Self-Alignment and Bonding of Microparts Using Adhesive Droplets

Sato, Kaiji,Lee, Keun-Uk,Nishimura, Masahiko,Okutsu, Kazutoshi Korean Society for Precision Engineering 2007 International Journal of Precision Engineering and Vol.8 No.2

This paper describes the self-alignment and bonding of microparts using adhesive surface tension to assemble microsystems in air. The alignment and bonding were tested experimentally using adhesive droplets, and the resulting performance was evaluated. The adhesive, which was inorganic and water-soluble before hardening, was diluted with water to a ratio of 10:1 so that its surface tension generated a sufficient restoring force for self-alignment. The experimental results showed that the average of the alignment errors obtained using the adhesive on $1.0\times1.0\times0.15-mm$ microparts was less than $2{\mu}m$ in the X and Y directions and 0.2 degrees in the e direction. These alignment errors were almost the same as those obtained using water. The use of a suitable adhesive had no negative effects on the alignment accuracy. The average tensile strength of the adhesive bond after self-alignment was $0.61N/mm^2$.

Self-Alignment and Bonding of Microparts Using Adhesive Droplets

Kaiji Sato,Keunuk Lee,Masahiko Nishimura,Kazutoshi Okutsu 한국정밀공학회 2007 International Journal of Precision Engineering and Vol.8 No.2

This paper describes the self-alignment and bonding of microparts using adhesive surface tension to assemble microsystems in air. The alignment and bonding were tested experimentally using adhesive droplets, and the resulting performance was evaluated. The adhesive, which was inorganic and water-soluble before hardening, was diluted with water to a ratio of 10:1 so that its surface tension generated a sufficient restoring force for self-alignment. The experimental results showed that the average of the alignment errors obtained using the adhesive on 1.0 × 1.0 × 0.15-㎜ micro parts was less than 2 ㎛ in the X and Y directions and 0.2 degrees in the θ direction. These alignment errors were almost the same as those obtained using water. The use of a suitable adhesive had no negative effects on the alignment accuracy. The average tensile strength of the adhesive bond after self-alignment was 0.61 N/㎟.

Practical Ultraprecision Positioning of a Ball Screw Mechanism

Kaiji Sato,Guilherme Jorge Maeda 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.2

This paper describes the problem of ultra precision positioning with a ball screw mechanism in the microdynamic range, along with its solution. We compared the characteristics of two ball screw mechanisms with different table masses. The experimental results showed that the vibration resulting from the low stiffness of the ball screw degraded the positioning performance in the microdynamic range for the heavyweight mechanism. The proposed nominal characteristic trajectory following (NCTF) controller was designed for ultra precision positioning of the ball screw mechanism. The basic NCTF control system achieved ultra precision positioning performance with the lightweight mechanism, but not with the heavyweight mechanism. A conditional notch filter was added to the NCTF controller to overcome this problem. Despite the differences in payload and friction, both mechanisms then showed similar positioning performance, demonstrating the high robustness and effectiveness of the improved NCTF controller with the conditional notch filter. The experimental results demonstrated that the improved NCTF control system with the conditional notch filter achieved ultra precision positioning with a positioning accuracy of better than 10 ㎚, independent of the reference step input height.

High-Speed Positioning of Ultrahigh-Acceleration and High-Velocity Linear Synchronous Motor

Kaiji Sato,Tadashi Hama 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

This paper describes the high-speed positioning of a moving permanent magnet linear synchronous motor (MPM LSM) utilizing itshigh thrust-to-mover mass ratio of 908 N/kg. The MPM LSM was designed to have a high static thrust-to-mover mass ratio for highaccelerationand high-velocity motion However, the MPM LSM has large inductances and large back electromotive force (EMF), bothof which slow down the current response and greatly reduce the available thrust force. Under the limited supply voltage condition,these features deteriorate the response of the MPM LSM, as represented by the acceleration and velocity characteristics. To reducethe effect of the features on the response, a simple and basic dynamic model of the MPM LSM is derived and used in the design ofa phase lead function for the high response. The effectiveness of the phase lead function, which improved the response, is examinedby straight motion and positioning experiments. The high-speed positioning performance is verified by using the control system withthe phase lead function. The experimental response to a step input of 300 mm shows acceleration higher than 500 m/s2, velocity higherthan 7.76 m/s and position error smaller than 2 mm.

Practical Ultraprecision Positioning of a Ball Screw Mechanism

Sato, Kaiji,Maeda, Guilherme Jorge Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.2

This paper describes the problem of ultraprecision positioning with a ball screw mechanism in the microdynamic range, along with its solution. We compared the characteristics of two ball screw mechanisms with different table masses. The experimental results showed that the vibration resulting from the low stiffness of the ball screw degraded the positioning performance in the microdynamic range for the heavyweight mechanism. The proposed nominal characteristic trajectory following (NCTF) controller was designed for ultra precision positioning of the ball screw mechanism. The basic NCTF control system achieved ultra precision positioning performance with the lightweight mechanism, but not with the heavyweight mechanism. A conditional notch filter was added to the NCTF controller to overcome this problem. Despite the differences in payload and friction, both mechanisms then showed similar positioning performance, demonstrating the high robustness and effectiveness of the improved NCTF controller with the conditional notch filter. The experimental results demonstrated that the improved NCTF control system with the conditional notch filter achieved ultra precision positioning with a positioning accuracy of better than 10 nm, independent of the reference step input height.

Novel and Compact Thermomagnetic Actuator Using Temperature-Sensitive Magnetic Materials

Tadashi Hama,Kaiji Sato 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.12

This paper describes the structure and characteristics of a novel compact actuator that uses a combination of temperature-sensitive magnetic materials (TSMMs) and permanent magnets (PMs). The actuator has the potential to generate a large force per volume, while the absence of a coil structure makes it easy to downsize. The structure and driving principles of the actuator were determined to exploit the advantages of this combination, and thrust force characteristics were examined through numerical analysis. The thrust force generated was measured based on the temperature of the TSMMs. The temperature characteristics were investigated experimentally and theoretically. In addition to thrust force, the energy consumption was experimentally examined with respect to the TSMM temperature. The results indicate that the proposed actuator performed better than a conventional electromagnetic actuator in generating a large continuous thrust force.

Practical Control of Non-Friction Mechanism for Precision Positioning

Shin-Horng CHONG,Kaiji SATO 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

This paper describes the practical control of non-friction mechanism for precision positioning. Non-friction mechanism is often used for precision positioning. Even though it has a simple structure, still, plant identification is compulsory needed during designing a conventional controller. This makes the controller non-user-friendly and non-practical-used in industry. For overcoming this problem, practical controller design procedure based on NCTF (Nominal Characteristic Trajectory Following) controller is proposed. NCTF controller consists of a nominal characteristic trajectory (NCT) and a PI compensator, which is free from exact modeling and parameter identification. The NCT is determined using an open-loop time responses of the mechanism. The PI compensator is used to make the mechanism motion to follow the NCT and it is tuned without given model parameters. Non-friction mechanism has non-damping a characteristic and often has a short-working range. A suitable current input to stop the non-damping mechanism within a short working range in open-loop condition and to be able to improve the damping characteristic of the mechanism is necessary. The positioning performances of two different current inputs are examined and discussed. The positioning performance of NCTF control system is evaluated based on simulation and experimental results.