Alternative structural material for precision machine components
Because machine tools and other
high precision machines in the metrology field rely upon high stiffness, long term stability and excellent damping characteristics of the base material for their static and dynamic performance, designers are now looking for alternative materials for their structures to improve the performance of their machines and make them more cost-effective in their production.
This article will show comparisons of widely used and an alternative material for precision machine tool and measuring machine structures.
The most widely used material for these structures are cast iron, natural granite and welded steel fabrications. The materials have advantages and disadvantages. Steel fabricated structures are seldom used where high precision is required due to the lack of long-term stability and very poor damping properties. Good quality cast iron which is stress-relieved and annealed, will give the structure dimensional stability and can be cast into complex shapes, but needs an expensive machining process to form precision surfaces after casting.
Also the castings need to be painted to reduce corrosion of the structure. Good quality natural granite is becoming more and more difficult to find but has a higher damping capacity than cast iron. Again, as with cast iron, the machining of natural granite is labour intensive and expensive.
