Study on the surface quality of 60vol% SiCp/Al2024 composites with large-grained

In this paper, the finite element cutting simulation model with irregular distribution of multiple particles is established, the stress and strain distribution of SiC particles in the process of machining, as well as the material removal mechanism are analyzed. The effects of cutting velocity and feed per tooth on the surface quality of the material are also analyzed. The effect of feed per tooth on subsurface damage is revealed. The results show that in the micro-milling of SiCp/Al2024 composites, the particle removal form is mainly crushing and extraction. The surface defects of the workpiece mainly include pits, scratches, cracks, and extrusion damage. When the cutting velocity increases, the surface defects gradually change to crack, which can improve the surface quality of the workpiece. Increasing the feed per tooth will increase the surface defects of the workpiece and lead to poor surface quality. When the feed per tooth increased from 0.428 µm to 0.714 µm, the subsurface damage thickness increased from 35.2 µm to 47.3 µm.

Evaluation The Performance Of Cvd And Pvd Coated Carbide Tool In Hard Turning Of Aisi-4340 Steel

The work introduced in this proposal tends to the surface unpleasantness and flank wear during hard turning of AISI 4340 steel (33HRC) utilizing CVD (TiCN/Spasm/Al2O3/TiN) multi-facet covered carbide device and PVD (TiCN/Al2O3) covered carbide device. Three variables (cutting rate, feed and profundity of cut) and three level factorial test plans with Taguchi’s L9OA and factual examination of difference were acted to explore the impact of these cutting boundaries on the apparatus and work piece as far as flank wear, and surface harshness. Additionally the examination of these impacts between previously mentioned sorts of apparatuses was finished. The outcomes show that for surface unpleasantness and flank wear, feed and cutting velocity were measurably huge and profundity of cut had least impact on both surface harshness and flank wear. For surface harshness, feed was more huge followed by cutting velocity for the two sorts of devices, while as, for flank wear cutting pace was more huge followed by feed for the two kinds of instruments. Surface completion was estimated in Ra boundary and a decent surface completion was acquired by PVD covered apparatus at low and medium rates, anyway with the speeding up the CVD covered carbide device showed better surface completion. Flank wear was estimated by utilizing optical magnifying instrument and the outcomes show that more wear happened in PVD covered carbide apparatus when contrasted with CVD covered carbide device under same cutting boundaries and natural conditions. Consequently for better surface completion at low and medium velocities PVD covered carbide apparatus is better and for higher paces, CVD covered carbide device is ideal. For low apparatus wear, CVD covered carbide device is liked.

Accurate Modeling of Working Normal Rake Angles and Working Inclination Angles of Active Cutting Edges and Application in Cutting Force Prediction

The normal Rake angle is an important geometric parameter of a turning tool, and it directly affects the accuracy of the cutting force prediction. In this study, an accurate model of the working normal rake angle (WNRA) and working inclination angle (WIA) is presented, including variation in the cutting velocity direction. The active cutting edge of the turning tool is discretized into differential elements. Based on the geometric size of the workpiece and the position of the differential elements, the cutting velocity direction of each differential element is calculated, and analytical expressions for the WNRA, WIA, and working side cutting edge angle are obtained for each differential element. The size of the workpiece is found to exert an effect on the WNRA and WIA of the turning tool. The WNRA and WIA are used to predict the cutting force. A good agreement between the predicted and experimental results from a series of turning experiments on GH4169 with different cutting parameters (cutting depth and feed rate) demonstrates that the proposed model is accurate and effective. This research provides theoretical guidelines for high-performance machining.

Experimental Research of Paperboard Cutting in Die Cutting Press with the Screw–Nut Transmission of Drive Mechanism of a Movable Pressure Plate

This paper reports experimental research of torques during paperboard cutting in the die cutting press with the screw–nut transmission in the drive mechanism of the movable pressure plate. The purpose of the study is to substantiate the practical implementation of the pressure plate drive mechanism with the use of screw–nut transmission for the production of cartons of paperboard blanks. The manufactured experimental bench for the research of paperboard blanks provides the possibility of getting dependencies of loads on different parameters of the die cutting process. The developed method of the experimental research envisages the use of the strain gauge method and the wireless module for data measurement and software for its processing that allow getting trustworthy results with minimum faults. As a result of experimental research studies, the impact of paperboard thickness and cutting velocity on torque values has been established. Results of experimental research allow getting trustworthy and systematised information about torque values depending on the thickness of the paperboard, the paperboard fibre direction and pressure plate displacement velocity. It is established that torque values on drive shaft during die cutting of paperboard blanks made of folding boxboard with thickness that lay in range of 0.3–0.7 mm. Experimental research studies show the impact of rotation speed of a drive shaft of the pressure plate drive mechanism on the torque value. The article shows the workability of the designed device with screw–nut transmission in the drive mechanism of a movable pressure plate.

