Reconfigurable Machine Research Articles

Development of part families for a reconfigurable machine

Purpose Reconfigurable machines tools (RMTs) are gaining momentum as the new solutions to customised products in the manufacturing world. The driving force, among others, behind these machines is the part envelope and the part family of products that they can produce. The purpose of this paper is to propose a new class of RMT known as a reconfigurable guillotine shear and bending press machine (RGS&BPM). A part family of products that this machine can produce is developed using hierarchical clustering methodologies. The development of these part families is guided by the relationship of the parts in the family in terms of complexity and geometry. Design/methodology/approach Part families cannot be developed in isolation, but that process has to incorporate the machine modules used in the reconfiguration process for producing the parts. Literature was reviewed, and group technology principles explored, to develop a concept that can be used to develop the part families. Matrices were manipulated to generate part families, and this resulted in the development of a dendrogram of six possible part families. A software with a graphic user interface for manipulation was also developed to help generate part families and machine modules. The developed concept will assist in the development of a machine by first developing the part family of products and machine modules required in the variable production process. Findings The developed concepts assist in the development of a machine by first developing the part family of products and machine modules required in the variable production process. The development of part families for the RGS&BPM is key to developing the machine work envelope and modules to carry out the work. This work has been presented to demonstrate the importance of machine development in conjunction with a part family of products that the machine will produce. The paper develops an approach to manufacturing where part families of products are developed prior to developing the machine. The families of products are then used to develop modules that enable the manufacture of the parts and subsequently the size of the machine. Research limitations/implications The research was limited to the development of part families for a new RGS&BPM, which is still under development. Practical implications The study reflects the development of reconfigurable machines as a solution to manufacturing challenges in terms of group technology approaches adopted in the design phase. It also highlights the significance of the concepts in the reconfigurable machine tool design. The part families define the machine work envelop and its reconfiguration capability. Social implications The success of the research will usher an alternative to smaller players in sheet metal work. It will contribute to the easy development of the machine that will bridge the high cost of machine tools. Originality/value The study contributes to the new approach in sheet metal manufacturing where dedicated machines may be substituted by a highly flexible reconfigurable machine that has a dual operation, making the investment for small to medium enterprises affordable. It also contributes to the body of knowledge in reconfigurable machine development and the framework for such activities, especially in developing countries.

Sequential optimisation of reconfigurable machine cell feeders and production sequence during lean assembly

ABSTRACTThis paper presents a manufacturing model for integrating reconfigurable machine cells as feeders of components to a multi-product assembly line exhibiting a prominent lean characteristic; synchronisation with Takt time. Two mathematical formulations in the form of combinatorial optimisation problems are developed to identify the best reconfiguration for the machines by optimum selection of the modules in the cells to minimise the total error with Takt time and then the optimum sequence of assembling the products to minimise the total reconfiguration time and effort. An elitist genetic algorithm (GA) meta-heuristic is employed twice in succession to search the optimal solutions for both the minimisation problems. The best machine configuration found from the first search is utilised further to identify the optimal assembly sequence. A hypothetical data set representing the features and parameters of the model in conformance with any typical mixed-model assembly is presented for illustration of computational procedure. Synchronisation among machine cells and tardiness are considered as performance evaluation measures to validate the effectiveness of the proposed model.

Dynamic and steady-state performance analysis for multi-state repairable reconfigurable manufacturing systems with buffers

