Manufacturing costs halved using RM
Dean Palmer takes a look at three manufacturing companies that have used rapid manufacturing techniques to reduce time to market and manufacturing costs
FIT, a German company that manufactures complex joystick steering systems, is using EOS’ DirectTool material for the fast development and economic small series production of its new ‘HI-Drive’ joystick, which has resulted in a 50% reduction in manufacturing costs compared to conventional tooling. HI-Drive is an innovative joystick that, by using an automatic translation, the construction vehicle (Hamm) always moves in the direction of the joystick deflection, whichever way the driver is sitting. It offers 16 different functions and consists of 15 plastic parts, including electronic devices, mechanical components and switches. The new joystick needed to be reliable and it had to last for 20 years under demanding construction site conditions. Injection moulding was in PA 6.6 GF30 and the plastic parts needed to be very accurate due to the assembly of complex geometries. Also, speed of turnaround for the joysticks was crucial because the firm needed to present the product at a forthcoming trade fair. The tool design involved dividing the parts into four ‘mother’ tools for optimum utilisation of the injection moulding machine. The volume of laser sintered inserts was minimised to reduce build times and material costs. The total volume of laser sintered material was reduced to just 3.1 litres for all 14 plastic parts. Reinforcement or armouring was developed in order to minimise the risk of breakages and small inserts (pins and blockings) were machined in steel. Tool design and modification took 120 hours of which 80 hours were spent generating data for milling and drilling. Laser sintering build time using EOS’ EOSINT M 250 Xtended laser sintering machine was 290 hours, using DirectMetal 20 in 40µm layer thicknesses. Machining of the reinforcements and steel inserts took 40 hours and 50 hours respectively, polishing took 40 hours; touching up 40 hours and total turnaround time was nine weeks, including a three-week delay due to design changes. The total cost, including first models, was less than 90k euros, half the cost of conventional tooling. 14 tools and 7,000 injection moulded production parts were made in nine weeks. Another German firm, Andreas Hettich, a manufacturer of laboratory centrifuges, recently developed a new centrifuge, the Rotomat. The aim was to develop a machine for the sedimentation and separation of blood components in a single device. The centrifuge incorporates a drum motor with six boxes and drip trays. The boxes have complicated geometries and the centrifuge has a rotational speed of 2,000 turns and an acceleration of 1,200g. The firm needed several tools for the production of the single parts and assembly was time consuming. Every bag was different and specific adaptations were necessary for individual customers. The company looked at the possibility of laser sintering the boxes and what risks were involved and whether it was sensible. Tests proved that by laser sintering the boxes, the functions could be integrated, product functionality improved and assembly costs reduced. It was also possible to laser sinter the washing rotor. Previously, Hettich had several tools to mould the 32 single parts and the special, steel-injection pipe had to be deburred which was also costly. With laser sintering, no tooling was needed, only two sintered single parts were necessary with one extra steel ring. The costs of deburring were eliminated. The optimised design was produced with laser sintering on demand using EOS’ P380 rapid manufacturing machine. Three million rapid parts Belgian company Quicktools is also using EOS’ laser sintering technologies for series production. The firm manufactured pulleys for a high speed loom recently and used tool inserts made from DirectSteel 20 and was able to produce more than 3 million pulley housings with these laser sintered inserts. DirectSteel is a tool steel that produces dense, pore-free parts with a hardness of up to 42 Rockwell C directly from the building process. Prior to its release in early 2004, the material had already been tested by several EOSINT M users. Kashiyama Kanagata, an innovative Japanese mould maker, built an injection mould for a mobile phone cover with inserts in DirectSteel H20. EOS, based in Warwick, works with major manufacturers, including Dyson, Ford, Land Rover, Jaguar, Unilever, Bentley Motors and Renishaw. Stuart Jackson, UK sales manager at EOS told Eureka that many companies are starting to see the benefits of moving to rapid manufacturing of complex, customised parts. The firm has recently launched its EOSINT M 270 system for direct metal laser sintering. Jackson said the new machine offers many innovations especially for DirectPart applications. “It has a new generation of laser, called a fibre laser. This finely focussed laser offers significantly improved detail resolution, while the high absorption of the laser wavelength, together with a patented variable focus system, increases both the building speed and system productivity.” Handling of the machine and powder has also been simplified and the machine also has a gas-tight process chamber which ensures a high purity of the process chamber atmosphere.