OPTIMAL FEED RATE CONTROL STRATEGIES FOR FRICTION DRILLING

The presented paper contains the results of research aimed at developing optimal strategies for controlling the feed rate in the friction drilling process. In particular, the use of linear variable feed rate for individual drilling stages and adaptive feed rate control have been tested. The experiments were carried out with the use of a CNC machine tool equipped with an axial force and torque sensor. Correlation between thrust force and torque was shown, respectively, in relation to the feed drive load and the drive of machine tool spindle. Based on this, a feed rate sensorless control strategy was created to protect against excessive and long-term overload both of the tool and the drives. The following assessment criteria were considered: drilling cycle time, maximum values of thrust and torque, maximum values of feed drive load and drive of machine tool spindle, maximum power and energy effect in the form of work necessary to perform during the drilling process and forming the hole flange. The obtained test results, made for low-carbon steel with a tungsten carbide tool, indicate the advantage of the approach based on the linear variable feed rate and adaptive control over the traditional drilling process based on the step change of the feed rate, according to the recommendations given by the tool manufacturers.

FPGA Implementation of Variable Feed Rate Algorithm for a Three Input Fuzzy Controller to Maintain the Cane Level

Fuzzy logic which is one of methodology of soft computing has provided to be brilliant choice for the many control system application. Fuzzy logic is practical to numerous fields. One of the uses of fuzzy logic is in sugar mill. It is very important to produce sugar at low cost. Irregular supply of sugar cane decreases the efficiency of cane juice extraction during manufacturing of sugar. To increase the efficiency of cane juice extraction it is necessary to sustain the cane height at desired level inside Donnelly chute. A methodology to develop a variable feed rate algorithm for three inputs fuzzy controller sustains the cane height at desired level and was developed with fuzzy logic tool box of MATLAB software. The developed fuzzy controller can be implemented by using HDL language and Xilinx Vivado 2016.2.

ENERGY-BASED CHARACTERIZATION OF PRECISION HARD MACHINING USING PARTIALLY WORN CBN CUTTING TOOLS

This paper highlights the performance of precision hard turning with CBN cutting tools from energy point- of-view with additional tool wear effect. For this purpose several wear tests were performed during which the tool nose wear VBC and the corresponding changes of component forces Fc, Ff and Fp were continuously measured. Based on the measured forces and geometrical characteristic of the uncut layer, specific cutting and ploughing energy were determined for several combinations of cutting parameters. Consequently, changes of energy consumption resulting from tool wear evolution for variable feed rate, depth of cut and tool nose radius were presented.