Today＇s production systems are demanded to exhibit an increased flexibility and mutability in order to deal with dynamically changing conditions, objectives and an increasing number of product variants within industr...Today＇s production systems are demanded to exhibit an increased flexibility and mutability in order to deal with dynamically changing conditions, objectives and an increasing number of product variants within industrial turbulent environments. Flexible automated systems are requested in order to improve dynamic production efficiency, e.g. robot-based hardware and PC-based controllers, but these usually induce a significantly higher production complexity, whereby the efforts for planning and programming, but also setups and reconfiguration, expand. In this paper a definition and some concepts of self-optimizing assembly systems are presented to describe possible ways to reduce the planning efforts in complex production systems. The concept of self-optimization in assembly systems will be derived from a theoretical approach and will be transferred to a specific application scenario---the automated assembly of a miniaturized solid state laser--where the challenges of unpredictable influences from e.g. component tolerances can be overcome by the help of self-optimization.展开更多
With hard turning, which is an attractive alternative to existing grinding processes, surface quality is of great importance. Signal processing techniques were used to relate workpiece surface topography to the dynami...With hard turning, which is an attractive alternative to existing grinding processes, surface quality is of great importance. Signal processing techniques were used to relate workpiece surface topography to the dynamic behavior of the machine tool. Spatial domain frequency analyses based on fast Fourier transform were used to analyze the tool behavior. Wavelet reconstruction was used for profile filtering. The results show that machine vibration remarkably affects the surface topography at small feed rates, but has negligible effect at high feed rates. The analyses also show how to control the surface quality during hard turning.展开更多
The classical design of experiments （DOE） method can optimize systems with one technical response and multiple inputs. The objective of this study is to optimize multiple technical responses at the same time by inte...The classical design of experiments （DOE） method can optimize systems with one technical response and multiple inputs. The objective of this study is to optimize multiple technical responses at the same time by integrating fuzzy logic transformation into a DoE system. The transformation from technical responses to the individual fuzzy responses and the overall fuzzy response are first defined, and the fuzzy response system is established. The method used to optimize the overall fuzzy response is introduced and discussed. The results show that the established fuzzy response system can optimize systems with multiple technical responses and multiple inputs.展开更多
The experimental determination of stability lobediagrams （SLDs） in milling can be realized by eithercontinuously varying the spindle speed or by varying thedepth of cut. In this paper, a method for combining boththe...The experimental determination of stability lobediagrams （SLDs） in milling can be realized by eithercontinuously varying the spindle speed or by varying thedepth of cut. In this paper, a method for combining boththese methods along with an online chatter detectionalgorithm is proposed for efficient determination of SLDs.To accomplish this, communication between the machinecontrol and chatter detection algorithm is established, andthe machine axes are controlled to change the spindle speedor depth of cut. The efficiency of the proposed method isanalyzed in this paper.展开更多
For precision machining, the hard turning process is becoming an important alternative to some of the existing grinding processes. This paper presents an analytical model for predicting cutting forces in hard turning ...For precision machining, the hard turning process is becoming an important alternative to some of the existing grinding processes. This paper presents an analytical model for predicting cutting forces in hard turning of 51CRV4 with hardness of 68 HRC. The cutting tool used is made from cubic boron nitride （CBN） with a wiper cutting edge. Formulas for differential chip loads are derived for three different situations, depending on the radial depth of cut. The cutting forces are determined by integrating the differential cutting forces over the tool-workpiece engagement domain. For validation, cutting forces predicted by the model were compared with experimental measurements, and most of the results agree quite well.展开更多
文摘Today＇s production systems are demanded to exhibit an increased flexibility and mutability in order to deal with dynamically changing conditions, objectives and an increasing number of product variants within industrial turbulent environments. Flexible automated systems are requested in order to improve dynamic production efficiency, e.g. robot-based hardware and PC-based controllers, but these usually induce a significantly higher production complexity, whereby the efforts for planning and programming, but also setups and reconfiguration, expand. In this paper a definition and some concepts of self-optimizing assembly systems are presented to describe possible ways to reduce the planning efforts in complex production systems. The concept of self-optimization in assembly systems will be derived from a theoretical approach and will be transferred to a specific application scenario---the automated assembly of a miniaturized solid state laser--where the challenges of unpredictable influences from e.g. component tolerances can be overcome by the help of self-optimization.
基金Supported by the DAAD (German Academic Exchange Service)
文摘With hard turning, which is an attractive alternative to existing grinding processes, surface quality is of great importance. Signal processing techniques were used to relate workpiece surface topography to the dynamic behavior of the machine tool. Spatial domain frequency analyses based on fast Fourier transform were used to analyze the tool behavior. Wavelet reconstruction was used for profile filtering. The results show that machine vibration remarkably affects the surface topography at small feed rates, but has negligible effect at high feed rates. The analyses also show how to control the surface quality during hard turning.
基金Supported by the Quality Management Group, WZL, RWTH Aachen University
文摘The classical design of experiments （DOE） method can optimize systems with one technical response and multiple inputs. The objective of this study is to optimize multiple technical responses at the same time by integrating fuzzy logic transformation into a DoE system. The transformation from technical responses to the individual fuzzy responses and the overall fuzzy response are first defined, and the fuzzy response system is established. The method used to optimize the overall fuzzy response is introduced and discussed. The results show that the established fuzzy response system can optimize systems with multiple technical responses and multiple inputs.
文摘The experimental determination of stability lobediagrams （SLDs） in milling can be realized by eithercontinuously varying the spindle speed or by varying thedepth of cut. In this paper, a method for combining boththese methods along with an online chatter detectionalgorithm is proposed for efficient determination of SLDs.To accomplish this, communication between the machinecontrol and chatter detection algorithm is established, andthe machine axes are controlled to change the spindle speedor depth of cut. The efficiency of the proposed method isanalyzed in this paper.
基金Supported by the DAAD (German Academic Exchange Service) on its exchange student program
文摘For precision machining, the hard turning process is becoming an important alternative to some of the existing grinding processes. This paper presents an analytical model for predicting cutting forces in hard turning of 51CRV4 with hardness of 68 HRC. The cutting tool used is made from cubic boron nitride （CBN） with a wiper cutting edge. Formulas for differential chip loads are derived for three different situations, depending on the radial depth of cut. The cutting forces are determined by integrating the differential cutting forces over the tool-workpiece engagement domain. For validation, cutting forces predicted by the model were compared with experimental measurements, and most of the results agree quite well.
