Interactive effects of seasonal-demand characteristics on manufacturing systems

In this paper, we identify different characteristics of seasonal demands and analyse their impact on manufacturing systems. In particular, we consider a single-stage production facility that has flexibility to adjust its production rates or inventory target levels. Using Markov decision process formulation, we analyse a model that minimises the total cost under infinite horizon discounted and average cost criteria. Through extensive numerical studies, we reveal several insights related to the individual and joint impact of seasonal demand characteristics that are of practical interests to manufacturers.     

Quality risk analysis in a cGMP environment: multiple models for comprehensive failure mode identification during the computer system lifecycle

Pharmaceutical quality systems use various inputs to ensure product quality and prevent failures that might have patient consequences. These inputs are generally data from failures that have already occurred, for example process deviations or customer complaints. Risk analysis techniques are well-established in certain other industries and have become of interest to pharmaceutical manufacturers because they allow potential quality failures to be predicted and mitigating action taken in advance of their occurring. Failure mode and effects analysis (FMEA) is one such technique, and in this study it was applied to implement a computerized manufacturing execution system in a pharmaceutical manufacturing environment. After introduction, the system was monitored to detect failures that did occur and these were analyzed to determine why the risk analysis method failed to predict them. Application of FMEA in other industries has identified weaknesses in predicting certain error types, specifically its dependence on other techniques to model risk situations and its poor analysis of non-hardware risks, such as human error, and this was confirmed in this study. Hierarchical holographic modeling (HHM), a technique for identifying risk scenarios in wide-scope analyses, was applied subsequently and identified additional potential failure modes. The technique for human error rate prediction (THERP) has previously been used for the quantitative analysis of human error risk and the event tree from this technique was adapted and identified further human error scenarios. These were input to the FMEA for prioritization and mitigation, thereby strengthening the risk analysis in terms of failure modes considered.     

Information processing-related infrastructural antecedents of manufacturing flexibility – a real options perspective

The relationship between manufacturing flexibility and environmental uncertainty has been widely studied; however, research involving manufacturing flexibility and associated infrastructural antecedents is sparse. In this paper, using the real options perspective, we develop a research model to explicate management support’s influence on an organisation’s manufacturing flexibility. We use a second-order, multi-dimensional construct and survey data collected from US manufacturers to test our hypotheses. The study provides evidence to suggest that management support through teamwork, information systems effectiveness, and integrated supply chain effectiveness enhances an organisation’s manufacturing flexibility.     

Effects of loading and routeing decisions on performance of flexible manufacturing systems

Research has found that while flexibility is purported to be a prime advantage of flexible manufacturing systems (FMS), it has not yet become a major competitive priority for American and European manufacturers. Moreover, many installed systems either are not very flexible or do not use the available flexibility to the best advantages. We suspect that inappropriate application of the conventional production management concepts to FMS is one of the major factors that hinders current FMSs from capturing their key advantage: flexibility. This paper takes a first step to examine why the conventional job shop loading and fixed routeing concepts fail to capture the flexibility of FMS. Once problems are identified we suggest ways to exploit the FMS flexibility. We further conduct an experiment to investigate FMS performance under different manufacturing policies and operating conditions. The results indicate that the performance of an FMS greatly diminishes when the conventional job shop loading and fixed routeing concepts are applied. This is because the inherent flexibility of the FMS is not fully utilized. Moreover, the operating conditions such as tooling duplication levels and operation processing time variation could also significantly affect the FMS performance.     

Implementation of a demand-pull system in a job shop environment

This paper describes an implementation of JIT concepts in a medium-sized make-to-order manufacturing company. We develop a hybrid production control system for the company based on separating jobs with high production volumes following a standard routeing from relatively low-volume jobs with more complex routeings. The machines processing the high-volume standard-routeing jobs are treated as a virtual flow shop and controlled by a hybrid push/pull system, while the remainder of the floor is managed as a job shop. Initial tests have shown that this system can significantly improve throughput and simplify the production scheduling task. We believe that the system can be applied to a wide range of industries with similar characteristics. We also describe the testing of the system and the circumstances under which its implementation was discontinued, which indicate some of the difficulties faced by small manufacturers in implementing such systems.     

Prioritising the types of manufacturing flexibility in an uncertain environment

Researchers have stressed that manufacturing system flexibility research requires a quantitative model allowing a manufacturing system to prioritize its flexibility dimension and promote the performance of the manufacturing system. A quantification model presented in the present research is demonstrated to assess the degree of environmental uncertainty and illustrates a method for delivering the requirement of flexibility improvement for the manufacturing system so that the company is able to prioritize the types of manufacturing flexibility which a manufacturing system requires in an uncertain environment. Quantitative approaches including quality function deployment (QFD), analytical hierarchy process (AHP), and grey relational analysis (GRA) have been employed to find a means for improving the flexibility of a manufacturing system to cope with environmental uncertainty. QFD is the focal approach for the deployment of the integrated structure of the research. AHP is applied to explore the relative weighted importance of environmental uncertainty factors, while GRA is used to find out the relationships between manufacturing flexibility and environmental uncertainty. A combination of these approaches reveals a useful tool for managers to prioritize the types of flexibility which a manufacturing system requires for coping with an uncertain environment. In particular, the present research studied the manufacturing flexibility requirements of a food company in Taiwan.     

