Brittle-Ductile Transition and Nano-Surface Generation in Single-Point Diamond Turning of Single-Crystal Germanium

2021 ◽  
Author(s):  
Guoqing Zhang ◽  
Yanbing Chen ◽  
Junhong Han ◽  
Jianpeng Wang
2014 ◽  
Vol 625 ◽  
pp. 742-747
Author(s):  
C.H. Mak ◽  
C.F. Cheung ◽  
M.J. Ren ◽  
L.B. Kong ◽  
S. To

This paper presents a study of cutting strategies on the surface generation in single-point diamond turning of micro V-groove patterns on precision roller drums. An aluminium precision roller drum with a diameter 250mm and 100 long was diamond turned with a V-groove pattern. A series of cutting experiments were designed to study the effect of the variation of various cutting parameters and cutting tool paths on the surface quality in diamond turning of the precision roller drum. The parameters under investigation included the depth of cut, number of steps and the depth for each cut when diamond turning V-grooves on the cylindrical surface of a workpiece. The measurement result indicates that the surface quality of V-grooves machined on the precision roller drums is affected by cutting strategies. The optimal cutting strategy for machining a V-groove pattern on a precision drum with 5µm depth was obtained.


Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 4 ◽  
Author(s):  
Jie Xiong ◽  
Hao Wang ◽  
Guoqing Zhang ◽  
Yanbing Chen ◽  
Jiang Ma ◽  
...  

Pd40Ni10Cu30P20 bulk metallic glass (BMG) is widely used in industrial fields due to its excellent oxidation resistance, corrosion resistance, and thermal stability. However, the lack of research on the machinability and cutting performance of BMG using single-point diamond turning (SPDT) limits its application for engineering manufacturing. In the present research, a series of turning experiments were carried out under different cutting parameters, and the machinability reflected by the quality of machined surface, chip morphology, and tool wear were analyzed. Based on the oxidation phenomenon of the machined surface, a molecular dynamics (MD) simulation was conducted to study the mechanism and suppression of the machined surface oxidation during the cutting. The results show that: (1) The Pd-based BMG had good machinability, where the machined surface roughness could go down to 3 nm; (2) irregular micro/nanostructures were found along the tool path on the outer circular region of the machined surface, which greatly affected the surface roughness; and (3) the cutting heat softened the workpiece material and flattened the tool marks under surface tension, which improved the surface quality. This research provides important theoretical and technical support for the application of BMG in optical mold manufacturing.


2011 ◽  
Vol 314-316 ◽  
pp. 984-987
Author(s):  
Qing Liang Zhao ◽  
Jun Yun Chen ◽  
Jian Luo

The swelling effect is an important factor to affect surface generation in SPDT. Face cutting experiments are conducted for copper, aluminum alloy and electroless nickel phosphorus to analyze the swelling effect including the relationship between it and cutting parameters as well as effect of material property. How the material swelling affects surface roughness is also studied in this paper. The results indicate that the swelling effect is influenced by spindle speed and material property more remarkably when compared to feed rate and depth of cut. In addition, a softer and more ductile material will lead to a stronger material recovery, a lower swelling proportion, a lower tool mark height and a smoother machined surface. The result reveals that the swelling effect must be considered when predicting surface roughness in SPDT


2011 ◽  
Vol 496 ◽  
pp. 150-155 ◽  
Author(s):  
Saurav Goel ◽  
Xi Chun Luo ◽  
R.L. Reuben ◽  
Waleed Bin Rashid ◽  
Ji Ning Sun

Silicon carbide can meet the additional requirements of operation in hostile environments where conventional silicon-based electronics (limited to 623K) cannot function. However, being recent in nature, significant study is required to understand the various machining properties of silicon carbide as a work material. In this paper, a molecular dynamic (MD) simulation has been adopted, to simulate single crystal β-silicon carbide (cubic) in an ultra precision machining process known as single point diamond turning (SPDT). β-silicon carbide (cubic), similar to other materials, can also be machined in ductile regime. It was found that a high magnitude of compression in the cutting zone causes a sp3- sp2 order-disorder transition which appears to be fundamental cause of wear of diamond tool during the SPDT process.


2006 ◽  
Vol 532-533 ◽  
pp. 989-992
Author(s):  
Chi Fai Cheung ◽  
Wing Bun Lee ◽  
Suet To

This paper presents a multi-spectrum analysis method for the characterization of the surface generation in single-point turning of brittle single crystals. The features on the diamond turned surfaces were extracted and analysed by the power spectrum analysis of the surface roughness profiles measured at a number radial sections of the workpiece. By the analysis of the variation of the spectral patterns in the multi-spectrum plots, the surface roughness and materials effect on surface generation are found to be strongly related to the power spectrum. This provides an important means to explain quantitatively the effect of factors affecting the surface generation in diamond turning brittle crystals.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1510
Author(s):  
Ninghui Yu ◽  
Lihua Li ◽  
Chea-su Kee

Aluminum alloy (Al6061) is a common material used in the ultraprecision area. It can be machined with a good surface finish by single-point diamond turning (SPDT). Due to the material being relatively soft, it is difficult to apply post-processing techniques such as ultraprecision lapping and ultraprecision polishing, as they may scratch the diamond-turned surface. As a result, a novel low-pressure lapping method was developed by our team to reduce the surface roughness. In this study, a finite element model was developed to simulate the mechanism of this novel lapping technology. The simulation results were compared with the experimental results so as to gain a better understanding of the lapping mechanism.


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