What is FDM 3D printing?
FDM(Fused Deposition Modeling) is a 3D printing process that thermoplastic filaments are melted and extruded by a heated printer head, deposite materials layer by layer on a flat platform to form a part.
How does FDM 3D printing work?
It heats and melts filamentary hot-melt materials and extrudes them through a nozzle with a fine nozzle.
1. The print head moves in the XYZ three directions and controls the material extrusion amount so that the material is printed layer by layer on the platform according to the set path.
2. The printing platform needs to be heated to help the material adhere. After printing one layer, the platform lowers slightly and starts printing the next layer.
3. By controlling the relative position of the print head and the platform, a complete three-dimensional model is printed layer by layer.
Common FDM 3D Printing Materials
ABS plastic has excellent comprehensive performance, it has good strength, flexibility and machinability. ABS plastic also have higher temperature resistance, makes it is a preferred plastic for mechinical parts.
The disadvantage of ABS plastic is that it will produce odor during the printing process, and because of the cold shrinkage of ABS, the model is easy to separate from the printing plate during the printing process.
Currently, PLA plastic is a widely used material for desktop 3D printer. PLA plastic is a biodegradable and made from starch of renewable plant resources.
Advantages of FDM 3D Printing
- Simple system construction, easy operation, low maintenance costs, and safe system operation.
- Use Non-toxic material, and the equipment system can be installed and used in office.
- It can produce parts of any complexity, often used for molding parts with complex internal cavities, holes and more.
- There is no chemical change in the raw material during the forming process, resulting in minimal warping and deformation of the parts.
- High material utilization rate, with long material lifespan.
- Support removal is simple, no need for chemical cleaning.
Disadvantages of FDM 3D Printing
- The surface of the printed parts have noticeable stripes.
- Strength along the vertical direction of the printing axis is relatively weak.
- Support structures need to be designed and fabricated.
- The entire cross-section needs to be scanned and coated, leading to longer forming times.
- Raw materials can be expensive.
Post-process for FDM Printed Parts
Remove Support Structures
First step, Use tools such as cutting pliers, tweezers and shovel knives to remove the part support structures made by FDM 3D printing.
Sanding is for removing burrs and machining lines from the part’s surface. Common tools for sanding include files and sandpaper which are usually used manually.
Polishing aims to make the part’s surface smoother and more even, achieving an effect close to a mirror-like or glossy finish. Mechanical polishing is the most commonly used method.
Coating is a process of applying material to the substrate’s surface, creating a protective, decorative, or function-specific layer.
Tips for FDM 3D printing
- To prevent warping issues, avoid large flat areas in your designs and incorporate fillets at sharp corners.
- Keep in mind that FDM parts are inherent anisotropy, so they may not be suitable for critical mechanical components.
- Due to material extrusion, vertical features (in the Z direction) should not be smaller than the layer height, typically ranging from 0.1 to 0.2 mm.
- The size of Planar features should not be smaller than the nozzle diameter.
- For wall thickness, it’s better at least 2 to 3 times larger than the nozzle diameter, generally minimum 1mm.
Application of FDM 3D printing
The aerospace industry is one of the first areas where FDM 3D printing technology has landed. Using 3D printing technology, lightweight aerospace parts can be printed, which not only reduces manufacturing and transportation costs, but also realizes the efficient production of parts.
For example, spacex’s Falcon 9 rocket uses 3D printing technology to create many key power components such as turbomuders. It is expected that the commercial space industry will significantly increase the proportion of 3D printing technology in the future.
The automotive industry is also an important application area for 3D printing technology. On flagship models such as the S Series, German Mercedes-Benz extensively uses 3D printing to produce automotive functional parts such as air conditioning vents and interior trim parts, which not only improves production efficiency, but also enables highly customized parts.
In the medical industry, the application of FDM 3D printing is also becoming more and more extensive. It can be used to custom printing of dental braces, artificial bones and other implants, which will help a lot for surgical success.