Today's Manufacturing Research Articles

Depth camera based collision avoidance via active robot control

A new type of depth cameras can improve the effectiveness of safety monitoring in human–robot collaborative environment. Especially on today's manufacturing shop floors, safe human–robot collaboration is of paramount importance for enhanced work efficiency, flexibility, and overall productivity. Within this context, this paper presents a depth camera based approach for cost-effective real-time safety monitoring of a human–robot collaborative assembly cell. The approach is further demonstrated in adaptive robot control. Stationary and known objects are first removed from the scene for efficient detection of obstacles in a monitored area. The collision detection is processed between a virtual model driven by real sensors, and 3D point cloud data of obstacles to allow different safety scenarios. The results show that this approach can be applied to real-time work cell monitoring.

Computation of supervisors for reconfigurable machine tools

The rapid reconfiguration of manufacturing systems is an important issue in today's manufacturing technology in order to adjust the production to varying product demands and types. In this paper, we study the control of reconfigurable machine tools (RMTs) with the aim of fast reconfiguration and an easy controller implementation. We first formulate a particular reconfiguration problem for RMTs in a discrete event system setting, and then provide a necessary and sufficient condition for its solution. Moreover, we propose a polynomial-time algorithm for the construction of a reconfiguration supervisor as the composition of one modular supervisor for each separate RMT configuration. Each modular supervisor operates in three modes. In the first mode, it tracks the plant state if its corresponding configuration is inactive. In the second mode, it performs a configuration change if its corresponding configuration becomes active and in the third mode, it follows the specified behavior of its corresponding configuration if the configuration is active. An important property of the proposed reconfiguration supervisor is that it performs reconfigurations in a bounded number of event occurrences. In addition, the modular realization of our reconfiguration supervisor enables controller modifications such as adding or removing configurations during run-time. All results presented in the paper are illustrated by an RMT example.

Based on CIMS Application of Small and Medium-Sized Enterprise Information System Integration

With the rapid development of market economy, enterprises face more intense market competition, especially manufacturing enterprises face huge challenges. How to shorten product time to market, improve product quality, reduce costs and provide high quality service is the enterprise in competition at the core of the problem. The development of CIMS conform to the trend of the development of manufacturing and computer today. In this paper, the information integration system based on CIMS application prospect in small and medium enterprises are analyzed and predicted, and the domestic small and medium-sized enterprises as an example of application in the enterprise information integration system based on CIMS problems are analyzed.

Optimization of Degree of Conformance in Multiresponse–Multistage Systems with a Simulation‐based Metaheuristic

In today's manufacturing and service systems, entities are progressed across the several stages of operations wherein one or more quality characteristic may be formed. The quality of final system outputs depends on the quality of intermediate characteristics as well as design parameters in each stage. This paper presents a new mathematical program to simultaneously optimize multiple quality characteristics in multiple stage systems. Multivariate form response surface methodology is applied with iterative seemingly unrelated regression as the estimation method to extract the relationships between the outputs and inputs in each stage. Because the intermediate response variables may act as covariates in the next stages, the probabilistic patterns of the response surfaces are considered by association with the quality of the previous stages. The objective function in the proposed model is the acceptance probability of the outputs based on predefined specification limits. A combination of Monte Carlo simulation and the genetic algorithm is also proposed to solve the final stochastic optimization model. At the end, the applicability of the proposed approach is illustrated by a numerical example. Copyright © 2014 John Wiley & Sons, Ltd.

Intelligent pumps: do they exist?

Today's competitive market forces manufacturers to use effective advertising slogans. In the pump industry area, we often encounter the terms ‘intelligent pump’ and ‘intelligent pump system’. In this article, Piotr Świtalski examines the question of whether or not such claims are an exaggeration.

Using Failure Mode and Effects Analysis to design a comfortable automotive driver seat

Given enough time and use, all designs will fail. There are no fail-free designs. This is especially true when it comes to automotive seating comfort where the characteristics and preferences of individual customers are many and varied. To address this problem, individuals charged with automotive seating comfort development have, traditionally, relied on iterative and, as a result, expensive build-test cycles. Cost pressures being placed on today's vehicle manufacturers have necessitated the search for more efficient alternatives. This contribution aims to fill this need by proposing the application of an analytical technique common to engineering circles (but new to seating comfort development), namely Design Failure Mode and Effects Analysis (DFMEA). An example is offered to describe how development teams can use this systematic and disciplined approach to highlight potential seating comfort failure modes, reduce their risk, and bring capable designs to life.

