22 Nov 2013
Industry-focused scheme to develop a variety of laser-based processes for making high performance components.
Singapore’s Agency for Science, Technology and Research (A*STAR) has launched a new development program focused on industrial additive manufacturing, with backing for three different laser-based techniques.
The technology development facility wants to foster a number of approaches in order to grow what it describes as an “internationally competitive” additive manufacturing (AM) industry to support domestic producers in Singapore.
The six AM technologies to be researched are: laser-aided additive manufacturing (LAAM); selective laser melting (SLM); electron beam melting (EBM); polyjet; selective laser sintering (SLS) and stereolithography (SLA).
A*STAR says that the emerging techniques are of particular significance to the aerospace, automotive, oil and gas, marine and precision engineering industries. A statement from the institution read:
“These industries are evolving into more complex and advanced high-mix, low-volume production, activities that require new technical skills, high-tech processes enabled by deep research and development capabilities.”
“Advanced manufacturing technologies like AM can help to strengthen Singapore's manufacturing, which constituted 20 percent of the country's gross domestic product in 2012.”
Tan Geok Leng, the executive director of A*STAR's Science and Engineering Research Council, commented: "This program aims to develop innovative additive manufacturing technologies and capabilities to transform the manufacturing landscape of Singapore.”
Professor Ng Wun Jern, the dean of engineering at Nanyang Technical University (NTU), added that the new program would provide support for manufacturers looking to scale up and integrate AM into their processes:
"The [AM program] will leverage upon NTU's strengths in engineering and its long history of industry linkages and collaborations," said Prof Ng. "NTU and A*STAR are well-placed to make this new program a success. Together, we are poised to support our industry's move into next generation manufacturing."
According to a report published this year by analyst Wohlers, the market size of AM is projected to grow five-fold from $2.2 billion in 2012 to $10.8 billion in 2021.
The key applications leading that market growth are expected to come from the automotive, medical and aerospace sectors, but although the general outlook is a positive one, a lack of materials, process and design engineering know-how will present a barrier to mass industry adoption in the near term.
The A*STAR-funded program is led by the Singapore Institute of Manufacturing Technology (SIMTech), which will work in close partnership with NTU on AM process design and development for direct manufacturing of components.
Two other A*STAR research institutes - the Institute of Materials Research and Engineering (IMRE) and the Institute of High Performance Computing (IHPC) will add expertise in materials development and modelling and simulation to support the collaboration.
AM techniques: the low-down
Not all additive manufacturing, or “3D printing” processs technologies rely on lasers or other photonics technologies – though many do. Here is how A*STAR describes the various approaches:
• Laser Aided Additive Manufacturing (LAAM): a technology for fabricating metal parts directly from a computer-aided design (CAD) solid model, using a metal powder injected into a molten pool created by a focused, high-powered laser beam.
At present, LAAM is mainly used for repair and remanufacturing, but hardly at all for direct parts manufacturing. The new program will deploy LAAM to manufacture large-format 3D components for the first time, with applications in the oil and gas and aerospace markets expected.
• Selective Laser Melting (SLM) builds objects layer upon layer from powders, using CAD models. Support structures are often needed to build structures, but this approach complicates part geometry and surface quality. A*STAR’s team will develop a novel algorithm for manipulating mass distribution to eliminate/reduce the use of support structures.
• Selective Laser Sintering (SLS) uses a high-power laser to fuse small particles of plastic, metal, ceramic, or glass powders into a three-dimensional shape. The technique has been gradually adopted in the manufacturing of component prototypes, albeit with limited functions and consistency.
• Stereolithography (SLA) employs a vat of liquid UV-curable photopolymer "resin" and an ultraviolet light source to build parts layer by layer. A*STAR’s work package will aim to develop low-cost photopolymers to fabricate printed components with superior impact strength and lower overall weight.
• Polyjet 3D printers jet layers of liquid photopolymer to create a 3D prototype which can be used immediately without additional post-curing. The 3D printer can also jet a gel-like support material specially designed to uphold overhangs and complicated geometries which is easily removed by hand and with water.
• Electron Beam Melting (EBM) uses electrons rather than photons to form metal parts from a 3D CAD model, with successive layers melted under a vacuum. EBM is regarded as a highly efficient manufacturing process with low residual stress and distortion, but suffers from rough surface finish and poor dimensional accuracy.