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What Is Fused Deposition Modelling?

Fused Deposition Modelling - 17 October, 2022
What Is Fused Deposition Modelling?
Vicki May
17 October 2022
Fused Deposition Modelling

Additive manufacturing technology has seen vast growth over the last few decades, with the development of much more affordable and effective technologies like fused deposition modelling.

Unfortunately, these technologies, and their acronyms, can be confusing, especially for those new to these additive manufacturing processes.

Fused deposition modelling (FDM) is a commonly found high-quality 3D printing technology. An FDM printer heats the filament to its melting point, then pushes the molten filament material through extruders and onto a surface to print the object layer by layer, from the bottom up. 

Because FDM is such a simple technology, most of us have seen FDM 3D printers, possibly without even realising it. The models you see running at 3D printing stores or hobby shops are most likely FDM printers.

Let’s look at fused deposition modelling and its printing process more closely.

What Is Fused Deposition Modelling?

Fused deposition modelling (FDM) is a 3D printing manufacturing process that involves pushing molten material through extruders onto a printing surface. The filament is usually a mixture of different plastics and other synthetic materials. As it is pushed through the extruders, the surface (or the extruder) moves to manufacture the product one layer at a time.

Many people refer to FDM technology as “Fused Filament Fabrication,” or FFF. This name is slightly easier to understand since products are fabricated through a process whereby the filament is fused into particular shapes. However, FDM and FFF are not precisely the same, though they are so similar; almost indiscernible. 

Fused deposition modelling is a system invented and patented by S. Scott Crump in 1989. The patent belongs to Stratasys. Though similar, FFF uses technology that’s just different enough from Stratasys’ patent not to incur lawsuits. Thus, people often use the terms interchangeably, but true FDM produces higher-quality prints with smoother surface quality.

What Does FDM Involve?

Fused deposition modelling printers have a heat-controlled nozzle mounted on an X-Y transport mechanism. The nozzle heats the filament, which is then extruded onto a printing bed that moves on the Z-axis. 

FDM printers are made with high-quality components, meaning they don’t need maintenance or repairs often. However, the filament must be replaced regularly.

What Can FDM Be Used For?

FDM is one of the most commonly used additive manufacturing technologies because it is affordable. As such, fused deposition modelling has various practical uses, including (but not limited to) the following:

  • Engineers use FDM for rapid prototyping to models of their products. It’s a quick and affordable way to create a realistic design model so you can see any potential shortcomings before the final production starts.
  • People use FDM to create product examples for sales teams. The mining industry, in particular, often has to manufacture massive pieces of equipment that are impractical to use in a sales meeting. FDM-printed small-scale models are the perfect solution since sales representatives can use them to demonstrate how the actual product will function.
  • Sometimes, FDM products are used as the final products. Any product that can be made out of plastic or certain synthetic materials can be 3D printed using FDB. The technology is often used in the automotive and aeronautics industries to make minor mechanical objects or pipes.
  • Hobbyists love to use fused deposition modelling. People use it to print anything from model aircraft to action figures. Tabletop gamers, like Dungeons and Dragons players, design their characters and then print them on FDM printers.
  • FDM is popular in education. Teachers use 3D printing to teach various STEM concepts from the primary school level up to high school. Engineering and design students use FDM printers to print out their creations for practical testing.

How Does FDM Printing Work?

The FDM printing process involves several steps; the first few don’t include the printer.

1. The Design Process

The first step in FDM printing is to make your design. It sounds obvious, but you must design it before you can 3D print anything. The design part is done using CAD (Computer-aided Design) software on a computer. There are various types of CAD software on the market. Some of these are free for students and hobbyists.

If you want to 3D print something in particular but don’t have CAD knowledge, you can always download a design from a website like Thingiverse.

2. Prepare Your Design For Printing

A finished CAD design is excellent, but a fused deposition modelling printer won’t be able to print it as-is. You need to convert the design into a series of instructions that the 3D printer can follow to print it. There are software packages available that can do this conversion for you. A notable example is Ultimaker Cura, but you will usually get some software with your FDM printer.

Once the software is open, you can import your design into it. The software will let you tweak some settings, like rotating the model or re-scaling it to make it bigger or smaller.

This software allows you to do two things:

  • You may have to add support structures to your design. For example, FDM printers can’t print large loose-hanging parts, like roofs on model houses. You need to add support beams to keep the roof up, which you can do during this step.
  • When you’re happy with the design, you can “slice” it. The software splits your design into layers and increments, then exports it as a G-Code file that the 3D printer can read and understand.

3. The Filament Extrusion Process

Once you have your G-Code file loaded into the printer, it will start heating the nozzle (and sometimes the printing bed) to a pre-determined temperature based on the melting point of your filament. 

Once it reaches the correct temperature, the FDM printer will start pushing the filament through the nozzle, where it melts. The molten material is then extruded through the nozzle onto the printing bed with a layer thickness of between 0.1 and 0.5mm.

4. The Printing Itself

The FDM printer will usually extrude molten filament in a pattern that vaguely resembles the outline of your print. This is to clean the nozzle and ensure no obstructions on the printing bed.

Now the nozzle will move around the X and Y axes to print the bottom layer of your model. When done with the first layer, the bed will lower slightly on the Z axis so that the nozzle can print the second layer.

This process repeats, building your model from the bottom up until the model is complete.

What Are The Advantages And Disadvantages Of FDM?

In an industry with so many different technologies, not all types of 3D printing are ideal for everyone. Like all other types, fused deposition modelling has advantages and disadvantages.

Advantages Of FDM

  • You can print relatively quickly. Compared to other 3D printing technologies, FDM is quite fast, even though it could take hours to print something.
  • FDM printers are affordable compared to other 3D printers, making them perfect for homes or small businesses.
  • FDM is budget-friendly. You can use a wide range of different filament types with an FDM printer, so you can print at any price point.
  • FDM’s print quality is very high. You will get a smooth and detailed print if you set the resolution and other settings high enough. 
  • FDM printers are infinitely scalable. Because the system is so simple and basic, it’s much easier to build a larger 3D printer than with other technologies.

Disadvantages Of FDM

  • FDM doesn’t offer the best quality. Though the settings provide high-quality prints, other 3D printer technologies (like SLA) offer much better quality.
  • FDM’s resolution is relatively low. Despite how high you can set it, other types of 3D printers can print much more refined details.
  • FDM prints can be structurally weak. Because the printer builds the models by pasting one layer of filament on top of the next, the areas between the layers (the creases) cause structural weakness. FDM is not the strongest type of 3D printing.


Fused deposition modelling is an affordable, high-quality way to 3D print models by placing layers of molten filament on top of one another. The process is slow, but it’s still one of the fastest 3D printing technologies. Despite a few disadvantages, FDM is the most popular choice for many people, and if you want to get started with 3D printing, FDM would be a wise choice. 

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