Session 5: Approaches considering cutting processes

Experimental analysis of the heat flux into the grinding tool in creep feed grinding with CBN abrasives
C. Wrobel, D. Trauth, P. Mattfeld, F. Klocke
Laboratory for Machine Tools and Production Engineering, RWTH Aachen University

This paper presents an experimental investigation regarding the heat flux into a the electroplated CBN abrasive wheel in creep feed grinding of 100Cr6 (1.3505, AISI 5210) and minimum quantity lubrication. For the first time, the influence of the heat flux into the grinding wheel on the thermal tool center point displacement is analysed by measuring the maximum temperature in the subsurface of the grinding wheel using embedded thermocouples.

Development of multidimensional characteristic diagrams for the real-time correction of thermally caused TCP-displacements in precise machining
M. Putz (a,b), C. Oppermann (a), M. Bräunig (b)
(a)    Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz
(b)    Institute for Machine Tools and Production Processes, TU Chemnitz

In the present paper the development of characteristic diagrams of cutting processes which relate the Tool Center Point (TCP) displacement to thermal tool load is explained. The heat fluxes in the system workpiece –chip –tool are estimated by means of FEA (finite element analysis) in order to achieve multidimensional dependencies as function of the cutting parameters. The approach allows the real-time correction of tool paths within the machine tool control crucial in precise machining operations. Model verification and result comparison with cutting experiments have been realized.

Measurement of near cutting edge temperatures in the single point diamond turning process
E. Uhlmann (a,b), D. Oberschmidt (b), S. Frenzel (a), J. Polte (b)
(a)    Institute for Machine Tool and Factory Operation, TU Berlin
(b)    Fraunhofer Institute for Production Systems and Design Technology IPK

Thermomechanical and chemical wear mechanisms influence the contact region between diamond tool and workpiece during ultraprecision(UP)-machining. The measurement of near cutting edge temperatures in the single point diamond turning process provides the opportunity of a holistic consideration of diamond tool wear to complement existing temperature models. For this reason thinfilm thermocouple arrays has been designed, fabricated and integrated in a diamond tool, which were used for cutting tests and process simulations. Hence, a connection between process temperatures and diamond tool wear could be identified.

Experimental investigation of heat flows during milling processes through infrared thermography and inverse modelling
T. Helmig (b), T. Augspurger (a), Y. Frekers (b), B. Döbbeler (a), F. Klocke (a), R. Kneer (b)
Laboratory for Machine Tools and Production Engineering, RWTH Aachen University
Institute of Heat and Mass Transfer, RWTH Aachen Univer.

Quantifying the heat flow into the tool and subsequently into the tool clamping is of para-mount importance for accurately predicting the thermal behavior of the manufacturing pro-cess. Yet there is a lack of methods for measuring these heat flows and as well for determin-ing them and their dependence on the process parameters. The heat flow acts as a thermal boundary condition on a resulting transient temperature field within the cutting tool, thus, posing a so-called inverse problem. Experimental investigations by means of infrared ther-mography are conducted for a milling process, in order to measure this transient tempera-ture field and using it to calculate affiliated heat flows into the tool, applying transient tem-perature models or thermodynamic considerations.

Thermally induced displacements of machine tool structure, tool and workpiece due to cutting process
O. Horejš, M. Mareš, J. Hornych
Research Center of Manufacturing Technology RCMT, Czech Technical University in Prague

A thermal error model for software compensation of machine tools is usually established from air cutting (AC) experiments. However, the accuracy of the AC model in real machining applications is often questioned. The paper describes experimental results of cutting process impact on thermally induced displacements of machine tool structure, tool and workpiece in a dry milling process. A series of tests were carried out on a 5-axis milling machine. Experimental results confirmed high impact of the cutting process on thermally induced displacements between the workpiece and the tool. It is also shown that real-time thermal compensation algorithms based on experimental data under load-free rotation of the spindle have a very poor estimation quality.