We present Error Compensation Software (ECS) which uses a decic polynomial model and three-dimensional surface measurement data for the fabrication of high precision freeform mirrors. ECS is designed based on a graphic user interface that includes an error calculation mechanism and surface distribution maps, and it accepts the Ultrahigh Accurate 3D Profilometer (UA3P) measurement data of the fabricated mirror surface. It exports surface coefficients and tool paths for the Single Point Diamond Turning (SPDT) machine which allows engineers to utilize the software during the compensation process. The ECS is based on Visual C++ and runs on the Windows operating system. The error compensation process with ECS has been applied to the 90 mm diameter aluminum freeform mirrors for usage in view infrared satellites, and the root mean square and peak-to-valley surface errors were reduced from 1.52 to 0.11 μm, and from 7.05 to 1.99 μm, respectively, satisfying the requirement of the infrared camera.
Micro needle arrays have been widely used within medical contexts, such as for drug delivery and nervous electrodes, and its fabrication methods have attracted attention recently. This paper describes a novel fabrication method for micro needle arrays on a tungsten metal plate using only laser beam machining. Tungsten material was ablated as combining laser beam scanning path to control needle structure. Overlapping laser beams from the combined scanning path causes thermal accumulation phenomena which removes the material. In this paper, controlling laser scanning path (Line Interval, Line Space, Number of Lines) and machining conditions (Power, Number of Scan), and the changing length and pitch of the micro needles were measured through SEM. Moreover, the piercing force for application in drug delivery and nervous electrodes was measured with a load cell system.
We present a rotating pair of mirrors based optical autocorrelator which is capable of providing a 0.1 m scanning range. The rotating mirror-pair technique enables rapid data update-rate, compactness, and simpler data post-processing compared to that of conventional linear motion-based optical autocorrelators. We optimized the geometrical design of the mirror-pair configuration by using off-the-shelf mirrors and conducted a simulation to calculate the expected capability of the scanning range. By exploiting a He-Ne laser as a light source, we validated the performance of the autocorrelator in its provision of a 100 mm scanning range and 0.2 Hz data update-rate, which was limited by the adopted commercial data sampling device, and not limited by the proposed principle. The developed autocorrelator is expected to be adopted for various applications that require sub-cm-1 spectroscopic resolution.
This paper describes the design of a 4-axis SCARA-Type robot in the form of a scalar robot for the loading and unloading of workpieces in machine tools. The 4-axis dedicated robot is a 4-degrees-of-freedom robot consisting of a joint 1, 2, 3 motor and a 180° rotating gripper made up of a horizontal gripper and a vertical gripper. It was designed in a scalar shape that is suitable for machine tools, and the size of each link and elbow was determined through structural analysis. Through additional structural analysis, the deflection of the end center of the workpiece fixed to the horizontal gripper and the vertical gripper was designed to be within 0.1 mm, and based on the design result, a 4-axis SCARA-Type robot was manufactured, and the basic motion characteristics of the manufactured robot were tested. As a result of the characteristic test, the manufactured 4-axis SCARA-Type robot operated smoothly, so it is judged to be adequate for usage in loading and unloading the workpieces in machine tools.
Citations
Citations to this article as recorded by
Design and develop a robot arm to automatically feed workpieces for laser engraving machines Trung Xuan, Duy Anh FME Transactions.2024; 52(4): 671. CrossRef
5-Axis Robot Design for Loading and Unloading Workpieces Han-Sol Kim, Gab-Soon Kim International Journal of Precision Engineering and Manufacturing.2023; 24(12): 2279. CrossRef
In this paper, we would like to introduce an in-line MTF (Modulation Transfer Function) measuring system which is compatible with the automated assembly process line of lens-modules in smartphone cameras. This in-line optical inspection system consists of a resolution chart module, Dual Cono-Scope Telecentric Lenses, imaging lenses, and a single detector. Unlike conventional measuring devices with many cameras that are more commonly used in the industry, this device can evaluate the MTF performance without reversing the lens module in an upside down position by applying a reverse projection method. So, it is possible to measure MTF for the full-fields of the lens module from any arbitrary desired positions, as well as the designated positions by using a single camera. This makes it compatible with the equipment of the automated production process line for lens modules. We will expect that the lens module production line will be diversified and fully automated through the application of this in-line optical inspection system.
Citations
Citations to this article as recorded by
Fabrication and Characterization of Automotive Aspheric Camera Lens Mold based on Ultra-precision Diamond Turning Process Ji-Young Jeong, Hwan-Jin Choi, Jong Sung Park, Jong-Keun Sim, Young-Jae Kim, Eun-Ji Gwak, Doo-Sun Choi, Tae-Jin Je, Jun Sae Han Journal of the Korean Society for Precision Engineering.2024; 41(2): 101. CrossRef
SEM Image Quality Improvement and MTF Measurement Technique for Image Quality Evaluation Using Convolutional Neural Network Chan Ki Kim, Eung Chang Lee, Joong Bae Kim, Jinsung Rho Journal of the Korean Society for Precision Engineering.2023; 40(4): 275. CrossRef
Three-dimensional (3-D) printing, with its capability for producing arbitrary shapes, has shown great potential for usage in patient-specific tissue engineering. However, if artificial tissues are fabricated directly through typical 3-D printing processes, the mechanical properties, particularly for softness or flexibility, significantly differ from those of natural tissues, resulting in inappropriate side effects during surgeries using vascular grafts. However, this can be overcome through the indirect 3-D printing of templates created with a thin-film formation process, such as dip coating. Dip coating is performed in two steps, including dipping/withdrawing a target base template from a polymer solution, and then drying the solvent into a solid thin film on the template. However, it is difficult to form a uniform layer on the arbitrary template because the gravitational flow of the coated solution disturbs the uniformity of the template as the solvent is drying. Therefore, we minimized the flow around the template after dip coating by rapidly removing the solvent removal by dipping the solution-coated template into ethanol. This reduced the solvent removal time and increased the viscosity of the coated solution, thereby alleviating the gravitational flow of the coated solution, and allowing us to successfully fabricate flexible vascular grafts.
Citations
Citations to this article as recorded by
Fabrication of Long Porous Vascular Grafts Using Nozzle-Transfer Dip-Coating System Seung-Mun Lee, Yeong-Seo Kim, Suk-Hee Park Journal of the Korean Society of Manufacturing Process Engineers.2023; 22(7): 11. CrossRef
A Study on the Mechanical Properties of a Biocompatible Conduit Structure based on Electrospun Fibers Jeong Hwa Kim, Jaewon Choi, Yong Jun Yoon, Young Hun Jeong Journal of the Korean Society for Precision Engineering.2022; 39(10): 739. CrossRef
This paper presents the characteristics of tapered roller bearings (TRBs) taking into consideration the effects of tapered roller angle error which may occur during manufacturing. To this end, a TRB model including tapered roller angle errors was developed. The effects of tapered roller angle error on the contact load distribution, bearing stiffness and fatigue life were investigated with respect to changes in the tapered roller angle error. A statistical analysis of the fatigue life of TRBs was also provided with respect to tapered roller angle error. Simulation results show that the tapered roller angle error changes the load distribution of the rollers and causes angular misalignment in TRBs, and subsequently, influences the bearing stiffness and fatigue life. The statistical analysis shows that the Weibull distribution is an acceptable method to represent the statistical fatigue life for the practical range of tapered roller angle errors.
First
Prev
