Increase of accuracy and balance of abrasive disks with different hardness

It is shown that the most efficient methods of abrasive disk quality improvement in the matter of abrasive disk accuracy and balance increase are vibro-mixing, formation in rotating press mold, burning between refractory plates and machining application with diamond tools.

Determination of precision conditions for measuring relative values in mechanical tests of various materials

The problem of insufficient detail of the requirements for the developed and certified measurement methods used in mechanical testing of various materials is considered. The compatibility of the requirements of metrological support for the results of quantitative chemical analysis and indirect results of mechanical tests for the wear resistance of materials when rubbing against a fixed abrasive is relevant. To ensure the accuracy of measurements, it is proposed to use the grain size of the abrasive material and the rotation speed of the abrasive disk as variable factors. In order to establish the requirements for the metrological characteristics of materials during mechanical tests, in particular, when determining the relative wear resistance, the conditions for precision measurements are justified. The results of a multi-stage experiment-testing of materials for wear resistance with the use of various research and consumables, measuring instruments and testing equipment are presented. The conditions for the organization of the experiment in the case of determining other relative mechanical characteristics of the materials under study for establishing precision indicators in the development of methods of mechanical tests for abrasive wear are proposed and justified. The application of the obtained results will allow developers of mechanical testing methods to establish metrological characteristics of materials in compliance with all the requirements of the State System for Ensuring the Uniformity of Measurements of the Russian Federation.

Open-Source Grinding Machine for Compression Screw Manufacturing

Some of the most promising distributed recycling and additive manufacturing (DRAM) technical systems use fused particle fabrication (FPF) or fused granular fabrication (FGF), where compression screws force post-consumer waste plastic through a heated nozzle for direct 3D printing. To assist the technical evolution of these systems, this study provided the details of an invention for a low-cost, easily replicable open-source grinding machine for compression screw manufacturing. The system itself can be largely fabricated using FPF/FGF following the self-replicating rapid prototyper (RepRap) methodology. This grinding machine can be made from a cordless cut-off grinder and < $155 in parts. The new invention is demonstrated to be able to cut custom screws with variable (i) channel depths, (ii) screw diameters, (iii) screw lengths, (iv) pitches, (v) abrasive disk thicknesses, (vi) handedness of the screws, (vii) and materials (three types of steel tested: 1045 steel, 1144 steel, and 416 stainless steel). The results show that the device is more than capable of replicating commercial screws as well as providing makers with a much greater flexibility to make custom screws. This invention enables the DRAM toolchain to become even more self-sufficient, which assists the goals of the circular economy.

Function-specific technology of hobbing cutter relieving for wheel hobbing gears with Novikov mesh

A productive worm of a hob for cutting Novikov gearing with two mash lines has a profile variable not only by a curvature radius, but also by its sign. A procedure is developed for relieving side surfaces of teeth of these milling cutters by a disk tool (abrasive disk) function-specific to ensure back angles of a milling cutter and realization quality of an initial contour of a gear with the production worm of a milling cutter.

The process of interaction between abrasive disk and a workpiece while grinding under ultrasonic vibrations

This research includes the analysis of kinematic relations between abrasive disk grains and the workpiece in the abrading process while applying ultrasonic vibrations (USV) on the workpiece. Supposition, that applying vibrations lied in axes of abrasive disk increases efficiency of disk grinding, has been set. Analytical approach showed dependences for calculating the grinding force. These dependences include changing of disk grains microcutting kinematics and mechanical characteristics of workpieces while applying USV. The technique of pilot studies is given. For imposing on preparation of USV used the device in which it was one of links of oscillatory system that provides the minimum losses of energy USV and high amplitude of fluctuations of preparation. Field researches have shown, that applying USV lied in axes of abrasive disk decreased the grinding force, the wear of disk, and high-level parameters of the processed surface roughness.

Stressed state simulation of discrete abrasive disk cutting surface

Grinding disks with high frequency discretization of a cutting surface allow not only breaking a cutting process and de-creasing its thermal intensity, but decreasing a vibration level of a technological system which has a positive effect upon quality of a surface worked. But, for realization of intensive grinding modes these tools should possess a mechanical strength not only in the central hole, but that of a discrete cutting surface. In this connection in modern CAE-complex CosmosWorks a computer simulation of a stressed state of a cutting surface and a central hole of the grinding disk subjected to a high-frequency discretization is carried out. On the basis of the simulation results there is developed a durable tool allowing the fulfillment of discrete grinding in intensive modes.

Effect of random component in tool profile deviations upon dynamics of external circular grinding

This paper reports the estimation carried out of the state influence of a disk work surface upon output indices of external circular grinding. There are offered dependences for the computation of a mathematical expectation, correlation function and dispersion of a current radius-vector. The analysis of influence of a profile random component upon a process dynamics is carried out. The examples of spectrum characteristics of a random component of a tool profile deviations, a square of module frequency characteristics of the system and power spectrum of tool center oscillations caused by random deviations in an abrasive disk profile are shown. The interrelations established allow forecasting the behavior of an external round grinding, computing corrective control impacts, and carrying out a billet surface effective working taking into account conditions changed. The outlooks for the further development of results obtained consist in their application for the choice of project solutions, the characteristics evaluation of technological grinding systems and grinding optimization at billet working on the automated equipment.

Quality and productivity increase at profile creep feed grinding of turbine blades

A new concept of working quality assessment and cutting mode setting at profile creep feed grinding of some complex conjugate surfaces simultaneously on a multiaxes NC machine is presented. The analysis of dynamic and thermo-physical phenomena at machining each of the conjugate surfaces grinded simultaneously by one profile abrasive disk is carried out. The simulators for the definition of contact patch parameters of a grinding disk and a billet at a creep feed grinding of different conjugate profile surfaces of turbine and nozzle blades of GTEs allowing the prediction of material removal intensity, grinding disk wear, and roughness of every surface on the basis of changes in cutting modes, disk characteristics, dynamics of elastic, thermal and operation processes in a technological system are shown. This procedure allows controlling the process of profile creep feed grinding to achieve preset parameters of surface quality, dimension accuracy in blade profiles of gas turbine engines, productivity increase and decrease of machining prime cost.

Structural Design and Analysis of Abrasive Disk for Biplane of Multiple Workpieces

The planetary lapping is an effective method to improve the precision and efficiency, to obtain the ideal grinding trajectory by changing the planetary structure on the basis of the traditional abrasive mechanism. In order to grinding double plane of multi workpieces at the same time, first the design specific analyze the trajectory, Then, the planetary grinding structure is designed according to the processing requirements, and finally, the trajectory of the lapping is simulated by the kinematics and geometry, in order to verify its availability. The grinding machine is not only has a high machining accuracy and machining quality, but also is simultaneously used in the multiple workpieces having different cross-section within a certain size, in addition, it improves the processing efficiency and reduces processing costs. tables etc.