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- Åkesson, Henrik, et al.
(författare)
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A First Prototype of an Active Boring Bar Tested in Industry
- 2006
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Metal cutting is a common process in the manufacturing industry. Vibration problem during metal cutting is a reality for these manufactures. The vibration level depends on many different parameters such as material type, dimensions of the workpiece and boring bar, cutting data and operation mode. Internal cutting is one of the most troublesome operation modes, without any continuous monitoring and control from an operator grave vibration levels quickly arises. From the industry point of view this is an expense in the production line. The reduced tool life and the coarse surface finishing caused by the large vibration will force the operator to stop the cutting process, either to change tool when it is broken or change cutting data like decreasing the cutting depth. Any interference like this increases the working time for each component tremendous. These problems have been located and examined in an industry producing and renovating components using a lathe. One lathe was chosen for further investigation by experimental modal analysis and analysis during operational mode. The examination was done in an environment with machining processes in full operation mode and also during non-working ours. After analyzing the problem different solution where scrutinized and a first prototype where constructed. The solution to the problem is an active boring bar. This paper will present the procedure from analyzing a problem in industry to the test of the first prototype of the solution.
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| 5. |
- Åkesson, Henrik, et al.
(författare)
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Active Boring Bar Prototype Tested in Industry
- 2006
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Metal cutting processes are common in the manufacturing industry. Vibration problems during metal cutting are a degrading reality in the manufacturing industry and have a negative impact on the productivity and increase’s the production costs. The vibration level depends on many different parameters such as material type, dimensions of the workpiece, tool, tooling structure, machine structure, the cutting data and operation mode. Internal turning is one of the most troublesome operation modes concerning vibration. It generally requires that extra care must be taken with pro-duction planning and in the preparations for the machining of a workpiece. Frequently, continuous monitoring and control by a skilled operator is required to avoid grave degrading vibration levels. The reduced tool life and the coarse surface finishing generally caused by large vibration levels will e.g. force the operator to stop the cutting process, either to change tool when it is broken or change cutting data like decreasing the cutting depth. Any interference like this increases the production time and cost for each component tremendously. In an industry producing and renovating compo-nents using different machine tools, a particular lathe used for internal turning of certain details with extensive vibration problem was chosen for further investigation by experimental modal analysis and vibration analysis during operation. The examination was done in an environment with ma-chine tools in full operation and also during non-working ours. After analyzing the problem different solutions for the reduction of the vibration problem was investigated and subsequently a first proto-type was constructed. The solution to the problem is active control of the tool vibration using an active boring bar. This paper will present the procedure from analyzing a problem in industry to the test of the first prototype of the solution.
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- Åkesson, Henrik, et al.
(författare)
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Analysis of Dynamic Properties of Boring Bars Concerning Different Clamping Conditions
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The boring bar is one of the most widely used type of tool holders in metal cutting operations. The turning process subjects the tool to vibrations, and cutting in deep workpiece cavities is likely to result in high vibration levels. The consequences of such vibration levels generally results in: reduced tool life, poor surface finishing and disturbing sound. Internal turning frequently requires a long and slender boring bar in order to machine inside a cavity, and the vibrations generally become highly correlated with one of the fundamental bending modes of the boring bar. Different methods can be applied to reduce the vibrations, the implementation of the most efficient and stable methods require in depth knowledge concerning the dynamic properties of the tooling system. Furthermore, the interface between the boring bar and the clamping house has a significant influence on the dynamic properties of the clamped boring bar. This report focuses on the dynamic properties of a boring bar that arise under different clamping conditions of the boring bar and are introduced by a clamping house (commonly used in the manufacturing industry). The dynamic properties of a boring bar (for different cases of boundary condition of the boring bar) are presented partly analytically but also experimentally.
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| 7. |
- Åkesson, Henrik, et al.
(författare)
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Dynamic Properties of Tooling Structure : Hydraulic Clamping versus Standard Screw Clamping in a Lathe Application
- 2008
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During turning, the metal deformation process excites the tooling structure and may result in high and degrading tool vibration levels. In internal turning the boring bar is generally the weakest link of the tooling structure. The boundary conditions imposed on the boring bar by the clamping housing influence the dynamic properties of a clamped boring bar. The dynamic properties of a clamped boring bar have been investigated for two different clamping housings; one that clamps the boring bar by means of hydraulic pressure and one that clamps the boring bar by means of clamping screws. Both experimental and analytical methods have been utilized in the investigation.
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- Åkesson, Henrik, et al.
(författare)
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Investigation of the Dynamic Properties of a Milling Tool Holder
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vibration problems during metal cutting occur frequently in the manufacturing industry. The vibration level depends on many different parameters such as the material type, the dimensions of the workpiece, the rigidity of tooling structure, the cutting data, and the operation mode. In milling, the cutting process subjects the tool to vibrations, and having a milling tool holder with a long overhang will most likely result in high vibration levels. As a consequence of these vibrations, the tool life is reduced, the surface finishing becomes poor, and disturbing sound appears. In this report, an investigation of the dynamic properties of a milling tool holder with moderate overhang has been carried out by means of experimental modal analysis and vibration analysis during the operating mode. Both the angular vibrations of the rotating tool and the vibrations of the machine tool structure were examined during milling. Also, vibration of the workpiece and the milling machine was examined during cutting. This re- port focuses on identifying the source/sources of the dominant milling vibration components and on determining which of these vibrations that are related to the structural dynamic properties of the milling tool holder.
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| 9. |
- Åkesson, Henrik, et al.
(författare)
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Investigation of the Dynamic Properties of a Passive Damped Boring Bar
- 2008
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Vibration problem during metal cutting is a degrading reality in the manufacturing industry and have a negative impact on the productivity which increases the over all production costs. Sometimes it’s also impossible to achieve the required tolerances. Different methods can be applied to reduce the vibrations, for example by using passively tuned damper or active control. This paper examines the dynamic properties of a boring bar with passive tuned damper, aiming on enhanced vibration con-trol combining passive control and active control. By combining these two methods it is likely that the performance of the passive tuned damper will be enhanced in the sense of wider working range with respect to cutting parameters and materials of workpieces. However, implementation of effi-cient and stable methods requires in-depth knowledge concerning the dynamic properties of the tooling system. The examination of the passive boring bar covers a wide range of cutting parame-ters and the main classes of workpiece materials. This is the first step in the development of a bor-ing bar involving two technologies complementing each other, that is, passive tuned damper and active control which is an already patented technology.
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