scholarly journals Thin-walled parts flexible fixture system rigid positioning support research

Author(s):  
Yong Chen ◽  
Yongmin Jiang
2013 ◽  
Vol 579-580 ◽  
pp. 670-674
Author(s):  
Chu Xiong Xie ◽  
Chun Fu Gao ◽  
Xin Sheng He ◽  
Zuo Cai Dai

As for the shortcomings of poor rigidity and strength of weak of thin-walled tube parts, a device of an adaptive PID controller which based on neural network has been proposed by regarding the thin-walled tube fixture system as the research object. The controller which integrates the characteristics of neural network and PID regulator can realize the self-tuning of PID parameters effectively and make the control system equip with the feature of fast response, small overshoot and strong robustness etc. Simulation results show that the controller can meet the system requirements commendably and it can implement the automatic chucking control of the thin-walled steel cutting process with fast and non-destructive in the experimental prototype.


2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Jinjie Jia ◽  
Yuwen Sun ◽  
Jinbo Niu

Auxiliary fixtures are widely used to enhance the rigidity of cylindrical thin-walled workpieces (CTWWs) in the machining process. Nevertheless, the accurate and efficient prediction of frequency response function (FRF) for the workpiece-fixture system remains challenging due to the complicated contact constraints between workpiece and fixture. This paper proposes an analytical solution for the comprehensive FRF analysis of the CTWW-fixture system. Firstly, based on the vector mechanics, the mode shape functions of the workpiece are presented using the classical theory of thin shell. The variable separation method is utilized to deal with the inter-mode coupling of the workpiece. Secondly, the motion equation of the CTWW with fixture constraints is established using analytical mechanics from the viewpoint of energy balance. Finally, the FRFs of the CTWW-fixture system are derived by means of modal superposition. Experimental modal tests verify that the predicted FRFs are in good agreement with the measured curves.


2021 ◽  
Author(s):  
Xiaohua Zhu ◽  
Yao Zhang ◽  
Tian Li ◽  
Liangliang Dong ◽  
Junlei Tang ◽  
...  

Abstract Combustion chamber casing is a key component of aeroengine, because of its poor rigidity, severe chattering occurs during milling, which seriously affects the surface quality and processing efficiency of the casing, and the existence of geometric nonlinear problems in the machining process makes it difficult to predict machining vibration. Therefore, it is of great significance to study the vibration law of thin-walled casing and reduce machining vibration. Aiming at the problem of vibration control of thin-walled casing, this paper proposes a new type of gasbag-rubber damping flexible fixture, which differ from the ordinary rigid fixture, this fixture has adjustable clamping force and good vibration damping ability. The key factors affecting the vibration response of the thin-walled casing are studied through establishing an equivalent dynamic model of the workpiece-fixture system. The research results show that the gasbag-rubber damping flexible fixture can effectively provide support stiffness, which is beneficial to reduce the vibration of the workpiece during processing; According to the actual thickness of different workpieces, the appropriate gasbag pressure is recommended to give play to the vibration damping performance of the fixture; It is recommended that the thickness of the rubber damping block in practice is 8~12mm. The research work in this paper has important guiding significance for the design and use of the gasbag-rubber damping flexible fixture, and provides an effective theoretical prediction for the vibration of the thin-walled casing.


Author(s):  
Ze Liu ◽  
Yu Sun ◽  
Yu Wang

Abstract The machining vibration of thin-walled parts affects the quality of the products. Thus, this paper proposes a new alternative support fixture system for vibration suppression of thin-walled parts. The system includes two movable supporting heads, which are periodically repositioned along the machining path in the form of alternating support to support the area close to the cutter, so as to improve the rigidity of the actual machining position of the thin-walled part. Around this new system, a dynamic model is established to analyze the workpiece vibration. Takeing as an example simply suppoted thin-plate, the influence of the supporting head’s location, stiffness coefficient and damping coefficient on vibration suppression are numerically analyzed in this paper. The result of the simulation demonstrates the alternative support fixture system is effective in vibration suppression of thin-walled parts.


Sign in / Sign up

Export Citation Format

Share Document