A Deeper Investigation Into The Thermal Drift OfA Linear Axis

Abstract

This presentation shows the results of actual tests performed on the shop floor of the user company with a view to understanding the real behaviour of the machine structure. The machine involved was a milling machine with table of fixed height, used for machining dies, whose 3 m long X axis, i.e. the table travel on the bed, was submitted to the test, because significant deviations occurred during normal use. The test lasted 100 minutes, and it was performed moving continuously the table at the rapid traverse rate between the two ends of the travel for 65 minutes, with measurements still being made for 35 minutes during the cool down period, with the table resting in the middle of the travel. Every 5 minutes the following quantities were measured, stopping the table at both ends of the travel: 2 linear positioning deviations EXX of the table, by laser 2 angular pitch deviations EBX of the table, by electronic level 2 angular roll deviations EAX of the table, by electronic level 2 angular yaw deviations ECX of the table, by a second laser 2 angular pitch deviations of the column, by electronic level 2 angular roll deviations of the column, by electronic level 3 temperatures, measured in different points of the bed. The three major sources of the total elongation of the travel, responsible for more than 80% of the final positioning deviation, have been identified and quantified.