Ultra-Precision Turning Technology of Gold Cone in Fast Ignition

2013 ◽  
Vol 562-565 ◽  
pp. 147-151
Author(s):  
Guo Li ◽  
Yan Hua Huang ◽  
Wei Chao Tong ◽  
Guang Hui Yuan ◽  
Yang Tao ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Wall Thickness ◽  
Single Point ◽  
Fast Ignition ◽  
Diamond Turning ◽  
End Effect ◽  
Processing Parameter ◽  
Ultra Precision ◽  
Cone Surface

Fast Ignition (FI) attracts much attention owing to its advantages. The fabrication of fast ignition targets is one of the key technologies in FI study. Based on the single point diamond turning (SPDT) technology, Diamond post-turning method is adopted in this paper for the fabrication of gold cone. It not only helps to reduce the end-effect of cone mandrel and consequently improve the coaxiality of internal and external cone surface, but also helps to improve the quality of cone surface and the wall thickness consistency. Besides, the processing parameter of diamond post-turning is experimentally studied in this paper for its effect on the cone surface roughness. According to results, the cone surface roughness is Ra 9.21nm, the wall thickness consistency is 3μm and the cone end surface roughness is Ra5.72nm。

Study, analysis, and characterization of ultra-precision diamond tools for single-point diamond turning

2020 ◽  
pp. 251659842096533
Author(s):  
RamaGopal V. Sarepaka ◽  
Sivasakthi Balan ◽  
Somaiah Doodala ◽  
Rakesh Singh Panwar ◽  
D. Rajendra Kotaria
Keyword(s):  
Surface Roughness ◽  
Diamond Tool ◽  
Single Point ◽  
Quality Parameters ◽  
Diamond Turning ◽  
Radius Of Curvature ◽  
Tool Selection ◽  
Diamond Tools ◽  
Surface Irregularities ◽  
Ultra Precision

In multiple applications of advanced instrumentation, single-point diamond turning (SPDT) is a popular and effective process to generate novel surfaces with nanometric surface roughness and sub-micron surface irregularities, albeit at a high cost. In SPDT, precision diamond tooling contributes significantly to the process cost escalation. Hence, for SPDT, it is vital to have an optimal precision diamond tool deployment. In this article, details of comprehensive precision diamond tool selection and tool characterization are discussed. Three makes of selected ultra-precision diamond (UPD) tools and standard diamond tools (of a global make), designated as CFT, are considered for this study. In this tool bench-marking exercise, the fabrication of Cu–Be alloy predesigned precision components (PDPCs) of a critical geometry is selected. UPD and CFT tools are deployed to fabricate (under similar machining-metrology conditions) the PDPCs. These diamond tools are evaluated in terms of the quality parameters (variation in radius of curvature, form error, and surface roughness) of the workpieces. Further, to explore the progressive wear of these tools, multiple machining cycles are conducted on these workpieces, and their quality parameters are analyzed. Thus, the precision diamond tools of three makes are benchmarked against the CFT tool. Based on the final outcome of this analysis, suitable recommendations are provided to precision diamond tool manufacturers to improve their product in terms of performance and optimized costs to meet the ever-growing tooling demands of the SPDT community.

Freeform machining of ophthalmic toric lens mould using fast tool servo-assisted ultra-precision diamond turning process

2020 ◽  
pp. 251659842093974
Author(s):  
Ishan Anand Singh ◽  
Gopi Krishna S. ◽  
T. Narendra Reddy ◽  
Prakash Vinod
Keyword(s):  
Surface Roughness ◽  
Single Point ◽  
Measurement Data ◽  
Surface Profile ◽  
Diamond Turning ◽  
Fast Tool Servo ◽  
Toric Surface ◽  
Machined Surface ◽  
Ultra Precision ◽  
A Minor

This research aims to establish a methodology for machining of toric lenses, using fast tool servo-assisted single point diamond turning and to assess the generated surface for its characteristics. Using the established mathematical model, toric surface is explained to understand the geometry and to generate the parameters required for fast tool servo machining. A toric surface with a major diameter of 18.93 mm and a minor diameter of 15.12 mm has been cut on the intelligent ultra-precision turning machine (iUPTM). The surface profile and surface roughness were measured. After analysing the measurement data of the machined surface, on two perpendicular axes of the toric lens, form accuracy of 0.49 µm peak-to-valley (PV), and surface roughness of 12 nm in Ra, 4–8 nm in Sa are obtained. From the experimental results obtained, it can be concluded that the proposed method is a reasonable alternative for manufacturing toric lens mould.

