• Journal of the Korean Society for Precision Engineering
• /
• v.6 no.3
• /
• pp.46-59
• /
• 1989

The purpose of test fixture is to mechanically couple energy from a shaker into a test specimen. And then it is necessary to design a fixture of shich the fundamental natural frequency is over than one half times as high as the highest frequency of interest. But the dynamic behavior of vibration test fixture is usually different from, often far different from, what has been calculated. In this paper, the optimal dimensionless frequency parameter, ${lambda}$'s, are calculated from the test results of a various and complex shaped fixtures.

• The Journal of Korean Academy of Prosthodontics
• /
• v.43 no.3
• /
• pp.338-351
• /
• 2005

Statement of problem. Accurate fit between the implant components is important because the misfit of the implant components results in frequent screw loosening, irreversible screw fracture, plaque accumulation, poor soft tissue reaction, and destruction of osseointegration. Purpose. This study is to evaluate the machining accuracy and consistency of the implant fixture/ abutment/screw interfaces of the internal connection system by using a Stereoscopic Zoom microscope and FE-SEM(field emission scanning electron microscope) Materials and methods. The implant systems selected in this study were internal connection type implants from AVANA(Osstem^{\circledR}), Bioplant(Cowell-Medi^{\circledR}), Dio(DIO^{\circledR}), Neoplant(Neobiotech 􀋓), Implantium(Dentium􀋓)systems. Each group was acquired 2 fixtures at random. Two piece type abutment and one piece type abutment for use with each implant system were acquired. Screw were respectively used to hold a two piece type abutment to a implant fixture. The implant fixtures were perpendiculary mounted in acrylic resin block. Each two piece abutment was secured to the implant fixture by screw and one piece abutment also secured to the implant fixture. Abutment/fixture assembly were mounted in liquid unsaturated polyester. All samples were cross-sectioned with grinder-polisher unit. Finally all specimens were analysed the fit between implant fixture/abutment/screw interfaces Results and conclusions. 1. Implant fixture/abutment/screw connection interfaces of internal connection systems made in Korea were in good condition. 2. The results of the above study showed that materials and mechanical properties and quality of milling differed depending on their manufacturing companies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1996.04a
• /
• pp.100-105
• /
• 1996

This paper proposes the method of experimental structural dynamic modification of fixture for environmental vibration test control. This method can predict the responses at any points on fixture utilizing the experimental data, and structural dynamic modification of fixture is made using the predicted responses for the spectra at the speciment attachment points to meet the specified reference spectrum. From the results of controlling the fixture before and after modification by conventional control method and optimal reference spectrum, which has been previously reported by the authors, the proposed method is shown to be an effective one.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.142-145
• /
• 2004

More complex geometric shapes, including freeform surfaces, are adopted for the design of products to emphasize styling or aesthetics. Modeling of these products is extremely difficult, and often impossible. Reverse engineering is an emerging technology that can resolve this problem by generating CAD models from the physical mockups or prototype models. The laser scanner if often used to acquire the surface information of the part, but is limited in its measuring direction, which if fixed only along the z-axis. A Designed fixture of new shape to supplement these problems in this paper. The new fixture using several joints and an tooling ball holder is designed considering the convenience of the part set-up and the accuracy of the registration. The location of the tooling balls can be arranged to avoid the occlusion of the part and to minimize the registration error. The new fixture is apply to an object part having freeform surfaces to verify the effectiveness of the proposed design.

