Том 37, № 8 (2017)
- Год: 2017
- Статей: 20
- URL: https://journals.rcsi.science/1068-798X/issue/view/14012
Article
694-700
701-703
Influence of elastic recoil on the hole precision when reaming thin-walled components
Аннотация
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.
704-707
Isothermal drawing of small boxes from anisotropic oval blanks
Аннотация
The forces involved in the isothermal drawing of thin boxes with large radii from anisotropic blanks are considered as a function of the die speed, the frictional conditions at tool–workpiece contact, and the working pressure.
708-713
Process model of digital manufacturing
Аннотация
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.
714-719
720-722
723-727
728-729
Influence of the surface roughness of the electrode tool on the productivity in electric discharge machining of steel
Аннотация
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.
730-732
733-738
739-743
Influence of diamond paste on abrasive finishing
Аннотация
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.
744-746
747-750
661-666
More efficient rotation of excavator platforms
Аннотация
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.
667-671
Control of membrane drives
Аннотация
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.
672-674
Deformation of instrument housings under external pressure
Аннотация
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.
675-678
Gas–magnetic bearings in high-speed rotor systems
Аннотация
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.
679-681
Creep of graphite blocks under irradiation in RBMK reactors
Аннотация
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.
682-685
Tribochemical kinetics of external friction
Аннотация
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.
686-693
