Cold forging of a hollow flanged part by an unconventional extrusion method

This paper presents a numerical analysis of a new cold forming process for a hollow part with an external flange. The following techniques were used: forward extrusion, an unconventional method of extrusion with a moving sleeve, and upsetting in a tapered die cavity. The billet (42CrMo4 steel tube) was formed at ambient temperature. The study aimed to investigate the proposed method in terms of forged part accuracy. The following are examined and discussed: material flow, process force parameters in relation to tool strength, energy consumption of individual operations, as well as the distributions of strains, stresses, temperature and Cockcroft-Latham integrals in the produced part. The study has confirmed that hollow forged parts with external flanges of relatively large diameters and heights can be cold formed in several operations using different techniques.

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.

Finite Element Simulation on Tool Strength of Rough Turning Cylinder

In this paper, numerical simulation method is used to study the turning tool strength by Deform 3D in the process of rough machining high strength steel (2.25Cr-1Mo-0.25V).It mainly studies the effect of the feed rate on the cutting force. At the same time, non-uniform distribution cutting force got from the simulation results is taken as the numerical simulation mechanical load of turning tool blade strength to study the influence of feed rate on the turning tool strength. The simulation results show that: with the feed increasing, the mechanical load that turning tool blade bears increases. The maximum effective stress and displacement of the turning tool blade is also increased.

Determination for Tool Edge Geometry and Cutting Conditions by Using FEM Simulations and Experiments

Hardened steel, Ni-based alloys and brittle materials are very difficult to machine using conventional cuttingmethods.A tool edge with a small nose radius can alleviate the regenerative chatter. In general, it is important for conventional cuttingto use the smallest possible tool nose radius. A sharp tool shape has an adverse effect on tool strength and the instability of machining process still occurs. A tool wear model with small nose radius proposed by past researchers is evaluated for predicting metal cutting tool wear when machining the copper. Tool temperature values are determined using finite element methods simulation. These temperatures are related to tool wear measured after metal cutting turning tests on a copper workpiece to determine tool edge geometry in low metal tool model.In this study, the effects of cutting conditions and tool edge geometry on process stability in turningare investigated through experiments and FEM simulations.

A New Approach to Five-Axis CNC Flute Grinding of Solid End-Mills

The traditional cutting tools grinding reveals inexact tool flutes that altered the tool strength and affect the chip evacuation capabilities. Moreover, the normal rake angles are neither exact nor varying smoothly on the rake face along the cutting edge. Adopting the rake face grinding process, the wheel shape and path are optimized using GODLIKE scheme in order to grind the tool flutes with exact helical and normal rake angles while keeping close matching to the designed flutes. A tapered ball-end mill is considered in this study due to its extensive role in five-axis sculpture surfaces machining. With this approach proposed, a simple grinding wheel replaces the complex wheels commonly used, and the deviation between the designed and the generated flutes reveals less than 4 % of the tool minor radius. Beside all, a relationship between the radial and the normal rake angles are established.

A Study on Diffusion Wear of Machining Tool and Simulation by Diffusion Couple

By choosing appropriate annealing temperature and annealing time, diffusion couples made of aluminum bronze and tool materials were prepared to simulate the diffusion and phase formation during the actual machining. These results were compared to those obtained from turning experiments. In agreement with results obtained from diffusion couple experiments, all turning experiments showed that major elements in both tool materials and workpiece diffused into their counterparts. The diffusion of C away from the tool will reduce the tool strength. It is helpful to use diffusion couple results to comprehend the diffusion effect in the actual turning process.

Experimental Study of Demolding Properties on Stereolithography Tooling

Direct tooling using stereolithography (SL) photopolymer has been developed as rapid tooling for short-run injection molds. However, the tool strength, thermal conductivity, and erosion resistance of SL mold are lower than that of the conventional metal mold. Previous study has showed that the tool life was limited under 200 shots and tool damage often occurs during part ejection. In this paper, experimental data from a demolding properties test are presented and discussed. The experiments were performed using various cooling time, hold pressure, and mold temperature. The experimental data were analyzed by measuring demolding force and surface roughness to evaluate tool life and failure mechanism in order to obtain a working range for the process parameters. The test result shows that the demolding force has close relation with cooling time and mold temperature.