Data Cleaning for RFID and WSN Integration

Today's manufacturing environments are very dynamic and turbulent. Traditional enterprise information systems (EISs) have mostly been implemented upon hierarchical architectures, which are inflexible to adapt changes and uncertainties promptly. Next-generation EISs must be agile and adaptable to accommodate changes without significant time delays. It is essential for an EIS to obtain real-time data from the distributed and dynamic manufacturing environment for decision making. Wireless sensor networks (WSNs) and radio-frequency identification (RFID) systems provide an excellent infrastructure for data acquisition, distribution, and processing. In this paper, some key challenges related to the integration of WSN and RFID technologies are discussed. A five-layer system architecture has been proposed to achieve synergistic performance. For the integration of WSN and RFID, one of the critical issues is the low efficiency of communication due to redundant data as redundant data increases energy consumption and causes time delay. To address it, an improved data cleaning algorithm has been proposed; its feasibility and effectiveness have been verified via simulation and a comparison with a published algorithm. To illustrate the capacity of the developed architecture and new data cleaning algorithm, their application in relief supplies storage management has been discussed.

Improvement Heuristics for Manufacturing System Design Using Complex Network Figures

Today's manufacturing systems are characterized by a high level of structural complexity, accompanied by a diverse, less uniform material flow. As this contribution will show, this development complicates the identification of work stations that limit the logistic target achievement, because the non-trivial network effects are hard to predict. However, this identification of key work stations is particularly important during the design and operation phase of a manufacturing system, as they allow a cost-optimal system improvement with limited inference on the operation. Our approach discusses the “bottleneck” oriented approach commonly applied today in the context of network effects in manufacturing systems and compares its performance to centrality measures from complex network theory.

Determination of Machinability Considering Degradation of Accuracy Over Machine Tool Life Cycle

The emergence of financially an environmentally conscious manufacturing has resulted in a need for efficient process planning in today's manufacturing system. Process planning based on nominal machine tool specifications, limits predictive capabilities with regard to the final part quality. More efficient process plans can be achieved once an accurate machine tool capability profile has been defined. Machine tool capability profiles deliver up-to-date resource attributes such as availability, health and applicability into the process-planning stage. A manufacturing resource's health degrades continuously throughout its life cycle due to environmental factors, part wear, operator competence, etc. Identifying and compensating for these factors during process planning may alleviate material wastage and machining estimate production time and cost via decision-making mechanisms. In this paper, the STEP-NC Standard is used to represent a model of machining resources, including worktable, spindle and tool status during a machine tool's operational lifespan. A prototype of machine tool capability profile enabled process planning system is then presented and tested to highlight the advantages of this approach.

Analysis of Surface Topology in Dry Machining of EN-8 Steel

Dry machining is gaining more and more importance in today's manufacturing science because of health hazards imposed by the use of coolants while machining. This paper presents a detailed analysis of surface topology in dry machining of EN-8 steel which is widely used material for general-purpose axles, shafts, gears, bolts and studs. Regression models are developed for Ra, Rq, and Rz parameters of surface topology which are very significant parameters from contact stiffness, fatigue strength and surface wear point of view. For all the regression models a good correlation is found between surface roughness and cutting parameters and hence these models can be used to predict the surface roughness within the range of cutting parameters under investigation. Regression models are compared with experimental values of roughness and with available geometrical models. Percent errors are also calculated by comparing regression models and experimental values and a geometrical model. It is found that the percent errors are very small for regression model as compared to geometrical model. Finaly performance of dry machining is compared with that of machining with coolant, no significant difference is found for the surface roughness with the dry machining and that of machining with coolant.

Recent Research and Development of Typical Cutting Machine Tool’s Energy Consumption Model

As the "mother of all machines" in today's mechanical manufacturing industry, machine tool has large quantity with high energy consumption but low energy efficiency. Therefore, scholars have done much work on establishing precise machine tool's energy consumption models. An overview of energy modeling of typical machine tools is shown from the three levels of cutting energy consumption, the whole machine tool's energy consumption during the machining stage, and machine tool's total energy consumption during the whole manufacturing process. The applications of these models are concluded into four aspects: optimization for energy saving, products' green manufacturing assessment, enterprise's resource configuration and machine tool's green design. The energy modeling trends of machine tools are discussed: the modeling object gradually tends to high-end CNC machine tools, the models become more specific, the combination with industrial application makes models become higher of values.

