The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform

Wei Gao - One of the best experts on this subject based on the ideXlab platform.

  • A micro optical probe for edge contour evaluation of Diamond cutting tools
    Journal of Sensors and Sensor Systems, 2014
    Co-Authors: Sungho Jang, Yuki Shimizu, So Ito, Wei Gao
    Abstract:

    Abstract. This paper presents a micro optical probe, which is employed to evaluate edge contours of single point Diamond tools with a size in a range of several millimetres. The micro optical probe consists of a laser source with a wavelength of 405 nm, an objective lens with a numerical aperture of 0.25, a photodiode for measurement, and a compensating optical system including another photodiode for compensation of laser intensity. A collimated laser beam, which is divided by a beam splitter in the compensating optical system, is focused by the objective lens so that the focused spot can be used as the micro optical probe. The micro optical probe traces over an edge contour of an objective tool while the signals of both the two photodiodes are monitored. The output of the photodiode for measurement is compensated by using that of the photodiode for laser intensity compensation to eliminate the influence of the laser instability. The signal of the photodiode for measurement is used to define the deviation of edge contour within the diameter of the micro optical probe. To verify the feasibility of the developed optical probe, the optical system was mounted on a Diamond Turning Machine, and some experiments were carried out. Two types of edge contours of the Diamond tools having a straight cutting edge and a round cutting edge were measured on the Machine.

  • Establishment of a measuring station on a Diamond Turning Machine for in-process cutting edge inspection of single point Diamond micro-tools
    International Journal of Nanomanufacturing, 2012
    Co-Authors: Sungho Jang, Yuki Shimizu, Takemi Asai, Wei Gao
    Abstract:

    This paper presents a measuring station based on an atomic force microscope (AFM), which is designed and constructed on a four-axis Diamond Turning Machine for inspection of the cutting edge profile of single point Diamond micro-tools. The measuring station is composed of an AFM probe unit for three-dimensional (3D) edge profile measurement and an alignment system with an optical sensor for aligning the probe-tip with the edge top of the tool chip. The alignment system greatly shortens the alignment time, which is essential for carrying out the edge profile measurement by the AFM. Measurement experiments of round nose micro-tools with nominal nose radii of 8 μm and less than 2 μm were carried out to demonstrate the performance of the measuring station.

  • An air-bearing displacement sensor for nanometrology of surface forms
    2012 IEEE International Instrumentation and Measurement Technology Conference Proceedings, 2012
    Co-Authors: Kang Won Lee, Katsutoshi Tanaka, Yuki Shimizu, Wei Gao, So Ito, Masahiko Fukuta, Yoshiaki Kai
    Abstract:

    This paper presents the experimental investigations for performance evaluation of an air-bearing displacement sensor as a measurement system for nanometrology of surface forms by using it. The experimental configuration and some considerations for the air-bearing displacement sensor are described. Then, in order to identify the basic performance of the sensor, a measuring force and displacement output of the sensor are evaluated on a vibration isolated table. The sensor is also mounted on a Diamond Turning Machine to evaluate the surface form of micro structures. A roll workpiece with Ni-P plating surface, on which micro-lens array are fabricated by using a FS-FTS (Force sensor fast tool servo) on the Machine tool, is employed as a specimen for measurement.

  • Experimental investigation of an air-bearing displacement sensor for on-Machine surface form measurement of micro-structures
    International Journal of Precision Engineering and Manufacturing, 2011
    Co-Authors: Kang Won Lee, YOUNG JIN NOH, Katsutoshi Tanaka, Mitsuhiro Fukuta, Yuki Shimizu, Wei Gao, Yoshikazu Arai, Yoshiaki Kai
    Abstract:

    This paper presents the experimental results of investigating the performances of an air-bearing displacement sensor for surface form measurement of micro-structures, such as micro-lenses, on an ultra-precision Machine tool. The sensor consists of a stylus for contacting the surface, a shaft for mounting the stylus, an air-bearing for suspending the shaft and a blade spring for applying the measuring force against the surface. At first experiments were conducted on a vibration isolated table to identify the basic performance of the sensor for displacement measurement. Then, the sensor was mounted on a Diamond Turning Machine for evaluating the performance of the sensor for on-Machine surface form measurement of micro-lenses. A roll workpiece, on which a micro-lens array was fabricated by using a fast tool servo on the Diamond Turning Machine, was employed as the specimen for the on-Machine experiment of surface profile measurement.

