JOIN USIn 1986, Chuck Hill obtained a patent for making three-dimensional objects calling the system ‘stereo-lithography’; in this system a beam of ultraviolet light was used to solidify a thin layer of liquid plastic, and repeating the process by adding more liquid plastic.
The firm 3D Systems he founded in Rock Hill South California in the US is currently producing jewellery, plastic grips for electric drills, dashboards of cars, artificial legs and is even making parts to build machines like itself.
A 3D printer, the first to be called by that name, was patented in 1993 by MIT professors Michael Cima and Emanuel Gibbs. In this system, a layer of powder of plastic, ceramic or metal is sprinkled on a metal platform and a print head deposits a binder liquid on the powder binding it together; the platform is lowered infinitesimally and the process repeated. The system called 3D printing, is known in industry as ‘additive’ manufacturing as opposed to conventional manufacturing termed ‘subtractive’ which involves cutting, drilling, and hammering metal.
Different processes
In 3D printing, the software installed in the printer takes a series of digital slices through a computer-aided design and sends descriptions of those slices to the printer, which prints it and adds successive thin layers till a solid object emerges.
The ‘ink’ in the 3D printer could be production-grade plastics, metals, ceramics or rubber-like substances. In the inkjet process, the inkjet head is used to spray a thin layer of liquid plastic onto a build tray, and the layer is cured by exposure to ultra-violet light; the build tray is lowered fractionally and subsequent layers are added.
The process of fused deposition modelling involves melting plastic in an extrusion head to deposit a thin filament of material to build the layers. Another process uses powder which is spread in a thin layer on the build tray and solidified with a liquid binder, or melted into the required pattern with a laser in a process called laser sintering.
Some researchers are already using 3D printers to produce simple living tissues such as skin, muscle and short stretches of blood. vessels. Bob Schwarz MIT Media Lab consultant has printed a grandfather clock with its gears, chains, faces and hands, which took a hundred hours of printing.
Neri Oxman and Steven Keating of MIT Media Lab have devised a system for printing concrete to eventually print a concrete structure. In this system the properties of concrete vary, being dense outside and lighter inside (emulating a palm tree), which is lighter and stronger than conventional concrete.
3D printers bring down the cost of one-off prototypes. Consumer goods like mechanical parts, shoes, architects’ models are now produced in 3D form for approval by customers, and can be reprinted in a few hours unlike the conventional prototype which could take weeks to emerge from the machine shop. As there are no economies of scale in 3D printing, it is ideally suited for both low volume production as well as mass customisation of finished goods.
Fluids flow more smoothly through rounded channels which is feasible in additive manufacture, unlike conventional manufacture where fluids have to flow round sharp corners, like gear boxes for cars. In the aerospace industry, metal parts have to be machined from high-grade titanium billets which is very expensive, where the wastage is 90 per cent.
Companies in the US, the UK, Germany, Holland, Belgium, Israel, South Africa and China which have acquired the patented technical knowhow produce an astonishing range of articles which would have been the stuff of science fiction twenty years ago. These include titanium parts in an airliner, medical implants (eg., femur dental and jaw implants), jewellery, football boots, ladies’ shoes, car parts, solid-state batteries, customised mobile phones; decorative lamp shades, and parts of a violin.
Even though 3D technology is more than two decades old, sales of 3D printers in India appear to have picked up only from 2003. Only advertisements promoting 3D printers with foreign technology are available on the internet; these do not mention the names of the companies who are the owners of the technical details, and the countries in which they are registered.
What is more important is that there is no information in the public domain- print media and the internet- on the products being manufactured in India with 3D printing, the companies manufacturing them, whether there is any value addition or innovation by any Indian company within the terms of the know how agreements and the volume of the trade.