3D Printing – Definition
Term 3D printing was coined by a Japanese Inventor Mr. Hideo Kodama in 1981; wherein he utilized UV light for hardening the polymers, thus creating solid shapes. Below are some of the definitions mentioned on various platforms for 3D printing operation:
The manufacturing of solid objects by the deposition of layers of material (such as plastic) in accordance with specifications that are stored and displayed in electronic form as a digital model.
3D printing, in full three-dimensional printing, in manufacturing, any of several processes for fabricating three-dimensional objects by layering two-dimensional cross sections sequentially, one on top of another.
Three-dimensional (3D) printing is an additive manufacturing process that creates a physical object from a digital design. The process works by laying down thin layers of material in the form of liquid or powdered plastic, metal or cement, and then fusing the layers together.
3D Printing Operation
Following are the steps involved in the generic 3D printing process:
- Creation of CAD file in .STL format (there are few other acceptable formats as well such as .OBJ, .3MF, .X3D, .WRL, .DAE etc.)
- Slicing the 3D structure and creating a .GCODE file (there are few other acceptable formats as well)
- 3D printing
- Production of final object
You can refer to the you tube video below on how an object is prepared layer by layer in a 3D printer (technique demonstrated is fused deposition modelling).
Various types of 3D printing processes:
There are about 8 techniques of 3D printing, each of which is explained in brief here:
The base platform is dipped in the liquid resin tank with the depth equal to the height of the first layer. UV laser is focused of the liquid resin, curing and eventually hardening, thus forming the layers, which then traces the X-Y geometry of the model. The platform is raised and the operation is repeated, after initial sweeping, till final shape is made
2. Selective Laser Sintering
In this technique, a laser is used to sinter powdered polyamide material at points in space and binding the material to create a solid structure
3. Fused Deposition Modelling
Also known as Fused Filament Fabrication, it is one of the widely used 3D printing technologies in which a structure is built by selectively depositing melted thermoplastic polymer filament in a pre-determined path layer-by-layer
4. Digital Light Process
In this technique, liquid polymer is exposed to light forming the 3D model as the liquid polymer
5. Multi Jet Fusion
In this technique, infrared lamps continuously illuminate the printing surface, fusing the powder particles which were initially wetted by a heat-conducting fluid.
There are similar other techniques such as Polyjet, Direct Metal Laser Sintering, Electron Beam Melting etc.
Out of the all the techniques mentioned above, Stereolithography is the major one, followed by Selective Laser Sintering and Fused Deposition Modelling.
Benefits of 3D Printing:
Applications of 3D Printing:
Electronics sector has the largest usage of 3D printing, followed by healthcare and automotive.
3D Printing Market:
- Market value in 2019: Approx. USD 12 billion
- Units shipped in 2018: Approx. 1.5 million
- Units expected to be shipped in 2027: Approx. 8 million
- CAGR growth: Approx. 15%
Key Market Players:
- Stratasys, USA
- 3D Systems, USA
- EOS, Germany
- GE, USA
- Materialise, Belgium
North America is the highest user of 3D technology; whereas, Asia Pacific region is the fastest growing region.
Anti-Gravity 3D Printing
Most of the 3D printing techniques mentioned above require a horizontal (bottom) surface for forming the 3D object, and is absolutely difficult on surfaces having irregular heights or are vertical; attributed to the gravitational force. Thus, 3D printing cannot be performed or is very difficult to perform on walls, ceilings and other coarse surfaces.
To overcome above mentioned problems, certain researchers from Fujian Institute of Research on the Structure of Matter, China and Joris Larmaan Lab, The Netherlands, are performing research in this area independently.
Researchers, Wang et al., from the Fujian Institute of Research on the Structure of Matter, China, prepared filaments of polycaprolactone filled with Nd-Fe-B powder, and also designed a magnetic platform to assist in its anti-gravitational flow. Through the research, they determined that, the tensile strength of the polycaprolactone filament loaded with 60 wt% Nd-Fe-B was similar to that of neat polycaprolactone filament, and the magnetic platform (photo shown below), provides anti-gravitational flow ability to the material.
- Working with thermoplastic material, thus is recyclable
- Even after filling with 60% filler, tensile properties match the base polymer
- Has anti-gravity flow property
- Filler cost increases the filament cost significantly
- Only tensile property of filled polycaprolactone filament is matching the base polymer properties; other mechanical properties need verification
- Getting this customized filaments could be difficult and costly
- Can the magnetic platform and filled filament be used with any existing 3D printing machines?
- Does the filler have an adverse effect on polymer properties or environment?
Whereas, researchers, Laarman et al., from the Joris Larmaan Lab, The Netherlands, used rapidly hardening thermo-setting resin in combination with their novel extrusion process. A static mixer-nozzle and a two-barrel constant-rate plunger extruder were used to mix the source material components (fig. 3). Both material components were pushed through the mixer at such speed that solidification took place precisely 1 mm away from the nozzle aperture. Two heaters were connected to the nozzle to speed up the curing process of the mixed material. The optimised scenario allowed a final speed of one meter of printed height per five minutes. Their process can be observed from the figure below.
- True anti-gravity flow possible
- I suppose temperature and cross-linker can be changed as per requirement. Thus, is customizable.
- Being a thermoset resin, it’s not recyclable.
- No information provided about the material used – resin and cross-linker
- Is a completely new technology and so it is not available commercially
- What is the exotherm of cross-linking and how is it controlled before actual application onto surface?
- Does the resin-crosslinker concentration need optimization for every change in substrate / region / atmosphere?
Dear Readers, do go through the above literature and let me know your viewpoints in the Comments section.
Thanks for reading!
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- Anti-gravitational 3D printing of polycaprolactone-bonded Nd-Fe-B based on fused deposition modelling; Journal of Alloys and Compounds 715 (2017) 146-153
- ANTI-GRAVITY ADDITIVE MANUFACTURING, 2014, UCL Press