China
Africa
Explore chapters and articles related to this topic
Servo Feedback Devices and Motor Sensors
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
As discussed previously, for a rotary application, resolution is the total number of steps representing one revolution of motion, often measured as the number of pulses per revolution (PPR) for rotary encoders or cycles per revolution (CPR) commonly for incremental encoders, where one cycle is equal to 360° electrical degrees. The final output resolution of linear encoder is determined by encoder count density (in terms of line per inch, LPI). Converting a rotary encoder resolution to a linear resolution using code disc size (which is often expressed as optical radius Ro) is expressed as LPI=CPRπRo2
Displacement
Published in Toru Yoshizawa, Handbook of Optical Metrology, 2015
Akiko Hirai, Mariko Kajima, Souichi Telada
There are several kinds of linear encoders. The magnetic-scale type and the magnet–electric type are the oldest types of linear encoders. They have scales with tiny magnet graduations on it. The resolutions of the magnetic type and the magnet–electric type are limited by the spacing of magnets on the scale tape. The optical scale has overcome the limit by making fine marks on glass using micro-fabrication technologies. We concentrate on the optical type linear encoders according to the concept of this book.
Nano electrical discharge machining – the outlook, challenges, and opportunities
Published in Materials and Manufacturing Processes, 2021
Deepak Kumar, Vivek Bajpai, Nirmal Kumar Singh
Perfilov et al.[78] used the piezo driving actuator (P-843.20, PI) to get a high dynamic response in the small interelectrode gap during EDM milling (Fig. 11). Specially designed kinematic pairs (flexure hinges) were used to get the free movement in work axes enabling with linear encoder for the stepper motor. Recently available nanopositioner, piezo driving microactuator may solve the issues related to positioning control. The discharge energy monitoring and control can be easily attainable in these stages within the specified gap. Furthermore, nanopositioning stages take less space for installation which reduces the overall size of the equipment and hence solves the problem associated with space constraint.
Screening and optimization method of defect points of G code in three axis NC machining
Published in International Journal of Computer Integrated Manufacturing, 2023
Dun Lyu, Yanhong Song, Pei Liu, Wanhua Zhao
KMC400 U five-axis vertical milling machining center is equipped with Kede GNC62 CNC system. The two G code files before and after optimization were input into the CNC system. By inserting G237 A5 D576 C2 in the G code, the interpolation setpoints position and Linear encoder data of each axis are collected. Among them, G237 represents the start of data collection. A5 represents the collection of X-axis, Y-axis and Z-axis data. D576 indicates that the data to be collected is the setpoints position and linear encoder. C2 means that the sampling period is 2 ms, and G238 indicates the end of data collection. By analyzing the setpoints and linear encoder data before and after optimization, the optimization method are verified.
An innovative application of double slider-crank mechanism in efficient of the scanning acoustic microscopy system
Published in Mechanics Based Design of Structures and Machines, 2023
Van Hiep Pham, Jaeyeop Choi, Tan Hung Vo, Dinh Dat Vu, Sumin Park, Byeong-il Lee, Junghwan Oh
In this study, a SAM system was developed to evaluate the quality of 12-inch silicon wafer (WFSAM). Figure 2 shows the schematic representation of the WFSAM system. The scanning module, P/R, and data acquisition (DAQ) system integrated to personal computer (PC) are the main components of the WFSAM system. The scanning module comprised a combination of fast and slow linear motions along the x-, and y-axes, respectively. The fast linear motion was driven by exploiting double slider-crank mechanism, whereas the slow linear motion was driven by the ball-screw mechanism. The slider-crank mechanism converts the pure rotational motion of the crank to pure linear motion of the slider. The crank is driven by a servo motor at a constant angular velocity. When the servo motor rotates one revolution in one second, the slider can complete one reciprocal motion along the x-axis, corresponding to a B-scan frame rate of 2 Hz. Therefore, the B-scan frame rate is n/30 Hz, where n is the numbers of revolutions of the servo motor in one minute (rpm). In the proposed design, four US transducers with the same characteristics were used in term of extending the scanning area and reducing the scanning time. The transducers were attached to two slider-crank mechanisms and semi-immersed into water in water tank containing a silicon wafer. To efficiently detect the internal defects of the wafer, a high frequency transducer at 100 MHz was used with a focal length of 8 mm and element diameter of 3 mm, which result in the resolution of 40.256 × 10−3 mm, following Eq. (3). Hence, the step size of 0.04 mm was set for wafer inspection by WFSAM. A four channel P/R with a pulse repetition frequency (PRF) of 40 kHz (PRN-300, Ohlabs Corp., Busan, Republic of Korea) was used to simultaneously send an electric signal to the four transducers and convert the reflected echo signals from the transducers into electric signal. These signals were collected to construct an image using a DAQ system that used a 16-bit digitizer with a 1 GS/s sampling rate. The movement of the scanning module was controlled by a PC through a microcontroller board. The transducer positions were detected by a linear encoder and synchronized with the P/R signals to trigger the DAQ, thereby starting the scanning process, which was conducted in three steps. First, the transducer was adjusted along the z-axis to determine the focal zone. Second, the scanning parameters were set by defining the scanning area, step size, and B-scan fame rate. Finally, the image was constructed and displayed on the PC monitor. The scanning time was calculated following Eq. (4):