Papers by Keyword: Deburring

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Authors: Kazumasa Shiramoto, Junki Shimizu, Akiyoshi Kobayashi, Masahiro Fujita
Abstract: A burr is most commonly created after machining operations, such as drilling. Drilling burrs, for example, are common when drilling almost any material. When burrs are broken during the operation of a machine including the parts with the created burrs, the broken piece is in fear of disturbing normal operation or damaging the parts of the machine, so that the sufficient deburring is requested because it can affect equipment performance, reliability, and durability. Several deburring method have been developed up to date. In the present report, we proposed a deburring method by means of applying underwater shock wave. The method is as follows: after all entrance of holes is closed with seal tape, the equipment is submerged, so that all passages for running fluid are filled with air. The explosive is set under water near the entrance of the main hole. As soon as the explosive is detonated, the underwater shock wave generated at the detonation point arrives at the entrance of the hole and breaks through the tape. The water flows into the hole with a high speed. The burr is broken by water hummer action of high speed. In the present investigation, the experiments of deburring are performed under some setting conditions of explosive. It is found by experimental results, that the burr is sufficiently removed with the newly proposed method. When the shock pressure is sufficiently high at the entrance of hole, the burr is broken surface is smooth as polished one. When the shock pressure is not sufficiently high, the broken surface of the burr is notched.
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Authors: Zhi Min Hou, Wei Xia, Dong Hua Deng, Qing Hua Wang
Abstract: Deburring is a major bottleneck in manufacturing organizations. Burrs on the milled surface need to be removed and the surface quality must be maintained. Abrasive waterjet (AWJ) has been used in various operation for a wide range of materials. But no detailed investigations are known to be carried out on AWJ deburring. An orthogonal experiment is designed to investigate the effects of the AWJ parameters on burr removal and on surface quality. The results show that AWJ can remove the burrs from the stainless-steel specimens effectively under the condition of proper parameters, and the parameters such as abrasive grit size and stand-off distance are important not only for burr removal but also for surface quality, and slurry concentration is another important factor for surface quality.
311
Authors: Kazumasa Shiramoto, Akiyoshi Kobayashi, Kazuto Takamiya, Masahiro Fujita
Abstract: When a few branched holes are made in order to cross a main hole at right angle, burrs are produced on the sidewall of the main hole at end of each branched hole. The principle of the process is as follows. After the specimen of which all holes are closed by using sealing tape is submerged, explosive set at the position a little apart from the entrance of the main hole is detonated. As soon as the generated underwater shock wave is arrived at the entrance of the main hole, the sealing tape is broken and the water stream with very high velocity flows into the main hole. The deburring is performed by the action of the water stream with very high velocity. The deburring is sufficiently succeeded in most case. When the main hole is closed, however, the deburring could not be succeeded at the branched hole very near closed position. In order to improve the insufficiency of the process, we designed new equipment in order that underwater shock wave may be concentrated at the entrance of main hole and the water stream with very high velocity, which is caused by the shock wave, may flow along sidewall on which burr is generated. In the present report, we propose the new method and give full account of the experimental results for deburring obtained by using the equipment.
183
Authors: Yuri M. Baron, S.L. Ko, Jung Il Park
Abstract: This paper analyzes the effectiveness of using Magnetic Abrasive Finishing (MAF) to remove burrs on drilled holes located on planes. Basic elements of the equipment in this method are a magnetic inductor; powder with magnetic and abrasive properties, which serves as the cutting tool; and the face electromagnetic inductor and the vibrating table, which were developed for deburring and finishing on flat surfaces. The performance of magnetic abrasive powders produced by industry is also evaluated. A new technique was developed to compare the performance of the magnetic abrasive powders and to find the powder that is appropriate for finishing and deburring drilled holes placed on a plane steel surface.
