## 4 Technical Solution for Method Implementation
The large number of starts/stops excludes the possibility of choosing alternative current motors, where the maximum frequency of connection is of the order of hundreds per hour, leaving continuous current motors and stepper motors to be considered. The option of choosing a stepper motor is therefore proposed as it allows discrete (incremental) angular displacements of its mobile part (the rotor). Moreover, the stepper motor can be programmed to stop at any of these positions, or intermediate positions, when commanded in micro-step mode. It can also synchronize with the command pulses, operating without slippage and allowing sudden starts and stops without loss of steps and at adjustable speeds within very wide limits. In addition, if the sizing is carried out correctly and the specifications are respected, the stepper motor does not need feedback sensors, being able to work in an open loop, thus simplifying the electrical drive scheme. The motion of the motor is enacted with each received command pulse, performing point-by-point positioning. The values of plate displacements having to be made for each tool's double stroke are introduced into the system using specialized software installed on a computer connected to the control panel of the electric motor. To validate the proposed solution of controlled actuation of a slotting machine table, an experimental stand was designed and executed (Figure 23) on which controlled motions of the mechanism for translation according to a given law could be obtained. The experimental set-up contains a translation mechanism actuated by a stepper motor, which is controlled with a DM542H driver (Figure 24), whose settings allow the obtaining of micro steps up to \(360^{\circ}/25,600=0^{\circ}0^{\prime}50.63^{\prime\prime}\), so less than a \(1^{\prime}\) arc. The driver was powered with a direct voltage obtained from a 220 V AC source/24 V DC, able to provide the required current, so that there is no loss of steps at the motor axis, with bad influences on the accuracy of command execution. Figure 23: Experimental set-up for controlling motions II, when using a stepper motor [25]. The driving was controlled through the Mach3 software version 3.043.066 installed on a computer that was connected to the stand through the parallel interface (Figure 25). The confirmation of displacement accuracy was obtained by actual measurement using a type RV 1846 optical ruler with a resolution of 5 \(\upmu\)m mechanically fixed to the movable element of the mechanism and connected to a reading system (see Figure 23). In addition, to make the axial clearance as small as possible, the movable element was connected to the stepper motor shaft by means of a ball screw, with a pitch of 4 mm. These components allowed for great motion accuracy, with a 10 \(\upmu\)m gear clearance when changing the direction of motion. As the motion is in one direction during the generation of a tooth gap, this clearance can be picked up by the positioning motions. The tests we carried out showed the feasibility of applying the proposed solution in order to obtain the table motion (motion II, Figure 22) according to a law resulting from the application of the method of smoothing the detached chip area. For this purpose, successive intermittent motions of the table were measured (with an optical ruler) and compared with the necessary/imposed ones. The results confirmed the coincidence between these values (with the maximum error of 10 \(\upmu\)m).