Fused Deposition Modelling (FDM) or Fused Filament Fabrication (FFM), is a 3d printing process that produces durable objects out of the same plastic that we see in everyday products. Furthermore, FDM processes industrial-grade thermoplastic materials. That’s what makes resulting parts so tough and durable when properly processed.
FDM 3d printers are revolutionizing the way industries design and manufacture their products. With FDM 3d printing, a designer can sketch an idea and test it the same day. Industries can cut out lead times and costs using FDM 3d prints. Let’s have a look at how FDM 3d printing technology actually works…
How does FDM work?
Thermoplastic parts are built using polymers that come in a filament form. The melted material is selectively deposited in a pre-determined path layer by layer to give shape to the final product. The whole process consists of 3 steps:
- The printer is first loaded with a spool of thermoplastic filament. The nozzle temperature increases to allow the thermoplastic to flow. Once the desired temperature has been attained, the filament is fed to the extrusion head and in nozzle where it melts and is extruded uniformly through the nozzle.
- The extrusion head that can move in the X, Y and Z direction, extrudes the melted material through a fine nozzle. The 3D printer deposits material in pre-determined locations layer-by-layer in accordance with the design of the product. Finally, the material is cooled off and solidified. This cooling can also be expedited by attaching cooling fans on the extrusion head.
- The printer moves in the X and Y axis to fill the area until a layer is finished. After finishing one layer, either the build platform moves down or the extrusion head moves up to start depositing the next layer. The printer repeats this process several times until the part is complete.
Materials used in FDM 3d printing
FDM 3d printing method uses a wide array of thermoplastic polymers which are industrial-grade plastics with very high strength when properly processed. Below are some common FDM materials and their properties:
- ABS – It has great strength and very high-temperature resistance. The only downside is that it is a little more susceptible to warping, particularly when processed outside of a temperature controlled chamber.
- PLA – Polylactic acid or PLA is a very common material used in FDM processing. It has excellent visual quality and printing parts is very easy with it. The downside is low impact strength due to exceptionally high rigidity.
- Nylon (PA) – This material has high strength and it is extremely resistant to wear and tear and chemical resistance. It tends to absorb moisture though which can impact its strength and durability in outdoor locations.
- PETG – PETG is food-safe, has good strength and it is easier to print parts with this material vs alternatives like ABS and PC.
- TPU – TPU is extremely flexible and is hard to break. However print times are long and processing parts using this material can be very difficult.
- PEI – PEI is an expensive material and requires a high temperature chamber, but it comes with excellent strength to weight ratio. It also features excellent chemical and fire resistance.
This is by no means an exhaustive list of the many materials available in FDM 3d printing. Every year new composite and copolymer materials are developed and released to enable new applications.
Benefits of FDM 3d Printing
It is no surprise that FDM 3d printing technology has ground-breaking advantages over traditional manufacturing methods. Let’s look at some of the salient benefits of using FDM 3d printing process:
- FDM technology is very simple-to-use, low power, clean and even office-friendly.
- Lead times are very short which gives designers the opportunity to design and manufacture parts and prototypes the same day.
- Due to low production costs, FDM 3d printing is the most cost-effective way of producing thermoplastic parts and prototypes.
- FDM 3d printers take advantage of a wide range of different materials. This makes it suitable for parts and prototypes requiring a diverse set of properties.
- FDM enables manufacturers to produce parts with complex geometries easily, particularly when using soluble supports.
Limitations of FDM Technology
There are drawbacks associated with every technology and same is the case with FDM 3d printing. There are certain limitations that designers have to keep in mind when using this technology.
- Most parts manufactured using FDM 3d printers require support structures. One problem with using support structures is that the surface finish is not very smooth at the supports. FDM parts almost always require some post processing due to support structures, which increases the overall cost and duration of the project.
- Even after post-processing, some visible layers remain on the parts manufactured with FDM technology.
- FDM technology works on the layer adhesion mechanism. This makes the parts manufactured with FDM inherently anisotropic. Hence these parts are more easily prone to breaking when stressed in a particular direction. Specifically, along the Z-axis.
FDM 3d printing method has definitely revolutionized the prototyping industry and is on its way to replacing traditional manufacturing technologies for producing thermoplastic parts. With build sizes of as small as 200mm3 to spanning well over 1000mm3, FDM enables you to produce durable parts of varying sizes. FDM technology is one of the cheapest and fastest methods for 3d printing thermoplastic products.