  • Edge profile measurement of micro-cutting tools on a Diamond Turning Machine
    Sixth International Symposium on Precision Engineering Measurements and Instrumentation, 2010
    Co-Authors: Takemi Asai, S. H. Jang, Y. Arai, Wei Gao
    Abstract:

    Single crystal Diamond micro-cutting tools, which are used for fabrication of precision micro-parts, have very sharp tool edges with radii in the range of tens of nanometers or even nanometers. Although there are many types of tools, the tools with a rounded nose are treated in this paper. They can be used for fabrication of very smooth and accurate surface with 3D micro structures such as micro-lens arrays, diffractive optical elements and so on. The Machined quality is highly depending on the tool edges' states and it is desired to manage them. This paper presents a measuring instrument based on atomic force microscope (AFM), which is designed and constructed for on-Machine measurement of the cutting edge profile. It is a combination of an AFM probe unit for 3D edge profile measurement and an alignment system with an optical sensor for aligning the probe-tip with the tool's edge top so that the measurement can be carried out in a short time. Measurement experiments of micro-tools with (nominal) nose radii of 8 μm and 0.2 mm are summarized to show the performance of the instrument. And the nose radii were evaluated as 7.2 μm and 0.188 mm, respectively.

Chun Hong Park - One of the best experts on this subject based on the ideXlab platform.

  • Measurement of slide error of an ultra-precision Diamond Turning Machine by using a rotating cylinder workpiece
    International Journal of Machine Tools and Manufacture, 2010
    Co-Authors: Wei Gao, YOUNG JIN NOH, Yoshikazu Arai, Jung Chul Lee, Joo Ho Hwang, Chun Hong Park
    Abstract:

    Two measurement methods of using a rotating cylinder workpiece, which are referred to as the one-probe method and the two-probe method, respectively, are proposed for measurement of the horizontal error motion (X-directional error motion) of the Z-slide of an ultra-precision Diamond Turning Machine. In the one-probe method, a displacement probe mounted on the opposite position of the turned (self-cut) cylinder workpiece with respect to the cutting tool is moved by the Z-slide to scan the workpiece being rotated by the spindle with its axis of rotation along the Z-axis. The Z-slide error can be obtained by an averaged output of the probe over one rotation without the influence of the spindle error and the surface form error of the cylinder. In the two-probe method, in addition to the displacement probe used in the one-probe method, another displacement probe is mounted at the position of the cutting tool. The rotating cylinder is scanned along the Z-direction by the two displacement probes simultaneously and the Z-slide error can be accurately measured by using the averaged output of the two probes over one rotation. Both the methods can measure not only the out-of-straightness component of the slide error but also the out-of-parallelism of the Z-slide axis with respect to the spindle axis. Experiments are carried out to verify the feasibility of the proposed methods.

  • Measurement and compensation of error motions of a Diamond Turning Machine
    Precision Engineering, 2007
    Co-Authors: Wei Gao, Satoshi Kiyono, Makoto Tano, Takeshi Araki, Chun Hong Park
    Abstract:

    Abstract This paper describes the measurement and compensation of error motions of a Diamond Turning Machine for nanofabrication of large sinusoidal metrology grids. The Diamond Turning Machine has a T-base design, which consists of a spindle with its rotation axis along the Z -direction and a cross-slide with its movement direction along the X -direction. A fast-tool-servo (FTS) unit is mounted on the X-slide to generate sinusoidal microstructures on a flat workpiece surface mounted on the spindle. The error motions of the X-slide and the spindle, which introduce Z -directional profile errors (out-of-flatness) on the grid surface, are measured and compensated. The out-of-straightness of the X-slide is measured to be approximately 60 nm over a travel of 80 mm by using the reversal method. It is also confirmed that the out-of-straightness of the X-slide has a 10-nm periodic component with a period of 11 mm corresponding to the diameter of the needles used in the roller bearing of the X-slide. The angular motion of the spindle is measured to be approximately 0.3″ by using an autocollimator, which can cause a 73-nm out-of-flatness over a workpiece 100 mm in diameter. The axial motion of the spindle is measured to be approximately 5 nm, which is the smallest error motion. The out-of-flatness of the workpiece is reduced from 0.27 to 0.12 μm through compensating for the error motions by utilizing the FTS unit based on the measurement results of error motions.

Satoshi Kiyono - One of the best experts on this subject based on the ideXlab platform.

