What is FDM 3D Printing?

Fused deposition modeling (FDM) is a term you’ve without a doubt stumbled across looked if you’ve ever looked into what a 3D printer is. This article will help you understand what FDM is, how it works, and what applications it works best for.

What is FDM?

Imagine a robot squeezing a syringe full of soft playdough into a square on a table. As that layer of playdough hardens, the robot squeezes another layer on top of the first, creating two layers of squares.

This process continues until the robot has made multiple layers of squares, resulting in a hard playdough cube.

Wouldn’t it nice if we could do that very same process with plastic? That is essentially how FDM 3D printing works.

We aren’t limited to cubes and basic shapes, however. FDM is capable of creating very complex 3D models.

FDM 3D printing is a process that uses a continuous extrusion of a thermoplastic material deposited in thin layers to create a 3D model.

Instead of playdough in our analogy, FDM uses thermoplastics, which are plastics that can be melted and then hardened again. Also, replace the syringe with something called an extruder, which moves in the x and y planes, as well as vertically.

The Intriguing Invention of the FDM Process…

The legend goes, that in 1988, Scott Crump was just looking for a simpler way to make a toy frog for his daughter.

Using a hot glue gun, he built layer upon layer until something resembling a frog was created.

“Eureka!”, he had just invented an industry-defining process! I bet all of you who lived in 1988 are now saying “why didn’t I think of that?”.

S. Scott Crump then Co-founded Stratasys and had a patent awarded in 1992. Stratasys’s first 3D printer was called the Stratasys 3D Modeler.

Over the next decade, the company would grow steadily, selling thousands of units.

Since the expiry of the patent, many companies have sprung up to innovate and capitalize on the process. This, along with the simplicity of the technology, has made FDM one of the cheapest processes in 3D printing, and therefore the most popular type of 3D printer.

Other Names for FDM?

Other names were used to define the process to avoid legal issues since the term fused deposition modeling was patented by Stratasys. Some of these other names are:

• Fused filament fabrication (FFF)
• Filament freeform fabrication (Also FFF)

If you see these terms, you can be assured that they mean the exact same thing.

How Does FDM Work?

Fused deposition modeling isn’t as complicated as it may seem at first.

First, a 3D model is created on a CAD program.

Then, a different program called a slicer takes the 3D model in and spits out code (called G-code), which the 3D printer can interpret. The code basically tells the extruder of the 3D printer how to move when placing material.

Fused deposition modeling uses wound up thermoplastic wires called filament. The thermoplastic material is capable of being melted and then oozed onto a surface (like toothpaste) and then left to dry.

The filament is pulled into a heated extruder where it is melted. The extruder is then moved automatically (according to the G-code) to the desired location to deposit the melted thermoplastic through a nozzle.

The nozzle makes the semi-liquid plastic discharge in thin lines, which is important for smooth surfaces. As the first layer of liquid plastic quickly cools, the extruder moves vertically to deposit the next layer on top.

The process continues until the part is finished.

Simple, right? This is, of course, is a very simple explanation of how FDM works. The process can get much deeper with things like heat beds.

Pros

• Low cost
• Uses filament (low cost and easy to handle)
• Fast
• Many available materials
• Easy to use

Cons

• Visible layers (lower resolution)
• Struggles with complex designs
• Some designs require support structures. (Cannot produce unsupported stalactites)
• Only small overhangs

Applications

FDM works best for making low-cost, quick prototypes, that don’t need to be complex or high resolution. Its simplicity/ease of use makes it a good 3D printer for beginners.

Overall, FDM is the most accessible and easy to use 3D printer for a wide variety of applications. If you’re searching for a low-cost 3D printer, an FDM type is most likely going to suit your needs. But you might look into SLA or SLS type 3D printers if you require high-quality parts.