Measurement And Simulation Calculation of Wire Bow Angle During The Diamond Wire Saw Process

The wire bow angle is an important factor that affects the shape precision of an ingot after the diamond wire sawing process. In this research, the wire bow angles of the inside and outside of an ingot were recorded with a high-speed camera. The effects of the processing parameters such as the wire tension force, feed speed, and wire speed on the wire bow angles inside and outside the ingot were analyzed. A numerical simulation model of the wire bow in the wire sawing process is presented in this paper to describe the wire bow angle inside the ingot. It was shown that the wire bow angle inside the ingot was smaller than that of outside the ingot for all of the processing parameters. The wire bow angles improved with the increase of the feed speed and decrease of the wire speed and the wire tension force. The results of the wire bow angle measurement of the inside ingot and the simulation calculation were similar for the process parameters.

Reducing the Energy Consumption of Circular Saws in the Cutting Process of Plywood

Cutting, as the most widely used machining process, is applied in both primary and secondary wood processing. Optimum cutting conditions that result in the high quality of the machined surface and low energy consumption are crucial for wood processing. The effects of the feed speed, cutting speed and average chip thickness on the energy consumption and surface temperature of a circular saw blade during the cutting process of two types of plywood with a thickness of h = 14 mm is described in this paper. In experimental measurements, two circular saw blades with cutting tungsten carbide inserts for wood were used as tools. One circular saw blade was standard, and was not surface treated (CSB1), and second circular saw blade (CSB2) differed by the powder coating surface and the length of the cutting edge. In the experiment, the energy consumption and the surface temperature of the circular saw blade was measured in order to find the optimal cutting conditions for the most energy-efficient cutting process. The results show that the cutting power and the surface temperature of the circular saw blade increased when the feed speed increased. The investigated values of the surface-treated circular saw blade were lower compared to the values of the standard circular saw blade. When comparing the lightweight plywood with the classic plywood, experimentally obtained cutting power values of the circular saw were made 19% lower on average by using the circular saw blade CSB1. When using the CSB2 circular saw blade, these values of the cutting power of the circular saw were 22% lower on average. The surface temperature of the circular saw blade is the highest on the outer edge (tooth root area 31.7 °C) and decreases towards the center of the circular saw blade. There must be a reasonable compromise between machine productivity and energy consumption.

Experimental Investigations On Optimizing Manufacturing Parameters For Electro-Spark Deposition Diamond Wire Saw

The third generation of superhard semiconductor materials, represented by single-crystal SiC, is used widely in microelectronics due to their excellent physical and mechanical properties. However, their high hardness and brittleness become the bottleneck of their development. Diamond wire saw (DWS) has become the mainstream tool for sawing hard and brittle crystal materials. However, the diamond abrasive is consolidated on the core wire through resin or electroplated nickel, and the holding strength is not high. When sawing superhard crystal materials, the efficiency is low. In order to improve the sawing efficiency of superhard crystal materials, it is of great significance to improve the wear resistance of wire saw and the holding strength of abrasive particles. Electro-spark deposition (ESD) can deposit electrode materials on the substrate with low heat input to achieve metallurgical bonding between metal materials. It can effectively improve the gripping strength of the abrasive grains. And the sawing ability of the wire saw to make the consolidated DWS by the ESD process. In this paper, the ESD equipment has been designed according to the characteristics of the ESDDWS process. The discharge gap size and electrode consumption are monitored in real-time by a single-chip microcomputer (SCM). Orthogonal experiments were carried out for the two motion modes. The effects of process parameters, such as (A) Grain size, (B) Abrasive content, (C) Pulse duration time, (D) Compacting pressure, (E) Current, (F) Electrode diameter, (G) Pulse interval time, (H) Reciprocating times, (I) Wire feed speed, on the quality of ESDDWS were analyzed. Through the extremum difference analysis, the optimal parameter combinations of ESDDWS were obtained. The results of the validation experiment are better than the original experimental results.

Multi-Stage Prediction of Feed System Time Series

In order to reduce the tracking error of the computer numerical control (CNC) feed system and improve the CNC machining accuracy, a novel prediction model is proposed based on fuzzy C-means robust variational echo state network. Firstly, the feed speed time series is clustered, and then reconstructed for different categories. The multi-stage robust prediction models are established to realize the multi-state robust prediction of the CNC machining feed velocity to reduce the tracking error of the feed system. Finally, the reference and actual time series with different feed speed are used to verify the established models. The results show that the proposed method can reduce the tracking error and realize the effective prediction of the time series of the feed system.

A multi-criteria decision-making in turning process using the MAIRCA, EAMR, MARCOS and TOPSIS methods: A comparative study

Multi-criteria decision-making is important and it affects the efficiency of a mechanical processing process as well as an operation in general. It is understood as determining the best alternative among many alternatives. In this study, the results of a multi-criteria decision-making study are presented. In which, sixteen experiments on turning process were carried out. The input parameters of the experiments are the cutting speed, the feed speed, and the depth of cut. After conducting the experiments, the surface roughness and the material removal rate (MRR) were determined. To determine which experiment guarantees the minimum surface roughness and maximum MRR simultaneously, four multi-criteria decision-making methods including the MAIRCA, the EAMR, the MARCOS, and the TOPSIS were used. Two methods the Entropy and the MEREC were used to determine the weights for the criteria. The combination of four multi-criteria making decision methods with two determination methods of the weights has created eight ranking solutions for the experiments, which is the novelty of this study. An amazing result was obtained that all eight solutions all determined the same best experiment. From the obtained results, a recommendation was proposed that the multi-criteria making decision methods and the weighting methods using in this study can also be used for multi-criteria making decision in other cases, other processes.

