What is 3D Printing? and How does it work?

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3D printing, also known as additive manufacturing, is the process of creating objects from a computer-aided CAD or 3D model, by adding liquid or powdered material layer by layer. Unlike conventional subtractive manufacturing whereby material is removed from raw stock and then forged, hammered or pressed into the desired shape, this method does not imply such processes, and is hence less cumbersome to use, incredibly precise and mitigates wastage of resources in the fabrication process. Now that we know, what is 3D printing let’s understand how does it work. 

How does 3D printing work?

The process of obtaining a 3D form starts with making the 3D CAD in a computer that converts it into variables such as the spatial movement of the printing head in all three dimensions, along with the amount of material at any given time. The 3D printer follows said instructions, resulting in a precise 3D printed part.

3D modeling software

There are various 3D modeling software’s available in the market today, ranging from hobbyist to industrial grade. Such software includes AutoCAD, Houdini, Autodesk Maya to name a few. Industrial grade modeling software can easily cost lakhs of rupees for licensing every year. Meanwhile, TinkerCAD, a browser integrated 3D modeling software is a useful utility for beginners as it is free to use, and is also quite sturdy.

In 3D printing, once the model is made, it then undergoes a process called slicing. It is the process of dividing the 3D model into hundreds or even thousands of individual horizontal layers which is then printed out one on top of the other, resulting in the physical manifestation of the 3D model.

What are different 3D printing methods

There are 7 different methods for 3D printing:

  • Vat Photopolymerisation
  • Directed Energy Deposition
  • Powder Bed Fusion
  • Material Extrusion
  • Material Jetting
  • Binder Jetting
  • Sheet Lamination

 

  • Vat Photopolymerisation

Vat Photopolymerisation is a process where a 3D model is printed by shining light from a traditional light source (DLP) or UV light (STL and CLIP) on a vat of resin, hardening it in the process. This process comes in three types – Stereolithography (STL), Digital Light Processing (DLP) and Continuous Liquid Interface Production (CLIP)

  • Directed Energy Deposition

This process uses a multi-axis robotic arm to which the 3D printing apparatus is mounted. The apparatus consists of a nozzle where powdered material is laid out in the required shape and then melted by using a high-power energy source such as a laser or electron beam, or a plasma arc.

  • Powder Bed Fusion

This process comes in three types – Multi-Jet Fusion (MJF), Selective Laser Sintering (SLS) and Directed Metal Laser Sintering (DMLS).

In MJF, a first arm deposits powdered material in the desired shape of the layer currently being printed, while a second arm containing inkjets deposit a binding and a detailing agent to ensure proper shape and dimensionality of the printed part.

In SLS, a high-power laser is used to fuse small particles of plastic, ceramic or glass laid out in a specific shape, giving rise to a solid mass of the material in that shape. DMLS follows the same process as SLS with the difference being that metal powder is used instead of plastics or ceramics.

  • Material Extrusion

This process follows the FDM process for 3D printing, where an extrusion nozzle lays out the shape of the 3D model layer by layer. The nozzle is fed from wound coils of raw material. The heated nozzle melts the material and can be moved horizontally or vertically, laying out the required shape layer by layer.

  • Material Jetting

In this method, the material is added drop by drop through a tiny diameter nozzle, similar to an inkjet printer, in the shape of the current layer of the 3D model being printed. This is then hardened to obtain the finished product.

  • Binder Jetting

In this process, both the powdered material to be printed with as well as a binder material is used to print the 3D structure. In the printing chamber, the powdered material is first spread in equal layers, and then the binder material is applied through jet nozzles which hold the powdered material together in the shape of the finished 3D object.

  • Sheet Lamination

In this process, sheets of metal, plastic or paper are glued/welded together layer by layer to obtain the final shape. In case of metals, sheet metal is laid out layer by layer which is welded together through ultrasonic welding and cut through a CNC process. Glue is used in case of paper, in the end materializing the 3D shape to be printed.

