FDM 3D Printing: Detail Explanation

The FDM or Fused Deposition Modelling is also known as Fused Filament Fabrication (FFF) is a 3D printing process which uses thermoplastic filament materials in continuous form. The thermoplastic filament coil is passed through an extruder which contains a heating coil. The extruder heats the filament just past its glass transition temperature, after which this molten filament is extruded on the print bed of the 3D printer. This “Material Extrusion” method is widely used in different industries.

S. Scott Crump the founder of Stratasys Ltd. was the first person who developed FDM technology and commercialized the first FDM 3D printer in 1988. Stratasys also trademarked the term “Fused Deposition Modelling” in the year 1991. 

These FDM 3D printers were expensive when it was first commercialized but after the expiration of the patent in 2009 many different companies entered the market offering cheap, DIY FDM 3D Printers like the Ultimaker, Prusa, and many others.

FDM Fabrication Process:

Every 3D Printing process starts by developing a CAD (Computer Aided Design) file in a 3D software. This 3D file is converted into STL (Stereolithography) file.

This file is then transferred to a repairing software where this 3D .stl files get some correction in triangle counts, surface smoothing, shell repair, etc.

After repairing the operator of the 3D Printer needs to put some support to this file which helps the file to print on the machine print bed. These supports are put manually or by using auto generating support given in almost all 3D Machine software. AutodeskNetfabb, Materialise Magics, these two software are used by almost every 3D modeling software users for repairing and support generation.

Autodesk Netfabb Software

Once the support structure is done the .stl file is now ready to print. The file is now processed into the machine software where it is cut horizontally into thin slices. The thickness of the slice depends on the microns you set in the instruction column. Normally the FDM printer micron range from 50 Micron to 400 Micron.

The whole 3D file is now converted into a set to program or machine language called the G-codes by which the 3D printer works.

The FDM 3D Printer consists of the print bend which has up and down movement guided by a stepper motor. An extruder containing heating coils which melts the thermoplastic filaments and drops the heated material on the print bed through a nozzle.

The extruder is mounted on a moving platform which moves in XY direction guided by the stepper motor as there should be precise movement of the extruder.

Stepper Motor attached to Extruder Platform

The melted filament is extruded in thin strands on the print bed layer by layer on the predetermined location as per the codes given by the 3D printer software. This melted filament solidifies as it touches the print bed or the layer printed before.

Sometimes the product is made hollow to reduce the weight and matrix or web type structure is made inside the product to give strength to the product. For this type of structure, the extruder needs to make multiple passes like the one when we fill colors with crayons which need an increase in filament cooling. A set of cooling fans is attached to the extruder which accelerates the filament cooling.

When one layer is completed the print-bed is moved down and the second layer starts. This process repeats until the product is printed.

FDM Materials:

The reason that FDM 3D printers are one of the successful and widely used technology is because of its variety of materials in production materials. These materials are regular thermoplastics, engineering materials, and high-performance thermoplastics materials. The use of these materials varies based on its mechanical properties, accuracy, and material price.

FDM Post Process:

Once the product is printed it undergoes support removal and post-processing. The supports given to the part are removed with the cutter or by hand as they are easy to remove. 

After the supports are removed the product needs some cleaning and smoothing as they show some visible lines on the object. Hand sanding and filing is done on most parts and some parts also need polishing to get a shining surface. Painting can be done on the 3D printed parts to make it look more attractive.

Facts about FDM 3D Printer:

FDM 3D Printers are very cost-effective in terms of machine procurement and even in outsourcing product manufacturing. It also takes very less time to finish the job which means we can get the work completed within 24 hours.

FDM printer can also print end-user engineering products. Materials like Nylon (PA), PTEG, TPU can be used to make industrial-grade parts with good mechanical, thermal, and chemical properties. Engineers in the industries get a huge benefit from FDM printing as they don’t have to wait for the broken part of the machine to be replaced, they can 3D print it and use it on their own.

FDM 3D Printer has made their position in many top industries like automobile companies like the Hyundai and BMW, food companies like Nestle, and many other giant manufacturing companies. It is used for product development, prototyping, and model concept as this technology is simple and cost-effective plus it does not damage the environment.

The medical and health care industry has started using 3D printer in their process. The FDM printer is used in the drug packaging sector which makes it popular in the medical sector as well.

Limitation FDM 3D Printer:

Despite all the advantages that FDM 3D printer has there are also some limitations which need to be consider before choosing FDM printer for your manufacturing setup:

• Unlike other 3D Printing technologies, FDM has the lowest dimensional accuracy and surface finish, so it is preferable to not use this technology for product which need detailed accuracy.
• Every FDM printed parts will have to undergo the post process of smoothing and polishing as the surface achieved is very rough and has visible lines.