Papers by Keyword: Laser Cutting

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Authors: Jürgen Fleischer, Steffen Kies, Christian Munzinger, Raphael Rilli
Abstract: Due to economical, ecological and functional reasons, lightweight-construction is continuously gaining importance. Therefore, lightweight space frames made of pipe profiles are subsequently of higher importance in today’s technology. Today, the lower limits of the production range of lightweight space frames are set by joining processes that require jigs. For a flexible variation in a small-scale production, the use of latching elements for the pre-attachment in the jigfree assembly of frame structures serves as a good approach. In consideration of the analysis of the actual situation this article takes up this approach and points out the potential enabled by latching elements. Subsequently, the implementation of laser cutting will be motivated and the results of the first experiments on reinforced and unreinforced profiles will be discussed. To conclude this article, the challenges and approaches for the integration of this procedure to an existing handling and machining kinematics will be pointed out, and finally the implementation potentials of the procedure within an entire process-chain will also be mentioned.
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Authors: Hu Zhu, Nan Li, Jin Lan Bai
Abstract: The sheet metal forming is widely used in aerospace, automobile and shipbuilding industry. CNC incremental forming is a kind of recently developed flexible and dieless forming technology. This paper introduce an integrated process of CNC incremental forming and 5-axis laser cutting based on machining features, and the structure of related special CAD/CAM system as well as its development methods.
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Authors: Yu Long Zhang, Tao Dong
Abstract: Membrane-based microfluidic devices have been demonstrated in recent literature to show a significant potential in developing low-cost but high-efficient analytical devices. Usually, the step of sampling and sample preparation is the most importance processes in the whole analytical experiments. This study designed and manufactured a low-cost kit for water sampling and sample preparation of waterborne pathogens, especially protozoan parasites. Subsequently, Saccharomyces cerevisiae was employed as the model microbe to verify the function of kit. The concepts of green design and agile manufacturing were reflected throughout this work. In the devices, membrane filters were fixed and locked in a pair of disposable filter holders, and then the filter set would be assembled with a volumetric sample container to filter the microorganism in water samples. After the sampling process, the used filter holder with microbes on the membrane would be taken out and conserved in a preservation buffer, which could protect the DNA/RNA molecules inside the cells. When these filter holders were transported to a remote laboratory, the sample preparation cassette will be used in the on-site extraction of the DNA/RNA from the cells on the membrane. At last, the eluate was made for further identification, i.e. NASBA tests. Eight kinds of candidate membrane filters were evaluated in the kit, and the function of the kit was verified.
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Authors: Marta Harničárová, Jan Valíček, Jana Müllerová, Milena Kušnerová, Radovan Grznárik, Pavel Koštial
Abstract: Laser - cut quality is mainly characterized by a degree of accuracy in shape, size and also by surface layer conditions after cutting associated with surface roughness. An experimental determination of surface tension (or tensor components) of clean metal surfaces is very difficult and there is no direct method for its measurement. Attention was paid to numerical derivation of surface tensions according to the surface topographical features in laser cutting technology. The surface tensions and temperature dependencies of several metallic materials have been determined and confirmed by data obtained from the literature. It was found to be in very good agreement between our results and data from different sources in the literature.
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Authors: Wim Serruys
Abstract: Three different and complementary ways of adaptive control are presented, each working on a different time scale. All three of them are made possible due to evolutions and developments in CNC controls. The first and most popular way of adaptive control is adaptive process control. Since the process variables in sheet metal equipment change significantly in milliseconds, the control loop must also perform on a sub second time scale. The second adaptive loop is adaptive production control. Modern CNC controls know what they are manufacturing and talk with higher production software. Instead of just executing a planning that came top down, the CNC has enough knowledge of its environment that it can propose an intelligent job sequence and hence react more effectively on unforeseen situations. These adaptive loops perform on a time scale of hours and days. The third adaptive loop is adaptive resource control. To produce sheet metal parts, we need several kinds of resources: human resources, material, consumables, energy and equipment. CNC sheet metal equipment is a considerable investment. However most production managers do not know how effective their resources are being used. By applying the principles of overall equipment effectiveness, we can close the resource control loop. This loop performs on a time scale of weeks and months.
