State space modelling of variation propagation in multistage machining processes for variable stiffness structure workpieces

Author(s):  
Kun Wang ◽  
Guilong Li ◽  
Shichang Du ◽  
Lifeng Xi ◽  
Tangbin Xia
2010 ◽  
Vol 36 ◽  
pp. 120-128 ◽  
Author(s):  
Z.J. Wen ◽  
Ping Yu Zhu ◽  
X.P. Zhang ◽  
H.C. Liu

A new state space model of multi-operational machining processes is presented for dimensional variation propagation, transformation and accumulation based on perturbation vectors (PV). Taking perturbation vectors (PV) for state vectors of part geometric variaton and the fixture variations for input vectors, the perturbation homogeneous transformation (PHT) is applied to analyze and derivate datum-induced deviation, re-location deviation, fixture error and machining error, and a state space model of variation propagation in multi-operational complicated machining processes is developed. Furthermore, a three-operation machining process of cylinder is given to illustrate the method presented. With the results of calculation and simulation, it is verified that the proposed model is effective and useful.


Author(s):  
Hui Wang ◽  
Qiang Huang ◽  
Reuven Katz

Variation propagation modeling has been proved to be an effective way for variation reduction and design synthesis in multi-operational manufacturing processes (MMP). However, previously developed approaches for machining processes did not directly model the process physics regarding how fixture, and datum, and machine tool errors generate the same pattern on part features. Consequently, it is difficult to distinguish error sources at each operation. This paper formulates the variation propagation model using the proposed equivalent fixture error (EFE) concept. With this concept, datum error and machine tool error are transformed to equivalent fixture locator errors at each operation. As a result, error sources can be grouped and root cause identification can be conducted in a sequential manner. The case studies demonstrate the model validity through a real cutting experiment and model advantage in measurement reduction for root cause identification.


2011 ◽  
Vol 130-134 ◽  
pp. 2573-2576
Author(s):  
Yan Wang ◽  
Ping Yu Jiang

This paper presents a type of architecture of multistage machining processes in small batch mode, named Small-batch Quality Control System (SQCS), through analyzing various process quality control methods. The SQCS integrates complex network, workpiece variation propagation model and process quality prediction. And then, the three key enabling technologies are discussed in detail. Sensor network could be used to acquire real-time quality data, which include workpieces’ physical and dimensional information. Based on the above mentioned ideas, a general model of stage flow in small batch mode is constructed in order to realize process-driven online quality control and improve product machining quality.


2020 ◽  
Vol 111 (9-10) ◽  
pp. 2987-2998
Author(s):  
Filmon Yacob ◽  
Daniel Semere

Abstract Variation propagation models play an important role in part quality prediction, variation source identification, and variation compensation in multistage manufacturing processes. These models often use homogenous transformation matrix, differential motion vector, and/or Jacobian matrix to represent and transform the part, tool and fixture coordinate systems and associated variations. However, the models end up with large matrices as the number features and functional element pairs increase. This work proposes a novel strategy for modelling of variation propagation in multistage machining processes using dual quaternions. The strategy includes representation of the fixture, part, and toolpath by dual quaternions, followed by projection locator points onto the features, which leads to a simplified model of a part-fixture assembly and machining. The proposed approach was validated against stream of variation models and experimental results reported in the literature. This paper aims to provide a new direction of research on variation propagation modelling of multistage manufacturing processes.


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