291
Authors: Matthias Pischan
Abstract: In aircrafts, hydraulic systems control moveable parts. For example parts like the front strut or the landing flaps. These parts are usually made from aluminium or titanium. Due to an increasing number of functions these valves show an increasing number of cross holes. The production process causes burrs at the intersection of the holes. Until now these burrs cant be removed reliably by an automated process. Remaining burrs can influence dimensional tolerances and reduce the efficiency and technical lifetime of the component. In some applications cross holes are used for the lubricant and coolant supply. In this case burrs can lead to blockades of critical passages or cause turbulences in the fluid. This can lead to leakage or bursting of the valve. Hence an uncontrolled removal of the burr during operation must be avoided. The consequence of these basic conditions is a time consuming manual deburring process. An automated deburring process of cross holes with industrial robots is usually performed with flexible abrasive brushes. Alternatively processes like AFM (Abrasive Flow Machining), ECM (Electro Chemical Machining) or TEM (Thermal Energy Machining) are used. Those processes are very efficient but require specialized equipment and cleaning processes for the used chemicals and the remaining abrasive paste. So they are not suitable for the deburring of safety related parts. This paper presents an experimental based approach for the robot based deburring of cross holes using industrial robots. For the deburring of cross holes several special tools are available. This article gives a short overview over the specific advantages and disadvantages of these tools. As the investigations revealed the best results can be achieved using the so called Orbitool developed by JWDone. The Orbitool is a tungsten carbide cutter developed for the deburring of cross holes. A better control of the required dimension at the intersection compared to brushes and other deburring methods is possible. Furthermore the tool can be used on machine tools and industrial robots and is flexible to a huge variety of bore diameters. The tool mainly consists of a ball shaped carbide milling cutter with a protective disk which is made of polished steel and a shaft of tool steel. To remove the burr the tool is moved along the bore axis into the smallest of the intersecting holes until the tip of the tool is close to the intersection. Then the tool is moved in radial direction to the bore surface until the tool axis corresponds to the interpolation diameter. This causes a deflection of the tool. In this situation only the protective disk is in contact with the bore surface. While the tool rotates it is moved towards the intersection in a helical motion. When the tool tip has reached the intersection the cutting edges get in contact with intersection and the deburring process begins. After the tool has passed the whole intersection it stops its rotation and is moved to the bore hole centre and then moved out of the workpiece. This paper deals with the optimization of the deburring process. The result mainly depends on the parameters movement speed of the robot, slope of the helical movement and rotational speed of the tool. The experiments are planned using DOE (Design Of Experiment) methods. Initial values for the optimization of the movement speed were determined by grid encoder measurements. Robotic specific parameters like the number of interpolating points and the influence of the path smoothing caused by the controller were also investigated. For the analysis of the burr and the secondary burr an optical 3-D measurement system is used. The results show that with the presented approach the burrs can be reliably removed. Before the deburring process the average burr height is about 60 μm and can be reduced so that there is no secondary burr visible. The result is a chamfer between 150 μm and 85 μm that depends on the process parameters. It can be demonstrated that a chamfer that is smaller than 100 μm leads to a secondary burr. Anyway the cycle time can be reduced from about 3 minutes for manual deburring to 30 seconds using an industrial robot. Additional wear analysis show that about 200 bore holes can safely be deburred.
147
Authors: Alberto Boschetto, Armando Ruggiero, Francesco Veniali
Abstract: In sheet metal processes the burrs cannot be completely eliminated during the process but can be minimized by optimization of the process parameters. Hence the deburring often becomes an essential secondary operation. Most of the deburring operations are hand-made and therefore several manufacturers tend to eliminate these tedious and labor-intensive operations due to time and cost issues. Moreover, clamping problems can arise which, together with the deburring forces, can induce dimension alterations and local deformations, particularly for thin sheets. Barrel finishing is an old technique commonly used to improve the surface roughness of complicated parts, but can find interesting applications also in the deburring. Aim of this work is to present an experimental investigation on the deburring of sheet metal performed by barreling. A technological model has been developed in order to assess the height of the burr as a function of the initial burr and of the working time.
193
Authors: Atsushi Nakayama, V. Lertphokanon, Minoru Ota, K. Egashira, K. Yamaguchi, N. Kawada, S. Kouno
Abstract: The authors developed Whirling Electrical Discharge Machining (Whirling EDM) [1] with the feedback circuit to control gap distance between tool electrode and workpiece. It was found that the probability of discharge was increased by feedback circuit [2]. However, the motor rotational speed control conditions were not optimized and the machining characteristics were not clarified. In this paper, the rotational behavior of tool electrode in Whirling EDM was observed by high-speed camera, and it was considered that the influence of motor rotational speed control conditions on machining characteristics and the relationship between electrical conditions and machining characteristics. As a result, the discharge probability was able to be increased by decreasing range of motor rotational speed in feedback circuit. In addition, the machining characteristics of Whirling EDM which are influenced by electrical conditions were clarified.
293
Authors: Yan Hua Zou, Takeo Shinmura
Abstract: A new magnetic deburring method for a drilled hole on the inside of tubing is proposed in this study. This internal deburring method applies the magnetic field assisted machining process by using a magnetic machining jig (permanent magnet tool). In this research, we examined experimentally the deburring of a drilled hole on the inside of SUS304 stainless steel tubing. A processing unit and magnetic machining jig were made, and the processing unit was set on a lathe machine. The deburring experiment was performed for a drill hole 3 mm in diameter. The results showed that the internal burr could be removed using this magnetic deburring process and the height of the burr could be successfully decreased from 163 μm to 1 μm. Thus, it was proved that this magnetic deburring method was effective for the internal deburring of long tubing.
243
Authors: S.L. Ko, Yuri M. Baron, Jung Il Park
Abstract: Several types of inductors with permanent magnets for deburring using the MAF process were investigated in this paper. The magnetic intensity of each system was measured at working gap to determine the proper system. Using the inductor with a permanent magnet, which was designed and manufactured as a result of the investigation, the heterogeneity of the finishing process and the variations in the location of the magnet poles and the amount of the powder were analyzed during the deburring process. The characteristic curve was calculated from the experimental data and used to compare the performance of each inductor. Under similar conditions, the permanent magnet inductor showed superior performance compared to the electromagnetic inductor in the deburring process.
237
Authors: Jakub Matuszak, Kazimierz Zaleski
Abstract: After milling process burrs can form as a result of plastic deformation of the material. Wire brushing can be used as a fully automated method of deburring on machining centres. In order to provide the same effects after brush change it is important to precisely determine the tool diameter. The article presents the method of dynamic diameter determination of circular brushes, which is the diameter of the brush during rotation.
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