• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.10
• /
• pp.94-100
• /
• 1999

Micro-EDM is widely used in machining of miro-parts such as micro-shafts and micro-holes. In order to select proper machining conditions and to reduce the machining time, it is necessary to understand machining characteristics under various machining conditions. Micro-hole machining tests were performed with round shape electrodes with different capacitances and voltages of the power source. The effects of the electrode rotational speed and diameter on the machining rate were also observed. From the experimental results, it was found that capacitance and voltage have significant effects on machining rate and the machined surface integrity. With higher capacitance and higher voltage, higher machining rate was observed together with poorer surface integrity. The electrode diameter was also found to have an effect on the machining rate and electrode wear.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2003.02a
• /
• pp.79-79
• /
• 2003

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.12
• /
• pp.183-190
• /
• 2003

In this paper, investigated are the machining characteristics such as material removal rate and machining time with respect to discharge area and capacitance in micro electrical discharge machining (MEDM). As discharge area determined by the electrode size and capacitance change, the optimal feedrate to allow the minimum machining time changes. The smaller discharge area is, the lower MRR becomes because of the area effect. As the capacitance increases, MRR also increases. However there is the limit capacitance beyond which the MRR does not increase anymore. As the discharge area increases, the limit capacitance also increases.

• Clinics in Shoulder and Elbow
• /
• v.8 no.2
• /
• pp.158-165
• /
• 2005

The Superior Shoulder Suspensory complex (SSSC) maintains a normal stable relationship between the upper extremity and the axial skeleton. Traumatic double disruptions of the SSSC frequently create an unstable anatomic situation and is difficult-to-treat. When this double disruption is managed conservatively, significant displacement can occur at either or both sites and result in long-term problems and functional disabilities. Therefore surgical management is generally necessary. The authors experienced two cases of double disruptions of the SSSC treated with arthroscopic surgery & and reported good results.

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.7
• /
• pp.139-144
• /
• 2008

Micro electrochemical machining was investigated to machine micro internal features. This method uses a micro disk tool electrode and can easily machine micro features inside of a micro hole, which are very difficult to make by the conventional processes. In order to limit the machining area and localize the electrochemical dissolution, ultra short pulses were used as power source and a micro disk electrode with insulating layer on its surface was used as a tool electrode. By electrochemical process, internal features, such as groove array, were fabricated on the stainless steel plate.

• Korean Journal of Computational Design and Engineering
• /
• v.6 no.4
• /
• pp.263-270
• /
• 2001

In stamping-die manufacturing, the first step is to build die patterns for lost wax casting process. A recent industry trend is to manufacture the die pattern using 3-axis NC machining. This study identifies technical considerations of the pattern machining caused by the characteristics of Styrofoam material, and proposes technical methods related to establishing a process plan and generating tool paths for optimizing the pattern machining. In this paper, the process plan includes the fellowing three items: 1) deter-mining a global machining sequence-a sequence of profile, top, bottom machining and two set-ups, 2) extracting machining features from a pattern model and merging them, and 3) determining a machining sequence of machining features. To each machining feature, this study determines the machining start point, generates the approach tool path, and proposes a tool path linking method fur reducing the distance of the cutter rapid motion. Finally, a smooth tool path generation and an automatic feedrate adjustment (AFA) method are introduced far raising the machining efficiency.

• Korean Journal of Computational Design and Engineering
• /
• v.3 no.3
• /
• pp.192-200
• /
• 1998

Even though most die-maker are using CAD/CAM systems rout NC tool-path generation, “front-end”CAD/CAM technologies have not been fully adapted to sculptured surface machining(SSM) nor are sufficiently utilized in die shops. This gap between die-making industry and CAD/CAM community persists mainly because of the lack of a SSM-process model through which the two groups communicate with each other. Proposed in this paper is a model of SSM-processes which is built around the concepts of machining stages, unit machining operations, and each machining stage is decomposed into a sequence of unit machining operations(UMOs). Identified in the paper are five machining stages and 17 types of UMO. Based on the framework of the proposed model, an example of inner-panel stamping-die machining processes is described in detail.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2005.05a
• /
• pp.407-412
• /
• 2005

For micro electrochemical machining (ECM), tool electrodes with various sizes and shapes are necessary. In this paper, tool electrodes were fabricated by micro electrical discharge machining (EDM). Electrode material is tungsten carbide which has high rigidity and good conductivity for micro electrochemical machining. Disk-type and sphere-type electrodes were fabricated to prevent taper shape of side walls or to produce spherical features. Various 3D micro structures were fabricated by electrochemical milling with developed electrodes.

• Korean Journal of Computational Design and Engineering
• /
• v.14 no.4
• /
• pp.254-260
• /
• 2009

Most commercial PDM (product data management) systems, which have been released recently by overseas famous software vendors, are still expensive and heavy to apply to small and medium enterprises (SMEs). Proposed in this paper are an architecture and functions of collaborative BOM (bill-of-material) management system (cBOM-MS) which supports the internal BOM management by BOM Navigator, provides SMEs with constructing the collaborative BOM via Collaborative BOM Portal, and proposes an interface to extract BOM automatically from commercial CAD systems. In the design of cBOM-MS, BOM Navigator and cBOM Portal are positioned separately to reinforce the information security about product data during product development process.

• Korean Journal of Computational Design and Engineering
• /
• v.14 no.5
• /
• pp.338-345
• /
• 2009

c-PMS(collaborative project management system) is a business process(BP) based tool to manage collaborative projects which accomplish common business objectives determined by mutual agreement of companies using limited resources and time. This study analyzes collaborative BP, collaborative projects, and their relation, and proposes the architecture and operation scenario of c-PMS consisted of business process asset management(BPAM) sub-system and project manage(PM) sub-system. BPAM sub-system models private and public BP using a client/server based modeler, defines collaborative BPs process from public BPs, and manages them as companies' asset on a web portal. PM sub-system globally manages collaborative project using planning, execution, monitoring, and analyzing functions.