QMT Features: July 2013
Laser melt unlocks AM potential
Unlock the huge potential for Additive Manufacturing: laser melt technology reduces lead times, tooling costs and minimizes waste product, as over 95% of the material is re-usable.

In the world of manufacturing technology, we occasionally experience breakthroughs that have the potential to transform the industry, enabling existing products to be made faster, cheaper and better, and opening up a world of new product possibilities.
Just like the advent of CNC machining, CAD/CAM, co-ordinate measuring machines and lasers, metal-based additive manufacturing will transform part production, but we are only at the start of this exciting journey.

Renishaw Laser Melting is a pioneering process capable of producing fully dense metal parts direct from 3D CAD, which has the power to unlock the potential for additive manufacturing. At the core of the process is the use of focused laser energy to fuse fine metallic powders, in a tightly controlled atmosphere, to form highly complex functional components that go way beyond the designs of today.

The metallic powder is distributed evenly across the build plate in layer thicknesses ranging from 20 to 100 microns forming the 2D cross section. The layer of powder is then fused using the laser in a tightly controlled atmosphere. The process is repeated, building up parts of complex geometries, layer by layer.

The technology is already widely employed for the manufacture of custom medical implants, lightweight aerospace and motorsports parts, efficient heat exchangers, injection moulding inserts with conformal cooling channels, and dental copings and crowns. Laser melting gives designers more freedom, resulting in structure and shapes that would otherwise be constrained by conventional processes or the tooling requirements of volume production, giving the opportunity to rethink the concept of “design for manufacture”.

The capability to safely process reactive materials such as titanium and aluminium is a standard feature on all Renishaw machines, with safe systems for process emissions and powder handling. The machine build chambers are a vacuum chamber that is filled with a controlled atmosphere of inert argon gas. Other materials currently supported include certain grades of stainless steel, tool steel, cobalt-chrome and inconel.

Laser melting users benefit from reduced lead times, tooling costs and minimal waste product, as over 95% of the material is re-usable after refinement in the Renishaw powder conditioning system. It is also complementary to conventional machining technologies.

Recent adopters of the Renishaw technology include Swansea University, one of the UK’s top research universities, and Directed Manufacturing Inc. (DMI), a leading US provider of additive manufacturing services. Both organizations have acquired a Renishaw AM250 laser melting machine.

At Swansea University the system is being used by a new Aerospace & Manufacturing multidisciplinary research team within the University’s College of Engineering. Part of the team’s focus is the ASTUTE (Advanced Sustainable Manufacturing Technologies) project, which targets the aerospace, automotive and high technology sectors and aims to create sustainable, higher value goods.  By applying Advanced Engineering techniques, such as additive manufacturing, to both the design of products and to the production process, the project aims ultimately to create new skilled jobs in the manufacturing sector in Wales.

Directed Manufacturing Inc (DMI) purchased a AM250 laser melting machine to augment its existing range of machines at its engineering facility in Texas, USA, where the company supplies production metal parts and complex geometric components to the medical, industrial, aerospace and defence industries. The machine has been sourced to respond to the demand from design engineers needing to reduce production lead times and costs.

The Renishaw AM250 is particularly advantageous to DMI because of its large build chamber, allowing the construction of parts up to 250 x 250 x 360 mm in size, but also because of the vast range of metal powders that can be used in part construction. This will allow DMI to supply metal parts in aluminium Al-Si-12, cobalt-chrome (ASTM75), H13 tool steel, inconel 718, inconel 625, stainless steel 316L, stainless steel 17-4PH, titanium CP, Ti-6Al-4V and Ti-6Al-7Nb via additive manufacturing.

Alex Fima, Directed Manufacturing Inc CEO explains: “We thoroughly researched our options and selected the Renishaw AM250 due to its reputation for building precision Titanium prototypes and parts.”

DMI also believe that additive manufacturing can provide multiple ways to save manufacturing costs. Much of the product development that Directed performs involves refining and redesigning parts to try to make them as material-efficient as possible. Parts produced through additive manufacturing can be highly intricate and do not have to be solid, meaning reductions in component weight without compromising performance.

A further advantage that DMI sees is the opportunity to optimise the part’s fit and effectiveness without having to worry about how the resulting shape will be cast or machined. For example, engine makers can modify components to optimise the flow of fuel or air, without having to make any geometric compromises because of the needs of traditional manufacturing.

James Hockey, senior technical sales at DMI also says that additive manufacturing requires no tooling or fixturing, making it economical for low volume, high-value production parts. However, he says that the greatest cost savings from additive manufacturing arguably come from reducing or eliminating assembly.

A complex subassembly of 10 or more pieces fastened or welded together could be redesigned to be made as a single, solid metal piece through additive manufacturing. While this approach is not inexpensive, neither is the labour and potential for error involved in assembling a critical component. When assembly-related costs can be avoided, additive manufacturing often can deliver dramatic cost reduction while it reduces the overall part count.

Simon Scott, director of Renishaw’s Additive Manufacturing Products Division says, “These sales further reinforce Renishaw’s growing reputation as a credible supplier within the additive manufacturing market. There is great potential for additive technologies to improve energy efficiency and product performance, which is being advanced by the work of pioneering organisations such as Swansea University and Directed Manufacturing.” l
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Rob Tremain Photographer
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