What is 3D printing? How does it work?

The Indian Space Research Organization (ISRO) on Thursday (May 9) successfully test-fired a liquid rocket engine made with the help of additive manufacturing technology known as 3D printing.

The PS4 engine used as the fourth stage engine of the Polar Satellite Launch Vehicle (PSLV) has been redesigned by ISRO for manufacturing using 3D printing.

Here’s what 3D printing is, how it works, and why ISRO built the engine using this technology.

What is 3D printing?

3D printing is the process of creating three-dimensional objects layer by layer using a computer-generated design. It is an additive process in which layers of a material, such as plastics, composites, or biomaterials, are built up into materials of varying shape, size, stiffness, and color.

How is 3D printing done?

To carry out 3D printing, one needs a personal computer connected to a 3D printer. All they have to do is design a 3D model of the required material in Computer Aided Design (CAD) software and press ‘print’. The 3D printer does the rest.

3D printers use a layer-by-layer method to create the desired object, which is the exact opposite of subtractive manufacturing processes. Think of the Italian sculptor Michelangelo creating his masterpiece, David. He carved a colossal statue from a single marble stone. This is a good example of subtractive manufacturing.

3D printers, on the other hand, create the object from the bottom up, layer by layer until it looks exactly as intended. “The (3D) printer generally works like a traditional inkjet printer in the direct 3D printing process.

A nozzle moves back and forth while dispensing layer-by-layer of a wax or plastic-like polymer, waiting for that layer to dry, then adding the next layer. It stacks hundreds or thousands of 2D prints on top of each other to create a three-dimensional object,” according to a report by online tech news outlet Build In.

Remarkably, these machines are capable of printing anything from simple objects like a ball or a spoon to complex moving parts like hinges and wheels.

“You can print an entire bike – handlebars, saddle, frame, wheels, brakes, pedals and chain – ready-assembled without using any tools. It’s just a question of leaving gaps in the right places,” The Independent reported in a report.

Why did ISRO use 3D printing to make the PS4 engine?
This technology helped ISRO reduce the number of parts in an engine from 14 to a single piece. The aerospace company was able to eliminate 19 weld joints and save 97% of raw materials. This significantly reduced the overall production time by 60%.