Theoretical research of the chip removal process in milling of the closed profile slots

Purpose: The chip removal from the cutting zone of closed slots (T-shaped, "dovetail", etc.) is relevant since the repeated cutting of the chip with the blades of the tool teeth leads to a decrease in the resource of the cutting tool and processing accuracy. However, theoretical studies of the processes of filling, accumulation, and movement of the chip have not been considered. The purpose of the research is to develop the theoretical foundations of the chip filling and removing processes from profile slots using pneumatic hydrodynamic action of pressure jets of cooling liquid. Design/methodology/approach: Several stages of the analysed process are considered, namely the separation and filling of the space between the cutter teeth with the chip, filling the machined slot with the chip, removing the chip element from the space between the cutter teeth, moving the chip element along the machined slot, moving the chip array along the machined slot, pneumatic hydrodynamic impact. Findings: The complex of mathematical models have been developed to describe the functioning of the chip removal system during the milling of the closed profile slots in this research. The set of the developed models makes it possible to determine the required values of the design and operating parameters of devices that ensure the chip removal from the cutting zone as a result of the use of inertial forces and the application of additional compulsory forces. Research limitations/implications: Theoretical studies were applied for T-shaped slots for milling cutters with diameters from 12.5 mm to 95 mm made of high-speed steel and carbide inserts during steels and cast irons processing. The use of pneumatic hydrodynamic action is limited by the diameters of the nozzle hole from 0.5 mm to 3 mm. Practical implications: The practical significance of the research lies in the ability to control the process of timely chip removal from the cutting zone and to prevent the repeated ingress of the chip under the milling cutter blade. This is achieved by a set of mathematical models that simulate the chip removal process. Research can be applied in production in slots milling, using a liquid not only to cool the cutting zone but also to remove the chip in a timely manner. Originality/value: Theoretical studies previously not carried out for closed profile slots are presented in the research.