or Polycarbonate material since these can withstand elevated temperatures better than other materials. They will still need to be shielded from the heat that radiates from exhaust components or other objects that generate lots of heat like other parts made of plastic.

Finishing Parts After They’ve Been Printed

Now that 3D printing has become more affordable, it has allowed the DIY crowd to create all kinds of custom parts at home. The parts you can design and print are on par with what can be fabricated in any factory, but the parts might not have that polished look. This is due to the layer lines created by the 3d printer as it prints a part. The colors of the filament are also limited, so it might not match the vehicle’s color perfectly.

While this may seem like a big problem, thankfully there is an easy solution to color-match and finish 3D-printed parts. Most 3D filaments can be sanded and painted fairly easily like any other plastic part. You just need to follow the same workflow you would painting any other plastic part to achieve your desired finish. That means you can color-match interior parts using paints from SEM Products or other companies to make your 3D-printed part look like it came on the vehicle from the factory.

One of the challenges you might face with designing parts is how you’ll attach them to the vehicle. This usually comes up when you’re trying to replicate a broken part, or create something totally new that was never on the vehicle to start with.

McCormack explains how you can overcome this issue.

“Through holes or studs are an easy option. We also like to use threaded fasteners since they’re a proven solution. Usually, it’s not a good idea to thread directly into plastic, especially if the item will need to be moved often. Luckily, there’s a really quick solution for this. Threaded inserts that can be melted into the parts. These inserts are inexpensive, and usually come in a pack of multiple sizes. Start with the desired fastener size, and then size a hole in your part that is the same OD as the threaded insert. To install the insert into the part, heat up the metal insert and press it into the hole. The fastest way we like to do this is to use a soldering iron, which allows us to heat and press in the insert in just a few seconds.”

No Part, No Problem: Designing Your Own Parts

What do you do if none of the .STL file sites have a file for something you need to print? Well, you can fire up any CAD/CAM software and create what you need to print. This opens up an entire universe of possibilities for any individual or automotive shop. Instead of creating prototypes or other parts out of metal to see if they’ll work, you can create them with a 3D printer out of plastic.

Matt Hollenbaugh, owner of Backyard CNC Werks explains the advantages of being able to use CAD/CAM software to design parts that can be 3D printed.

“You can physically model a part in 3D as you create it. When you want to produce these parts, that model is what your printer uses for the data. Without that model, you can’t print the item. The accuracy and features that can be designed are infinite, your imagination is the limiting factor. With certain CAD/CAM software, you can do performance analysis, and design analysis to see how your part will perform with certain stresses put on it.”

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You can create parts for your vehicle in CAD/CAM software from scratch. If you need a custom solution to hold some tools you can create that as well.

The ability to design and print parts will save you money and time. A 3D-printed part is far more affordable to create than something made of metal, and it will allow you to design a more refined product. For your average DIY person, this means you don’t have to invest in expensive machines to create parts or prototypes. You can 3D print the part, test it, make sure it works, and then have a shop make the part out of whatever material is required.

“Oftentimes, the conventional methods of CNC machining or injection molding for one-off parts doesn’t make sense from a financial standpoint. Once a printer is tuned and up and running, there is very little maintenance and setup needed to get them humming away on parts. The software that is used is both free and highly automated, so beginners can easily take advantage of that to save time and headaches. For our business, it allows us to take on the one-off restoration or custom projects at a fair cost that other guys won’t touch,” McCormack says.

You can also design and print your own tools or jigs that can be used around the shop. There are countless specialty tools out there that work great, but have limited use around the shop. You can design your own version of these tools that can be printed. McCormack says they design and print things like alignment and indexing tools, tubing centerline markers and drilling jigs, camera mounts, stencils, and tool organizers to use around the shop. You can also modify a tool or part in CAD/CAM software so it will work for your specific application before you print it.

What if you need to make something out of metal or another composite material for a project? Well, you can use 3D printing and design software to make that task easier.

“Recently, we designed and made a custom hood scoop for a C2 Corvette by using 3D-printed molds to pull a fiberglass part. Another cool way to use printed molds is for metal forming, where we have seen dies made and put in a press to dimple sheet metal panels. Even a simple drill guide or soft jaws to hold organic shapes squarely in a vise are all smart ways to save time and energy and come out with a better, more repeatable product with the help of 3D printing,” McCormack explains.

Using A 3D Scanner To Make Custom Parts

There are plenty of parts you can design in CAD/CAM software to print, but some items just might be too complex to create. If you’re really serious about 3D printing solutions at home or in your shop, a 3D scanner is an excellent tool to invest in. There are all kinds of scanners at different price points available today. You get what you pay for with these scanners, so it’s wise to really do your research and see which one will work best for your needs.

“For a replication or customization project, if you want the best accuracy, it is highly encouraged to start with a 3D scan. You can think of 3D scanning sort of like sonar on ships and submarines, where a signal is sent out, and what comes back to the receiver is based on the shape of the object. Instead of sound, the scanner emits a specific light pattern, which a camera then reads to pull dimensions from the object in front of it. It is incredibly accurate, pulling surface dimensions down to a few thousandths of an inch. This data is compiled into a file that we can edit and view digitally, and is where we start most of our projects,” McCormack says.

After you scan an object and create the file, you can import it into your CAD/CAM software. Once you’ve got the object in the software you can start to design what parts you need that will work with this object. A good example of using a 3D scanner would be for an engine swap that needs a custom accessory-drive system. You can scan the engine bay to get dimensions and use that information to create parts to be 3D printed for test fitting.

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You can go from scanning, to modeling, to printing with the right equipment.

The 3D scanner can also be used to scan a part that will be the base for another part you need for a project.

“Once you have the dimensions from the part, either by scan or manually measuring, it’s time to jump into the design, or ‘modeling’ of the part. Remember that just like a blueprint, the scanner only tells you where things are, but it does not output a file that is ready to be manufactured. The modeling of parts on a computer is called computer-aided design (CAD), and there are several free and paid options that have different strengths. Our favorite CAD software is Solidworks, but for personal use, Fusion360 or Sketchup are good low-cost starting points,” McCormack explains.

Technology has changed how things are made and there’s no reason you can’t take advantage of this at home in your garage or in a shop that builds performance vehicles. A 3D printer will open up a world of creative opportunities that are only limited by your imagination and willingness to learn something new. So, if you’re feeling creative and adventurous in the shop, a 3D printer could be something you want to invest in to take your projects to a new level.