## 4 Tests  
The deburring process carried out for the production of engine blades is aimed at achieving two results: removing burrs that are harmful during operation and giving the appropriate radius to all machined edges. Such action will guarantee the safety of the worker during turbine assembly and the safe operation of the entire engine during its life. In order to carry out the deburring process, the work piece being processed should be brought into contact with the rotating brush. During the tests (Figure 5), the work piece placed in the holder is moved by the robot along the programmed trajectory against the rotating brush mounted on the industrial grinder. Measurement values such as torque, force, and blunting radius are acquired by the force sensor and laser profilometer and then recorded in the database. In order to carry out the correct brushing process, it is necessary to remove the burr and give the appropriate radius to all machined edges. For this purpose, it is necessary to prepare an appropriate sequence of movements of the work piece in relation to the brush. Based on the experience related to the implementation of the manual process, it was decided to copy the movements of the locksmith and program the manipulator in such a way that it would perform the movements of the locksmith as accurately as possible. The movements performed by the locksmith are presented in Figure 6.  
In the manual process, the operator, after completing the first sequence shown schematically in the figure, rotates the work piece by 180 degrees and repeats the entire sequence. It was noticed during the tests that the mentioned sequence can be implemented more simply by changing the direction of rotation of the tool. \begin{table}
\begin{tabular}{c c} \hline \hline
**Input Data** & **Output Data** \\ \hline Tool rotational speed, rpm & Radius of edge break, mm \\ Time of the operation, s & All burrs removed, yes/no \\ Depth of engage—tool and work piece, mm & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Input and output data for deburring process. Figure 5: Test stand (1—controller ABB IRC5, 2—industrial robot ABB IRB 2400, 3—Force Control, 4—work piece, 5—tool, 6—industrial grinder, 7—laser profilometer). In the initial phase of the tests, the aim was to examine the values of forces and moments occurring during the process of edge deburring. For this purpose, a number of tests were carried out at different values of the rotational speed of the brush. In the end, two speeds were selected. For the initial test, it was decided to cover the potential maximum scope of the rotational speed. Based on experience from manual process, it was chosen to start from maximum rotational speed of brush used during manual deburring operation--1600 rpm. At higher speeds, the worker is unable to hold the work piece for the entire shift (great fatigue, pain in the wrists). As a maximum limit, for automated test stand tests it was decided to use 3000 rpm--this is maximum speed allowed by available industrial grinders. Data were recorded using the Force Control package [43,46,49,50]. Table 3 presents the observed differences between the initial state and the change in force and torque during the operation. The results of the first trials, i.e., the values of the observed forces and moments, confirm the correctness of the sensor selection as they are within the measurement range according to the specification. Due to the negligibly small difference between the initial state and the forces obtained during the tests (a change of about 25% between the two rotational speeds used) in relation to the changes of moments (a change of about 130% between two used rotational speeds), it was decided to focus on the values of moments in further tests considered. In the second stage of the tests, a number of tests were carried out (each test was repeated three times) aimed at verifying the moments occurring during the deburring process depending on the rotational speed of the tool and the depth of insertion of the work piece into the brush (Figure 7).