IMPROVING THE EFFICIENCY OF MILLING HOLES WITH A SMALL-SIZED TOOL IN THE CONDITIONS OF AUTOMATED PRODUCTION

The purpose of the paper. In order to solve the problems of increasing the efficiency of machining operations of small diameter holes by milling, the optimal range of cutting modes and helix pitch for the machining strategy with helical interpolation is established. The reduction of labor intensity and costs of hole machining when treating holes in alloyed corrosion-resistant steels is experimentally confirmed. Research methods. In this paper, the issues of machining blind holes by helical interpolation milling with end cylindrical carbide cutters of relatively small dimensions in parts made of 12X18N10T alloy are considered. The features of this machining are availability of significant axial and radial components of the cutting forces with relatively low tool strength. This leads to the fact that a key factor of the tool failure is its mechanical failure, the cause of which is an increase in cutting forces due to the edge of the cutter being chipped. Research results and novelty. It has been experimentally proved that the most rational machining parameters to ensure the specified accuracy and surface quality of the machined holes when using a strategy of helical interpolation milling will be the choice of the helix pitch p = 0.2 mm, the feed range F = 0.075-0.11 mm /tooth, which corresponds to the minute feeds of the milling center 450-675 mm/min. Conclusions. The optimal range of cutting modes is found in the feed range from 450 to 675 mm/min, with a helical interpolation pitch of 0.2 mm. The accuracy and roughness of the holes obtained by milling with end mills with a diameter of 3 mm for steel 12X18N10T is evaluated.

Broad temperature range ferrielectric liquid crystal with subwavelength helix pitch

The ferrielectric liquid crystal (FerriLC) phase with the helix pitch po of about 100 nm was revealed in a broad temperature range from -3°C to + 35°C in a mixture containing an achiral smectic-C (SmC) biphenylpyrimidine and two non-mesogenic chiral diesters of 4,4”-terphenyl dicarboxylic acid.

Modifications of FLC Physical Properties through Doping with Fe2O3 Nanoparticles (Part I)

The aim of this paper is to show, by systematic studies, the influence of γ-Fe2O3 nanoparticles on the physical parameters of the liquid crystalline matrix, exhibiting a ferroelectric phase in a wide temperature range. The detailed research was carried out by using diffraction (PXRD), microscopic (OM, SEM, FCPM, POM), thermal (DSC), optical (TLI), electric and spectroscopic (FTIR) methods. We show that even the smallest concentration of γ-Fe2O3 nanoparticles largely modifies the parameters of the ferroelectric SmC* phase, such as spontaneous polarization, switching time, tilt angle, rotational viscosity, dispersion anchoring energy coefficient and helix pitch. The admixture also causes a significant reduction in the temperature of phase transitions, broadening the SmA* phase at the expense of the SmC* phase and strong streaking of the texture. We present and explain the non-monotonic modification of these parameters with an increase in the nanoparticle concentration. The influence of oleic acid admixture on these parameters is also widely discussed. We have shown that certain parameters of organic-metal nanocomposites can be controlled by the appropriate amount of metal admixture.

Ultra-short helix pitch and spiral ordering in cholesteric liquid crystal revealed by resonant soft X-ray scattering

The spontaneous formation of chiral structures offers a variety of liquid crystals (LC) phases that could be further tailored for practical applications. In our work, the characteristic features of spiral...

Influence of 4-(2-S(+)-Methylbutyloxy)Benzoic Acid on Mesomorphic and Physico-Chemical Properties of 4-Butyl-4'-Octanoyloxyazobenzene

Mesomorphic, optical, dielectric, and orientation properties of nematic liquid crystal 4-butyl-4'-octanoyloxyazobenzene doped with chiral 4-(2-S(+)-methylbutyloxy)benzoic acid have been studied. The clearing temperatures of the mixtures were measured by polarizing microscopy. An estimation of the mesophase destabilization with the introduction of the dopant was carried out. The helix pitch of the induced chiral nematic mesophase was measured. The effect of the chiral dopant on anisotropic characteristics of the mesophase has been studied. An insignificant increase in the optical and dielectric anisotropy is associated with the formation of liquid crystal – dopant supermolecules due to hydrogen bonds –COOH…OCO–.