http://www.engineeringnews.co.za/article/getting-real-2013-01-18

3D printing may shape a new manufacturing revolution

Published 18 Jan 13       By: Joanne Taylor
Additive manufacturing, more commonly known as three-dimensional (3D) printing, is consumer and industry ready. It is gaining momentum as a viable tool for home use and the manufacturing of parts, from scissors handles to titanium aircraft spares.

Early examples of 3D printing emerged in the 1980s, but the printers were large, expensive, difficult to acquire and limited in what they could produce, explains Vaal University of Technology (VUT) Science and Technology Park professor Deon de Beer.

The process of additive manufacturing, laser additive manufacturing (LAM) and 3D printing is a layer-by-layer technique of producing 3D objects directly from a digital model, using computer-aided design (Cad) or animation modelling software. Modern 3D printers melt the material before it is extruded and layered onto the printing surface to form the object it is programmed to print.

The technology can be used to produce spare parts for nearly every object ever made, making the revival of discontinued products possible, as it can be designed on Cad software and subsequently printed.

The term ‘3D printing’ was coined by Massachusetts Institute of Technology’s (MIT’s) Professor Ely Sachs, who recruited MIT graduates Jim Bredt and Tim Anderson to develop a reliable and commercialised method based on a desktop inkjet printer modified to extrude a binding solution onto a bed of powder, instead of extruding ink onto paper. The ensuing patent led to the creation of modern 3D printing and the creation of modern 3D printing companies Z Corporation (founded by Bredt and Anderson) and ExOne.

The technology is used in the fields of jewellery making, footwear prototypes, industrial design, architecture, engineering and construction; in the automotive, aerospace, dental and medical industries; and in education, geographic information systems and civil engineering.

Endless Possibilities
The possibilities of the applications of 3D printing are endless, as research and development (R&D) on the materials that can be used is ongoing and, currently, the materials that are used include polyurethane rigid foam, alumide, polyamide, acrylonitrile, polylactide, fibreglass, carbon fibre, polyresins and various metal powders, such as steel, titanium and aluminium.

In South Africa, the Council for Scientific and Industrial Research (CSIR) National Laser Centre (NLC) is conducting R&D on a suite of metal LAM processes and systems that are expected to benefit the local manu-facturing industry by enabling the manufacturing of fully dense metal components from constituent metallic powders.

The goal of the CSIR’s additive manufacturing programme is to advance the knowledge, capabilities and economic opportunities in the South African industry.

LAM is key in the beneficiation of South Africa’s titanium resources and efforts are in place to establish a viable titanium component manufacturing industry that will enable the local aerospace industry to have a competitive international advantage.

The CSIR is focusing its resources on LAM to identify critical components and industries that can benefit from the technology.

A high-speed, large-area selective laser-melting programme is in place to establish a first generation of equipment capable of building aerospace components with dimensions equal to or smaller than 2 m by 0.6 m by 0.6 m.

The third programme of the CSIR entails working on an ultra-high-speed LAM, which aims to create systems to meet future market demands once LAM has successfully been introduced onto the market.

“Successful completion of the CSIR’s initiatives will enable a new knowledge base and capacity that will generate sustainable opportunities in additive manufacturing,” says NLC contract R&D manager Francois Prinsloo.

The cost of rapid prototyping technology is plummeting, which presents new oppor- tunities for entrepreneurs who find the technology surprisingly easy to use. Hobbyists are using machines that are bought in kit form. They build the printer themselves, enabling them to print their own figurines. One possibility for the at-home kit is to interest the youth at an earlier age.

Looking Local
VUT runs an initiative called the Idea 2 Product Lab, which emerged from the need to have an affordable and customisable platform to support innovators. It is an affordable setup that enables interaction with clients, even in rural areas, as they seek to develop a product. The lab is operated in a scientific manner, using the format of an experiment by constantly searching for a mode that is suitable for the client and the laboratory. VUT is also developing a mobile laboratory concept to increase rural impact.

The objective of empowering students and communities to develop their ideas into a prototype has a dual focus – the generation, refinement and improvement of the initial idea and the culmination of the idea into a physical prototype.

The 3D printing industry in South Africa is beyond the rapid prototyping stage, where entrepreneurs can develop a prototype of a product they wish to make. Production can now go into the final par-quality materials. The Rapid Product Development Association of South Africa was launched during its first yearly international con- ference, hosted by the CSIR in 2000, following several national meetings to establish a community of practice.

“South Africa had a late start with rapid prototyping on 3D printers. The first system was available in 1990 and it had increased to only three systems in 1994,” says De Beer.

The first machine was brought into South Africa through an initial investment by Tshwane University of Technology manager of the Institute for Advanced Tooling Bob Bond, and so the adoption of the technology started, supported by a group of private investors under US-based manufacturers 3D Systems and Rapid Design Technologies, followed by research at universities and supported by technology transfer programmes and industry- awareness workshops.

Additive vs Subtractive
Prinsloo explains that the difference between additive and subtractive manu- facturing is that the latter involves the removal of material from a substrate to create the desired component. This can result in up to 90% of the original material being wasted. In contrast, additive manu-facturing limits wastage as the desired component is grown into a near-net shape that requires very little postmachining.

LAM and additive manufacturing are used in the aerospace and automotive sectors, as they provide cost-effective solutions to the refurbishment, repairing and manufacturing of spare parts.

LAM is one form of additive manufacturing and is also known as laser cladding, laser metals disposition, selective laser sintering and direct laser sintering. Though slightly different, all the processes involve depositing metal powder on a substrate and then melting the material with a focused beam of high-power laser under controlled atmospheric conditions and eventually creating a new 3D object by building up layers of the material. This process allows the manu- facture or repair of metal parts for various applications.

This technology is becoming increasingly popular in the manufacturing and repairing of spare parts for aircraft, motor vehicles and even medical applications. The technology for fixing a part through additive manu- facturing offers an affordable alternative to replacing an entire part for local institutions like power utility Eskom, chemicals pro- ducer Sasol, steel and mining company ArcelorMittal and transport company Transet instead of importing or manu- facturing a replacement part.

Prospects
De Beer says 3D printers are being tested for use in space and the possibility of these being sent with astronauts on deep-space missions is becoming reality.

In an age where news, books, music, videos and communities are subjects of digital dematerialisation, the development of 3D printing has a bright future in rapid prototyping and in the manufacturing of plastic and metal objects, as well as in the medical, art and space industries, he adds.

Several experimental bioprinters have been built since the 1980s. In Japan, the University of Toyama’s science engineering professor, Makoto Nakamura, created a bioprinter that prints biotubing similar to that of a blood vessel and he hopes to develop a printer that can print entire human organs, ready for transplant. R&D on bioprinters is ongoing and there have been some success stories, but the technology will not be commercially available until it has been approved by the various regulatory authorities.

Bredt explains that the trend in 3D printing is motivated by the expiration of many basic patents in the technology. As these tech- nologies become publicly available, small-scale developers will be able to create specialised machines for various niches and develop low-cost alternatives.

De Beer concludes that desktop 3D printers are already available at about R15 000 and are capable of an output in colour and in multiple materials. These devices will provide a solid bridge between cyberspace and the physical world, creating an important manifestation of the second digital revolution.