Machining-Induced Work Hardening Behavior of Inconel 718 Considering Edge Geometries

As a representative type of superalloy, Inconel 718 is widely employed in aerospace, marine and nuclear industries. The significant work hardening behavior of Inconel 718 can improve the service performance of components; nevertheless, it cause extreme difficulty in machining. This paper aims to investigate the influence of chamfered edge parameters on work hardening in orthogonal cutting of Inconel 718 based on a novel hybrid method, which integrates Coupled Eulerian-Lagrangian (CEL) method and grain-size-based functions considering the influence of grain size on microhardness. Orthogonal cutting experiments and nanoindentation tests are conducted to validate the effectiveness of the proposed method. The predicted results are highly consistent with the experimental results. The depth of work hardening layer increases with increasing chamfer angle and chamfer width, also with increasing feed rate (the uncut chip thickness). However, the maximum microhardness on the machined surface does not exhibit a significant difference. The proposed method can provide theoretical guidance for the optimization of cutting parameters and improvement of the work hardening.

Design and Development of a Numerical Model and Study on Kinematic Analysis of a Circular Diamond Saw Blade for Ceramics

Diamond tools are currently being used by an increasing number of architects, miners and construction engineers because they are faster and easier to use than older, more traditional instruments like sledge hammers and pneumatic and hydraulic jacks. Bridge and highway surfaces are cut with diamond asphalt and concrete cutting machines to provide for quick, clean, and easy section removal and replacement. The entire cost is reduced since diamond tools take less time and manpower The experiment is carried out to validate the performance of diamond saw blades by taking into consideration characteristics such as normal force, tangential force, cutting speed, cut depth, and peripheral velocity. In present exploration work we are introductory phase of plan conclusion of a jewel device cutting edge with various segmental like 8,12,16,20 corn meal by utilizing Solid works programming we are planning the apparatus cutting edge after that we are imported in Ansys Software for Analysis reason. Computing the necessary qualities for examination and estimations of earthenware tiles likewise are some other stone molecule. Another power model of cutting is presented and inferred numerical demonstrating for chip thickness. Identical chip thickness to coarseness space proportion is gotten from the new power model another outspread opening like profile is presented. Fragmented sort jewel saw sharp edge with the measurement of 400 mm and different portion, for example, 8, 12, 16 and 20 are planned in Solid works effectively. An examination study between existing roundabout outspread space and cone like opening is done to decide deformity, stress dispersion, vibration and temperature conveyance.

Shoulder Damage Model and Its Application for Single Point Diamond Machining of ZnSe Crystal

The damaging of ZnSe crystal has a significant impact on its service performance and life. Based on the specific cutting energies for brittle and ductile mode machining, a model is proposed to evaluate the damage depth in the shoulder region of ZnSe crystal during single point diamond machining. The model considers the brittle-ductile transition and spring back of ZnSe crystal. To verify the model, the elastic modulus, hardness, spring back, and friction coefficient of ZnSe crystal are measured by nanoindentation and nanoscratch tests, and its critical undeformed chip thickness is obtained by spiral scratching. Meanwhile, orthogonal cutting experiments are conducted to obtain the different shoulder regions and cutting surfaces. The shoulder damage depth is analyzed, indicating that the effect of the feed on the damage depth at a high cutting depth is stronger than that at a low one. The model is verified to be effective with an average relative error of less than 7%. Then, the model is used to calculate the critical processing parameters and achieve a smooth ZnSe surface with a roughness Sa = 1.0 nm. The model is also extended to efficiently predict the bound of the subsurface damage depth of a cutting surface. The research would be useful for the evaluation of surface and subsurface damages during the ultra-precision machining of ZnSe crystal.

Estimation of Minimum Uncut Chip Thickness during Precision and Micro-Machining Processes of Various Materials—A Critical Review

Evaluation of the phenomena characterizing the chip decohesion process during cutting is still a current problem in relation to precision, ultra-precision, and micro-machining processes of construction materials. The reliable estimation of minimum uncut chip thickness is an especially challenging task since it directly affects the machining process dynamics and formation of a surface topography. Therefore, in this work a critical review of the recent studies concerning the determination of minimum uncut chip thickness during precision, ultra-precision, and micro-cutting is presented. The first part of paper covers a characterization of the precision, ultra-precision, and micro-cutting processes. In the second part, the analytical, experimental, and numerical methods for minimum uncut chip thickness estimation are presented in detail. Finally, a summary of the research results for minimum uncut chip thickness estimation is presented, together with conclusions and a determination of further research directions.