Smart Process Manufacturing for Formulated Products

We outline the smart manufacturing challenges for formulated products, which are typically multicomponent, structured, and multiphase. These challenges predominate in the food, pharmaceuticals, agricultural and specialty chemicals, energy storage and energetic materials, and consumer goods industries, and are driven by fast-changing customer demand and, in some cases, a tight regulatory framework. This paper discusses progress in smart manufacturing—namely, digitalization and the use of large datasets with predictive models and solution-finding algorithms—in these industries. While some progress has been achieved, there is a strong need for more demonstration of model-based tools on realistic problems in order to demonstrate their benefits and highlight any systemic weaknesses.     

Computer-aided production management issues in the engineer-to-order production of complex capital goods explored using a simulation approach

This paper describes the exploration of manufacturing planning and control issues in the capital goods industry using a simulation approach. The companies produce products which have deep and complex product structures and are produced in low volume on an engineer- or make-to-order basis (ETO, MTO). The work reported here draws on the results of surveys of companies involved in the manufacture of capital goods which identified their characteristics of ETO and MTO capital goods companies and their strategic issues. The planning and control approaches adopted in the manufacturing facilities and the difficulties experienced in the application of computer-aided production management (CAPM) systems were also examined. The simulation model developed enables complex manufacturing systems to be modelled and was configured to represent a typical ETO/MTO facility using industrial data. A series of full factorial experiments were performed to explore a number of production management problems identified in surveys including capacity planning, assembly planning and scheduling strategies. Conclusions are drawn on the effects on performance and capacity of: applying minimum set-up and processing times for both major and minor activities; using different data update periods and assembly lead times; and adopting various scheduling and despatching approaches. These results are compared with those obtained by other workers who used survey techniques alone, and have implications for the manufacturers of capital goods.     

Taxonomy of the manufacturing strategies of large Spanish industrial companies

This work presents a classification of the manufacturing strategies of large Spanish industrial companies in Spain. For this purpose the various international empirical studies on alternative manufacturing strategies have been taken as a reference, reviewed and compared. The database used in this study is made up of information on 114 factories and has been designed using the information from a survey mailed to the industrial companies which have production plants in Spain and which in the financial year of 1994 (reference date of this research) employed over 200 workers. Cluster analysis methodology has been used and the classification criterion taken was the competitive advantages or strengths of each factory concerning the five competitive priorities in manufacturing: efficiency, flexibility, quality, delivery and customer service. Finally, this work identifies a taxonomy of the manufacturing strategies of a sample of the largest industrial companies in Spain, differentiating three alternative production strategies: flexible marketoriented manufacturers, low-cost quality manufacturers and delivery-based manufacturers. Large industrial companies analysed compete in manufacturing, basically following a choice of three criteria: flexibility, quality or delivery. The companies belonging to each of the three categories identified maintain common and lasting manufacturing objectives and policies.     

Performance comparison of virtual cellular manufacturing with functional and cellular layouts in DRC settings

This study investigates the performance of virtual cellular manufacturing (VCM) systems, comparing them with functional layouts (FL) and traditional, physical cellular layout (CL), in a dual-resource-constrained (DRC) system context. VCM systems employ logical cells, retaining the process layouts of job shops. Part family-based scheduling rules are applied to exploit the benefits of group technology while retaining the flexibility and functional synergies of the job shop. Past studies of VCM have been based entirely on single-resource-constrained (SRC) systems, i.e. as purely machine-limited systems, assuming that resources such as labour and tooling do not restrict the output. However, given the fact that labour forms a second major constraining resource, and many of the advantages associated with cellular manufacturing are derived from labour flexibility, it becomes necessary to extend the research to DRC systems. In this study, we assume several levels of labour flexibility in all three systems, in addition to other relevant factors such as lot size, set-up reduction, and labour assignment rules. It is shown that VCM can outperform efficiently operated FL and CL in certain parameter ranges, as preliminary research has shown so far. However, it is shown that CL tends to outperform both VCM and FL in the parameter ranges customarily advocated for CL, namely, low lot sizes, adequate levels of set-up reduction, cross training of workers, and worker mobility within cells.     

