Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
DEVELOPMENT OF AN EXPERIMENTAL METHODOLOGY FOR REAL-TIME THERMAL ERRORS COMPENSATION OF MACHINED WORKPIECES IN A 5-AXIS MACHINING CENTER IN NON-CONTROLLED TEMPERATURE ENVIRONMENT CONDITION
Submission Author:
Marcelo Otavio dos Santos , SP
Co-Authors:
Marcelo Otavio dos Santos , Ed Claudio Bordinassi, Adalto de Farias, Rodrigo Stoeterau, Gilmar Batalha
Presenter: Marcelo Otavio dos Santos
doi://10.26678/ABCM.COBEM2021.COB2021-0148
Abstract
The objective of this work was to carry out machining tests on engine heads manufactured in AlSi6Cu4 aluminum to estimate the contribution of the heat generated in the machining with a minimum amount of lubrication in the thermal error of the part, evaluating the contribution of ambient heat in the part heating and its consequences for the precision loss in the machining and finally develop a model of compensation of the thermal errors and to implement it in the CNC’s machine. The machine used to carry out the tests was a 5-axis GROB universal machining center, model G550AB. For the machining tests, 45 parts were used. The temperature in the room was 20ºC during all the tests carried out, which were divided into three stages. In step 1, 20 parts were machined, 5 with an initial temperature of 20°C, and another 15 previously heated to 25°C, 30°C and 35°C, totaling 4 batches of 5 parts each. In step 2, 10 parts were machined, 5 of them initially at 20°C and another 5 initially at 30°C. All machined parts had their temperature measured by a probe and some of their machined characteristics measured in CMM (Coordinate Measuring Machine). After analyzing the results obtained, a methodology for correcting thermal errors was proposed in step 3. After implementing the correction model at the machine's CNC, 15 more parts were machined to verify its effectiveness. The heating of the pieces was carried out by storing them in an electric oven with temperature control. During machining, the workpiece temperature was measured at each tool change using a M&H temperature probe model 25.44 HDR. The proposal for thermal compensation of the part was based on the calculation of thermal expansion coefficients from the results obtained during stages 1 and 2 of machining, and inserted directly into the machine's CNC for each machined characteristic. For verification and validation of the proposed methodology, 15 parts were machined, divided into 5 parts at 25°C, 5 parts at 30°C and 5 parts at 35°C, all with compensation. All of them were subsequently measured in CMM. The thermal errors obtained when comparing the machined parts at 20°C with the parts at 35°C reached at 29 μm. Analyzing the results obtained after the thermal compensation of the machined parts it is possible to affirm that the developed methodology was effective, reducing the thermal errors between 62% and 96%.
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