Distributed Control Architecture for Wireless Sensor Networks Using IEC 61499 Function Blocks for Industrial Automation

Wireless Sensor Networks (WSN) technology is rapidly becoming a feasible solution for monitoring and control at the lowest level of manufacturing automation systems. This paper presents a distributed approach for modeling WSN for applications of intelligent manufacturing automation and control. The proposed approach uses IEC 61499 function blocks, which is a new industry standard in the context of manufacturing automation. The distributed modeling of WSN through the function blocks provides flexibility and scalability to the low-level monitoring and control of the manufacturing systems, which are two important challenges in today's conventional manufacturing control systems. The proposed model is a replacement of the conventional centralized control architecture, where local processing is performed rather than having a central control unit.

Determination of characteristic rheological parameters in Portland cement pastes

The standard use of admixtures in Portland cements (with and without mineral additions)-based concrete manufacture today has made the physical–chemical interaction among the various components a highly topical issue.One way to analyse the resulting effects is discussed in this paper, which substantiates the importance of a careful selection of the parameters used to evaluate the rheological behaviour of plain fresh pastes of Portland cements. To this end, the pastes studied in this research contained no mineral additions.The initial analysis explored the variations in rheometer response depending on angular velocity and phase duration. Ramp direction, number of angular velocities and the size of the inter-velocity steps were also studied. Lastly, the importance of allowing the cement paste sample to rest during the measurement sequence was also analysed.These trials were conducted on two types of Portland cements with completely different mineralogical compositions. They were repeated every 20min prior to the initial setting time, more exactly up to the first nadir on their heat of hydration release curves, determined in earlier conduction calorimetry studies.The results showed that parameter selection in designing a scheme to evaluate the rheological behaviour of fresh Portland cement pastes had a substantial effect on the response obtained. That response was also highly dependent upon the degree and type of hydroxy-induced alkalinity in the liquid phase of the pastes, in turn a result of the mineralogical and chemical composition of the PCs, in particular their N2O and K2O (%) contents, which therefore proved to play a prominent role in rheological behaviour.

Modeling of the influence of sample preparation sequences when measuring selectively induced residual stress depth profiles

The selective introduction of compressive residual stresses is gaining increasing importance as design tool in today's manufacturing process chains. Manufacturing processes such as shot peening or hydraulic autofrettage are used to improve the surface integrity, and hence the fatigue life of the components. However, measuring the corresponding residual stress depth profiles is a challenging task as the results will always include the manufacturing and preparation history of the components. In this paper, results of residual stress measurements with X-ray diffraction and optical hole-drilling after autofrettage and sample preparation are presented and compared to a finite element analysis for two representative geometries. The presented approach can be used to predict the influence of the mandatory sample preparation procedure. As a consequence, the effectiveness of the manufacturing process to improve the surface integrity can be predicted more precisely and wrong interpretations of the measured residual stress depth profiles can be avoided.

Model Terintegrasi Penjadwalan Batch dan Pm dengan Kriteria Minimalisasi Biaya Simpan, Setup dan Pm pada Mesin dengan Increasing Failure Rate

Development of today's manufacturing systems leads to the getting shorter in product life cycle, more variety of products, as well as increasing in consumer demand for quality and timeliness. Thus the accuracy and speed of decision-making within the manufacturing system becomes important. This paper proposes an integrated model of batch scheduling and preventive maintenance scheduling, in assumption no non-conforming parts to the criteria of minimizing the total saving cost, setup cost, preventive maintenance cost in minimizing the actual flow time on a machine with increasing failure rate. An example is provided to show how the model and algorithm work.