Where is 3D printing used?

  • Rapid Prototyping

In the early years of 3D printing technology, this was one of its only practical use, i.e. for quickly giving a digital shape to a prototype in the form of a 3D model and then printing it out using 3D printing, allowing for the cheap and quick materialization of prototype parts. Even today, 3D printing is widely used for different variations of the same purpose and at the same time has managed to lend practicality to other uses with advances in various processes and technologies related to 3D printing.

  • Aviation and Automotive industries

Both the aviation and the automotive industries have long adopted the 3D printing technologies for rapid manufacturing of tools, jigs and fixtures. In recent years, 3D printed parts have come so close to matching the real material in terms of strength, rigidity, flexibility, etc. that entire parts in commercial/military aeroplanes and cars have been manufactured using 3D printing, such as the 3D printed fuel nozzles used in the GE LEAP engines which have made their way onto the Boeing 787 Dreamliner.

  • Aerospace

In the aerospace industry too, 3D printing is a technology that has been employed for quite some time now, in manufacturing fixtures, tools and even full-fledged parts. This is done in order to minimize the wastage of materials used and the time and energy it takes to build the same part through traditional manufacturing processes, all of which are considerable expenses to bear on an already costly spacecraft, satellite, etc.

  • Healthcare

There have been many instances of human body implants being 3D printed. This is done to achieve the tremendous precision in manufacturing required to match the shape of the original body part to be replaced with, as the shape of a said body part can vary tremendously for every unique individual so that the result stays in its place without affecting other natural body functions and feels as natural as possible.

In the dental industry, crowns, dentures and clear aligners are already trendy products where 3D printing is used all over the world. 3D printing is also set to massively impact tissue engineering where layers of living cells are deposited on a gel medium and built up to form 3D structures. In this way, it shall one day be possible to print organs and body parts using 3D printing technologies.

  • Food and Education

3D printing technology in the food industry has already been in use for quite some time with restaurants such as Food Inc and Melisse using this as their USP to attract customers all around the world. In educational centres such as schools and universities, 3D printing has found many unique applications. In schools, 3D printers are used to materialize an idea a student might have in an inexpensive manner. At the same time, universities offer various degree programs on software such as Maya and AutoCAD and utilize 3D printing in their research labs to quickly design and manufacture prototypes in a precise and inexpensive way.

  • Consumer Products

In the consumer industry, 3D printing is either in the process of widespread adoption or has already been adopted in order to reduce material wastage in any fabrication and manufacture process to drive down costs and increase profit margins. Already 3D printing technology is used in commodities such as eyewear, footwear and jewellery. 

In the footwear industry, midsoles are a popular part where 3D printing technology is already widely adopted. In the eyewear industry, a customer might soon be getting custom made frames for the unique shape of their skull, which are comfortable to wear, and at the same time, doesn’t break the bank. Eye lenses are already a commodity which in its fabrication has already seen widespread adoption of 3D printing technology. 

In the manufacture of a single eye lens, almost 80% of a blank (raw material from which lenses are made) is wasted in subtractive manufacturing, and this number only stacks up when how many times an individual changes eye lenses are taken into account. This drives up the cost, which can otherwise be offset by using 3D printing to not waste such a vast amount of raw material during fabrication.

Conclusion

3D printing has come a long way from its early days of being practical only for rapid prototyping. Today 3D printing technology can boast of having impacted the way we fundamentally imagine objects being given shape from raw materials. While retaining its advantages of precision of the finished product and minimized wastage of raw materials, scientists are working hard towards minimizing its disadvantages of time and scale of manufacture, and as time progresses, we can only expect to see more meaningful impacts this technology shall have on our day to day lives.

1 COMMENT

  1. Hi there i am kavin, its my first occasion to commenting anywhere, when i read this paragraph i thought i could
    also make comment due to this brilliant post.

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