scholarly journals Simulation and Experimental Study on the Surface Generation Mechanism of Cu Alloys in Ultra-Precision Diamond Turning

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 573
Author(s):  
Zhang ◽  
Guo ◽  
Chen ◽  
Fu ◽  
Zhao
Keyword(s):  
Tool Wear ◽  
Diamond Tool ◽  
Surface Characteristics ◽  
Diamond Turning ◽  
Generation Mechanism ◽  
Surface Generation ◽  
Machining Parameters ◽  
Nose Radius ◽  
Cu Alloys ◽  
Ultra Precision

The surface generation mechanism of the Cu alloys in ultra-precision diamond turning is investigated by both simulation and experimental methods, where the effects of the cutting parameters on the surface characteristics are explored, including the workpiece spindle speed, the cutting depth, the feed rate and the nose radius of the diamond tool. To verify the built model, the cutting experiments are conducted at selected parameters, where the causes of the error between the simulation and the machining results are analyzed, including the effects of the materials microstructure and the diamond tool wear. In addition, the nanometric surface characteristics of the Cu alloys after the diamond turning are identified, including the finer scratching grooves caused by the tool wear, the formation of the surface burs and the adhesion of graphite. The results show that the built model can be basically used to predict the surface topography for the selection of the appropriate machining parameters in the ultra-precision diamond turning process.

scholarly journals Dual-Axial Tool Servo Diamond Turning of Hierarchical Micro-Nano-Structured Surfaces

2021 ◽  
Vol 5 (2) ◽  
pp. 58
Author(s):  
Xiaonan Pu ◽  
Zihui Zhu ◽  
Li Chen ◽  
Peng Huang ◽  
Yulin Wang ◽  
...  
Keyword(s):  
Basic Feature ◽  
Secondary Structures ◽  
Diamond Turning ◽  
Surface Generation ◽  
Machining Parameters ◽  
Structured Surfaces ◽  
Tool Marks ◽  
Ultra Precision ◽  
One Step ◽  
The One

This paper reports on a dual-axial tool servo diamond turning method for the one-step fabrication of hierarchical micro-nano-structured surfaces. With respect to the dual-axial servo motion (XZ), the z-axis motion can generate the primary surface with a complex shape, and the x-axis motion is used to synchronously form the secondary structure via controlling the residual tool marks. The toolpath determination algorithm for the developed turning method is described in detail, and the effect of the machining parameters on the basic feature and sizes of the generated secondary structures is investigated through conducting the numerical simulation for both toolpath and surface generation. The simulation result indicates that the additional x-axial motion is effective for the deterministic generation of a variety of secondary structures. Finally, taking advantage of an ultra-precision lathe with a self-developed tri-axial FTS, a hierarchical surface with high accuracy is practically generated.

Chip Formation in Ultra-Precision Machining of Nitrocarburized Steels

2012 ◽  
Vol 516 ◽  
pp. 293-298 ◽  
Author(s):  
Jen Osmer ◽  
Ralf Gläbe ◽  
Ekkard Brinksmeier
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Chip Formation ◽  
Diamond Tool ◽  
Compound Layer ◽  
Surface Generation ◽  
Precision Machining ◽  
Surface Compound ◽  
Steel Alloys ◽  
Ultra Precision

For the replication of optical glass or plastic components moulding inserts with surface roughness in the nanometre range and form accuracy in the micron or sub-micron range are needed. Despite these requirements the applied moulding insert material has to suit further needs like high temperature stability and resistivity against abrasive and chemical wear. To satisfy the specific requirements of replication processes steel alloys can be heat treated in a way to meet these demands. Unfortunately, these steel alloys cannot be machined with single crystal diamond tools because catastrophic diamond tool wear occurs. In recent years good progress in the field of ultra precision machining of steel has been made by nitrocarburizing the steel alloy. This leads to a sub-surface compound layer which is diamond machinable with surface roughness Sa < 10 nm and reduced diamond tool wear. But the ultra precision machining of these nitrocarburized steels introduces new challenges caused by the high hardness of the compound layer. Typical values are about 1200HV0.025. Therefore, this paper presents results from ultra precision machining processes focusing on the material behaviour during the cutting process. Influences of depth of cut and material composition on the surface generation can be found by evaluating chip formation and the resulting chips. Furthermore, the sub-surface of ultra precision machined steels is characterized by metallographic analysis to evaluate the influence of the nitrocarburizing process on ultra precision machining. In conclusion this paper presents the results for a deeper understanding of the material removal mechanisms in ultra precision machining of nitrocarburized steels.