Determination of kinematic and geometric parameters of multi-scraper chain trange excavators on the basis of the semi-blocked critical depth regime of soil cutting

Trench excavators with a chain-scraper working body became widespread in the construction of linearly extended objects. Increasing workloads and rising energy prices call for optimizing the parameters of construction machinery. The most important component of the process of digging the soil with a chain-scraper working body is cutting the soil with scrapers (knives).When calculating the cutting forces, the working body is taken as a complex mechanical system of traction chains and transverse beams, on which in a certain order are arranged and fixed scrapers-knives with known angular parameters. Separation of chips from the soil is carried out by each scraper in the conditions of blocked, semi-blocked and free cutting of the soil. It should also be borne in mind the change in resistivity and energy consumption of soil cutting with a change in chip thickness. The minimum energy consumption of soil destruction takes place at a critical depth of cut. To reduce the energy consumption of the soil destruction process, a method of calculating the parameters of chain-scraper working bodies of trench excavators is proposed, which is based on critical depth cutting of soils. The initial data for the calculation are: technical productivity, m3 / h; maximum trench depth, m; trench width, m; physical and mechanical characteristics of soils (coefficient of adhesion, specific gravity, angles of internal and external friction). The proposed calculation method allows to determine the technological and geometric parameters of the chain-scraper working body with critical depth cutting of soils.

Prediction of Nonlinear Micro-Milling Force with a Novel Minimum Uncut Chip Thickness Model

The minimum uncut chip thickness (MUCT), dividing the cutting zone into the shear region and the ploughing region, has a strong nonlinear effect on the cutting force of micro-milling. Determining the MUCT value is fundamental in order to predict the micro-milling force. In this study, based on the assumption that the normal shear force and the normal ploughing force are equivalent at the MUCT point, a novel analytical MUCT model considering the comprehensive effect of shear stress, friction angle, ploughing coefficient and cutting-edge radius is constructed to determine the MUCT. Nonlinear piecewise cutting force coefficient functions with the novel MUCT as the break point are constructed to represent the distribution of the shear/ploughing force under the effect of the minimum uncut chip thickness. By integrating the cutting force coefficient function, the nonlinear micro-milling force is predicted. Theoretical analysis shows that the nonlinear cutting force coefficient function embedded with the novel MUCT is absolutely integrable, making the micro-milling force model more stable and accurate than the conventional models. Moreover, by considering different factors in the MUCT model, the proposed micro-milling force model is more flexible than the traditional models. Micro-milling experiments under different cutting conditions have verified the efficiency and improvement of the proposed micro-milling force model.

Cutting Force Modeling and Experimental Study for Ball-End Milling of Free-Form Surfaces

In order to improve the machining quality and efficiency and optimize NC machining programming, based on the existing cutting force models for ball-end, a cutting force prediction model of free-form surface for ball-end was established. By analyzing the force of the system during the cutting process, we obtained the expression equation of the instantaneous undeformed chip thickness during the milling process and then determined the rule of the influence of the lead angle and the tilt angle on the instantaneous undeformed chip thickness. It was judged whether the cutter edge microelement is involved in cutting, and the algorithm flow chart is given. After that, the cutting force prediction model of free-form surface for ball-end and pseudocodes for cutting force prediction were given. MATLAB was used to simulate the prediction force model. Finally, through the comparative analysis experiment of the measured cutting force and the simulated cutting force, the experimental results are basically consistent with the theoretical prediction results, which proves that the model established in this paper can accurately predict the change of the cutting force of the ball-end cutter in the process of milling free-form surface, and the error of the cutting force prediction model established in this paper is reduced by 15% compared with the traditional cutting force prediction model.

Study the Surface and Chip Formation of Wood Materials by Milling Method

This paper discusses the experimental study and the mechanism of chip formation, sliding and cutting in processing wood milling surface. The main objective is to determine chip thickness upon the coefficient k and tool tip radius ρ. Technically, when analysing we use FCCCD's second-order response surfaces method and analysis of variance (ANOVA) for determining the coefficient k upon the factors of milling cutter diameter D, the feeding per tooth Sz and tool tip radius ρ. According to the obtained experimental results, we determined the value domain of the machine's working factors so that the cutter tool tip can slide or cut the chip on the milled surface of tropical wood materials. From the coefficient k, we can determine the slide length Lsl which gives reason for the abrasion phenomenon of the front or rear sides of the cutter. The results allow us to choose the geometrical parameters ​​for milling cutter, apart from the working parameters for processing the surface of wood materials with the highest quality as possible.