Modern industry faces increasing demands for high-precision manufacturing. Not only are designs becoming more and more complex, with dimensions specified down to microscopic levels, but also these items frequently have to be produced as individual, customised parts or in very small batches.
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The medical and aerospace sectors are two industries where the demand for this type of component is common. But such manufacturing is time-consuming and expensive, taking days if not weeks to make a single part.
The EU-funded IMPALA project explored the exciting potential of laser technology to transform this type of high-precision, low-volume manufacturing. ‘Revolutionise’ is an over-used word, but in this context it seems entirely justified. Laser technology opens the possibility of new manufacturing techniques which could reduce timescales from weeks to just hours - and slash costs as a result.
With their ability to melt tiny amounts of material – in this case metallic powder – in a highly precise way, using minimal heat input, lasers can be guided by computers to build up a product, layer by microscopic layer. Known as Laser Additive Manufacturing Processes (LAMPs), the techniques are similar to those of 3D printing. Fusing tiny layers of powder at a time, LAMPs can achieve accuracy down to the micrometre level. They allow more complex geometries, more advanced product functionality, or even entirely new product designs not currently possible through existing methods like casting or machining.
The laser additive process also results in the almost complete elimination of waste. In some machining processes, often using high-value metals, as much as 95% of the material is machined away. With lasers, only the powder needed to make the item is used.
While there has already been considerable activity in the development and use of LAMP technology in a range of manufacturing contexts, the specific focus of IMPALA (Intelligent Manufacture from Powder by Advanced Laser Assimilation) was the development of the technology to optimise its suitability for customised or small-to-medium production batches. To do this, the research team concentrated on improving three crucial aspects of the process.
The first aspect the project focused on was the technology’s potential for customisation, to enable the production of small batch sizes or individual items and a quick switch-over when a different item is required. The second was miniaturisation. Whereas current LAMP technology can deposit layers of powder as small as 200 or 300 micrometres, the electrode within a cochlear implant, for example, has a typical width of 20 or 25 micrometres. The third goal was improved production cycle time. For medium- to high-volume products, LAMP methods have reduced cycle times to hours or days compared with weeks for conventional manufacturing. Achieving a similar reduction in small-volume production posed a major challenge.
The results were impressive. IMPALA scientists produced a number of items for a range of end-user businesses who were part of the project team. These included a dental bridge, produced with a cycle-time of just 30 minutes compared with the two days currently required to make one by hand. A casing for a cochlear implant, an item that needs to be crafted individually for each patient, was manufactured at a cost-reduction of 42% per item - saving EUR 741,000 per year on a volume of 30,000 items.
For the aerospace sector, IMPALA team used LAMP technology to manufacture the metal guards that protect jet engine turbine blades. Known as ‘metal leading edges’, these have a complex shape and need to be accurately configured. IMPALA researchers reduced the production time from the conventional two weeks to just nine hours – with an estimated potential saving to the project partner (GE) of EUR 300,000.
“What we have done is prove the feasibility of this technology for a number of components,” says Dr Emma Ashcroft of TWI Ltd in the UK, the project coordinator. “The aerospace and medical industries are taking a particular interest in this technology and driving it forward. In the medical sphere, for example, a patient’s CT scan data can be used with laser additive manufacturing to ensure that a body part is designed and manufactured to fit perfectly – a hip replacement, a dental implant, or facial reconstruction,” she adds.
The competitive benefits to Europe are expected to be significant. Dr Ashcroft estimates that the new additive manufacturing process pioneered by IMPALA “could help European businesses, especially SMEs, add between 20% and 50% to the annual turnover.”