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.

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.

Cyclic shear angle for lamellar chip formation in ultra-precision machining

2020 ◽  
Vol 234 (13) ◽  
pp. 2673-2680 ◽  
Author(s):  
Shaojian Zhang ◽  
Pan Guo ◽  
Zhiwen Xiong ◽  
Suet To
Keyword(s):  
Chip Formation ◽  
Diamond Tool ◽  
Orthogonal Cutting ◽  
Rake Angle ◽  
Shear Angle ◽  
Precision Machining ◽  
Cyclic Shear ◽  
Intrinsic Mechanism ◽  
Classical Models ◽  
Ultra Precision

Shear angle is classically considered constant. In the study, a series of straight orthogonal cutting tests of ultra-precision machining revealed that shear angle cyclically evolved with each lamellar chip formation, i.e. cyclic shear angle. It grew up from an initial shear angle of 0° to a final shear angle 90°- α ( α: tool rake angle) and underwent a series of transient shear angles like classical shear angles and a critical shear angle. The critical shear angle is the sum of the half of the tool rake angle and the characteristic shear angle determined by material anisotropy without the friction effect. Moreover, a new model was developed. Further, a series of face turning tests of ultra-precision machining verified that the cyclic shear angle was the intrinsic mechanism of cyclic cutting forces and lamellar chip formation to induce twin-peak high-frequency multimode diamond-tool-tip vibration. Significantly, the study draws up an understanding of shear angle for the discrepancy among the classical models.

Finish Cutting of Carbide Mold with Thermally Affected Layer by Diamond Tool

2012 ◽  
Vol 565 ◽  
pp. 382-387
Author(s):  
Kazuki Imazato ◽  
Koichi Okuda ◽  
Hiroo Shizuka ◽  
Masayuki Nunobiki
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Cutting Force ◽  
Diamond Tool ◽  
Depth Of Cut ◽  
Good Surface ◽  
Finish Cutting ◽  
Ultra Precision ◽  
Cutting Experiments ◽  
Edm Process

This paper deals with finish cutting of thermally affected layer on cemented carbide by a diamond tool in order to machine efficiently the carbide mold with high accuracy and good surface without a polishing. The microstructure of thermally affected layer left by EDM process was observed and analyzed by EPMA. Its hardness and thickness were measured. Subsequently, the cutting experiments were carried out by using a PCD tool and an ultra-precision cutting machine. The effects of the thermally affected layer on the surface roughness, the cutting force and the tool wear were investigated. As a result, it was confirmed that the cutting force decreased with an increase in the depth of cut. Furthermore, it was found that the tool wear and the surface roughness obtained by cutting the thermally affected layer were greater than those of the original workpiece.

Diamond Tool Wear in the Ultra-Precision Cutting of Large Electroless Nickel Coated Molding Dies

2011 ◽  
Vol 5 (3) ◽  
pp. 283-288 ◽  
Author(s):  
Akira Shinozaki ◽  
◽  
Yoshiharu Namba
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Diamond Tool ◽  
Thin Foil ◽  
Electroless Nickel ◽  
Observation System ◽  
Shape Error ◽  
Shape Accuracy ◽  
Small Surface ◽  
Ultra Precision

In recent years, in a field of space science, large and high precision aspherical molding dies which are used to make aspherical thin foil mirrors for the hard Xray telescope are needed. Therefore to establish the ultra-precision cutting method for these dies is overly expected. In the actual manufacturing, the largemolding die is required to have both high accurate shape accuracy and very small surface roughness as the finished product. To machine the large molding die which has these high accuracies, we should know factors to cause various errors such as shape error and surface roughness and so on. Because it is necessary to machine the large molding die by using NC machining system that automatically corrects shape error finally. Especially, the tool wear of diamond tool is one of the big factors that influences shape error and surface roughness, so it needs to correct the amount of tool wear while ultra-precision cutting of large molding dies. From these points of view, in this research, a tool wear of diamond tool which is used in the ultra-precision cutting of large electroless nickel coated molding dies is considered with an on-machine measurement and observation system.

Diamond Tool Wear Measurement by Profilometry Method for Ultra-precision Machining of Silicon

2019 ◽  
Vol 18 ◽  
pp. 1510-1516
Author(s):  
Garima Singh ◽  
Vinod Mishra ◽  
Vinod Karar ◽  
S.S Banwait
Keyword(s):  
Tool Wear ◽  
Diamond Tool ◽  
Precision Machining ◽  
Wear Measurement ◽  
Ultra Precision

Study on Surface Finish of Carbon Steel by Ultra-Precision Diamond Cutting

2014 ◽  
Vol 1017 ◽  
pp. 367-372
Author(s):  
Yoshiki Kamoi ◽  
Koichi Okuda ◽  
Hiroo Shizuka ◽  
Masayuki Nunobiki
Keyword(s):  
Surface Roughness ◽  
Carbon Steel ◽  
Tool Wear ◽  
Carbon Content ◽  
Surface Finish ◽  
Diamond Tool ◽  
Diamond Cutting ◽  
Finished Surface ◽  
Ultra Precision

This paper describes an influence of the cutting atmosphere and the carbon content on the surface roughness and tool wear in CO2-blow cutting of carbon steel with a diamond tool. The cutting tests were carried out by changing the cutting atmosphere and carbon contains in order to investigate the effect on the improvement of surface finish and the reduction of tool wear. The results indicated that the roughness on finished surface was improved by cutting in CO2 gas blow atmosphere and the tool wear increased with a decrease in the carbon content.

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.

Characterization of Cutting-Induced Heat Generation in Ultra-Precision Milling of Aluminium Alloy 6061

2013 ◽  
Vol 552 ◽  
pp. 201-206
Author(s):  
Su Juan Wang ◽  
Suet To ◽  
Xin Du Chen
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Heat Generation ◽  
Feed Rate ◽  
Dimensional Accuracy ◽  
Precision Machining ◽  
Machined Surface ◽  
Single Crystal Diamond ◽  
Ultra Precision ◽  
Alloy 6061

The technology of ultra-precision machining with single crystal diamond tool produces advanced components with higher dimensional accuracy and better surface quality. The cutting-induced heat results in high temperature and stress at the chip-tool and tool-workpiece interfaces therefore affects the materials and the cutting tool as well as the surface quality. In the ultra-precision machining of al6061, the cutting-induced heat generates precipitates on the machined surface and those precipitates induce imperfections on the machined surface. This paper uses the time-temperature-precipitation characteristics of aluminum alloy 6061 (al6061) to investigate the effect of feed rate on the cutting-induced heat generation in ultra-precision multi-axis milling process. The effect of feed rate and feed direction on the generation of precipitates and surface roughness in ultra-precision raster milling (UPRM) is studied. Experimental results show that heat generation in horizontal cutting is less than that in vertical cutting and a larger feed rate generates more heat on the machined workpiece. A smaller feed rate produces a better surface finish and under a larger feed rate, scratch marks are produced by the generated precipitates and increase surface roughness.

Monitoring life of diamond tool in ultra-precision machining

2015 ◽  
Vol 82 (5-8) ◽  
pp. 1141-1152 ◽  
Author(s):  
C. Y. Chan ◽  
L. H. Li ◽  
W. B. Lee ◽  
H. C. Wong
Keyword(s):  
Diamond Tool ◽  
Precision Machining ◽  
Ultra Precision
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