Materials Used In 3D Printing and Additive Manufacturing

By G.P. Thomas

Topics Covered

What is 3D Printing?
What Materials are Used to Make the Printer?
Plastic in 3D Printing
Metals Used to Print 3D Objects
Other Materials Used to Print 3D Objects
Applications of 3D Printing
References

What is 3D Printing?

3D Printing, as the name suggests, is a process wherein a solid three-dimensional object is printed layer by layer from raw material, which could potentially lead to a whole new era in manufacturing. The process is also known as additive manufacturing or desktop fabrication.

Firstly, a three-dimensional design is created and saved in STL format, which is then sent sent to a 3D printer. The design is then printed layer by layer to fabricate a real object. Several specific technologies used for 3D printing include:

  • Selective laser sintering (SLS)
  • Fused deposition modeling (FDM)
  • Stereolithography (SLA)

What Materials are Used to Make the Printer?

An example of how a 3-D printer, The MakerGear Mosaic, is put together is given below:

  • The Frame has nine sections that are laser cut from 0.200" plywood and assembled by securing them with the built-in captive-nut mortise-and-tenon joints.
  • The Y-axis system is probably the largest sub-assembly including the Y-axis motor mount, which is normally preassembled and in this step, it is decorated with various components such as the stepper motor, the linear rail and the timing belt.
  • The Y-axis assembly is straightforward including fixing the idler pulley shaft, the bolting motor, linear rail and rail stops to the already assembled frame. The X-axis timing belt is then installed and adjusted.
  • The Z-axis assembly includes installing two hardened precision ground steel shafts that guide the build platform along its vertical travel path, the Teflon-coated lead screw driving it and the stepper motor turning the lead screw. At this stage, the Z-axis limit switch is also installed.
  • The extruder assembly includes the preassembled motor, filament drive or hot end groups and the cooling fan. The heater, fan and temperature sensor are also connected at this stage.
  • The build assembly includes installing and adjusting the leveling platform, mounting the heating element and the build surface and making the related electrical connections.
  • The electronics assembly includes wiring and installing the electronics controlling the printer. Firstly, the Ardiuno and the RAMP shield attached to it are mounted on the printer frame. Next, connections from the extruder wiring harness, the build platform wiring harness and other components are clipped to the printed circuit board. Lastly the power supplies are connected and the printer is formally assembled.
  • The options and preferences of operating the printer are varied and depend on the computer being used, the operating system on the computer as well as CAD, CAM and printer control programs chosen.

Plastic in 3D Printing

In terms of raw materials that are put into the printing system to create the 3-D objects, there seem to be relatively few limitations on what can be used.  

Currently, plastics are the most widely used materials in additive manufacturing, and the important ones are listed below: 

  • ABS - acrylonitile butadiene styrene or 'lego' plastic – a very common choice for 3D printing
  • PLA - polylactic acid – Is available in soft and hard grades, is becoming very popular and may overtake ABS in the near future
  • PVA - polyvinyl alcohol – This is used as a dissolvable support material or for special applications.
  • PC – polycarbonate – Polycarbonate requires high-temperature nozzle design and is in the proof-of-concept stage.
  • SOFT PLA - polylactic acid – Is rubbery and flexible, available in limited colors and sources. As 3D printing spreads, may get easy to find.

Metals Used to Print 3D Objects

The Materials Science fraternity will also be very interested in 3-D printing for the range of possibilities involving metals. Some of the metals used in 3D printing include the following:

  • Steel
  • Stainless steel
  • Titanium
  • Gold
  • Silver

Other Materials Used to Print 3D Objects

A range of other manufacturing materials can be used for 3D printing that include nylon, glass-filled polyamide, epoxy resins, wax, and photopolymers.

As mentioned above, there appear to be few limits on what materials can be used for additive manufacturing. Some of the more unusual materials that have been used are detailed below:

  • Chocolate – Material engineers have devised a way to use chocolate in 3D printers to obtain some delicious treats. With the help of computer-aided manufacturing systems found in 3D printers innovative designs can be developed with this delicious material.
  • Bio-Ink - Biomedical professionals such as Anthony Atala are researching the use of materials such as bio-ink. Bio-ink comprises stem cells and cells from a patient, which can be laid down, layer by layer to form a tissue. Human organs such as blood vessels, bladders and kidney portions have been replicated using this technology.
  • Bone Material - A research team headed by Dr Sushmita Bose from Washington State University printed a bone-like material comprising silicon, calcium phosphate and zinc. This bone-like material was integrated with a section of undeveloped human bone cells. In about a week, growth of new bone was seen along the structure. This new material dissolved eventually and did not harm the patient.
  • Objet Digital Material - Objet has transformed the 3D printing world by introducing printers that can make use of several materials at the same time. These multi-jet printers can create fine models offering a range of textures, colors and attributes. These mixtures are referred to by Objet as digital material.
  • Objet Tango Family - Objet has also introduced a rubber-like material that is probably the only one of its kind in 3D printing. Although it is not exactly rubber, it shows a lot of similarity to rubber.
  • Hot Glue - A common hot glue gun was hooked up by designers to their CAM system and although hot glue may not be significant, the results if any obtained by hobbyists will truly be fascinating.
  • Full Color Sandstone - This material enables the production of 3D printed creations with almost any color. Fine designs for action figures, architecture and character models are becoming highly popular with this material. It is even possible to print the human face on sandstone through 3D printing and the results are not that bad.
  • Glass - Ground up glass powder is spread layer by layer, bonded with adhesive spray then baked resulting in 3D printed glass product.
  • Medication - Engineers and doctors are working together to create 3D-printed medication. Medication need not be always purchased from pharmacies, the days are not far away when they can be printed!!
  • Skin - Similar to bio-ink, 3D printers can help in skin regeneration. This could bring about a change in how patients receive treatment. If this technology truly develops, the potential for regenerative medical application will be tremendous.

Applications of 3D Printing

A key application of 3D printing is the medical industry. Surgeons can produce mockups of parts of their patient that need to be operated on. With 3D printing, it will be possible to make a part from scratch in just few hours. It enables developers and designers to move from the flat monitor screen to the exact three-dimensional part.

However, there are many fields that 3-D printing can be applied to, and this list will only continue to grow in the future. Currently 3D printers are being used to develop toys, aerospace components, art, jewelry, fashion design, architecture and interior design. What the future will hold for this revolutionary technique is very much open to debate. 

References


Date Added: Feb 4, 2013 | Updated: Dec 12, 2013
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