Diamond Insert Wear when Turning Rapidly Solidified Aluminium RSA 443 of High-Silicon Content

2015 ◽  
Vol 828-829 ◽  
pp. 265-271 ◽  
Author(s):  
Zwelinzima Mkoko ◽  
Khaled Abou-El-Hossein
Keyword(s):  
Tool Wear ◽  
Diamond Tool ◽  
Natural Diamond ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Edge Wear ◽  
Rapidly Solidified

Rapid solidification of molten metals has been recently used to generate a new group of alloys having ultra-fine microstructures and high end mechanical properties. Therefore, such alloys can be successfully used in the optics industry to produce diamond machined mirrors and mould inserts for plastic lens injection. Rapidly solidified aluminium grades characterised by their ultra-fine grains can be used to replace traditional optical aluminium such as 6061-T6 which has coarse microstructure when making optics. However, there is currently no data available on the performance of these new grades in terms of diamond tool wear when machined in single-point diamond turning operation. This paper reports on the wear mechanisms of natural diamond tools when turning RSA 443 which is a new aluminium grade produced by rapid cooling process. Although this new aluminium grade enjoys fine microstructure, it is harder than traditional optical aluminium because of its increased content of silicon (about 40%). Therefore, there is a need to establish a deeper understanding of diamond tool performance when using diamond turning of optical components from this material. In this study, three machining parameters, namely cutting speed, feed rate, and depth of cut, were varied at three levels and the edge wear of the diamond inserts was observed using scanning electron microscopy after 4 km of cutting distance. The first observations from this preliminary study show that tool wear of diamond is more sensitive to the change in cutting speed than it is for other cutting parameters. Wear is relatively high (12 µm) at the lowest cutting speed (500 rpm). However, at high cutting speed (3000 rpm) the edge wear was small (3 µm). This could be attributed to the increased impacts of cut the material on the cutting edge. The study also reports on the surface finish obtained at the different combinations of cutting parameters.

scholarly journals An Investigation of the Cutting Strategy for the Machining of Polar Microstructures Used in Ultra-Precision Machining Optical Precision Measurement

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 755
Author(s):  
Chen-Yang Zhao ◽  
Chi-Fai Cheung ◽  
Wen-Peng Fu
Keyword(s):  
Precision Measurement ◽  
Detection Algorithm ◽  
Surface Generation ◽  
Precision Machining ◽  
Tool Geometry ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Ultra Precision ◽  
Transition Points ◽  
Cutting Strategy

In this paper, an investigation of cutting strategy is presented for the optimization of machining parameters in the ultra-precision machining of polar microstructures, which are used for optical precision measurement. The critical machining parameters affecting the surface generation and surface quality in the machining of polar microstructures are studied. Hence, the critical ranges of machining parameters have been determined through a series of cutting simulations, as well as cutting experiments. First of all, the influence of field of view (FOV) is investigated. After that, theoretical modeling of polar microstructures is built to generate the simulated surface topography of polar microstructures. A feature point detection algorithm is built for image processing of polar microstructures. Hence, an experimental investigation of the influence of cutting tool geometry, depth of cut, and groove spacing of polar microstructures was conducted. There are transition points from which the patterns of surface generation of polar microstructures vary with the machining parameters. The optimization of machining parameters and determination of the optimized cutting strategy are undertaken in the ultra-precision machining of polar microstructures.

Multiresponse Optimization of Al Alloy-SiC Composite Machining Parameters for Minimum Tool Wear and Maximum Metal Removal Rate

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Rajesh Kumar Bhushan
Keyword(s):  
Tool Wear ◽  
Metal Removal ◽  
Removal Rate ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Al Alloy ◽  
Machining Parameters ◽  
Metal Removal Rate ◽  
Nose Radius ◽  
Multiresponse Optimization

