Effect of Rolling Texture on the Anisotropy of Surface Roughness in the Single-Point Diamond Turning of Polycrystalline Aluminum(Ultra-precision machining)

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.

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

Journal of Micromanufacturing ◽

10.1177/2516598420939745 ◽

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.

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Ultra-Precision Turning Technology of Gold Cone in Fast Ignition

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.562-565.147 ◽

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。

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Effects of the Tool Angles on the Machined Surface Quality of KDP Crystal in Diamond Turning

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.364-366.297 ◽

2007 ◽

Vol 364-366 ◽

pp. 297-301 ◽

Cited By ~ 7

Author(s):

Jing He Wang ◽

Ming Jun Chen ◽

Shen Dong ◽

Shi Qian Wang

Keyword(s):

Surface Roughness ◽

Surface Quality ◽

Rake Angle ◽

Diamond Turning ◽

Precision Machining ◽

Machined Surface ◽

Kdp Crystal ◽

Factors Affecting ◽

Ultra Precision ◽

Back Angle

In the ultra-precision machining of KDP crystal, there are many factors affecting the surface quality[1-3]. The experiments show that the rake angle and back angle of the tool have significant effects on machined surface roughness. Therefore, an efficient way to improve the surface roughness is to select a proper negative rake angle. In this study, the ANSYS static analysis method was employed to analyze the stress field distribution within the whole cutting region. A finite element simulation model was set up to calculate the residual stresses variation with tool’s angles, which can be considered to select optimal rake and back angles in the ultra-precision machining of KDP crystal. Results show that the optimal tool rake angle and back angle are -49° and 7°, respectively. Finally, by using different tool angles to process KDP crystal and utilizing AFM to analyze the surface roughness, it can be found that the measurement results agree well with what are deduced from theoretical calculation.

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Manufacturing Process of Terahertz Radar Reflector Based on Ultra-Precision Machining Technology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.713-715.633 ◽

2015 ◽

Vol 713-715 ◽

pp. 633-636

Author(s):

Di Li ◽

Song Bao Luo ◽

Jian Ming Zhang ◽

Chang Yu Xu ◽

Chang Tao Pang

Keyword(s):

Single Point ◽

Cutting Tools ◽

Diamond Turning ◽

Precision Machining ◽

Diamond Cutting Tools ◽

Single Crystal Diamond ◽

Aluminum Sample ◽

Ultra Precision ◽

The Cost ◽

Better Than

This paper presents a technique for processing Terahertz radar reflector by SPDT (Single Point Diamond Turning) based on LODTM (Large Optics Diamond Turning Machine). This technique applies single crystal diamond cutting tools for ultra-precision machining, and thus could obtain high-precision optical mirror, which could be used as the Terahertz radar reflectors. An experiment for aluminum sample had been done to demonstrate the availability of the technique, and a pair of Terahertz radar reflectors were obtained. The precision of the reflectors, detected through precision coordinate measuring technology, was better than the designed requirement. The experiment results showed that Terahertz radar reflectors generated by deterministic ultra-precision machining technique based on LODTM would have advantages in figure accuracy and roughness and so on, which could be helpful to improve the precision and low the cost of Terahertz radar system.

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