• Journal of Korean Institute of Industrial Engineers
• /
• v.21 no.1
• /
• pp.51-65
• /
• 1995

This paper presents an automatic fixture planning system for machining processes of prismatic parts. A rationalized approach to integrate fixture planning with process planning is proposed and representation schemes for workpiece, part design information with features, machine tools, cutting tools and fixtures are developed. The proposed system implements two activities of fixture planning such as machining of reference surfaces and machining of features. For machining of reference surfaces, the machining sequence of reference surfaces is determined by using decision tables, which are drawn from relations of part dimension, degree of surface roughness, fixture type and its capacity, cutting tool's capacity and experienced planners' knowledge. For machining of features, a preferential machining orientation is selected for its feature which can be machined in more than one direction, and features with the same machining orientation are grouped, and the machining sequence of features is determined by interactive mode. A case study is performed to show the performance of the proposed system.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.82-84
• /
• 1993

A method for simulating general characteristics and temperature characteristics of magnetizing fixture coil of the capacitor discharge impulse magnetizer-magnetizing fixture system using SPICE is presented. This method has been developed which can aid the design, understanding and inexpensive, time-saving of magnetizing circuit. As the detailed characteristics of magnetizing circuit can be obtained, the efficient design of the magnetizing circuit which produce desired magnet will be possible using our SPICE modeling. Especially, The knowledge of the temperature of the magnetizing fixture is very important to forecast the characteristics of the magnetizing circuits tinder different conditions. The capacitor voltage was not raised above 810[V] to protect the magnetizing fixture from excessive heating. The temperature estimation method uses multi-lumped model with equivalent thermal resistance and thermal capacitance.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.905-910
• /
• 2003

Most of previous research on machining process planning has not fully included consideration on fixturing. With fixture components properly assembled with the part workpiece in a CAD modeling environment, necessary geometric information of fixture elements and their interrelations with the part model can be obtained so that machining process plans could incorporate fixturing considerations. This paper introduces an interactive fixturing system called I-Fix. I-Fix is a dowel-pin based modular fixture system, and it has been developed using Solid Edge CAD system and Visual Basic. Through customized operations of the assembly commands of the CAD system, I-Fix significantly simplifies user operations and thus reduces fixturing time. Furthermore, I-Fix enhances user convenience by providing general guidance about the fixture components and fixturing methods.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.1 s.256
• /
• pp.1-10
• /
• 2007

This paper presents a design guidance of jig/fixture for flexible manufacturing system based on the verification of a base assembly motion instability. In flexible assembly system, the base assembly needs to be maintained in its assembled state without being taken apart. This requires stability in motion while the base assembly is handled or tilted. Therefore, the instability of the base assembly motion should be considered when determining the guide line of designing jig/fixture by evaluating a degree of the motion instability of the base assembly. To derive the instability, first we inference collision free assembly directions by extracting separable directions for the mating parts and calculate the separability which gives informations as to how the parts can be easily separated. Using these results, we determine the instability evaluated by summing all the modified separabilities of each component part within base assembly.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.548-554
• /
• 1996

A new method to locate modular fixtures using an optimization technique is proposed. The optimal fixture arrangement is derived to minimize the elastic deformation of a workpiece. That is, a fixture arrangement is regarded better if it minimized the elastic deformation of the workpiece while fixing a workpart of course. In this approach, the workpiece is projected into two dimensional domain to simplify the 3-dimensional fixture arrangement problem into 2-dimensional one. Thus the problem is reduced to find the optimal positions of one horizontal clamp and three locators which minimize the total deformation of the workpiece and the design variables are the location of the contact points between the boundary of the workpiece and the 4-fixels. The Genetic Algorithm is used for the optimization by mapping each design variables to a gene of a chromosome. The fitness value is the total strain energy of the workpiece calculated by the fin element analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.10a
• /
• pp.95-98
• /
• 2005

Shafts having asymmetry or odd number of symmetry in the cross-section can not be simply manufactured by conventional incremental radial forging. In order to manufacture such shafts, the new concept of incremental forging with one punch and a flexible fixture is developed by suggesting a flexible fixture, instead of two opposed punches used in radial forging, so that the flexible fixture only supports the workpiece while the punch is moving during forming. A new flexible fixture is designed using the steel shots and vacuum technology. An equilateral triangular cross-section is selected as the sample shape to be manufactured by the proposed manufacturing method. The desired triangular cross-sectional shaft is manufactured with the errors of $3.0\%$.