• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.453-454
• /
• 2006

This paper describes a processing verification technique for developing about end-milling cutters. Developed software is processing verification module for manufacturing. By using cutting simulation method, we can obtain center points of finding wheel via Boolean operation between a grinding wheel and a cylindrical workpiece. The obtained CL data can be used for calculating NC data. After then, we can simulate by using designed grinding machine and NC data. This research has been implemented on a commercial CAD system by using the API function programming. The operator can evaluate the cutting simulation process and reduce the time of design and manufacturing.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.12
• /
• pp.86-92
• /
• 2002

This paper presents a new model of NC verification in NC milling using z-map. The model can describe the motion of machine tool like a real machine effectively. The model uses x, y, and z directional feed rate as well as cutting data for modeling Z-map of workpiece. The model verifies the over-cut, the under-cut and the surface topography using NC codes and cutting conditions. To investigate the performance of the model, simulation study was carried out. As the results, the model gave the geometry accuracy of workpiece, the surface topography, and the chip loads.

• IE interfaces
• /
• v.7 no.1
• /
• pp.30-36
• /
• 1994

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.9
• /
• pp.27-34
• /
• 2011

Cognitive Radio, which is proposed to improve the efficiency of wireless communication systems is the system to share primary user's frequency bands with a secondary user. In this situation, a secondary user uses NC-OFDM (Non-contiguous Orthogonal Frequency Division Multiplexing) to transmit data effectively without interfering with the primary user's spectrum. However, NC-OFDM, in common with contiguous OFDM, degrades the performance of the system by generating high PAPR (Peak-to-Average Power Ratio). In this paper, firstly, we analyse PAPR corresponding to the distribution of subcarriers in NC-OFDM. Then the PAPR reductions that employ the PTS (Partial Transmit Sequence) and SLM (Selective Mapping) are evaluated. Finally, the computational complexities of the PTS and SLM adopting pruned-FFT are compared with conventional PTS and SLM. Further, it is shown that the NC-OFDM with pruned-FFT is more efficient than the contiguous OFDM in terms of computational complexity and PAPR reduction performance.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.551-554
• /
• 2002

The paper discusses new approach for machining operation simulation using enhanced Z map algorithm. To extract the required geometric information from NC code, suggested algorithm uses supersampling method to enhance the efficiency of a simulation process. By executing redundant Boolean operations in a grid cell and averaging down calculated data, presented algorithm can accurately represent material removal volume though tool swept volume is negligibly small. Supersampling method is the most common form of antialiasing and usually used with polygon mesh rendering in computer graphics. The key advantage of enhanced Z map model is that the data structure is same with conventional Z map model, though it can acquire higher accuracy and reliability with same or lower computation time. By simulating machining operation efficiently, this system can be used to improve the reliability and efficiency of NC machining process as well as the quality of the final product.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.636-642
• /
• 1996

본 연구는 4축 또는 5축 NC 공작기계에 사용되는 Rotary Table의 오차를 측정하고 이를 보정하기 위한 연구이다. 먼저 일반적인 Rotary Table에 대한 오차모델이 설정되었으며, Rotary Table에서 존재하는 6가지의 오차를 각각 측정하였다. 측정방법은 3개의 길이오차는 1 개의 정밀볼(Master ball)과 3개의 LVDT, 3개의 각도 오차는 6각 폴리곤과 Autocollimator를 사용하여 측정하였다. 측정된 오차 성분들은 오차모델을 이용하여 보상치를 계산하였으며, 이 값은 추후 원래의 측정오차와 비교하는 방법으로 모델의 정확성을 검증할 것이다. NC 공작기계상에서 Rotary Table의 실제 보상 실험을 위하여 30$^{\circ}$간격으로 정밀한 볼이 장착된 볼-테이블을 설계하였다.

• Journal of Life Science
• /
• v.28 no.6
• /
• pp.663-670
• /
• 2018

This study was performed to confirm the antioxidative and hair-growth-promotion effects of a fermented compound composed of five materials, namely Allium cepa, Cucurbita spp., Glycine max Merr., Pinus sylvestris leaf, and Sesamum indicum. An additional compound composed of two materials was composed of Allium cepa and Cucurbita spp. Antioxidative effects were measured based on DPPH radical-scavenging activity and total flavonoid content. Fermented 5-type natural compounds (5NC) showed higher DPPH radical-scavenging activity and flavonoid content than those of fermented 2-type natural compounds (2NC). Hair-growth promotion was demonstrated in vivo. Alkaline phosphatase (ALP), oid contentontenteptidase phospactivity, and macroscopic observation were measured. Experimental animals were divided into four groups based on the samples they were administered: water, pansildil (P-CON), 5NC, and 2NC. Samples were administered orally once a day at a fixed time for four weeks. Both ALP and ${\gamma}eeksactivity$ increased in the 5NC group compared with the 2NC group. In macroscopic observation, the P-CON group grew the most and were most similar to the state before shaving. The 5NC group grew hair similar to the P-CON group. In all the results, the 5NC group showed greater antioxidative and hair-growth-promotion effects than the 2NC group. Consequently, 5NC could be used as an ingredient for hair-growth promotion.

• Journal of the Society of Naval Architects of Korea
• /
• v.42 no.1 s.139
• /
• pp.64-72
• /
• 2005

Digital manufacturing is a technology to simulate the real manufacturing process using the virtual model representing the physical schema and the behavior of the real manufacturing system including resources, processes and product information. Therefore, it can optimize the manufacturing system or prevent the bottleneck processes through the simulation before the manufacturing plan is executed. This study presents a method to apply the digital manufacturing technology for the steel cutting process in shipyard. The system modeling of cutting shop is carried out using the IDEF and UML which is a visual modeling language to document the artifacts of a complex system. Also, virtual NC simulators of the cutting machines are constructed to emulate the real operation of cutting machines and NC codes. The simulators are able to verify the cutting shape and estimate the precise cycle time of the planned NC codes. The validity of the virtual model is checked by comparing the real cutting time and shape with the simulated results. It is expected that the virtual NC simulators can be used for accurate estimation of the cutting time and shape in advance of real cutting work.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.725-729
• /
• 2000

This paper presented a new model of NC verification in ball end milling. The model verifies the over cut the under cut and the surface roughness using NC file generated from CAM and cutting condition. The model uses Z-map model to verify workpiece. In this paper, the model used the velocities of x, y and z direction and obtained a center point of a ball end mill for modeling Z-map of workpiece. To investigate the performance of the model simulation study was carried out. As the results, the model gave geometry accuracy of workpiece, the surface roughness and the chip loads in finish cutting that can predict tool chipping.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.1
• /
• pp.93-100
• /
• 1994

5-axis CNC machining is being used in the manufacturing of tire mold, screw, and turbine blade because it can produce complex workpiece more efficiently and accurately than 3-axis CNC machining does. However, it is difficult to calculate the CL data in 5-axis CNC machining. This paper describes an efficient method to modify and edit the NC code and a data structure for representation of the workpiece produced by 5-axis CNC machining. Wireframe display of tool path and shading display of workpiece are used to represent verification results. Machining errors can be evaluated quantitively using the data structure based on the workpiece data model. The methods are implemented in a program with a IBM-PC and MS-Windows.