1) What is volumetric accuracy in a machine tool?
RH: Machine geometry is a function of moving a certain amount of mass along the way system. This movement of mass needs to move straight without pitch, yaw, and
Picture two points of space within the machining cube. In theory, these two points have a perfect position in
2) Why is high volumetric accuracy important to aerospace manufacturing?
RH: Aerospace components require high-precision dimensional accuracy, and that accuracy must be reliable and stable throughout production. Some of these aerospace programs have a very long life cycle – sometimes up to 20 years, and many of these applications require a machine tool volumetric accuracy of 20µm to 25µm; some even less than that.
3) How can you check volumetric accuracy on a machine tool?
RH: Mitsui Seiki was the first company to introduce the taper cone-cutting test to check 5-axis geometric accuracy to ensure all five axes of the machine tool are properly coordinated and working together as designed. For every 5-axis machine produced, we take what looks like a spiral double gear blank, mount it on a 45° fixture on the table, and flank mill the entire OD of that
4) How do you build a machine that achieves high volumetric accuracy?
RH: Volumetric accuracy is first dictated by
Other key elements are spindle thermal control, ball screw drunkenness control – ensuring that the thread was put on concentrically – using large, rigid castings with high nickel content for thermal stability.
The machines constructed in our highly controlled assembly environment allow Mitsui Seiki to offer products with a 5-year accuracy guarantee.
5) Can compensation routines in the control system achieve volumetric accuracy?
RH: The short answer is no. Even in extremely high precision machine building, we rely on a certain amount of control compensation for positioning accuracy. But the fundamental way to achieve long-term high volumetric accuracy is in the construction and assembly characteristics and methodologies.