


Vol 37, No 8 (2017)
- Year: 2017
- Articles: 20
- URL: https://journal-vniispk.ru/1068-798X/issue/view/14012
Article






Influence of elastic recoil on the hole precision when reaming thin-walled components
Abstract
The finite-element method is used to investigate the elastic surface displacement of a hole reamed in a lug at points where the radial cutting force is applied. On that basis, formulas are derived for determining the distortion of the machined hole surface, with allowance for all the relevant factors.






Process model of digital manufacturing
Abstract
Simulation of the business process in manufacturing is considered. The main attributes and stages of the business process are described. For the example of automated machining, the business process is broken down into its components. A logical relation is established between the subprocesses (functions). Their inputs and outputs controlling the implementation of the process are described. A process model of digital manufacturing is developed in the methodology of the IDEF0 standard.












Influence of the surface roughness of the electrode tool on the productivity in electric discharge machining of steel
Abstract
The influence of the surface roughness of the electrode tool on the productivity in electric discharge machining of 38Х2Н2МА steel is investigated. In the finishing of 38Х2Н2МА steel, there is no need to use electrode tools with surface microprojections shorter than 1.1 μm in order to ensure that the roughness of the machined surface corresponds to microprojections of height 1.1–1.6 μm. In practice, the manufacture of electrode tools with microprojections smaller than 1.1 μm is uneconomical.









Influence of diamond paste on abrasive finishing
Abstract
Abrasive finishing by diamond pastes is experimentally studied, with variation in the concentration of diamond grains and in the quantity of paste applied to the lap. In the experiments, the optimal quantity of abrasive paste applied to a lap of diameter 220 mm is determined: 75 mg. The productivity is somewhat higher in finishing by paste with a higher concentration of abrasive particles. The roughness of the machined surface is practically independent of the quantity and concentration of the diamond paste applied to the lap; it remains within the same class.









More efficient rotation of excavator platforms
Abstract
In the rotation of an excavator platform, energy is mostly consumed in acceleration and deceleration. The energy consumed in platform rotation may be reduced by uniform redistribution of the load over the whole contact surface, with equalization of the time of load action.



Control of membrane drives
Abstract
A method is proposed for increasing the efficiency of membrane drives by adjusting the effective area of the membrane. A device with adjustable effective area of the membrane is developed, with variation in the rod force by changing the working pressure in the chamber.



Deformation of instrument housings under external pressure
Abstract
To determine the stress–strain state of housings and instruments, a module based on a tensometric sensor is developed and used in experiments. The experimental results are compared with the values obtained in a standard experiment on laboratory equipment. The applicability and adaptability of the new module are confirmed.



Gas–magnetic bearings in high-speed rotor systems
Abstract
The cantilever overhang of a shaft on gas–magnetic bearings significantly affects the output characteristics of a high-speed rotor system. The rotational precision and rigidity of the rotor may be increased by adaptive control of the magnetic forces.



Creep of graphite blocks under irradiation in RBMK reactors
Abstract
Computer simulation of the stress–strain state of graphite blocks in prolonged thermal and neutron irradiation is considered, in a three-dimensional formulation. Allowance is made for the anisotropy of the graphite’s thermophysical properties, as well as crack initiation and growth. Creep of the material is taken into account, in the absence of plastic deformation, and its influence on the properties of the graphite blocks is assessed.



Tribochemical kinetics of external friction
Abstract
The kinetics of external friction is compared with the molecular–mechanical theory of friction. It is shown that research on the topochemical kinetics of adhesive binding is still in its early stages. Calculation methods that incorporate experimental data must be developed.


