Fused Deposition Modeling (FDM)
FDM is the most common type of 3D printing. It’s used by industry professionals and in-home hobbyists to print creations large and small. Learn about the pros and cons of FDM printing and how it compares to SLA and SLS.
What is fused deposition modeling (FDM)?
Fused deposition modeling is a 3D printing technology that melts plastic to create a 3D object, layer by layer. You can use a number of thermoplastic 3D filaments for FDM printing, such as TPU, PLA, ABS and others. FDM filaments typically come in a spool, and the material is fed into an extruder. FDM printers melt the 3D printer filament and use a nozzle to push the material through as it moves horizontally and vertically over a build platform.
If you’re new to the world of 3D printing, FDM is the best place to start. FDM printing is easy to understand, and materials (printers and filaments) are affordable for the average consumer or business looking to get into 3D printing.
Once you get the feel for the FDM printing method, you can upgrade your materials to high-performance filaments and level up your applications. You can scale your designs by easily extending your build area. Likewise, you can scale up the quantity of prints you produce thanks to the low cost-to-size ratio of FDM printing.
What can you make with fdm?
Pretty much anything! Common applications of FDM include rapid prototyping and simple, proof-of-concept models, but there are thousands of uses depending on your material type and end-use goals. With flexible, durable TPU, you can make sneaker insoles or protective casings for pliers. With more rigid materials, you can print a neat figurine of your favorite comic book hero or durable quick-print parts for your shop machines.
Types of FDM Printers
The versatility and availability of 3D printers have risen in the past decade while the price of FDM printers has dropped, making them accessible to smaller companies and hobbyists. FDM printers start at a few hundred bucks and increase in size and features, up to multimillion-dollar machines operated by large-scale manufacturers.
There are two main types of FDM printer extrusion configurations: Direct Drive and Bowden.
In the popular Direct Drive 3D printers, the extruder sits directly atop the hot end. This allows for better, more stable material control, especially when using flexible and specialty filaments. However, the stacked configuration is heavy, and the backlash and vibration during the quick movements of printing can cause imperfections.
Bowden printers separate the extruder and the hot end, allowing faster print speeds. With less machinery on top of the hot end, there’s less vibration experienced during the constant back and forth motion of printing. One of the disadvantages of a Bowden 3D printer is the fine-tuning you’ll need to do to print various 3D printer filaments successfully. While some TPUs can be tricky to print on a Bowden, Cheetah® and Armadillo® are known to feed well on this type of printer.
One of the major advantages of FDM 3D printing over SLA or SLS methods is the ability to extrude multiple materials into one design. You can stop your print, reload new material, and keep going, or opt for a dual extruder 3D printer.
Pros & Cons of FDM Printing
Pros of FDM
- Great for beginners, but used by professionals with a high-performance filament
- Printers are affordable, thanks to low-cost parts and straightforward technology
- Materials are affordable, with a lot of variety in color and performance
- Easily switch between material types without extensive upgrades
- Ability to print multi-material projects with or without a dual extruder
Cons of FDM
- The extrusion process doesn’t yield as finely detailed prints as SLA or SLS
- Can require extensive post-processing to get a professional look and feel
- Layering can cause weak points depending on the type and quality of material
- Not suited for mass production of parts and objects
FDM vs SLA
How does FDM compare to SLA? SLA, or stereolithography, is a high-end 3D printing technology and the first 3D printing method invented. The process uses a laser or projector light source to transform liquid resin into solid plastic, layer by layer. With SLA, you can make functional prototypes, impressive hobby models or custom dental molds.
What sets SLA prints apart from FDM is the intricate detail capabilities and smooth surface quality. While both processes form objects in layers, SLA layers have better adhesion and deliver a more professional look. When it comes to speed, SLA and FDM are comparable, but SLA requires a few extra steps to post-process to remove resin impurities. Additionally, SLA prints require a support structure, like scaffolding, to prevent part collapse and to ensure a strong build.
While SLA equipment costs have come down in recent years, SLA 3D printers are not the best option for new users. The liquid materials can be messy, are difficult to store and aren’t as easy to handle as FDM filament on a stackable spool.
SLA could be a good option for a small- to medium-sized business looking to create sleek functional prototypes. If it’s quick, proof-of-concept prints, FDM is the more affordable option.
FDM vs SLS
How does FDM compare to SLS? SLS, or selective laser sintering, uses (you guessed it) lasers to fuse polymer powder into a hard plastic object. The most common material used in SLS printing is nylon because it’s strong and flexible and holds up well against impact, sunlight and other elements. SLS prints are ideal for showing off the intricacies of your designs.
The main advantage of SLS prints over FDM prints is the accuracy and ability to handle complex geometries. SLS prints don’t require a support structure, so you have much more flexibility in what you design and print.
However, an SLS 3D printing setup comes with a steep price tag. An SLS system and materials cost tens of thousands of dollars, and you’ll need a bit of training on the equipment before you hit print. SLS prints also require some post-processing due to the grainy finish.
FAQs about FDM
Is FDM the same as FFF?
Yes, fused deposition modeling and fused filament fabrication are one and the same. Fused deposition modeling was coined by Stratasys, where it got its start.
Is 3D printing expensive?
That depends on a number of factors, including what type of printing technology you use, what type of printer you have, the quality of your materials, what you want to create and more. If cost is a factor, FDM extrusion printing equipment and materials are the easiest to start with and scale.
How does FDM printing work?
Fused deposition modeling is a 3D printing process that extrudes melted thermoplastic filament through a nozzle that’s moving in all directions above a build platform. The type of materials and size and type of printer can vary the quality and process slightly.