Elliptical torus cutter tool path generation based on minimum distance computation

In mould manufacture the elliptical torus cutters are used for their high cutting velocity, but the special geometry also brings issues in tool path generating and machining quality controlling. In this paper a guide curve tool path generating method for elliptical torus cutters is presented with the cutter location points computed by a minimum distance algorithm and the path spacing determined by an adaptive method. In the minimum distance algorithm, the calculation is resolved into an iterative process from point to freeform surface and an algebraic calculation process from point to elliptical torus surface considering the geometry of the cutter, which reduces the iterative process and improves the computing speed. In the adaptive path spacing method, the contacting geometry between the elliptical cutter and the workpiece surface is analysed and the relations among the scallop height, the tool tilt angle and the path spacing are deduced, based on which the guide curves are adjusted in advance to control the scallop height. Calculating examples and experiments are carried out, showing that the consuming time of cutter location (CL) points computation algorithm is reduced by 30% comparing to earlier method, and the adaptive path spacing method performs better than constant method in both scallop height controlling and tool path shortening. The results indicate that the presented tool path generating method can help to reduce both the machining and machine waiting time as well as ensuring the machining quality.

Forming process and evaluation of chip in machining of high-strength steel by an independent-developed microgroove turning tool

Chip morphology is one of the evaluation indexes of cutting performance of cutting tools, and chip forming process has a direct and important influence on chip morphology. High-strength steel 40CrMnMo is one of typical oil country tubular goods (OCTG) and difficult-to-cut materials, and its chip morphology represents the machining quality of OCTG. The chip forming process of a new independent-developed microgroove turning tool for turning oil country tubular goods 40CrMnMo is researched, combining machining experiments with theoretical analysis. Research results show that with the increase of cutting speed, the initial radius of curvature of the chip fluctuates slightly, but the overall trend is upward. However, the ultimate radius of curvature decreases and the chip’s radius ratio also decreases. The relative ideal chip can be obtained if the proper cutting velocity and feed rate are given. Chip morphology results from the comprehensive effect of the two processes: The fracture and separation process of the workpiece during passing through the shear deformation zone and the process of curling and breaking away of the chip after passing through the rake face of the tool. The research results have a certain guiding significance for controlling the cutting process of machining the other material with similar performance.

MULTI-OBJECTIVE OPTIMIZATION OF TURNING PROCESS USING A COMBINATION OF TAGUCHI AND VIKOR METHODS

This study presents the solving process of the multi-objective optimization problem using VIKOR method (Vlse Kriterijumska Optimizacija Kompromisno Resenje, in Serbian) when turning the EN 10503 steel. The cutting velocity, feed rate, depth of cut, and insert nose radius were chosen as the input parameters with three levels of each parameter. Taguchi L9 orthogonal array was used to design the experimental matrix with nine experiments. By the combination of Taguchi and VIKOR methods, the multi-objective optimization problem was successfully solved with optimal values (cutting velocity of 78.62 m/min, feed rate of 0.08 mm/rev, cutting depth of 0.5 mm, and insert nose radius of 0.4 mm. Using these the optimized input parameters, the surface roughness, cutting force and vibration component amplitudes (in X, Y, Z directions), and material removal rate (MRR) were 0.621 µm, 191.084 N, 300.162 N, 51.727 N, 4.465 µm, 7.492 µm, 10.118 µm, and 60.009 mm3/s, respectively. This proposed method could be used to improve the quality and effectiveness of turning processes by improving the surface quality, reducing the cutting force and vibration amplitudes, and increasing the material removal rate.

Experimental investigation of the effects of cryogenic cooling on tool life in Ti6Al4V milling

In this paper, the results of an experimental campaign of cryogenic milling are presented and discussed. For this purpose, a specific experimental setup that allowed to feed the liquid nitrogen LN through the tool nozzles was used. Tool life tests were carried out at different cutting speeds. The tool duration data were collected and used to identify the parameters of the Taylor’s model. Different end-of-life criteria for the tool inserts were even investigated. The achieved results are compared to those obtained using conventional cooling. It was observed that at low cutting velocity, conventional cooling still assures longer tool lives than in cryogenic condition. Since in cryogenic milling the increasing of the cutting velocity is not so detrimental as in conventional cutting, at high cutting speed (from 125 m/min) longer tool durations can be achieved. Statistical analyses on the model parameters were carried out to confirm the presented findings. The analysis of the effect of the cooling approach on the main wear mechanisms was also reported. At low cutting speed, adhesion and chipping phenomena affected the tool duration mainly in cryogenic milling.

Temperature effect on mechanical and tribological properties of WNiCoFe alloy powder for cutting tools

In order to improve the wear resistance of WNiCoFe alloy for cutting tools, WNiCoFe alloy powder is prepared by multiple metals electrolysis, alloy powder and its sintered morphology is observed and phase is analyzed using X-ray diffractometer and scanning electron microscope (SEM), the effect of sintering temperature on its physical mechanics and friction properties was studied. The results show that the prepared WNiCoFe alloy powder is alloyed to some extent, irregular and finer particle size, the diffraction peaks of Co3Fe7 and Fe19Ni are formed in addition to the elemental Fe; the maximum hardness of the sintered is 107.6HRB, the maximum bending strength at three points is 1638.3 mpa, the maximum density is 96.2%, and wear loss is 0.498–0.555 g when WNiCoFe alloy powder is sintered at 800∘C. Diamond tools are made with WNiCoFe alloy powder as the main matrix composition, and cut hard stone, cutting velocity is 8.6 m2/h and life is 11.3 m2/m, which has a good comprehensive performance.