  • surface profile measurement of a sinusoidal grid using an atomic force microscope on a Diamond Turning Machine
    Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2007
    Co-Authors: Wei Gao, Ju Aoki, Satoshi Kiyono
    Abstract:

    This paper describes the surface profile measurement of a XY-grid workpiece with sinusoidal microstructures using an atomic force microscope (AFM) on a Diamond Turning Machine. The sinusoidal micro-structures, which are fabricated on an aluminum plate by fast tool servo-assisted Diamond Turning, are a superposition of periodic sine-waves along the X- and Y-directions (wavelength (XY): 150 μm, amplitude (Z): 0.25 μm). A linear encoder with a resolution of 0.5 nm is integrated into the AFM-head for accurate measurement of the Z-directional profile height in the presence of noise associated with the Diamond Turning Machine. The spindle and the X-slide of the Machine are employed to spirally scan the AFM-head over the sinusoidal grid workpiece. Experiments fabricating and measuring the sinusoidal grid workpiece are carried out after accurate alignment of the AFM cantilever tip with the spindle centerline.

  • Measurement and compensation of error motions of a Diamond Turning Machine
    Precision Engineering, 2007
    Co-Authors: Wei Gao, Satoshi Kiyono, Makoto Tano, Takeshi Araki, Chun Hong Park
    Abstract:

    Abstract This paper describes the measurement and compensation of error motions of a Diamond Turning Machine for nanofabrication of large sinusoidal metrology grids. The Diamond Turning Machine has a T-base design, which consists of a spindle with its rotation axis along the Z -direction and a cross-slide with its movement direction along the X -direction. A fast-tool-servo (FTS) unit is mounted on the X-slide to generate sinusoidal microstructures on a flat workpiece surface mounted on the spindle. The error motions of the X-slide and the spindle, which introduce Z -directional profile errors (out-of-flatness) on the grid surface, are measured and compensated. The out-of-straightness of the X-slide is measured to be approximately 60 nm over a travel of 80 mm by using the reversal method. It is also confirmed that the out-of-straightness of the X-slide has a 10-nm periodic component with a period of 11 mm corresponding to the diameter of the needles used in the roller bearing of the X-slide. The angular motion of the spindle is measured to be approximately 0.3″ by using an autocollimator, which can cause a 73-nm out-of-flatness over a workpiece 100 mm in diameter. The axial motion of the spindle is measured to be approximately 5 nm, which is the smallest error motion. The out-of-flatness of the workpiece is reduced from 0.27 to 0.12 μm through compensating for the error motions by utilizing the FTS unit based on the measurement results of error motions.

  • on Machine measurement of a cylindrical surface with sinusoidal micro structures by an optical slope sensor
    Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2006
    Co-Authors: Wei Gao, Makoto Tano, Shinji Sato, Satoshi Kiyono
    Abstract:

    This paper describes the measurement of a cylindrical surface with sinusoidal micro-structures over a large area on a Diamond Turning Machine. The sinusoidal micro-structures, which are fabricated on the periphery surface of a cylinder by the fast tool servo-based Diamond Turning, are superposition of periodic sine-waves along the cylinder axis and the cylinder circumference with amplitudes of 100 nm and wavelengths of 100 μm, respectively. An optical two-dimensional (2D) slope sensor with a multi-spot light beam is developed for measurement of the 2D local slopes of the sinusoidal micro-structured surface. A cylindrical lens is employed in the sensor for removing the influence of the curvature of the cylinder surface. Experiments of fabrication and measurement of the sinusoidal micro-structured surface on an ultra-precision Diamond Turning Machine are carried out.

  • Replication of a sinusoidal grid surface by hot embossing and UV-casting
    Optomechatronic Systems Control, 2005
    Co-Authors: Naoya Tsurumi, Wei Gao, Akihide Kimura, Satoshi Kiyono
    Abstract:

    This paper describes the replication of a precision sinusoidal grid surface, which is used as the measurement reference of a surface encoder for measurement of planar motions. The profile of the grid surface is a superposition of sinusoidal waves in the X-direction and the Y-direction with spatial wavelengths of a hundred micrometers and amplitudes of a hundred nanometers. The master surface is fabricated on a Diamond Turning Machine equipped with a fast tool servo. Two kinds of replication methods, the hot embossing and UV casting are employed for replicating the grid surface on polymer materials. The replication on a glass plate is also carried out by UV-casting. The replication systems and some experimental results are presented.

Young-bong Bang - One of the best experts on this subject based on the ideXlab platform.

