| 1. |
- Lagö, Thomas L, et al.
(författare)
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Design of an Efficient Chatter Control System For Turning and Boring
- 2002
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Konferensbidrag (refereegranskat)abstract
- In the turning operation chatter or vibration is a frequent problem, which affects the result of the machining, and, in particular, the surface finish. Tool life is also influenced by vibration. Severe acoustic noise in the working environment frequently occurs as a result of dynamic motion between the cutting tool and the workpiece. In all cutting operations like turning, boring and milling vibrations are induced due to the deformation of the workpiece. This implies several disadvantages, economical as well as environmental. Many different solutions to minimize the problem have been developed but the fundamental problem is still there. The true nature of the vibrations, its causes, and implications were revealed in a doctor’s thesis in 1999. This has led to a break through in this research area. Since then, through recent research results at Blekinge Institute of Technology, a new approach to controlling vibrations in cutting operations in a lathe has been implemented in a product called ActicutTM, developed by Active Control Sweden AB. This new method controls vibrations in the cutting direction.
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| 2. |
- Lagö, Thomas L, et al.
(författare)
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Performance of a Chatter Control System for Turning and Boring Applications
- 2002
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Konferensbidrag (refereegranskat)abstract
- In the turning operation chatter or vibration is a frequent problem, which affects the result of the machining, and, in particular, the surface finish. Tool life is also influenced by vibration. Severe acoustic noise in the working environment frequently occurs as a result of dynamic motion between the cutting tool and the workpiece. In all cutting operations like turning, boring and milling vibrations are induced due to the deformation of the workpiece. This implies several disadvantages, economical as well as environmental. Many different solutions to minimize the problem have been developed but the fundamental problem is still there. The true nature of the vibrations, its causes, and implications were revealed in a doctor’s thesis in 1999, [1]. This has led to a break through in this research area. Since then, through recent research results at Blekinge Institute of Technology, a new approach to controlling vibrations in cutting operations in a lathe has been implemented in a product called Acticut®, developed by Active Control Sweden AB. This new method controls vibrations in the cutting direction using embedded sensors and actuators and a filtered-x LMS algorithm. This paper will discuss the application but also the algorithm and its main numerical properties to accomplish a good result, still maintaining its stability properties.
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| 3. |
- Pettersson, Linus, et al.
(författare)
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Active Control of Boring Bar Vibrations in Cutting Operations
- 2002
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Konferensbidrag (refereegranskat)abstract
- Internal turning or boring operations have a history of being a cumbersome manufacturing process. The manufacturing industries are facing tougher tolerances of their product surfaces and a desire to process hard to cut materials and therefore the vibrations must be kept to a minimum. An increase in the productivity is also interesting from a production point of view. When cutting in pre-drilled holes the boring bar is usually long and slender and is thereby inclined to vibrate destructively concerning the machining result. The knowledge of the vibrations involved in boring operations and active control of external turning operations, have given a good basis for the active control solution in boring operations. The active control solution is based on a standard boring bar with an embedded piezo ceramic actuator placed at the peak modal strain of the boring bar. An accelerometer is also included in the design, mounted as close as possible to the cutting tool. The control algorithm is a filtered X LMS algorithm built on a feedback approach since the original excitation, the cutting process, cannot be observed directly. Preliminary results show reduction of the vibration in the boring bar by up to 30dB.
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| 4. |
- Pettersson, Linus, et al.
(författare)
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Active Control of Internal Turning Operations Using a Boring Bar
- 2002
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Konferensbidrag (refereegranskat)abstract
- Vibrations in internal turning or boring operations are usually a cumbersome part of the manufacturing process. The manufacturing industries are having problems with these kinds of cutting operations. When cutting in pre-drilled holes the cross sectional area of the boring bar is limited at the same time as it is long. Since a general boring bar is long and slender it is sensitive to external excitation and thereby inclined to vibrate. The vibration problem affects the surface finish in particular. The demand for smaller and smaller tolerances of the surface finish leads to that the manufacturing industry seeks for a solution to the boring bar vibration problem. The tool life is also likely to be influenced by the vibrations involved in a cutting operation. Another problem in boring operations is the high noise level in the cutting process. The noise level in the environment of the operators is today more and more regulated, especially in the western world. Active vibration control will reduce the amount of vibrations in the cutting operations. Since the noise is induced by the vibration of the boring bar, the noise level will also be reduced due to the cancellation of the noise source. Preliminary results show reduction of vibrations in the boring bar by up to 30dB.
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| 5. |
- Pettersson, Linus, et al.
(författare)
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Active Control of Machine-Tool Vibration in a CNC Lathe Based on an Active Tool Holder Shank with Embedded Piezo Ceramic Actuators
- 2001
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Konferensbidrag (refereegranskat)abstract
- In the turning operation chatter or vibration is a frequent problem affecting the result of the machining, and, in particular, the surface finish. Tool life is also influenced by vibration. Severe acoustic noise in the working environment frequently occurs as a result of dynamic motion between the cutting tool and the workpiece. These problems can be reduced by active control of machine-tool vibration. However, machine-tool vibration control systems are usually not applicable to a general lathe and turning operation. The physical features and properties of the mechanical constructions or solutions involved regarding the introduction of secondary vibration usually limit their applicability. An active control solution for a general lathe application has been developed. It is based on a standard Industry tool holder with an embedded piezo ceramic actuator and an adaptive feedback controller. The adaptive controller is based on the well known filtered-x LMS-algorithm. It enables substantial reduction of the vibration level by up to 40 dB at 3.4 kHz.
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| 6. |
- Pettersson, Linus, et al.
(författare)
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Active Control of Machine-Tool Vibration in Cutting Operations in a General Lathe
- 2001
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Konferensbidrag (refereegranskat)abstract
- In the general lathe the turning operation chatter or vibration is a frequent problem affecting the result of the machining, and, in particular, the surface finish. Tool life is also influenced by vibration. Severe acoustic noise in the working environment frequently occurs as a result of dynamic motion between the cutting tool and the workpiece. These problems can be reduced by active control of machine-tool vibration. In a general lathe the physical features and properties of an ctive control system usually limit their applicability. By using piezo ceramic actuators some constraints regarding the mechanical construction of the active tool holder can be circumvented. An active control solution for a general lathe application has been developed. It is based on a standard industry tool holder with an embedded piezo ceramic actuator and an adaptive feedback controller. The adaptive controller is based on the well known filtered-x LMS-algorithm. It enables substantial reduction of the vibration level by up to 40 dB at 3.4 kHz.
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| 7. |
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| 8. |
- Pettersson, Linus, et al.
(författare)
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Adaptive Control of Machine-Tool Vibration Based on an Active Tool Holder Shank with an Embedded Piezo Ceramic Actuator
- 2001
-
Konferensbidrag (refereegranskat)abstract
- In the turning operation chatter or vibration is a common problem affecting the result of the machining, and, in particular, the surface finish. Tool life is also influenced by vibration. Severe acoustic noise in the working environment frequently occurs as a result of dynamic motion between the cutting tool and the workpiece. These problems can be reduced by active control of machine-tool vibration. However, machine-tool vibration control systems are usually not applicable to a general lathe and turning operation. The physical features and properties of the mechanical constructions or solutions involved regarding the introduction of secondary vibration usually limt their applicability. An adaptive active control solution for a general lathe application has been developed. It is based on a standard industry tool holder shank with an embedded piezo ceramic actuator and an adaptive feedback controller. The adaptive controller is based on the well known filtered-x LMS-algorithm. It enables substantial reduction of the vibration level by up to 40 dB at 3.4 kHz.
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