Tackling perishability in multi-level process industries

The classical multi-level lot-sizing and scheduling problem formulations for process industries rarely address perishability issues, such as limited shelf lives of intermediate products. In some industries, ignoring this specificity may result in severe losses. In this paper, we start by extending a classical multi-level lot-sizing and scheduling problem formulation (MLGLSP) to incorporate perishability issues. We further demonstrate that with the objective of minimising the total costs (purchasing, inventory and setup), the production plans generated by classical models are often infeasible under a setting with perishable products. The model distinguishes different perishability characteristics of raw materials, intermediates and end products according to various industries. Finally, we provide quantitative insights on the importance of considering perishability for different production settings when solving integrated production planning and scheduling problems.     

Exploratory study of the adoption of manufacturing technology innovations in the USA and the UK

Manufacturing technologies, appropriately implemented, provide competitive advantage to manufacturers. The use of manufacturing technologies across countries is difficult to compare. One such comparison has been provided in the literature with a study of US and Japanese practices in advanced manufacturing technology use using a common questionnaire. The present study compares the use of 17 different technologies in similar industries in the USA ( n = 1025) and UK ( n = 166) using a common questionnaire. Largely, there are remarkable similarities between the two countries. This may partly correlate with the heavy traffic in foreign direct investment between the two nations. Notable differences are (1) across-the-board, US manufacturers are ahead of the UK firms in computerized integration with units inside and outside manufacturing organizations; (2) US manufacturers show higher labour productivity, which is consistent with macro-economic data, and (3) more UK manufacturers report the use of soft technologies such as just-in-time, total quality manufacturing and manufacturing cells. Hypotheses for future investigation are proposed.     

Does Centralising Global Account Management Activities in Response to International Retailers Pay Off?

• This study provides insights into how manufacturers adopt their Global Account Management (GAM) activities in response to the increasing expansion of retailers. Specifically, we focus on the manufacturers?? central coordination of two types of GAM activities: strategic and tactical activities.
• We analyse the manufacturers?? associations with international retailers and with GAM effectiveness and efficiency by using data from 172 manufacturers. Moreover, we consider the suppliers?? dependence on their key retail accounts to be an important moderator within the consumer goods sector.
• In particular, manufacturers respond to the centralisation of the retailers?? purchasing activities by centralising strategic GAM activities, such as customer strategy, information processing, or price systems. Additionally, manufacturers respond even stronger by centralising tactical activities, such as category management, marketing, or logistics. Although the centralisation of strategic activities drives GAM effectiveness and efficiency, the centralisation of tactical activities does not. This finding might be explained by the specific context of manufacturer-retailer relations. Finally, we find that, although the decision to centralise GAM activities pays off, the benefits are contingent on the particular type of GAM activity and the level of customer dependency.

     

Understanding Powder Caking as a Consequence of a Range of Mechanisms by Means of Powder Rheometry

Over 70% of materials in the food, chemical, and pharmaceutical industries (from raw materials, additives, and intermediates through to manufactured products) are supplied as relatively free-flowing powders, intended to be suitable for the manufacturing process or final application. For logistical reasons however these materials will often have to be stored for extended periods during which time some powders have the potential to gain strength due to prolonged and undisturbed particle/particle interactions. This is generally referred to as “caking” and can significantly limit the ability of a powder to pass through the process train without interruption as well as detrimentally impacting product quality.

This paper will present case studies that evaluate the flow properties of different powder systems that are affected by chemical-, moisture-, and temperature-based caking mechanisms. It will show how the propensity to cake can be effectively quantified with respect to the powders’ flow properties and how this can assist in understanding and adapting the processing environment to retain optimal processability.     

Flexibility and manufacturing system design: An experimental investigation

Manufacturing industries today are faced with steady and unrelenting changes to the environment in which they operate. In order to survive and profit, manufacturing facilities must be designed such that they exhibit desirable system-level flexibility characteristics. The relationships between flexibility and manufacturing system design, however, remain largely unexplored. This paper investigates the effects of manufacturing system design on product, mix, production, and volume flexibilities, and on trade-offs between these flexibility types, for different product environments. Of particular concern is the determination of whether or not flexibility trade-offs can be avoided, and if so, how. Simulation experiments are performed to determine flexibility values for 16 different manufacturing system design 'approaches' and two levels of part processing flexibility. A total of 800 different manufacturing system/product set combinations are investigated. The results indicate that the effects of manufacturing system design on flexibility are not always intuitive, and that they can change depending upon the level of part processing flexibility present. In addition, however, they show that flexibility trade-offs are not inevitable: multiple flexibility types can be increased in value simultaneously through proper selection of the design approach.     