  • Fabrication of free-form surfaces using a long-stroke fast tool servo and corrective figuring with on-Machine measurement
    International Journal of Machine Tools & Manufacture, 2009
    Co-Authors: Ho-sang Kim, Kwang-il Lee, Kyoung-min Lee, Young-bong Bang
    Abstract:

    Fabrication of free-form surfaces that are frequently demanded for the construction of optical imaging systems is described. To obtain a tool motion with large amplitude and high bandwidth, a novel long-stroke fast tool servo is proposed and installed on the Z-axis of a Diamond Turning Machine as an additional synchronized axis. In addition, a special on-Machine measurement device is used to measure the optical parameters of the Machined surface and to compensate for the residual form of errors that are commonly produced in the Diamond Turning process. Actual machining test results show that the proposed procedures are capable of generating the copper free-form mirrors of 50 mm diameter to a form accuracy of 0.15 μm in peak-to-valley value error.

Yoshikazu Arai - One of the best experts on this subject based on the ideXlab platform.

  • Experimental investigation of an air-bearing displacement sensor for on-Machine surface form measurement of micro-structures
    International Journal of Precision Engineering and Manufacturing, 2011
    Co-Authors: Kang Won Lee, YOUNG JIN NOH, Katsutoshi Tanaka, Mitsuhiro Fukuta, Yuki Shimizu, Wei Gao, Yoshikazu Arai, Yoshiaki Kai
    Abstract:

    This paper presents the experimental results of investigating the performances of an air-bearing displacement sensor for surface form measurement of micro-structures, such as micro-lenses, on an ultra-precision Machine tool. The sensor consists of a stylus for contacting the surface, a shaft for mounting the stylus, an air-bearing for suspending the shaft and a blade spring for applying the measuring force against the surface. At first experiments were conducted on a vibration isolated table to identify the basic performance of the sensor for displacement measurement. Then, the sensor was mounted on a Diamond Turning Machine for evaluating the performance of the sensor for on-Machine surface form measurement of micro-lenses. A roll workpiece, on which a micro-lens array was fabricated by using a fast tool servo on the Diamond Turning Machine, was employed as the specimen for the on-Machine experiment of surface profile measurement.

  • Measurement of slide error of an ultra-precision Diamond Turning Machine by using a rotating cylinder workpiece
    International Journal of Machine Tools and Manufacture, 2010
    Co-Authors: Wei Gao, YOUNG JIN NOH, Yoshikazu Arai, Jung Chul Lee, Joo Ho Hwang, Chun Hong Park
    Abstract:

    Two measurement methods of using a rotating cylinder workpiece, which are referred to as the one-probe method and the two-probe method, respectively, are proposed for measurement of the horizontal error motion (X-directional error motion) of the Z-slide of an ultra-precision Diamond Turning Machine. In the one-probe method, a displacement probe mounted on the opposite position of the turned (self-cut) cylinder workpiece with respect to the cutting tool is moved by the Z-slide to scan the workpiece being rotated by the spindle with its axis of rotation along the Z-axis. The Z-slide error can be obtained by an averaged output of the probe over one rotation without the influence of the spindle error and the surface form error of the cylinder. In the two-probe method, in addition to the displacement probe used in the one-probe method, another displacement probe is mounted at the position of the cutting tool. The rotating cylinder is scanned along the Z-direction by the two displacement probes simultaneously and the Z-slide error can be accurately measured by using the averaged output of the two probes over one rotation. Both the methods can measure not only the out-of-straightness component of the slide error but also the out-of-parallelism of the Z-slide axis with respect to the spindle axis. Experiments are carried out to verify the feasibility of the proposed methods.

  • Nanometric edge profile measurement of cutting tools on a Diamond Turning Machine
    Fifth International Symposium on Instrumentation Science and Technology, 2008
    Co-Authors: Takemi Asai, Yoshikazu Arai, Yuguo Cui, Wei Gao
    Abstract:

    Single crystal Diamond tools are used for fabrication of precision parts [1-5]. Although there are many types of tools that are supplied, the tools with round nose are popular for machining very smooth surfaces. Tools with small nose radii, small wedge angles and included angles are also being utilized for fabrication of micro structured surfaces such as microlens arrays [6], diffractive optical elements and so on. In ultra precision machining, tools are very important as a part of the machining equipment. The roughness or profile of Machined surface may become out of desired tolerance. It is thus necessary to know the state of the tool edge accurately. To meet these requirements, an atomic force microscope (AFM) for measuring the 3D edge profiles of tools having nanometer-scale cutting edge radii with high resolution has been developed [7-8]. Although the AFM probe unit is combined with an optical sensor for aligning the measurement probe with the tools edge top to be measured in short time in this system, this time only the AFM probe unit was used. During the measurement time, that was attached onto the ultra precision Turning Machine to confirm the possibility of profile measurement system.