Reconfigurable manufacturing systems (RMSs) are considered the solution of choice when variable production capacity and functionality are required. A combinational approach, which integrates the steady-state probabilities of repairable reconfigurable machine tools (RMTs) and inventory-state probabilities of buffers through an improved universal generating function, is introduced in this study to assess the compound performance indicators (CPIs) of a repairable RMS. This paper contributes to the existing literature by considering the availability of buffers to calculate the CPIs of an RMS. In the proposed approach, the dynamic-state probability for each RMT is determined with a homogeneous continuous-time Markov model, and steady-state probability is obtained as the limit of the dynamic probability as time tends to infinity. In addition, a descriptive input-output information flow, which combines the conveying processes of the machined parts through buffers with the Poisson process, is proposed to determine the inventory-state probabilities of the buffers. Moreover, the explicit expressions of the CPI and expected performance rate (for the RMS and its constituent RMTs) are determined, and the validation procedure and technical details of the performance analysis for the Monte Carlo simulation are presented. Finally, a non-serial, repairable, multi-state RMS with multiple buffers that produces three types of engine cylinder heads is presented to validate the proposed approach. The simulation results verify the accuracy of the performance assessment of the RMS. It is useful for performance improvement in terms of machine reliability, resource utilisation efficiency, and decision-making concerning the configuration of RMS with buffers.

Reconfigurable machine tools: a perspective

Short life cycle of the products, large product variants and unanticipated changes in customer demand in a dynamic social context pose a significant challenge for design of an appropriate manufacturing system. Reconfigurable machine tool, which is the foundation block for reconfigurable manufacturing system is envisaged as a solution that caters to the current market forces. This paper discusses the reconfiguration mechanisms, which enable transformation of conventional machine tools, such as, drilling, lathe and milling machines into reconfigurable machines that will achieve the objectives. It is expected that, this work will help designers and practicing engineers by making them aware of the reconfiguration mechanisms, which have become a necessity for the very survival of the manufacturing sector by lowering the overall capital costs and, therefore, the per unit fixed costs.

An environmental evaluation of a milling machine range: a case study on reconfigurable approach

Purpose: The aim of this paper is to describe the adaptation process of the LCA methodology under a modular approach (LCI data and LCIA data based on modules) in parallel to a reconfigurable design (reconfigurable manufacturing system) that enables a faster and easier quantified environmental claim for a range of milling machines. Methods: Life cycle assessment (LCA) is identified as a proper tool to evaluate potential impacts of products over the environment. However, the compilation of LCA data from one or a range of milling machines could be difficult and tedious, because, firstly they are complex products, secondly the final results have to ensure a good representability and, finally, render the assessment process cost-effectively. The analysis was performed following a cradle-to-use approach. The LCA study was performed in compliance with [18] V2.0 developed in framework of the EPD® System. Results: The LCA results show that the contribution of downstream processes is the most significant in all studied impact categories, since the relative contributions are: 89% in the GWP and AP categories and 77% in the POCP and EP categories, because of the demanded electricity during the lifetime of the machines, with values greater than 94% of the impact of downstream processes. The upstream processes present a moderate contribution in the POCP and EP categories, being their relative contribution major than 20% in both of them, because of cast iron (≈ 60% in POCP) and low-alloy steel (≈ 20% in POCP) materials which form part of the structural modules as well as pumps and motors (≈ 40% in EP). Discussion and Conclusions: The study takes a holistic view of the production and consumption of a milling machine range. The case study presents the adaptation of LCA methodology for a range of milling machines, in order to develop the EPD of these products. Simultaneously the LCA calculation of 28 machine reconfigurations is achieved through 9 modules, thus reducing time efforts and costs. The weakness of the representative check is located in the inventory analysis of the use stage. A future work could include a sensitivity analysis to evaluate more user conditions.

A conceptual development of reconfigurable drill machine tool (RDMT)

Reconfigurable machine tools are emerging as new generation machine tools for dealing with the fluctuating market scenario and immense competition between original equipment manufacturers. New approaches, mechanism and designs principles are required for the development of these machine tools in manufacturing systems. A lot of research work has been done in reconfigurable machine tool (i.e. lathe, milling, shaper, NC, CNC etc.) but still less work has been conducted to develop reconfigurable drilling machine. This paper presents a modular approach to develop Reconfigurable Drilling Machine Tool, which will allow the machine not only to reconfigure the modules in a certain way for performing a specific task but also to develop a new type of machine which can incorporate all the features of reconfiguration for the production of multiple part families on a single platform. A module library, which includes basic and auxiliary modules, is implemented on this machine tool to explain the core features (i.e. scalability, modularity, convertibility and flexibility). Probably, this proposed design contributes a theoretical approach for the reconfiguration features of drilling machine in Reconfigurable Manufacturing System and this proposed design is illustrated through a figure, which is developed on design software (i.e. solid works platform).

