Papers by Keyword: Fixture

Abstract: By using data from a conventional uniaxial test of the composite laminate in the design processes, safety factors might be overestimated which lead to unnecessary increase in size, cost and weight of the structure. Therefore, various bi-axial tests have been conducted in order to achieve the more realistic design. However, there is still a lack of reliable biaxial testing data to verify failure initiation and propagation of composite materials, due to the difficulties and expense of conducting these tests. In this study, a novel bi-axial testing fixture which can produce the tension – tension, tension – compression, compression – compression bi-axial loading conditions with different displacement ratios was developed with one loading actuator. This device is a cost-effective alternative for bi-directional material characterization tests which is utilized to validate of theoretical failure models.

Abstract: High voltage overhead transmission line is a transmission tower used to conduct electricity with a voltage of 35 kV to 230 kV. In the installation of the HV overhead transmission line tower structure, one of the main things that need to be considered is the installation of stub that can affect the sturdiness of the tower. This research aims to design and make a stub setting fixture on the HV overhead transmission tower installation. The research process began with data observation and literature study of tower stub installation in the 150kV 2xZebra Andolo – Kasipute Sec.1 installation project of PT. PLN Persero UIP South Sulawesi, then designed the stub setting fixture components, design data analysis, and fixture manufacturing. The results of the analysis of the design structure experienced do not exceed the limits of the material stresses of the component, the analysis of machine elements in the stub setting fixture is able to withstand the loads experienced by the component. It is expected that there will be improvements and development of fixture in the form of more efficient forms of construction and operation, and can use analog and digital controls in terms of fixture operation in subsequent development and research.

Abstract: Today, an artificial tooth root called a dental implant is used to replace lost tooth function. Treatment with dental implants is considered an effective and safe method. However, in some cases, the use of dental implants had some failures. The success of dental implants is influenced by several biomechanical factors such as loading type, used material properties, shape and geometry of implants, quality and quantity of bone around implants, surgical method, lack of rapid and proper implant surface's integration with the jaw bone, etc. The main purpose of functional design is to investigate and control the stress distribution on dental implants to optimize their performance. Finite element analysis allows researchers to predict the stress distribution in the bone implant without the risk and cost of implant placement. In this study, the stresses created in the 3A.P.H.5 dental implant's titanium fixture and screw due to the change in abutment angles tolerance have been investigated. The results show that although the fixture and the screw's load and conditions are the same in different cases, the change of the abutment angle and the change in the stress amount also made a difference in the location of maximum stress. The 21-degree abutment puts the fixture in a more critical condition and increases the chance of early plasticization compared to other states. The results also showed that increasing the abutment angle to 24 degrees reduces the stress in the screw, but decreasing the angle to 21 degrees leads to increased screw stress and brings it closer to the fracture.

Abstract: Fixtures are use to ensure the orientation and position of workpiece and cutting tools in machining systems. Drill bush guide / holder or are part of a specific category of elements and mechanisms, found in the fixtures structure: elements for size adjustment and guidance for cutting tools. These drill guide bush/ holder are used for guidance of drills, in order to ensure a certain position of the tool regarding the certain reference elements of the workpiece, or to increase the stiffness of drills, when the tool diameter is reduce, or when the surface of the machined workpiece is inclined. The drill bushes are placed in the fixture body, directly or through drill bush guide plates/ drill bush support plates. The characteristic feature of these bush plates is the console length. Sometimes, the bush guide plates can have large lengths that affect the dynamic stability. The bush guide plates are dynamically excited by the direct contact with the drill of the bush. If the natural frequency of vibration of the plate is equal or higher than the excitation frequency of the machining process, then the resonance phenomenon can appear.

Abstract: In the paper a research methodology was developed and used to determine the rigidity in transversal direction of modular fixture structures. The paper presents experimental results regarding the total deformation of modular structure consisting of ”narrow” modules from modular kits. The research conducted showed the different evolution of deformation curves in the case of modular structure, with different shape and different sizes of modules, in the case of similar loads. The experimental results indicate displacements of the entire modular structure alongside the base plate and, also, tilting. The measured deviations of modules from fixture structure may cause "dimensional"/ position deviations (linear displacement of the measurement base) and deviations of shape and orientation-position (angular displacement of the measurement base) of the workpiece during severe machining conditions.

Abstract: In manufacturing industries, workpiece clamping is one of the basic requirement prior to machining process as the clamping system is responsible to maintain the workpiece rigidity and withstand the cutting force generated from the machining process. Besides, Clamping device is one of the reasons which influence the surface integrity of a part. Clamping workpieces for machining can be challenging especially for intricate non-symmetric geometry and vulnerable parts. In this study, a new system has been designed and developed where the workpiece is submerged in a fluid and the fluid is completely frozen to form ice that holds the workpiece rigidly. This ice clamping system can hold any parts of the workpiece regardless of their geometry and fragility. To freeze the desired workpiece, the energy required for 942 cm³ of clamping fluid was 98.43 kJ. Total freezing time was 90 minutes. Further development on the system is required in terms of improving freezing time and de-freezing of the work-piece.

Abstract: The Long girder end parts are one of the types structure in aerospace equipment, the complex structure parts, machining parts. Usually the parts be processed on the NC milling machine, through the analysis of processing craft, design a kind of quick change type, Multi-station clamp device, instead of processing the parts on the multi-axis nc machine tool; at the same time of guarantee machining accuracy, in order to improve the production efficiency and reduce the cost of production.

Abstract: The article deals with the principles of fixtures design and their application at virtual modelling in CAD/CAM system. The computers have became an important part of our life and about its benefits nobody doubts. The designers have got the strong tools into the development hands that use the potential of computer techniques for the creation of completely new applications, which alleviate the solution not only of common problems, but already the special defined, too. New technologies bring the change of mind. The classic way “production on the base of drawing” is often substituted by computer aid technology that thanks to three dimensional graphic enables to solve the difficult phases of the body design direct in its real version of full-value stereometric body. In the article are described the principles of the fixtures design using CAD/CAM system following by application of these rules for machining of complex shape armature.

Abstract: One of the most important parameters used in the evaluation of machining technological systems is the dynamic quality, represented by the system stability and the specific feature of the reaction to the external factors, during the machining process. The dynamic quality of the machining system is given by the dynamic quality of the machine tool, cutting tool, cutting tool holding device, workpiece fixture. The dynamic behavior of the machining system is given by the behavior of the elastic subsystem of the workpiece and tool. In the case that the deformation of the machine tool is negligible in relation with the two subcomponents of the technological system, mentioned, these can be studied separately. It is important to determine which is the weakest link of the technological system or to determine which is the component that can lead to the loss of the stability of the entire system. In the paper it is studied the dynamic behavior of the turned long, flexible workpieces. The workpieces are clamped in the lathes chuck and in the tailstock. The natural vibrational frequencies are determined according to a series of parameters as the diameter of the workpieces, axial forces applied by the tailstock.

Abstract: In the paper a research methodology was developed and used to determine the rigidity in the axial direction.The paper presents a the experimental results regarding the total deformation of narrow modules found in the structure of modular sets. The research conducted showed the different evolution of deformation curves in the case of modular structure composed of modules, with different shape and different sizes, in the case of similar loads