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Authors: Xiao You Zhang, De Qiang Chu, Tadahiko Shinshi, Teruaki Fukuoka, Takahiro Nakai
Abstract: This paper describes an adaptive control method for a magnetic drive actuator that used for the laser cutting to realize high speed and high accuracy machining. Firstly, a zero bias current method and a nonlinear compensator are examined and used for the actuator. Secondly, an adative control method is presented. Finally, the coefficient of the gap-current-force is estimated and the effectiveness of the presented control method is verified by experiments. The experimental results show that the coefficient of the gap-current-force reduces exponentially depending on the increase in the length of the air gap. By using the adaptive control, the peak-to-peak vibration amplitude of the lens holder is reduced from 1.95um to 1.55um.
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Authors: Shi De Wu, Ze Yu Ma, Jing Feng Yang
Abstract: Designed a method based on the complexity of multiple nested parts to extract and analyze the information of parts. In order to simplify the algorithm and improve the efficiency of the program, a data structure stored all information of entities was presented. The theory of the region method was introduced in this paper, and a specific algorithm was designed to judge the nested relationship between contours by using this theory and entities information. Finally, the computational result can be used to determine the contour cutting order.
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Authors: M. Masur, F. Liébana, U. Stute
Abstract: At present, small and medium-sized enterprises (SME) in the sheet metal industry performing 3-d laser cutting have to invest a considerable amount of time in offer preparation, although there is a low probability of obtaining the order. The offer calculation is mostly done manually and rapidly, as estimation. For example, the length of the contours to be cut are extracted from drawings and summed up. The actual production time for problem areas of the workpiece geometry like sharp angles and narrow radii can only be calculated by a post-processor simulation, or by a comparison with a similar workpiece that was manufactured before. This complicates the cost calculation and adds an unknown factor to it. Therefore, only experienced employees can estimate the costs for the cutting of 3-d workpieces. The aim of the proposed automatic cost calculation algorithm is the quick machining time calculation for 3-d laser cutting. Less experienced persons should be able to use a pre-configured tool. Characteristic numbers are generated on the basis of the workpiece geometry. They describe all necessary machine work that is required to manufacture the current workpiece. In a next step, the dynamic machine behaviour for these problem areas needs to be examined. It is projected to specific machine parameters. As example the acceleration and the maximum cutting velocity are basic parameters. By connecting the characteristic numbers with the machine parameters, the machining time for a specific machine is calculated. This machining time is an important factor for the cost calculation. The characteristic numbers can also be used to find similar workpieces within a database. This database contains existing and already evaluated offers. As a plausibility check the user can search for similar offers and compare them with the currently prepared one.
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Authors: Jun Hu, Fan Deng, Xian Chen Qiu
Abstract: This paper proposed an optimized algorithm for discretization of cutter location points on the laser cutting path of three-dimensional surface. The initial discretization step size was calculated due to the curvature of the curve on the starting point and accuracy requirements. A reference sphere was established by taking the initial discretization step size as the radius. The initial cutter location point was located on the intersection of the reference sphere and the processing path. The radius of reference sphere was dynamically adjusted by dichotomy according to string height difference in order to get the optimal cutter location on the path to be processed. This algorithm has a high computational efficiency. And an automatic programming software used for three-dimensional laser cutting was developed based on this algorithm.
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Authors: Imed Miraoui, Mohamed Boujelbene, Emin Bayraktar
Abstract: In the present study, high-power CO2 laser cutting of steel plates has been investigated and the effect of the input laser cutting parameters on the cut surface quality is analyzed. The average roughness of the cut surface of the specimens, produced by different laser beam diameter and laser power, were measured by using roughness tester. The scanning electron microscopy SEM is used to record possible metallurgical alterations on the cut edge. The aim of this work is to investigate the effect of laser beam diameter and laser power on the cut surface roughness and on the heat affected zone width HAZ of steel plates obtained by CO2 laser cutting. An overall optimization was applied to find out the optimal cutting setting that would improve the cut surface quality. It was found that laser beam diameter has a negligible effect on surface roughness but laser power had major effect on roughness. The cut surface roughness decreases as laser power increases. Improved surface roughness can be obtained at higher laser power. Also, laser beam diameter and laser power had major effect on HAZ width. It increases as laser power increases.
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