Перестраиваемые автоматы на подстановках

Перестраиваемые автоматы на подстановках

Tightly Coupled Machine Learning Coprocessor Architecture With Analog In-Memory Computing for Instruction-Level Acceleration

Low-profile mobile computing platforms often need to execute a variety of machine learning algorithms with limited memory and processing power. To address this challenge, this work presents Coara, an instruction-level processor acceleration architecture, which efficiently integrates an approximate analog in-memory computing coprocessor for accelerating general machine learning applications by exploiting analog register file cache. The instruction-level acceleration offers true programmability beyond the degree of freedom provided by reconfigurable machine learning accelerators, and also allows the code generation stage of a compiler back-end to control the coprocessor execution and data flow, so that applications do not need high-level machine learning software frameworks with a large memory footprint. Conventional analog and mixed-signal accelerators suffer from the overhead of frequent data conversion between analog and digital signals. To solve this classical problem, Coara uses an analog register file cache, which interfaces the analog in-memory computing coprocessor with the digital register file of the processor core. As a result, more than 90% of data conversion overhead with ADC and DAC can be eliminated by temporarily storing the result of analog computation in a switched-capacitor analog memory cell until data dependency occurs. Cycle-accurate Verilog RTL model of the proposed architecture is evaluated with 45 nm CMOS technology parameters while executing machine learning benchmark computation codes that are generated by a customized cross-compiler without using machine learning software frameworks.

Reconfigurability in cellular manufacturing systems: a design model and multi-scenario analysis

Within cellular manufacturing systems (CMSs), families of parts are assigned to manufacturing cells, composed by homogeneous sets of machines. In conventional CMSs, each cell is devoted to the production of a specific part family, reducing material handling and work-in-process. Despite their flexibility, such systems still suffer from coping with the present market challenges asking for dynamic part mix and the need of agility in manufacturing. To meet these challenges, the recent literature explores the idea of including elements of the emerging reconfigurable manufacturing paradigm in the design and management of CMSs, leading to the cellular reconfigurable manufacturing system (CRMS) concept. The aim of this paper is to propose an original linear programming optimization model for the design of CRMSs with alternative part routing and multiple time periods. The production environment consists of multiple cells equipped with reconfigurable machine tools (RMTs) made of basic and auxiliary custom modules. By changing the auxiliary modules, different operations become available on the same RMT. The proposed approach determines the part routing mix and the auxiliary module allocation best balancing the part flows among RMTs and the effort to install the modules on the machines. The approach discussion is supported by a literature case study, while a multi-scenario analysis is performed to assess the impact of different CMS configurations on the system performances, varying both the number of cells and the RMT assignment to each of them. A benchmarking concludes the paper comparing the proposed CRMS against a conventional CMS configuration. The analysis shows relevant benefits in terms of reduction of the intercellular travel time (− 58.6%) getting a global time saving of about 53.3%. Results prove that reconfigurability is an opportunity for industries to face the dynamics of global markets.

