FDM 3D Printers

FDM 3D Printers

Like many other manufacturing methods there are subsets of 3D printing methods that work a differently to achieve different goals. The most common 3D printing method and the one you might picture when you hear "3D printing" utilizes FDM, or FFF, technology, which stands for "Fused Deposition Modeling" or "Fused Filament Fabrication" (these are two names that describe the exact same thing). FDM 3D printers work by taking a single, long strand of plastic called "filament" and with the use of stepper motors and a motherboard within the 3D printer, softening the plastic to a point where it can be reliably extruded out of a heated nozzle and laid down in precisely dictated toolpaths. Material sciences for plastics are well established and refined which makes this a reliable process to work with and keeps material costs low. You can vary the strength, rigidity, heat resistance, or UV resistance of your finished 3D print by choosing a material that has been designed to maximize the desired properties, offering much more freedom for your finished 3D print's use case than any other 3D printing method.

About FDM 3D Printers

What is an FDM 3D printer?

An FDM 3D printer is a type of 3D printer that takes a long strand of plastic, heats it up, and extrudes it into a controlled path to recreate some digitally designed object. The key parts of an FDM 3D printer are its hotend, which actively heats and melts incoming plastic, and its extruder, which pulls material off a spool and feeds it to the hotend.

Which is better, FDM or SLA?

Each tool has its purpose and different kinds of 3D printers follow the same rationale. FDM 3D printers are better at creating large parts at the fraction of the cost of an SLA 3D printer, but the surface has a noticeably rougher texture. In general, FDM 3D prints are better suited for large 3D prints, heavy-use 3D prints, or 3D prints that need to have unusual qualities like flexibility, ductility, and strength.

How much is an FDM 3D printer?

FDM 3D printers come in a wide price range, from as little as $189 to the $10,000 neighborhood. The pricier you go the less the user should need to do to get a successful print and to maintain the machine. Low-cost 3D printers forgo all the bells and whistles with the expectation that the user will be ready to troubleshoot, repair, and tune their 3D printer to perform as they want it to and upgrade as necessary as time goes on.

What are the advantages to FDM 3D printing?

With FDM 3D printing there comes some distinct advantages: material diversity, easy iteration, and simple cleanup. Because FDM 3D printers are plastic based machines, there is an entire industry of material science to create formulations specifically crafted to better support the needs of a successful 3D print rather than the needs of injection molding; it's much easier to find ways to vary the formulation of plastics for different finished properties than it is to do the same for resin based 3D printing. Depending on the size and complexity of your design you can go from concept to a 3D print of your first draft in only a couple of hours. You will often need to iterate on the design and see what works and what doesn't once you have a real model in your hand to observe. At that point you can make some changes to your design, print out just the problem areas rather than the entire model, and continue to make adjustments, costing only a few cents per iteration. Where other 3D printing methods need solvents and post-processing stations to manage the messy cleanup, FDM 3D printing at a minimum only needs some tools to remove supports like pliers, tweezers, and files or at the more advanced end of options you can soak your PVA filament supported part in warm water to dissolve the support material. Overall, you will want to lean on FDM 3D printers for their speed, cost, and versatility in usable materials.

Are FDM printers faster than resin printers?

In almost all scenarios, yes. Printing a 20mm cube with an FDM 3D printer will take dramatically less time to 3D print than a resin 3D printer. Conversely, 3D printing many small and intricate 3D models at the same time (like tabletop miniatures or jewelry) will be dramatically faster using a resin 3D printer. This is basically the only instance where FDM 3D printing is slower. However, if you intend to do any post-processing on the finished 3D prints, it may be faster to go with a resin 3D print to avoid sanding, filing, and shaping the intricate details of your model to remove the layer striations inherent in any 3D print; layers in a resin 3D print are on average 4 times thinner than an FDM 3D print and will require much less elbow grease to sand away and smooth the surface. 

Is FDM printing strong?

When you choose the right material for the job, yes. Each material you might choose from when FDM 3D printing brings its own pros and cons. For example, PLA is the most basic material you can FDM 3D print with but its also one of the strongest. Unfortunately, it's not very ductile which means that if you were to print a shelf bracket and overloaded the shelf, you wouldn't see or hear that the bracket is failing; it will be just fine on your wall one second and tumbling down the next. A better choice might be PETG or ABS, as these two will bend a little before failing, allowing you to catch the failure before it happens and your mementos come crashing to the floor. Adjusting the wall count (that follow the perimeter of the 3D model) increases the strength of the 3D print as well, so you can increase the wall count to increase strength of your part. This is all done in the slicing program (called a slicer) as well so once you have a working model you can adjust the settings as you see fit to have print setting match the desired use case; keep all the strength-centric and aesthetic settings coarse for your first prototype, but increase all of these settings once you are ready for a final product.

Is FDM printing stronger than resin?

Resin 3D prints tend to be brittle and will chip and fracture under the slightest bit of stress. FDM 3D prints tend to last quite a bit longer when exposed to the same stresses. Generally, this is simply a facet of the technology as there is a sort of "grain" to the FDM 3D prints that helps them hold together, but resin 3D prints are closer to being chemically bonded so there is less "grip" to hold everything together.

What is the strongest filament?

If "strong" is defined as being the most able to hold up the most weight before failing, then plain polycarbonate is hard to beat. If you use any of the BASF Ultrafuse materials and follow all the post-processing guidelines the finished parts will be 100% metal and far stronger than the best polycarbonate 3D print. 

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