Reducing the noise during cutting force measuring

Článek je zaměřen na problematiku měření řezných sil na obráběcích strojích pomocí piezoelektrických dynamometrů. Při měření dochází k výraznému zkreslení snímaných veličin vlivy okolí, což způsobuje chyby při vyhodnocování daných veličin. Tento problém je řešen pomocí speciálního vybavení zkonstruovaného na KTO.The contribution is aimed to cutting force measuring at machine tools realised by dynamometers. Measured values are distorted by noise from external influences. The distorsion might cause errors in measured values analysis. This problem is solved using a specially designed equipment that was designed at the Departement of Machining Technology. The first figure shows the chosen profile and its shape. The second figure represents the main dimensions of the measuring table and gives some information about parts of the measuring table. The 3-D CAD model of the table is in the figure 3. The parts used for the table are in the figure 4. The fifth figure shows the process of table assembly. A part of frame is showed up left. Mounted wheels and full frame is up right. The whole table with unfinished shielding is down left. The finished table is down right. The measuring system placed into the measuring table is in the figure 6 (The piezoelectric dynamometer KISTLER is placed in the workspace of CNC milling machine MCV 750A). An example of unshielded measured data is in the figure 7. The left graph shows full behaviour of measured force which was obtained by a weight. The right graph shows the scaled part of measured data. This part was chosen from stabilized section of force behaviour. An example of shielded measured data is in the figure 8. The left graph shows full behaviour of measured force. The right graph shows the scaled part of measured data. This part was chosen from stabilized section of force behaviour. The table one displays the need values for evaluation of measured data. Minimal value of the force is in the second column. Maximal value is in the next column. Mean value of the force is in the fourth column. Difference between maximal and minimal value is in the next column. The last column contains the maximal difference from mean value represented in percents. The main aim of experiment was successfully done. The difference from mean value was reduced by 14 %. This reduction leads to increase of accuracy of measuring and evaluating the data