scholarly journals Lz-Transform Method and Markov Reward Approach for Flexible Manufacturing System Performance Evaluation

2019 ◽  
Vol 9 (19) ◽  
pp. 4153
Author(s):  
Wenbin Zeng ◽  
Guixiang Shen ◽  
Bingkun Chen ◽  
Ilia Frenkel ◽  
Igor Bolvashenkov ◽  
...  

This article presents a performance evaluation of a flexible manufacturing system (FMS), in which the system and its components can have different performance levels ranging from perfect functioning to total failure. An original multistate transition process for the FMS’s main component, Computerized Numerical Control (CNC) machine tools, proposed in the current article and treated as an aging process because of its increasing failure rate is investigated. The Markov reward approach is utilized to analyze the availability of CNC machine tools and sensitivity analysis of each non-operational state to the machine’s downtime. To overcome the “state explosion problem” in the subsequent FMS performance evaluation process, an application of the Lz-transform method is proposed to determine the performance evaluation and availability of such aging multistate FMS. An illustrated case is presented to demonstrate the performance evaluation process. The results show that the suggested methods can be implemented in engineering decision making and construction of various aging multistate FMS related to demands, availability, and output performance.

Author(s):  
P Vichare ◽  
A Nassehi ◽  
S Newman

The capability of any manufacturing system primarily depends on its available machine tools. Thus machine tool representation is a vital part of modelling any manufacturing system. With the rapid advances in computerized numerically controlled (CNC) machines, machine tool representation has become a more challenging task than ever before. Today's CNC machine tools are more than just automated manufacturing machines, as they can be considered multi-purpose, multi-tasking, and hybrid machining centres. This paper presents a versatile methodology for representing such state-of-the-art CNC machining system resources. A machine tool model is a conceptual representation of the real machine tool and provides a logical framework for representing its functionality in the manufacturing system. There are several commercial modelling tools available in the market for modelling machine tools. However, there is no common methodology among them to represent the wide diversity of machine tool configurations. These modelling tools are either machine vendor specific or limited in their scope to represent machine tool capability. In addition, the current information models of STEP-NC, namely ISO 14649, can only describe machining operations, technologies, cutting tools, and product geometries. However, they do not support the representation of machine tools. The proposed unified manufacturing resource model (UMRM) has a data model which can fill this gap by providing machine specific data in the form of an EXPRESS schema and act as a complementary part to the STEP-NC standard to represent various machine tools in a standardized form. UMRM is flexible enough to represent any type of CNC machining centre. This machine tool representation can be utilized to represent machine tool functionality and consequential process capabilities for allocating resources for process planning and machining.


Author(s):  
Roberto Pérez ◽  
Arturo Molina ◽  
Miguel Ramírez-Cadena

In the present, the technology related to the micro/meso manufacturing is promising as a key enabling technology for maximizing high value manufacturing. This paper addresses a new methodology to design reconfigurable micro/mesoscale CNC machine tools in the integrated product, process, and manufacturing system development context. This is followed by a description of the design of a reconfigurable two-axis first-generation test bed CNC micromachine tool that was developed to assess the feasibility of the new design method. The test bed utilizes a high-speed miniature spindle that is required to obtain appropriate cutting velocities for the efficient cutting of metals, use micro-actuators for the axis movements and open-architecture controllers, in order to guarantee the reconfigurability properties of the micromachine. Results indicate the new methodology enhances the design of reconfigurable micro/mesoscale CNC machine tools in the integrated product, process, and manufacturing system development context, following the prescriptive models of design.


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