Development of decision support system for sustainability evaluation: a case study

The industries have created threat to the present environment through their manufacturing methods. Moreover, the excessive utilization of natural resources have led to scarcity and triggered danger for the future generations. So there exists a vital need for the modern companies to renovate their manufacturing technologies. Thus, a new concept of manufacturing process known as sustainable manufacturing has been introduced and it gained great importance in the present scenario. Sustainable manufacturing means the production of goods in such a way that it utilizes minimum natural resources and produces safer, cleaner, and environment-friendly products at an affordable cost. The purpose of this article is to assess the sustainability level of a manufacturing organization taking into consideration various factors needed for insuring sustainability. During the course of this research, a sustainability model was developed using fuzzy logic and the sustainability index was calculated. Manual calculation of sustainability index consumes more time and it is mistake prone. So, in order to avoid such inadequacies, a computer-based decision support system was developed designated as fuzzy-logic-based sustainability evaluation decision support system. The system calculates the fuzzy logic sustainability index, Euclidean distance, and fuzzy performance importance index. This model will help the companies to analyze various aspects of sustainability within their organization and work toward further improvement of it.     

The effects of product modularity on launch speed

Extant literature suggests that product modularity positively and directly impacts the timeliness and frequency of new products as well as manufacturing performance, particularly flexibility. Little is known about the nature of these relationships, however, since few empirical studies have been done. Important questions remain unanswered including whether the effect of modularity on launch speed is direct or indirect, and what role other constructs might play. This study explores these issues by examining the effects of product modularity on launch speed within a holistic framework that considers the roles of product platforms and manufacturing flexibility. Drawing upon dynamic capabilities theory in the resource-based view, the model depicts product modularity as antecedent to product platforms, product platforms as antecedent to manufacturing flexibility and manufacturing flexibility as antecedent to launch speed. The model is strongly supported by an analysis of 93 manufacturers. Results reveal a positive effect of product modularity on launch speed, but it is delivered through the mediating effects of product platforms and manufacturing flexibility. In contrast to earlier work, the findings show modularity alone is an insufficient condition for the timely and frequent introduction of new products. Rather, launch speed is engendered by a ‘gestalt’ of dynamic capabilities.     

MPS with multiple freeze fences in multi-product multi-level MRP systems

In the current severe competitive marketplace, customers are now expecting better quality, price and service, and demanding higher flexibility. To survive in this highly demanding and competitive manufacturing environment, many manufacturers are forced to improve flexibility in their manufacturing management systems. Traditionally, manufacturers use a single freeze fence in their master production schedule (MPS). Within the single freeze fence, even if a more accurate sales forecast is available, no schedule change is allowed. This paper introduces a new approach to improve MPS flexibility by imposing a freeze fence on each item in the bill of materials (BOM). This new approach allows schedule changes within certain periods of the traditional single freeze fence subject to the availability of component supply. It allows manufacturers to react more quickly to market trends. When applying multiple freeze fences, allocating limited component supply is required. In this study, a mathematical model for allocating limited component supply is developed and a simulation model is built to study the performance of multiple freeze fences. In terms of customer service level, the results show that the multiple freeze fences approach performs equally well and even better in certain manufacturing environments compared with the single freeze fence. In terms of end-item inventory, using the multiple freeze fences approach can achieve much lower end-item inventory. It is intuitively believed that higher commonality will result in a higher service level. However, the results of the simulation experiment show that higher commonality may lead to a lower customer service level, except for the case where all components are common.     

CONWIP-based production lines with multiple bottlenecks: performance and design implications

This research focuses on CONWIP, a closed production control system where all containers traverse a circuit incorporating the entire production line. We develop estimates, for an important level of work in process inventory, for four important performance measures: the means and variances of time between departures and flowtime. We develop our estimates through the concept of a “conceptual bottleneck machine”. This concept enables us to develop an analogy between deterministic and stochastic systems. This concept also allows us to handle migrating bottlenecks, an issue generally neglected. The model is widely applicable, assuming only finite means and variances of the processing time distributions. We test our model computationally, both against existing models and on a wide range of randomly generated problems. Finally we detail insights, obtained from our analytical model, into how CONWIP production systems operate. These insights enable us to explain the sources of the values of our performance measures, thus aiding system design and modification.     

Implementation of an object-oriented tool for the simulation of manufacturing systems and its application to study the effects of flexibility

Although there is a reasonable number of currently available modelling tools for the analysis and evaluation of flexible manufacturing systems, these models, in general, neglect flexibility. They do not consider that in a flexible manufacturing system there is the possibility of different operation sequences. As a consequence, while flexibility in manufacturing is much 'in vogue', the development of models that are able to improve the understanding and consequences of having flexibility is still incipient in the literature. This paper presents work to develop a tool to support the analysis of flexible automation. The tool described is an objectoriented discrete-event simulator, called OOSimFlex, capable of modelling different alternative systems design and analysing a manufacturing system using multiple performance measures under different manufacturing flexibility levels. The paper describes the major theoretical concepts employed for the development of a highly flexible and interactive simulation model environment.