Study of Factors Affecting the Surface Quality in Ultra-Precision Diamond Turning

2000 ◽  
Vol 15 (4) ◽  
pp. 481-502 ◽  
Author(s):  
C. F. Cheung ◽  
W. B. Lee
Keyword(s):  
Surface Quality ◽  
Diamond Turning ◽  
Factors Affecting ◽  
Ultra Precision

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

2007 ◽  
Vol 364-366 ◽  
pp. 297-301 ◽  
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.

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.

Effect of cutting parameters on surface quality during diamond turning of micro-prism array

2016 ◽  
Vol 231 (3) ◽  
pp. 555-561 ◽  
Author(s):  
Dongxu Wu ◽  
Peng Zhang ◽  
Huiming Wang ◽  
Zheng Qiao ◽  
Bo Wang
Keyword(s):  
Surface Quality ◽  
Surface Defects ◽  
Cutting Speed ◽  
Side Surface ◽  
Cutting Parameters ◽  
Diamond Turning ◽  
Dominant Factor ◽  
Controlled Cooling ◽  
Cutting Depth ◽  
Ultra Precision

In order to achieve the high-quality roller mold used in roll-to-roll fabrication of optical prism films, this article investigates the effects of cutting parameters on surface quality during diamond turning of micro-prism array, and some cutting experiments are carried out on home-made ultra-precision drum roll lathe. The surface defects such as micro pits and burrs are presented and discussed at different cutting parameters. The experimental results show that, when the cutting depth is more than 4 µm, the plowing force becomes the dominant factor to remove material, which may cause the generation of micro pits on the side surface of micro prism. During multiple-step diamond turning of micro-prism array, the final cutting depth is recommended not to exceed 2 µm; in this case, there is no generation of micro pits and the height of burr is less than 13.6 nm. Moreover, the well-controlled cooling and chip evacuation can effectively improve the influence of cutting speed on surface quality. Finally, micro-prism array with pitch of 40 µm is successfully machined without apparent surface defects.

scholarly journals Theoretical prediction and experimental verification of the unbalanced magnetic force in air bearing motor spindles

2019 ◽  
Vol 233 (12) ◽  
pp. 2330-2344 ◽  
Author(s):  
Quanhui Wu ◽  
Yazhou Sun ◽  
Wanqun Chen ◽  
Qing Wang ◽  
Guoda Chen
Keyword(s):  
Surface Topography ◽  
Surface Quality ◽  
Magnetic Force ◽  
Research Work ◽  
Diamond Turning ◽  
Surface Generation ◽  
Air Bearing ◽  
Machined Surface ◽  
Spindle Shaft ◽  
Ultra Precision

Dynamic vibrations of air bearing motor spindles have significant influence on the surface quality in ultra-precision machining. In this article, the influence of the vibration caused by the unbalanced magnetic force on the diamond turning is investigated on the basis of the theoretical and experimental method. A permanent magnet motor model (10 poles and 12 slots) is built and then simulated to gain a periodic unbalanced magnetic force. The effects of unbalanced magnetic force on the inclination of the spindle shaft is analyzed, which would affect the surface quality of the workpiece, and the surface topography of the workpiece is predicted during an unbalanced magnetic force acting on air bearing motor spindle. The theoretical analysis and experimental turning results validate that the angle between the direction of unbalanced magnetic force and the feed direction has a certain relationship with the profile of the machined surface. Also, under different turning speeds and directions, the surface topography of the machined workpiece shows a 10-cycle-per-revolution pattern, which has good agreement with the simulations of periodic unbalanced magnetic force. This research work provides a theoretical foundation for the fault diagnosis of air bearing motor spindle caused by motor rotor eccentricity and its effect on surface generation in turning.

Effects of Axial Spindle Vibration on Surface Generation in Ultra-Precision Diamond Turning

2016 ◽  
Vol 679 ◽  
pp. 67-71
Author(s):  
Shao Jian Zhang ◽  
Suet To
Keyword(s):  
Surface Quality ◽  
Crucial Role ◽  
Diamond Turning ◽  
Surface Generation ◽  
Simplified Model ◽  
Machined Surface ◽  
Proposed Model ◽  
Ultra Precision ◽  
Spindle Vibration ◽  
Mass Spring

In ultra-precision diamond turning (UPDT), axial spindle vibration (ASP) plays a crucial role influencing nanometric surface quality. In this study, a simplified model for ASP is proposed to study its effects on surface generation in UPDT as the spindle is idealized as a mass-spring-damper system. Significantly, the model successfully explains that ASP induces radial patterns at a machined surface. More importantly, this proposed model can be employed to easily predict and understand the effects of ASP on surface generation in UPDT.

Ultra-Precision Machining Technology of the Soft and Brittle Functional Crystal

2008 ◽  
Author(s):  
C. P. Lu ◽  
H. Gao ◽  
R. K. Kang ◽  
X. J. Teng ◽  
Q. G. Wang
Keyword(s):  
Surface Quality ◽  
Modern Technology ◽  
Diamond Turning ◽  
Precision Machining ◽  
Machining Efficiency ◽  
Magnetorheological Finishing ◽  
Precision Grinding ◽  
Ultra Precision ◽  
Definition Of ◽  
Important Branch

As an important branch of materials, soft and brittle functional crystals (SBFC) are widely used in the field of modern technology. However, the softness, brittleness, deliquescence, and strongly anisotropic natures of these materials present a challenge for their ultra-precision machining. The definition of SBFC is firstly given and their applications in many fields are also presented. For the ultra-precision machining technologies to satisfy the applied requirements, many methods such as single diamond turning, ultra-precision grinding, magnetorheological Finishing and so on, are successfully applied in SBFC materials, the challenges and difficulties occurred during machining these SBFC materials, such as KH2PO4, CdZnTe and CaF2, etc., are reviewed and the limits are also analyzed in detail. Moreover, many novel machining methods are suggested to achieve better surface quality and enhance machining efficiency.

Development of a Non-Contact Tool Setting System for Precision Diamond Turning

2006 ◽  
Vol 505-507 ◽  
pp. 367-372 ◽  
Author(s):  
Choung Lii Chao ◽  
T.A. Cheng ◽  
D.C. Lou ◽  
Chung Woei Chao
Keyword(s):  
Contact Point ◽  
Diamond Turning ◽  
Optical Diffraction ◽  
Sampling Step ◽  
Error Band ◽  
Sampling Distance ◽  
Tool Shape ◽  
Tool Setting ◽  
Ultra Precision ◽  
Cnc Controller

Precise and efficient tool setting technique and accurate tool shape monitoring are of essential importance in ultra-precision diamond turning operation. The traditional way of tool setting are typically laborious, inefficient and rely heavily on experience. A big part of the tool setting is done by using a contact probe such as LVDT. The contact tool setting station can normally, depending on the resolution of the probes, place the tool tip to within a 1~10μm positioning accuracy. However, it is running the risk of damage the delicate tool tip and has the ambiguity introduced by contact point of tool and touch probe. The optical/non-contact way of setting the tool do have the advantage of not having to touch the tool, but its resolution is limited by the optical diffraction limit and the resolution of the CCD device used (mm/pixel). A non-contact precision tool setting system is developed and built in this study using edge-detection image processing and sub-pixel dividing techniques in conjunction with CNC controller of the precision turning machine to improve the system presently available. Depending on the sampling distance of the images, the error band gets wider when the sampling step becomes larger. In the case of 0.1μm sampling distance the obtained error band was within ±0.1μm and the results showed that tools of different shapes namely round, half-round and sharp tool could all be positioned to within an error band of ±0.1μm by using the developed tool setting system.

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