Abstract: The light emitting diode (LED) development technology is an important topic for green industry. This study focused on the efficient cleaning for LAO hydrolysis material, which is a potential LED substrate. The 99.5% ethanol or an alternative solution is used to clean the LAO substrate and dry with the help of anhydrous gas. To improve the cleaning performance, the Taguchi-based orthogonal array of experimental planning and the Grey Relation Analysis are employed to optimize the cleaning parameters. Four control factors are cleaning time, soaking time, PVA sponge type, drying method. The multiple performance characteristics of responses include the residual traces of impurities and water mark after the cleaning process for LAO substrate. With the proposed cleaning process, the surface foreign matter removal rate of target 80% and the residual water marks of declining to 20% are achieved.
Abstract: Tube spinning is a metal forming process used to manufacture axisymmetric products. This study chose a seamless thick-walled steel tube to manufacture a high pressure vessel. Finite element analysis was successfully applied to the neck-spinning process of a thin-walled tube; however, previous research has not investigated the neck-spinning process of thick-walled tubes. Therefore, the aim of this research was to investigate numerically the neck-spinning process of thick-walled tubes at an elevated temperature. The commercial software Abaqus/Explicit was adopted in the simulation. This paper compares experimental and simulation results on thickness distribution and outer contour of the spun tube. During the final stage, the average deviations between the simulation and experiment were 6.74% in thickness and 4.97% in outer contour. The simulation results correspond with those derived in the experiment.
Abstract: There are many advantages in nitriding process, but the formation of white layer sometimes results in trouble. The formation of white layer can be reduced by controlling the nitriding atmosphere appropriately. In this experiment, the nitriding atmosphere is prepared by mixing NH3 and H2. An oxygen sensor is used to detect the condition of the atmosphere, and the value of output voltage (EMF) is used as a signal for controlling the flow rate of H2. The experimental results show that the thickness of white layer can be reduced effectively by controlling the flow rate of H2 through the voltage reading of the atmosphere. Meanwhile, the hardness and the depth of nitriding layer could still be maintained. For nitriding at 550 °C, no white layer is formed when EMF is controlled above 1160 mV and a satisfying hardness distribution of the nitriding layer can be obtained when EMF is controlled at 1140 mV.
Abstract: One of the key issues regarding multi-axis contour following tasks in modern high-precision machining applications is how to effectively reduce contour error. Generally, among existing approaches, the Cross-Coupled Control (CCC) structure is widely used in multi-axis contour following tasks to improve contouring accuracy. However, when a servomechanism is operated in reverse or low-speed motions, the inherent friction force and external disturbance effects will degrade the CCC performance. Therefore, to cope with the aforementioned problems, this paper exploits the Karnopp friction model-based compensator and the Virtual Plant Disturbance Compensator (VPDC) to improve tracking performance as well as contouring accuracy. Moreover, an integrated motion control scheme is also developed to further improve contouring performance. The proposed scheme consists of two position loop controllers with velocity command feedforward, a modified CCC, two friction force compensators, and two disturbance compensators. To evaluate the performance of the proposed approach, several free-form contour following experiments have been conducted on an X-Y table driven by two linear motors. Experimental results verify that the proposed approach can significantly enhance contouring performance for free-form contour following tasks.
Abstract: During large-size gear manufacturing by form grinding, the actual tooth surfaces will differ from the theoretical tooth surface because of errors in the clamping fixture and machine axes and machining deflection. Therefore, to improve gear precision, the gear tooth deviations should be measured first and the flank correction implemented based on these deviations. To address the difficulty in large-size gear transit, we develop an on-machine scanning measurement for cylindrical gears on the five-axis CNC gear profile grinding machine that can measure the gear tooth deviations on the machine immediately after grinding, but only four axes are needed for the measurement. Our results can serve as a foundation for follow-up research on closed-loop flank correction technology. This measuring process, which is based on the AGMA standards, includes the (1) profile deviation, (2) helix deviation, (3) pitch deviation, and (4) flank topographic deviation. The mathematical models for measuring probe positioning are derived using the base circle method. We also calculate measuring positions that can serve as a basis for programming the NC codes of the measuring process. Finally, instead of the gear profile grinding machine, we used the six-axis CNC hypoid gear cutting machine for measuring experiments to verify the proposed mathematical models, and the experimental result was compared with Klingelnberg P40 gear measuring center.
