Papers by Author: Quang Cherng Hsu

Abstract: The proposed paper aims at the development of extruding seam square tube of AA7075 high strength aluminum alloy by simulation and experiment. There are several factors related to extrusion load such as billet temperature, billet dimension, flow stress, die cavity and product geometry. The extrusion loads and die stresses for hot extruding square tube with respect to different product have been investigated. Since AA7075 behaves high forming resistance comparing to AA6063 and AA6061, the product design and die design should be modified in order to meet with the limitation of extrusion machinery. Moreover, AA7075 has high thermal welding crack behavior by comparing to AA7003. Therefore, In order to provide high contact pressure enough to conduct solid welding for the split AA7075 materials in welding chamber, the specific die cavity design has been finished. Then, the solid welding pressure can be increased. The research results show that under the same forming conditions such as fixed ram speed and billet temperature, the extrusion force for the product with thick thickness is small than the one with thin thickness. The same result was obtained for die stress. A square tube extrusion experiment has been conducted by installing die set into forward extrusion machinery. The experiment and simulation results have been compared and discussed.

Abstract: Large size TFT-LCD (Thin-Film Transistor Liquid-Crystal Display, which is commonly called as panel) is made after lots of processes and is cut based on the required size in the last process. Deckle-edge (Burr) and other defects were produced by cutting. Therefore, it needs to examine the products’ defects before grinding the edges or the following processes. This research developed a new type and high-efficiency apparatus for panel-edge inspection. The defects are sorted based on three types “Fractures, Cracks and Dark-spots” by using image-subtraction, binary thresholding, and blob-analysis methods. The proposed system can improve the efficiency on panel-edge inspection for panel manufacturers. The production of flat panel-edge inspection can be increased to over 40% which can resolve the bottleneck processes for panel industry.

Abstract: Along with social progress, people pay attention to health. Modern people choose the gym to maintain posture and body functions well, therefore, the gym popularize everywhere. Popularity of expensive fitness equipment to bring a lot of convenience, but different users share of fitness equipment have different condition, often caused damage by use, which is the most important factor for the material fatigue damage. This study chose the exercise bike parts “self run bushing” to create a fatigue life assessment mechanism. In this study, to the fatigue analysis was conducted, by using finite element analysis according to the material S-N curve and Miner cumulative damage theory in a series of cyclic loading. To analyze fatigue life, analytical and experimental studies through mutual verification were conducted which can obtain the expectation life period of the self run bushing. The load spectrum based on different user can also be considered in this study. Based on the design frequency from different users, after the study of distribution of reliability and failure, the most appropriate time-out and the best replacement time can be obtained.

Abstract: Direct extrusion by porthole – bridge die configuration has been successfully used to fabricate products with hollow cross sections for 6000 series aluminum alloys. However, if for 7000 series aluminum alloys, this situation alerts since different alloy composition such as Cu causing hollow extrusion failed due to not enough welding strength in seam. In order to determine the solid welding conditions during hollow extrusion with porthole die structure for high strength aluminum alloy, an easy tooling configuration has been designed. The proposed method is easy and cheap because there is no necessary to conduct experiment in controlled environment such as in vacuum chamber of Gleeble test or in a protective atmosphere. A seam and hollow extrusion for square tube has been conducted to obtain the welding strength comparison to the proposed solid welding method which shows good agreement.

Abstract: Image-processing technology is widely used in industry for automatic inspection and measurement through the capturing of object images by CCD (Charge-Couple Device) cameras and the built-in algorithms. VR (Virtual Reality) is a high-end user interface that involves real-time simulation and interactions through multiple sensorial channels. Three important characteristics of VR are: immersion, interaction, and imagination which enable the users more direct and useful communications with manufacturing prototyping systems. In this paper, an image processing system was developed for measuring small parts such as 3C rivets automatically. If using optical sensors to measure such small parts, the mechanism is complicate. However, if using image process technology, the mechanism is simple and the measurement is efficient. All we have to do are to develop measuring algorithms as well as computer programs. A VR-based image processing system was also developed by importing 3D CAD objects and applying the relationships between these objects. Therefore, the image processing algorithms as well as the layout of the measurement system can be tested by using the proposed VR system without any real machine such as transfer mechanism, CCD camera, and computer with image processing program.

Abstract: Due to the rapid progress of industrial development, the formation of lightweight and small-size parts is becoming increasingly important. Especially in the IC and 3C industry, the sheet metal forming of miniature parts is especially interesting. Size effects such as specimen dimension, blank thickness, punch corner dimension, grain size, and grid dimension (for strain measurement), as well as the microstructure of material and surface condition all seriously influence the forming of miniature parts. In this paper, systematic experiments including Erichsen stretch forming and hydraulic bulge, and strain analyzers including for circular and rectangular grids are described for establishing the relationships of sheet metal formability to process parameters. The details of the experimental procedures and results are presented and discussed.