In this research, the a novel finishing machine was used for hight-precision surface of spherical ball products that have been widely used for on/off valve for hydrogen energy flowing system and in medical field such as artificial hip joint component. The spherical balls products are the workpiece that made by Co-Cr-Mo alloys with 32-mm in diameter and Sa≈ 0.30μm in surface roughness. Their surface roughness was successfully improved via the magnetic abrasive tools that controlled the magnetic field of permanent magnets. The critical input conditions were selected as rotational speed: 800rpm, gap: 3mm, tool grain size: 1-μm finishing time: 0, 3, 6, 9, 12, and 15min. The results of this research showed that under the given finishing conditions, the high surface quality in the terms of surface precision of spherical ball products are successfully achieved, in which the surface roughness is reduced from 0.30-μm to 0.04-μm within the short finishing time at 12min. Therefore, it can be concluded that a novel finishing machine is feasible to be used for improving the surface roughness of spherical ball products, resulted in high surface precision of materials.

Recently, with the development of ultra-precision technology, the quality improvement of optical parts and various products is emerging. The need for a difficult-to-cut material that is light and exhibits high hardness and high strength physical properties is being emphasized. Ultra-precision machining processing solutions for these difficult-to-cut materials are being actively developed. In this research, experiments were performed using a DTM machine equipped with a laser-assisted machining module for ultra-precision machining of CaF2 materials that are brittle but exhibit high transmittance in a wide range from ultraviolet to infrared.

Recently, automobile manufacturing companies, which are major customers of them, are requiring IATF 16949 (ISO/TS 16949) certification as a mandatory requirement to secure product quality. In particular, IATF 16949 : 2016, revised in October 2016, was reinforced product traceability requirements for production information management by lot in the production process. Therefore, small and medium-sized precision parts processing companies in the automobile industry are very difficult to survive due to quality and price competition for customers satisfaction. MES (Manufacturing Execution System) is required to solve this problem. However, small and medium sized precision parts processing enterprises are reluctant to introduce the MES which is not suitable for the manufacturing environment of them such as high cost and low utilization. Even if the system is introduced, it is difficult to operate and maintain the system because the lack of computer manpower. In this paper, we propose a method for building a lot tracking system for small and medium precision parts processing companies by reviewing relevant literature and analyzing cases. In addition, by managing the production history for each lot of the final product in the system, we will grasp the effect of reducing the quality failure cost obtained by minimizing the range of defect selection.

Magnetic abrasive finishing (MAF) process is a surface improvement method, which the magnetic field of permanent magnet or electromagnet is used to control the abrasive particles during the finishing process. The magnetic abrasive tools are filled between the N-pole and S-pole of Nd-Fe-B type permanent magnets. Tungsten carbide bar (WC) is a high hardness material and its compressive strength is much higher than the other materials. Therefore, due to its superior mechanical properties, it has been widely used in cutting or machining process. Because the smooth surface of tungsten carbide is required in cutting tools, thus the magnetic abrasive finishing process was applied for achieving its surface accuracy and dimensional accuracy. The results showed that the surface roughness of tungsten carbide bar was improved from Ra: 0.23㎛ to Ra: 0.02㎛ in 120 sec by magnetic abrasive finishing process.

In this paper, we describe experiment results using a vibration assisted hybrid femtosecond laser (λ:795 nm) ultra- precision machining system. The hybrid system we have developed is possible that optical focal point of the femtosec- ond laser constantly and frequently within the range of PZT(piezoactuator) vibrator working distance. Using the hybrid system, We have experimented on brass and studied about differences of result of hole aspect ratio compare to general experiment setup of femtosecond laser system. Aspect ratio of a micro hole on brass is increased as 54% with 100 Hz vibration frequency and surface roughness of the side wall also improved compare to non-vibration.

High-pressure abrasive entrained jet have rapidly become important machining technology over the last two decades. However, suspension jet by high-pressure has been recently developed for packaging sawing. Ideally, diamond materials should be used for components in abrasive water-jet systems that are subject to high erosive conditions. Using the diamond orifices improve maintenance and extend wear part life. This paper gives insights to using an abrasive suspension jet with diamond orifice. The influences of orifice material and orifice design are evaluated.

The KASINICS (Korea Astronomy and Space science Institute Near Infrared Camera System) is a ground-based near-infrared (NIR) imaging instrument. KASINICS has offner relay optics to reduce unwanted infrared light. For the offner optics, we adopted an ultra precision machining process which is installed at KBSI (Korea Basics Science research Institute). Since the offner relay optics is made of aluminum 6061 metal material, we did several tests to reach the specification. We found that a 0.497mm radius nose bite and 220m/min machining speed are best tool and condition to make this offner optics with the precision machine. In this paper, we report the technical method of ultra precision machining and results of the KASINICS offner optics.