Improving the Surface Roughness of a CVD Coated Silicon Carbide Disk by Performing Ductile Regime Single Point Diamond Turning

2008 ◽  
Author(s):  
Deepak Ravindra ◽  
John Patten
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Surface Quality ◽  
Removal Rate ◽  
Single Point ◽  
Extreme Environments ◽  
High Hardness ◽  
Diamond Turning ◽  
Ductile Regime Machining

Silicon carbide (SiC) is one of the advanced engineered ceramics materials designed to operate in extreme environments. One of the main reasons for the choice of this material is due to its excellent electrical, mechanical and optical properties that benefit the semiconductor, MEMS and optoelectronic industry respectively. Manufacture of this material is extremely challenging due to its high hardness, brittle characteristics and poor machinability. Severe fracture can result when trying to machine SiC due to its low fracture toughness. However, from past experience it has been proven that ductile regime machining of silicon carbide is possible. The main goal of the subject research is to improve the surface quality of a chemically vapor deposited (CVD) polycrystalline SiC material to be used in an optics device such as a mirror. Besides improving the surface roughness of the material, the research also emphasized increasing the material removal rate (MRR) and minimizing the diamond tool wear. The surface quality was improved using a Single Point Diamond Turning (SPDT) machining operation from 1158nm to 88nm (Ra) and from 8.49μm to 0.53μm (Rz; peak-to-valley).

A Study of Factors Affecting Surface Quality in Ultra-Precision Raster Milling

2007 ◽  
Vol 339 ◽  
pp. 400-406 ◽  
Author(s):  
M.N. Cheng ◽  
Chi Fai Cheung ◽  
Wing Bun Lee ◽  
Sandy To
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Dynamic Characteristics ◽  
Diamond Turning ◽  
Factors Affecting ◽  
Cutting Geometry ◽  
Milled Surface ◽  
Ultra Precision ◽  
Process Factors

Ultra-precision raster milling is an emerging manufacturing technology for the fabrication of high precision and high quality components with a surface roughness of less than 10 nm and a form error of less than 0.2 μm without the need for any subsequent post polishing. Surface quality of a raster milled surface is affected by process factors and material factors, respectively. The process factors involve cutting conditions, cutting strategies, and relative vibration between the tool and the workpiece which are related to the cutting geometry and the dynamic characteristics of the cutting process. The material factors considered are material property and swelling of the work materials. Due to different cutting mechanics, the process factors affecting the surface quality are more complicated, as compared with ultra-precision diamond turning, such as swing distance and step distance. This paper presents an experimental investigation of the distinctive process factors affecting the surface roughness in ultra-precision multi-axis raster milling. Experimental results indicate that the influence due to the process factors can be minimized through a proper selection of operational settings and better control of dynamic characteristics of the machine.

Test and study on mirror quality of ultra-precision diamond turning

2014 ◽  
Author(s):  
Yanyan Chang ◽  
Tao Sun ◽  
Zengqiang Li ◽  
Baosen Wu
Keyword(s):  
Diamond Turning ◽  
Ultra Precision

Comparison of Processing Features between Semi Bonded Abrasive Lapping and Loose Abrasive Lapping

2009 ◽  
Vol 416 ◽  
pp. 439-442
Author(s):  
Xun Lv ◽  
Ju Long Yuan ◽  
Dong Hui Wen
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Processing Parameters ◽  
Good Surface ◽  
Ultra Precision ◽  
New Processing ◽  
Short Time

Semi bonded abrasive lapping is an effective ultra-precision lapping method. It can obtain good surface quality of workpiece in short time. This paper focused on the differences of processing features by comparing semi bonded abrasive lapping and loose abrasive lapping in several groups processing parameters. The results showed that the surface roughness of workpiece in semi bonded abrasive lapping was far superior to that of loose abrasive lapping in same processing parameters. And the MRR (material removal rate) of semi bonded abrasive lapping was slightly lower than that of loose abrasive lapping. For these features of semi bonded abrasive, a new processing flow would also be proposed in this paper.

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