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The paper deals with the problem of determining the power characteristics of face milling process by computer modelling in DEFORM 3D environment. The influence of the rake face shape of round face mill inserts on the contact area of the chips with the inserts surface, the conditions of the chip removal, the dynamic power loads both during the inserts entry into the workpiece and after the cutting are investigated. The efficient use of inserts with cylindrical rake face in the face mills designs proved, as these results in the decrease of the chip contact area with the inserts surface and improvement of the chip removal conditions. It results in the reduction of the tool dynamic force load, both at the time of entrance to the workpiece, and during cutting. Using computer modelling of the milling process for parts flat surfaces made from hardened high-strength steel and titanium alloy, strength characteristics are determined for the operation conditions with the stepped face mill with cylindrical rake face of the inserts and the standard mill with round inserts. For the stepped face mill the reduction of both impact loads during the entrance the insert to the workpiece and the average values of the component Pz of the cutting force is confirmed in comparison with the standard mills for the various processed materials. The reduction of torque from component Pz action creates the premises for reducing the effective power of the main movement of the machine drive, what can be used for machining with increased depth of cutting on low power machines. This may be another way of increasing the efficiency of the face milling of difficult-to-cut materials.

The article is devoted to the designs improvement of face mills with round inserts on the basis of a systems approach. The increasing a cutting efficiency with face mills is provided by improving their designs in the following aspects: increasing the tool life, accuracy and productivity, improving the quality of the machined parts surface. Analysis of the operating conditions of the milling cutters is carried out element by element (body, shank, inserts and their location, etc.), these components are considered as one system. The technological system (machine, holder, workpiece, tool) is presented as a supersystem, which is under the influence of active, intermediate acting, reactive and derivative factors. The article decomposes into elements (cutting, body, base and fastening parts) of a standard face mill with round inserts and performs their system analysis relatively the occurrence of adverse cutting conditions. On the basis of this the scheme of structural improvement aspects of face mills designs is developed. As a result of structural improvement and variants synthesis, the authors propose concepts of face mills designs for different machining conditions.

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