Design of delayed reconfigurable manufacturing system based on part family grouping and machine selection

To improve the convertibility of reconfigurable manufacturing system (RMS), the concept of delayed reconfigurable manufacturing system (D-RMS) was proposed. RMS and D-RMS are both constructed around part family. However, D-RMS may suffer from ultra-long system problem with unacceptable idle machines using generic RMS part families. Besides, considering the complex basic system structure of D-RMS, machine selection of D-RMS should be addressed, including dedicated machine, flexible machine, and reconfigurable machine. Therefore, a system design method for D-RMS based on part family grouping and machine selection is proposed. Firstly, a part family grouping method is proposed for D-RMS that groups the parts with more former common operations into the same part family. The concept of longest relative position common operation subsequence (LPCS) is proposed. The similarity coefficient among the parts is calculated based on LPCS. The reciprocal value of the operation position of LPCS is adopted as the characteristic value. The average linkage clustering (ALC) algorithm is used to cluster the parts. Secondly, a machine selection method is proposed to complete the system design of D-RMS, including machine selection rules and the dividing point decision model. Finally, a case study is given to implement and verify the proposed system design method for D-RMS. The results show that the proposed system design method is effective, which can group parts with more former common operations into the same part family and select appropriate machine types.

Reconfigurable machine tools design for multi-part families

Reconfigurable machine tools (RMT) are the core facility of reconfigurable manufacturing systems (RMS), and structure design is the fundamental research involving RMT. The existing prototypes of RMT are limited to a specific part family, which suffers from reconfiguration difficulty and module sustainability issues. Therefore, a design philosophy of RMT for multi-part families with new design principles based on reconfigurability is proposed in this paper. Modularity and integrability are the basic principles, scalability, convertibility, and customization are the primary design principles, and reusability and symmetry are the auxiliary design principles. By implementing the new design principles, a two-step design method of RMT is proposed. First, a basic three-main-module structure, including the base, function arm, and workstation, is created. Second, customized components are selected to customize the functions for a specific part family, which can be reconfigured to meet the demand of other part families using other customized components. A prototype of RMT illustrates the proposed design philosophy to specify the basic three-main-module structure. The basic configurations of the RMT prototype are given, as well. The reconfigurability of the RMT prototype is analyzed from the perspectives of scalability, convertibility, and reconfiguration time. Based on topology optimization, the performance of the RMT prototype is improved. The case study implements milling and turning functions, demonstrating the practicality of the proposed design philosophy, where the processing of typical parts is also analyzed. Furthermore, the reconfiguration process among multi-part families is discussed in the case study.

A methodology of setting module groups for the design of reconfigurable machine tools

The modular design of reconfigurable machine tools (RMTs) is the key enabling technology to reconfigurability. A systematic methodology for setting the constituent modules of RMTs is proposed in this paper. According to the structural and functional characteristics of the components that construct the machine tools, the geometry modules and the basic structure modules are generated, and on this basis, the conceptual autonomous functional modules of RMTs can be constructed. According to the reconfigurable manufacturing process planning for a part family, the optimal processing plans of a family of parts can be obtained, which include a series of processing segments. And through the generated motion-schemes of a RMT of each processing segment, the RMT configurations can be constructed from a set of the autonomous functional modules to meet the process requirements. Finally, a set of RMT modules with particular sizes and structures can be generated, which will be used to construct RMTs to accommodate required changes in existing products or parts. Taking the production of a gearbox part family as an example, the validity of the method is verified.

Configuration design of scalable reconfigurable manufacturing systems for part family

Intense global competition, dynamic product variations, and rapid technological developments force manufacturing systems to adapt and respond quickly to various changes in the market. Such responsiveness could be achieved through new paradigms such as Reconfigurable manufacturing systems (RMS). In this paper, the problem of configuration design for a scalable reconfigurable RMS that produces different products of a part family is addressed. In order to handle demand fluctuations of products throughout their lifecycles with minimum cost, RMS configurations must change as well. Two different approaches are developed for addressing the system configuration design in different periods. Both approaches make use of modular reconfigurable machine tools (RMTs), and adjust the production capacity of the system, with minimum cost, by adding/removing modules to/from specific RMTs. In the first approach, each production period is designed separately, while in the second approach, future information of products’ demands in all production periods is available in the beginning of system configuration design. Two new mixed integer linear programming (MILP) and integer linear programming (ILP) formulations are presented in the first and the second approaches respectively. The results of these approaches are compared with respect to many different aspects, such as total system design costs, unused capacity, and total number of reconfigurations. Analyses of the results show the superiority of both approaches in terms of exploitation and reconfiguration cost.