Optimization in turning means determination of the optimal set of the machining parameters to satisfy the objectives within the operational constraints. These objectives may be the minimum tool wear, the maximum metal removal rate (MRR), or any weighted combination of both. The main machining parameters which are considered as variables of the optimization are the cutting speed, feed rate, depth of cut, and nose radius. The optimum set of these four input parameters is determined for a particular job-tool combination of 7075Al alloy-15 wt. % SiC (20–40 μm) composite and tungsten carbide tool during a single-pass turning which minimizes the tool wear and maximizes the metal removal rate. The regression models, developed for the minimum tool wear and the maximum MRR were used for finding the multiresponse optimization solutions. To obtain a trade-off between the tool wear and MRR the, a method for simultaneous optimization of the multiple responses based on an overall desirability function was used. The research deals with the optimization of multiple surface roughness parameters along with MRR in search of an optimal parametric combination (favorable process environment) capable of producing desired surface quality of the turned product in a relatively lesser time (enhancement in productivity). The multi-objective optimization resulted in a cutting speed of 210 m/min, a feed of 0.16 mm/rev, a depth of cut of 0.42 mm, and a nose radius of 0.40 mm. These machining conditions are expected to respond with the minimum tool wear and maximum the MRR, which correspond to a satisfactory overall desirability.

scholarly journals Measurement and Compensation of Tool Contour Error Using White Light Interferometry for Ultra-Precision Diamond Turning of Freeform Surfaces

2020 ◽  
Vol 14 (4) ◽  
pp. 654-664 ◽  
Author(s):  
Kodai Nagayama ◽  
◽  
Jiwang Yan
Keyword(s):  
White Light ◽  
High Efficiency ◽  
Diamond Tool ◽  
Microlens Array ◽  
Diamond Turning ◽  
Contour Error ◽  
Form Accuracy ◽  
Freeform Optics ◽  
Ultra Precision ◽  
Quick Measurement

In ultra-precision diamond turning of freeform optics, it is necessary to obtain submicron-level form accuracy with high efficiency. In this study, we proposed a new method for the quick measurement and compensation of tool contour errors to improve the form accuracy of the workpiece. In this method, the nanometer-scale contour error of a diamond tool is quickly and precisely measured using a white light interferometer and then compensated for, before machining. Results showed that the contour of a diamond tool was measured with an error less than 0.05 μm peak-to-valley (P-V) and the feasibility of error compensation was verified through cutting experiments to create a paraboloid mirror and a microlens array. The form error decreased to 0.2 μm P-V regardless of the contour error of the diamond tools when cutting the paraboloid mirror, and that of the microlens array was reduced to 0.15 μm P-V during a single machining step.

Experiment and Discussion on Ultrasonic Vibration-Assisted Single Point Diamond Turning of Die Steels

2012 ◽  
Vol 497 ◽  
pp. 1-5
Author(s):  
Xiao Dan Xie ◽  
Yong Li ◽  
Cam Vinh Duong ◽  
Ahmed Al-Zahrani
Keyword(s):  
Tool Wear ◽  
Ultrasonic Vibration ◽  
Single Point ◽  
Cutting Parameters ◽  
Diamond Turning ◽  
Machining Process ◽  
Die Steels ◽  
Ultra Precision ◽  
Promising Solution ◽  
Vibration Parameters

Traditionally, single point diamond turning (SPDT) can not process ferreous metals because of acute tool wear. Ultrasonic vibration-assisted cutting(UVC) provides a promising solution for the problem. In this paper, for the aim of directly obtaining mirror surface on die steels, UVC method was used combining with SPDT process. Experiments were carried out on an ultra precision turning machine, cutting parameters and vibration parameters were well-chosen, and two kind of feed rates, two kinds of prevailing die steels were experimented. Mirror surfaces were successfully achieved on face turning, with the best roughness of Ra16.6nm. And the surface roughness, surface texture and tool wear in machining process were discussed.

Cutting Force Evolution and its Power Spectrum Analysis with Tool Wear Progress in Ultra-Precision Raster Milling

2014 ◽  
Vol 625 ◽  
pp. 20-25
Author(s):  
Guo Qing Zhang ◽  
Suet To ◽  
Gao Bo Xiao
Keyword(s):  
Power Spectrum ◽  
Tool Wear ◽  
Cutting Force ◽  
Spectrum Analysis ◽  
Diamond Tool ◽  
Power Spectrum Analysis ◽  
Spectrum Density ◽  
Ultra Precision ◽  
The Time Domain ◽  
Cutting Experiments

In this paper, cutting force and its power spectrum analysis at different tool wear levels are explored. A dynamic model is established to simulate the measured cutting force compositions, and a series of cutting experiments have been conducted to investigate the cutting force evolution with the tool wear progress. Research results reveal that in the time domain, the cutting force in UPRM is characterized as a force pulse follows by a damped vibration signals, the vibration can be modeled by a second order impulse response of the measurement system. While in the frequency domain, it is found that the power spectrum density at the natural frequency of dynamometer increases with the progress of tool wear, which therefore can be utilized to monitor diamond tool wear in UPRM.

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