A laser cell that combines additive and subtractive machining methods for repairing components has been developed as the result of a project called Reclaim. Riccardo Tosi of the UK’s Manufacturing Technology Centre, who spoke about Reclaim at the Mach event in April, sets out the business case for building such a hybrid system
During the past few years the use of lasers has become more popular thanks to cost savings and the high levels of quality, reliability, and handiness this technology offers. Flexibility of choice is what the laser market can now offer; different lasers depending on application and end use.
In September 2009, the Reclaim project, supported by funding from the Technology Strategy Board (now called Innovate UK), started with the aim of ‘Remanufacturing high value products using a combined laser cladding, inspection and machining system’.
The result, developed by a consortium of eight UK organisations, is a fully integrated remanufacturing cell designed for repairing high-value engineering products. The system incorporates inspection and a 200W fibre laser for cladding, as well as high-speed machining in one cell, and is able to switch between processes automatically. It uses CAD/CAM software from Declam and a Sprint scanning head developed by Renishaw.
After three and half years of development, the successful delivery of the project highlighted the possibility of combining subtractive and additive techniques inside a single hybrid cell.
Since then, a build-up team that included Hamuel, Hybrid Manufacturing Technologies (HMT), Delcam, and the Manufacturing Technology Centre (MTC) showcased the hybrid system at the EMO manufacturing show in 2014. The idea was to demonstrate the use of hybrid technology – incorporating both additive and subtractive machining – and its benefits. Removing and re-depositing material on a blade leading edge was shown during the exhibition; this helped visitors get a better understanding of the capability of the process, and allowed the end user and competitors to realise the potential of the new combined system. The hybrid instrument launched at the show was awarded the EMO’s prestigious Best Multifunction Machine prize.
A hybrid approach can support different manufacturing and remanufacturing activities, such as adding new features, coating surfaces or renewing a damaged or worn area, using a combined additive plus subtractive solution.
Numbers suggest that companies are keen to extend the lifespan of their products, reducing costs and meeting the strict legislation agreed by countries in order to reduce emissions. A hybrid system can offer a flexible solution to change the approach to manufacturing challenges. There are more than half a dozen manufacturers offering a hybrid solution within their own machine portfolio.
So what are the current limitations preventing more widespread uptake of hybrid technology in the market? The potential marketplace is enormous, especially considering the value of being able to regenerate a worn out part, resulting in significant environmental and financial benefits. Decreasing energy consumption and the use of raw material can support a reduction in manufacturing time and cost savings, which can be considered a profitable route to address legislation. In fact, a manufacturing design that considers end-of-life strategies is considered a higher quality product with more commercial viability.
Where is the technology at now and where can this market go? During the manufacturing event, Mach 2016, at the NEC in Birmingham, UK, I saw several stands displaying hybrid systems, or where companies were claiming to have a hybrid solution under development. I noticed an interest from several machine builders in developing a hybrid solution in order to be part of the growing worldwide market, even if it is still not well understood. What I really see is a growing market where most of the expertise captures the flexibility and the advantages that the hybrid solution can offer.
Having a laser installed inside a CNC system can generate significant benefits, but there can also be difficulties compared with the traditional method of using a milling or turning system. Embedding a laser system inside an automatic machine can generate flexibility in terms of the applications available inside the unit or saving space on the shop floor. Think about what a fibre laser is able to do or the range of processes it is able to cover; melting material can be interesting in relation to additive manufacturing, but many other applications should be explored. What about using a fibre laser in a smarter or more flexible way? How many applications are possible when using this type of laser? Well, staying inside the manufacturing world, assisted by a CNC system, I can imagine delivering solutions such as marking, cleaning, and hardening. If budget and inspiration are high, drilling and cutting can also be envisioned. And shock peening? But what can really be done inside a CNC environment, where bearing and high tolerance assemblies are the core of the system? Before blowing powder or hazardous material in a CNC system, it is worth reflecting on which solution can withstand being inside an automatic machine where coolant and vibrations are the main actors.
A number of challenges were faced during the development of the system, one example being the installation of a fibre laser inside a five-axis milling machine without over-bending the cable. Putting excess strain on the cable would break the fibre core delivering the laser beam used to melt – at that time – a nickel based alloy (IN718). Another challenge was the design of a carousel loadable cladding head, its settings, and software to give a flexible tool path during deposition.
The hybrid market is growing; solutions and case studies are available. More combined development between machine builders and end users is required to take it to the next step and improve the current state-of-the-art of the systems. Research institutes and R&D companies are now pushing the technique and good results are being achieved, but more development needs to be done to allow this new growing market to become a reality.
S. Webster and S. Mitra, 2015, ‘Competitive strategy in remanufacturing and the impact’, Journal of Operations Management, no. 25, pp. 1123-1140.
A. King, S. Burgess, W. Liomah and C. McMahon, 2006, ‘Reducing waste: repair, reconditioning, remanufacture or recycle?’, Sustainable Development, no. 14, pp. 257-267.