Machine layout design problem under product family evolution in reconfigurable manufacturing environment: a two-phase-based AMOSA approach

Reconfigurable manufacturing systems (RMSs) are designed to manufacture a specific product, incorporating the scalability to other products in the same family. This ability is based primarily on the reconfiguration capabilities offered by reconfigurable machines tools (RMTs). This paper addresses one of the most important aspects related to the reactivity of RMSs. More specifically, it considers the relations, which link the conceived system with two important environments: its logical environment, i.e., the product family (products that share similarities) in which the RMS can evolve, and its physical environment, i.e., the physical workshop that implements this RMS. We study the machine layout problem by considering the product family evolution where two sub-problems are addressed. The first sub-problem concerns the evolution of the product, in the same family, towards new products to meet the evolutions and the requirements of the customers. The second sub-problem deals with the machine layout problem based on the results of the first sub-problem. For this, our two-phase-based approach combines the well-known metaheuristic, archived multi-objective simulated annealing (AMOSA), with an exhaustive search–based heuristic to determine the best machine layout for all the selected machines of the product family. The developed approach is based on the initially generated process plans of products (in the product family) for the RMS design under performance metrics. Moreover, the proposed layout must, at its best, respect both the constraints imposed by the generated process plans and those depicting the available location in the shop floor where machines can be placed. An illustrative numerical example is proposed to demonstrate the applicability of our approach.

Development of Operator Theory in the Capacity Adjustment of Job Shop Manufacturing Systems

With the development of industrial manufacture in the context of Industry 4.0, various advanced technologies have been designed, such as reconfigurable machine tools (RMT). However, the potential of the latter still needs to be developed. In this paper, the integration of RMTs was investigated in the capacity adjustment of job shop manufacturing systems, which offer high flexibility to produce a variety of products with small lot sizes. In order to assist manufacturers in dealing with demand fluctuations and ensure the work-in-process (WIP) of each workstation is on a predefined level, an operator-based robust right coprime factorization (RRCF) approach is proposed to improve the capacity adjustment process. Moreover, numerical simulation results of a four-workstation three-product job shop system are presented, where the classical proportional–integral–derivative (PID) control method is considered as a benchmark to evaluate the effectiveness of RRCF in the simulation. The simulation results present the practical stability and robustness of these two control systems for various reconfiguration and transportation delays and disturbances. This indicates that the proposed capacity control approach by integrating RMTs with RRCF is effective in dealing with bottlenecks and volatile customer demands.

An Approach to Develop Shaper Cum Slotter Mechanism: A Reconfigurable Machine Tool

The traditional structure of machines (such as lathe, milling, shaper, slotter, drilling and planer) has become questionable because of the modular concepts (such as modularity, scalability, convertibility, mobility and flexibility) and reconfiguration becomes a promising approach towards modular manufacturing machines, in which manufacturing techniques are independent of changes. In this area, reconfigurable machine tool (RMT) forms a new class of modular machines in current manufacturing scenario where the manufacturing industry put a strong pressure on good quality and price reduction. The capabilities of the machines tool and manufacturing systems in reconfigurable manufacturing system (RMS) change with each reconfiguration (both software and hardware modules). In this case, an approach is presented for reconfiguration of horizontal shaper machine for developing the modular shaper cum slotter machine in a manufacturing system by adding some auxiliary (like Scott Russel mechanism) and some basic modules and the reconfiguration features of traditional shaper and slotter machine are also discussed. The proposed approach is illustrated with a figure, which has been designed on 3-D design tool (solid-works software platform). It is expected that, this work will help designers and practising engineers by making them aware of the reconfiguration mechanisms on traditional shaper machine, which have become a necessity for the very survival of manufacturing by lowering the operational costs.

