Model-Based Determination Of Process Force In Multi-Axis Milling

Proceedings of the World Congress on Mechanical, Chemical, and Material Engineering

Abstract

Milling is a machining process in which productivity is highly dependent on the process force between the milling tool and the workpiece.Therefore, force control strategies are introduced to reduce the production time while ensuring a desired process force.In order to produce more complex geometries, the machine tool is provided with additional rotational degrees of freedom of the machine table or the milling tool, which is referred to as multi-axis milling.In a machine tool with a rotating machine table, inertial and gravitational forces disturb the measurement of the process force provided by the table dynamometer.This contribution introduces a model-based determination of the process force.Gravitational and inertial forces are calculated and subtracted from the measurement.Furthermore, the measured process force is transformed to align the measured process force with the process force determined by numerical engagement simulation.Experiments with and without a milling operation are conducted to validate the model quality.In the conducted experiments, the process force determined in a milling operation with a rotated machine table has a relative error of less than 13.3 % in x-and y-direction compared to a milling operation without rotation and same engagement conditions.In contrast, the process force in z-direction has a relative error of up to 38.3 % due to unmodelled disturbances.For a force control strategy, mainly the determination of the process force in the x-and y-direction is relevant.Therefore, the model is sufficiently accurate in order to be tested in a milling process with a force control strategy.

Authors 5

1. Patrick Ochudlo corresponding Aachen Institute of Automatic Control (IRT)

   RWTH Aachen University

   Affiliation as printed

   Institute of Automatic Control , RWTH Aachen University Campus-Boulevard 30 , 52074 Aachen , Germany

   Institute of Automatic Control, RWTH Aachen University Campus-Boulevard 30, 52074 Aachen, Germany

2. Adrian Karl Rüppel Aachen Laboratory for Machine Tools and Production Engineering (WZL)

   RWTH Aachen University

   Affiliation as printed

   Laboratory for Machine Tools and Production Engineering , RWTH Aachen University Campus-Boulevard 30 , 52074 Aachen , Germany

   Laboratory for Machine Tools and Production Engineering, RWTH Aachen University Campus-Boulevard 30, 52074 Aachen, Germany

3. Sebastian Stemmler Aachen Institute of Automatic Control (IRT)

   RWTH Aachen University

   Affiliation as printed

   Institute of Automatic Control , RWTH Aachen University Campus-Boulevard 30 , 52074 Aachen , Germany

   Institute of Automatic Control, RWTH Aachen University Campus-Boulevard 30, 52074 Aachen, Germany

4. Thomas Bergs Aachen Laboratory for Machine Tools and Production Engineering (WZL)

   RWTH Aachen University

   Affiliation as printed

   Laboratory for Machine Tools and Production Engineering , RWTH Aachen University Campus-Boulevard 30 , 52074 Aachen , Germany

   Laboratory for Machine Tools and Production Engineering, RWTH Aachen University Campus-Boulevard 30, 52074 Aachen, Germany

5. Dirk Abel Aachen Institute of Automatic Control (IRT)

   RWTH Aachen University

   Affiliation as printed

   Institute of Automatic Control , RWTH Aachen University Campus-Boulevard 30 , 52074 Aachen , Germany

   Institute of Automatic Control, RWTH Aachen University Campus-Boulevard 30, 52074 Aachen, Germany