Investigation of Cutting Performance of a Circular Saw Blade Based on ANSYS/LS-DYNA

The circular saw blade is widely applied in rock processing; its cutting performance significantly impacts rock processing. Therefore, the numerical simulation model of rock cutting with the flexible circular saw blade has been established to investigate the effects of cutting parameters on the stress and cutting force of circular saw blade, and the damage and stress of rock in the circular saw blade cutting into rock vertically at constant feed speed and rotation speed. The research results indicate that the stress of the saw blade and rock rises with the increase of feed speed and rotation speed of the saw blade. Furthermore, the rock damage and the cutting force of the circular saw blade increase with the increasing feed speed and decrease with increasing rotation speed. The circular saw blade cutting force, vertical force, and horizontal force increase with the rising distance between the double circular saw blade. However, the axial force decreases. The research results of cutting hard rock with the flexible circular saw blade can aid in the optimization of cutting parameters and improve cutting efficiency.

Cortical bone grinding mechanism modeling and experimental studyfor damage minimization in craniotomy

Craniotomy, as a part of neurosurgery, implies a safe opening of the skull with mechanical equipment. Grinding is a traditional machining method that can accurately and efficiently remove bone tissue. Aiming at low-damage and high-efficiency bone grinding, this study analyzed the kinematic law of a single abrasive grain during the grinding process. The theoretical model of grinding force was established based on the calculation of specific energy and friction force. The grinding test platform was set up, and the full factorial experimental design was performed to link the grinding force evolution with different processing parameters. The experimental results obtained on porcine femurs validated the model predictions where the grinding force grew with feed speed and grinding depth; it exhibited a decreasing trend with rotation speed, followed by increasing one.

Transferability of the working envelope approach for parameter selection and optimization in thin wall WAAM

This work aims to propose and assess a methodology for parameterization for WAAM of thin walls based on a previously existing working envelope built for a basic material (parameter transferability). This work also aimed at investigating whether the working envelope approach can be used to optimize the parameterization for a target wall width in terms of arc energy (which governs microstructure and microhardness), surface finish and active deposition time. To reach the main objective, first, a reference working envelope was developed through a series of deposited walls with a plain C-Mn steel wire. Wire feed speed (WFS) and travel speed (TS) were treated as independent variables, while the geometric wall features were considered dependent variables. After validation, three combinations of WFS and TS capable of achieving the same effective wall width were deposited with a 2.25Cr-1Mo steel wire. To evaluate the parameter transferability between the two materials, the geometric features of these walls were measured and compared with the predicted values. The results showed minor deviations between the predicted and measured values. As a result, WAAM parameter selection for another material showed to be feasible after only fewer experiments (shorter time and lower resource consumption) from a working envelope previously developed. The usage of the approach to optimize parameterization was also demonstrated. For this case, lower values of WFS and TS were capable of achieving a better surface finish. However, higher WFS and TS are advantageous in terms of production time. As long as the same wall width is maintained, variations in WFS and TS do not significantly affect microstructure and microhardness.

Study on Medium-Thick Al-Alloy T-Joints by Dual P-GMAW Bilateral Synchronous Welding

The T-joints of medium-thick 6082 Al-alloy plates created by dual pulsed gas metal arc welding (P-GMAW) and bilateral synchronous welding were investigated to improve weld quality using the adaptive deposition method, which calculates the minimum amount of deposition according to the welding condition, groove size, and cross-sectional area, effectively reducing the heat input and deformation of the welds on the basis of weld filling. The optimized linear energy with a wire feed speed (WFS) of 9.5 m/min can ensure a well-formed weld with a complete root fusion, and high-quality T-joint welds were obtained both in root openings of 0 mm and 1 mm. The biggest penetration was 4 mm, which was four times more than that of the result from a single torch welding process. When the distance between the two welding torches exceeded 20 mm, the molten pool was completely separated, and process pores were observed in the unfused root zone. Influenced by the thermal cycles in asymmetric welding, the hardness distribution changed: the width of the softer zone at the base plate with the fore arc was smaller than that zone with the rear arc. Furthermore, dual P-GMAW bilateral synchronous welding with an asymmetric heat source can further reduce the deformation of the welded joint by about 20% compared to that of symmetric welding.

Multi-stage Inner Conical Hole Hydraulic Self Driving Rotating Magnetic Field Assisted Electrolytic Machining

Aiming at the problem of poor surface quality of multi-stage inner conical hole parts in electrochemical machining, a hydraulic self driving rotating magnetic field assisted electrochemical machining method is proposed, a hydraulic self driving rotating flow field model is established and simulated, and the structure of cathode tail blades is optimized. The simulation results show that when the number of cathode blades is 3 and the thickness of blades is 0.8mm, When the electrolyte flow rate is not less than 5m/s, the impeller at the tail of the cathode mandrel can rotate stably. A hydraulic self driving rotating magnetic field assisted electrochemical machining cathode is designed. When the machining voltage is 10V, the electrolyte temperature is 30 ℃, the electrolyte pressure is 1.6Mpa, the cathode feed speed is 5mm / min, and the electrolyte is 5%NaCl+16%NaNO3+4%NaClO3 composite electrolyte, the comparative experimental study of multi-stage inner conical hole electrochemical machining process with and without rotating magnetic field is carried out, The results show that the surface roughness of the workpiece without magnetic field is Ra0.847μm under the same processing parameters . With the addition of rotating magnetic field, the surface roughness of the workpiece is Ra0.437μm. The surface quality was improved by 48.41%.