The spindle is a key component of the machine tool and it determines the quality of the final product, as well as the efficiency of the machine tool itself. Therefore the spindle run accuracy must be measured to achieve the best machining results. This often involves removing the spindle from the machine and sending it for analysis. It can then be loaded statically or dynamically during testing.

The research team at the Institute of Production Machines, Systems and Robotics, the Faculty of Mechanical Engineering, Brno University of Technology, has designed and tested a method of measuring spindle run accuracy under static load, with the spindle still in the machine. There is no need to remove it and send it somewhere else.

The basis of the new solution is applying a defined static load which allows not only the changing final accuracy of the spindle run, but also the temperature load on the spindle and headstock depending on the changing speed, to be monitored. Both a contact and contact-less measuring device can be used and it can be supplemented with temperature sensors which can be located on selected places of the machine.

This method is unique in that the spindle at the upper part of the measuring mandrel is loaded with a static force via the bearing located on this mandrel. This loading allows the entire lower part to be used to measure errors in the spindle run and it provides enough space to locate the loading units.

The device for measuring spindle run accuracy under a static load is illustrated in the figure above and is utility model protected.

Source of the pictures: the archives of the authors