Vol 36, No 5 (2016)

Static self-braking of wedge-based free-wheel mechanisms is investigated by means of a nonconservative boundary-element model. The distribution of the contact characteristics in the kinematic pairs of the self-braking mechanisms is established. Their stress–strain state is determined.

Special stays must be used to increase the precision and productivity in the machining of long stepped shafts. Recommendations are made for optimization of the design of a mobile stay by means of special mobile supporting rods.

Thermal conditions for the additive manufacture of components by melting metal and alloy wire are presented. In an experiment, a prototype 3D printer is used to print components in vacuum.

An experimental system is developed for the calibration of thin-walled precision pipe by transverse compression and expansion using a multisector tool. Formulas are derived for the basic parameters of the system.

Preliminary surface deformation (rolling) is proposed in the turning of polymers. The dependence of the surface roughness on the rolling and cutting conditions is derived.

A simple turret head has been developed for numerically controlled machine tools. This system has a pneumatic rotary drive for the tool disk and pneumatic clamps. It may be used to replace imported models.

Roughing methods for the external surfaces of revolution of hard-to-machine workpieces are analyzed. On that basis, a new roughing method is proposed, with the use of both a cutter and a mill.

Simulation of multitooth milling reveals the shortcomings of current CAM systems. An example illustrates the potential for expanding CAM systems so as to take account of vibration in developing the control software for numerically controlled machine tools.

Experimental hardening curves are plotted for the analysis of the cutting process in strain-hardening materials. As examples, approximate formulas for specific carbon steels are presented.

Numerical modeling of the spark plasma sintering of square plates from aluminum-oxide and tungsten-carbide powder is considered. The rounding radius of the plates is 0.8, 1.2, or 1.6 mm. The distribution of the temperature and mechanical stress within each sample and also within the mold is determined. The results are used for preliminary assessment of the possibility of spark plasma sintering of cutting plates.

A method is proposed for matching components in the selective assembly of bearings. The method involves selecting paths associated with redistribution of the flux. This is a procedure with a finite number of steps.