Distributed feedback control algorithm in an auction-based manufacturing planning and control system

In today's manufacturing enterprise, customer service performance is highly dependent on the effectiveness of the company's manufacturing planning and control system (MPCS). Most of the current MPCSs that employ the centralised planning approach can have drawbacks, such as structural rigidity, difficulty in designing a control system, and lack of flexibility. An auction-based manufacturing planning and control system (AMPCS) allows negotiation-based decision making, however, the distributed scheduling algorithm usually attempts to achieve only its objective without considering the global objective, and a contradiction problem might occur between the local objective and the overall system performance. Therefore, the objective of this research is to develop a distributed scheduling algorithm called a closed-loop feedback simulation (CLFS) approach for an AMPCS which includes adaptive control of the auction-based bidding sequence to prevent the first bid first serve rule and may dynamically allocate production resources to operations. CLFS iteratively adjusts the bidding sequence using the deviation between the predicted completion time and the due date to improve the scheduling performance. The results obtained from the computational experiments show that the proposed CLFS algorithm can obviously improve production performance compared to previous studies.

무전해 니켈도금 소재의 초정밀 가공에서 V-형상 미세 패턴 가공한계에 대한 실험적 평가

The continuing demand for increasingly slimmer and brighter liquid crystal display (LCD) panels has led to an increased focus on the role of light guide panels (LGPs) or optical films that are used to obtain diffuse, uniform light from the backlight unit (BLU). The most basic process in the production of such BLU components is the micromachining of V-shaped grooves. Thus, given the current trend, micromachining of V-shaped grooves is expected to play increasingly important roles in today's manufacturing technology. LCD BLUs comprise various optical elements such as a LGP, diffuser sheet, prism sheet, and protector sheet with V-shaped grooves. High-aspect-ratio patterns are required to reduce the number of sheets and enhance light efficiency, but there is a limit to the aspect ratio achievable for a given material and cutting tool. Therefore, this study comprised a series of experimental evaluations conducted to determine the machining limit in microcutting V-shaped grooves on electroless nickel plated die materials when using single-crystal diamond tools with point angles of <TEX>$20^{\circ}-80^{\circ}$</TEX>. Cutting performance was evaluated at various cutting speeds and depths of cut using different machining methods and machine tools. The experimental results are that V-shaped patterns with angles of <TEX>$80^{\circ}$</TEX> or up can be realized regardless of the machining conditions and equipment. Moreover, the feed rate has little effect on machinability, and it is thought that the fly-cut method is more efficient for shallow patterns.

Multiple material additive manufacturing – Part 1: a review

Interest in multifunctional structures made automatically from multiple materials poses a challenge for today's additive manufacturing (AM) technologies; however the ability to process multiple materials is a fundamental advantage to some AM technologies. The capability to fabricate multiple material parts can improve AM technologies by either optimising the mechanical properties of the parts or providing additional functions to the final parts. The objective of this paper is to give an overview on the current state of the art of multiple material AM technologies and their practical applications. In this paper, multiple material AM processes have been classified and the principles of the key processes have been reviewed comprehensively. The advantages and disadvantages of each process, recent progress, challenging technological obstacles, the possible strategies to overcome these barriers, and future trends are also discussed.

The concurrent application of lean production and ERP: Towards an ERP-based lean implementation process

Lean production and enterprise resource planning systems are often quoted as being the two most important strategies for achieving competitive advantage in today's global manufacturing environments. Though IT has traditionally been viewed as a contributor to waste within lean production, we suggest that modern developments in IT and the onset of hybrid “push-pull” production control mechanisms have allowed ERP and lean approaches to converge towards a state where ERP systems can in fact be used to support the deployment of lean practices. This paper analyses typical lean and ERP implementation processes contained within the scientific literature, and by further examining a concurrent implementation process in real-time, we develop and propose a process for ERP-based lean implementations. Our findings suggest that the implementation of a contemporary ERP system can act as a catalyst for the application of lean production practices.

Contact-less and Programming-less Human-Robot Collaboration

In today's manufacturing environment, safe human-robot collaboration is of paramount importance, to improve efficiency and flexibility. Targeting the safety issue, this paper presents an approach for human-robot collaboration in a shared workplace in close proximity, where real data driven 3D model of a robot and multiple depth images of the workplace are used for monitoring and decision-making to perform a task. The strategy for robot control depends on the current task and the information about the operator's presence and position. A case study of assembly is carried out in a robotic assembly cell with human collaboration. The results show that this approach can be applied in real-world applications such as human-robot collaborative assembly with human operators safeguarded at all time.