Abstract: In recent years, cloud computing has become a new trend of Internet applications and can potentially bring benefits and new business models for various industries and applications. In this paper, we first review two traditional Internet-based remote monitoring and control (RMC) architectures, i.e. AVMS (Automatic Virtual Metrology System) for equipment monitoring and ZDPMCS (ZigBee-based Distributed Power Monitoring and Control System) for power monitoring. Then, their corresponding new architectures based on cloud computing are developed. Specifically, a cloud-computing-based intelligent equipment monitoring architecture (CCIEMA) is proposed. The CCIEMA mainly consists of three parts: cloud side-providing various equipment monitoring related cloud services, equipment side-containing several equipment managers for monitoring and controlling equipment, and client side-including various Web-based GUIs for users to interact with the system. Based on the proposed CCIEMA, various prediction models can be created on the cloud and then downloaded to the equipment manager for performing yield rate prediction, machining precision conjecture, and remaining useful life prediction. By the same approach, we also propose a new power monitoring and control architecture based on cloud computing and ZigBee, called CZPMCA, and show its major operational scenarios. The potential benifits of the proposed CCIEMA and CZPMCA are described as well, compared to the tradiotional RMC architectures. The research results can be useful references for constructing various RMC systems using cloud computing.
Abstract: This paper proposes the integral formula of exposure energy density during the movement of work piece to investigate the exposure energy distribution on the photoresist surface. The photoresist was divided into finite nodes to combine the integral formulas of exposure energy density to calculate the relative concentration variation of the photoactive compound (PAC) at each finite node of photoresist interior layer. This paper further combines with Mack’s development model and calculates the average full-width at half maximum (FWHM) of near field photolithography. This study conducted sensitivity analysis to determine how adjusting groups of control parameters influences FWHM and working depth (Hmax). Group A, in which the probe aperture was the adjusted parameter, had the most influence, followed by Group B, in which exposure energy/μm was the adjusted parameter, and Group C, in which development time was the adjusted parameter.
Abstract: Texture metrology of large optical components causes many practical problems, from handling heavy units in the laboratory, to applying existing bench top devices, unable to access most of the part area. Application of an on-machine device allows these practical issues to be overcome and provides an opportunity for an automated metrology process. We describe our work on a texture interferometer that is mounted onto a Zeeko optical polishing machine for in-process surface texture measurements on large optics.
Abstract: A rapid manufacturing process was demonstrated to fabricate a microfluidic device to amplify specific DNA fragments in less than 8 hours. Microfluidics was derived from microelectromechanical system (MEMS) with lithography technique on the substrates of silicon and glass, which made the microfluidic product have a higher fabrication cost and laborious fabrication steps. This rapid approach only requires three steps for a PDMS microfluidic device: metal mold insert manufacturing, PDMS casting, and glass bonding. Each step did not require complicated equipments or procedures, and make this approach very attractive in rapid prototyping and experimental optimization with microfluidic devices. In this work, a brass mold insert was manufactured by a micromilling machine, followed by the standard PDMS casting and glass bonding to fabricate a microfluidic device. Polymerase chain reaction (PCR) to amplify specific DNA fragments, a typical microfluidic example, was successfully realized on this PDMS microfluidic device. This rapid and low cost (compared to conventional lithography) fabrication approach can provide researchers a lower entry to polymeric lab-on-a-chip either on PDMS or thermoplastic substrate for various applications.
Abstract: Solar panels conduct electricity through aluminum strips on substrate surfaces. Ultrasonic roll welding can weld the conductive aluminum strips onto the glass substrates. This paper illustrates vibration characteristics and optimal design of amplitude horns used in the ultrasonic welding roll. Based on theoretical equations, this study used the ANSYS software to establish the parametric model according to design requirements. With the parametric model as the initial design, this study conducted modal analysis and harmonic analysis to obtain the vertical mode and disc bending mode of the horn, and measured the resonant frequency, amplitude amplification rate and stress distribution. Finally, this study implemented and verified the optimal coupled disc tool of the ultrasonic horn.