Cylindricity is a key parameter to describe the accuracy and quality of the small-size cylindrical parts. Cylindrical parts such as needle roller bearing is widely used as a core part in RV gearboxes, hydraulic pumps and other mechanical components, and the geometric accuracy of the needle roller affects the performance and service life of the mechanical product. The small-size cylindrical part is also used as precision standard part to help measure and position. The cylindricity error can propagate with the manufacture and assemble process. Therefore, the cylindricity is of great significance in the fields of industrial robots, aerospace, medical devices, and so on. It is necessary to evaluate the cylindricity of the small-size cylindrical part and analyze the measurement uncertainty to guarantee the geometric accuracy and improve the device performances.
Non-contact cylindricity measuring of the small-size cylinder is investigated by the chromatic confocal sensor in both relatively fixed and unfixed manners. The uncertainties of the both cylindricity measurement systems need to be analyzed and compared. When applying both measurement systems, the measuring accuracy is negatively affected by angular misalignments of the small cylinder and the measuring light source when the linear scan method is used. When the unfixed scheme is applied, the motion error of the precise translation stage has negative impact on the scanning process. The mounting and distribution error of the light spots effect the scanning coordinate precise when using the fixed scheme. The different sources are discussed respectively. According to the uncertainty result of the coordinates, a measurement uncertainty analysis is carried out through numerical calculations based on a Monte Carlo method. Proven by the experiments, the final result shows the fixed line spot manner has advantages in accuracy due to the better stability of the measurement system.
In the integrated chip industry, there is a growing demand of defect detection, and the autofocus capability of microscopy can significantly enhance efficiency. This paper presents a novel technique based on an autofocus methodology known as the eccentric light beam approach. Specifically, we have developed a line-stripe-shaped laser beam projection system that uses a linear array CCD, offering high resolution and instant response. The simple design of the linear array CCD overcomes noise interference caused by system processing tolerances and reduces signal processing complexity. In accordance to the proposed system, we designed a novel algorithm called adaptive multiscale windowing to calculate the centroid of the linear array image which is an essential criterion of the defocus value. Additionally, we explore the relationship between sample defocus amount and the centroid position shift of the received signal. We build the motion part with the resolution of less than 1 micron and response speed of less than 100 milliseconds. From the experiments conducted, we achieved the accuracy of less than 1 micron and the focusing speed within 0.2 second.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.