FDM is the most widely used 3D printing technology: it represents the largest installed base of 3D printers globally and is often the first technology people are exposed to. In this article, the basic principles and the key aspects of the technology are presented. A designer should keep in mind the capabilities and limitations of the technology when fabricating a part with FDM, as this will help him achieve the best result. 3d printing services in delhi mumbai pune india
How does FDM work?
Here is how the FDM fabrication process works:
A spool of thermoplastic filament is first loaded into the printer. Once the nozzle has reached the desired temperature, the filament is fed to the extrusion head and in the nozzle where it melts.
The extrusion head is attached to a 3-axis system that allows it to move in the X, Y and Z directions. The melted material is extruded in thin strands and is deposited layer-by-layer in predetermined locations, where it cools and solidifies. Sometimes the cooling of the material is accelerated through the use of cooling fans attached on the extrusion head.
Common FDM Materials
Polylactic Acid (PLA)
It is probably the easiest to work as well as environment friendly. It is basically bio degradable plastic that has been derived from sources such as corn starch and sugar canes. This is available in soft and hard grades. With the increase in the popularity of PLA, this material is expected to overtake ABS in the near future.
Polylactic acid (SOFT PLA)
It belongs to the softer version of the PLA that was discussed in the earlier point. It is rubbery and quite flexible but is available in limited colors and sources.
Acrylonitrile butadiene styrene (ABS)/ Home printers
It is popularly known as Lego plastic and is considered to be the best material to work with as it is strong and very safe. It is made from spaghetti like filaments. It is available in a wide range of colors and is used for making of toys, bumper stickers etc.
Polyvinyl Alcohol Plastic (PVA)
It is a type of plastic that is used as dissolvable support materials or is used for special applications. Makerbot and Shapeways are manufacturing lower-cost desktop printers like the Makerbot replicator 2; the material that these printers are using is PVA.
t requires a high temperature nozzle design and is not widely used.
It requires a high temperature nozzle design and is not widely used.
The higher end printers use powder based materials for the construction of 3D models. The various powders available by which printing can be done are:
It is a strong and flexible material that allows a high level of detailing on the model. It is commonly called as white, strong & flexible / durable plastic / white plastic. It is a very strong and highly flexible plastic that is very fine and is basically a white granular powder. Due to these characteristics it is used in the interlocking and moving parts of the model.
FDM parts can be finished to a very high standard using various post processing methods, such as sanding and polishing, priming and painting, cold welding, vapor smoothing, epoxy coating and metal plating. An extensive article on post processing of FDM parts can be found here
Benefits & Limitations of FDM
The key advantages and disadvantages of the technology are summarised below:
FDM is the most cost-effective way of producing custom thermoplastic parts and prototypes.
The lead times of FDM are short (as fast as next-day-delivery), due to the high availability of the technology.
A wide range of thermoplastic materials is available, suitable for both prototyping and some non-commercial functional applications.