Elastic Load Balancing for Dynamic Virtual Machine Reconfiguration Based on Vertical and Horizontal Scaling

Today, cloud computing applications are rapidly constructed by services belonging to different cloud providers and service owners. This work presents the inter-cloud elasticity framework, which focuses on cloud load balancing based on dynamic virtual machine reconfiguration when variations on load or on user requests volume are observed. We design a dynamic reconfiguration system, called inter-cloud load balancer (ICLB), that allows scaling up or down the virtual resources (thus providing automatized elasticity), by eliminating service downtimes and communication failures. It includes an inter-cloud load balancer for distributing incoming user HTTP traffic across multiple instances of inter-cloud applications and services and we perform dynamic reconfiguration of resources according to the real time requirements. The experimental analysis includes different topologies by showing how real-time traffic variation (using real world workloads) affects resource utilization and by achieving better resource usage in inter-cloud.

Engineering Design Featuring the Life Cycle Approach for Reconfigurable Machine Tool

The evolution of design has come of age and the new design approaches that look at the rapid change and short life cycles of products is taking the centre stage. Competitiveness and the cost of products determine the lifeline of an organisation. The traditional machine tools such as the dedicated and flexible machines are designed on the principle of machine design. The development of reconfigurable machines seeks a new approach to design that not only encompasses the existing approaches but should include new design approaches as well. The success of a designed product maybe measured by the capability of the system that produces it. It is critical when designing a product that the organisation’s technological and manufacturing system capabilities be considered as failure to do so may lead to production designs that are not manufacturable. A good design system ensures quick delivery of a quality, reliable and safe product. This research therefore seeks to develop an integrated approach to design that incorporates design for manufacturing, design for assembly, concurrent engineering, eco-design and reconfigurable design as critical components for reconfigurable machine tool. Literature on these systems was reviewed to integrate the different design paradigms. The results of the study give a new approach to a reconfigurable machine design based on the integration of the five design approaches and their impact in the life cycle of a product.

A Real-Time Software Defined Networking Framework for Next-Generation Industrial Networks

Industry 4.0 brings in a whole set of new requirements to engineering industrial systems, with notorious impact at the networking layer. A key challenge posed by Industry 4.0 is the operational flexibility needed to support on-the-fly reconfiguration of production cells, stations, and machines. At the networking layer, this flexibility implies dynamic packet handling, scheduling, and dispatching. SoftwareDefined Networking (SDN) provides this level of flexibility in the general Local Area Network (LAN) domain. However, its application in the industry has been hindered by a lack of support for real-time services. This paper addresses this limitation, proposing an extended SDN OpenFlow framework that includes realtime services, leveraging existing real-time data plane Ethernet technologies. We show the OpenFlow enhancements, a real-time SDN controller, and experimental validation and performance assessment. Using a proof-of-concept prototype with 3 switches and cycles of 250μs, we could achieve 1μs jitter on timetriggered traffic and a reconfiguration time between operational modes below 10ms.

Reconfigurable Multi-Butterfly Parallel Radix-r FFT Processor

The design of reconfigurable multi-butterfly parallel radix-r FFT (Fast Fourier Transform) processors is proposed. FFT is widely used in signal processing, and the application needs real-time and high performance, while most of the traditional designs are limited to the power of two, which wastes the buffers and multipliers in big data. In response to the problem, we improve the parallel FFT algorithm with the design of reconfigurable control machine combined with buffer/multiplier, and the cost function with the input of radix/number/paddling number/time consuming is deduced. Constrained with the number of buffer and multipliers, the radix and number can be computed with the optimum cost function, and the resolution space of computing performance and hardware cost is presented. The proposed guarantees the real-time performance with better flexibility compared with the previous literature, and the comparison also suggests the effectiveness of the design.