R I McIntosh

Rapid changeover - a pre-requisite for responsive manufacture

The ability to effect rapid changeover on a manufacturing line, from one product to another, is a key pre‐requisite for increased flexibility, lead time reduction and responsive manufacture. However it is a rarity for changeover times to be part of the design specification of a new machine tool or tooling system and even when it is, there are few design guidelines for translating the required changeover time into reality. This paper describes a set of “design for changeover” rules that have been derived from action research, carried out within a variety of companies. The rules address the design of machines, tooling, ancillary equipment and the products themselves and their use has been shown, through case studies, to lead to a significant reduction in changeover time and a leaner, more responsive manufacturing environment.

An assessment of the role of design in the improvement of changeover performance

Discusses the derivation of current changeover improvement methodologies from the work of the Japanese engineer/consultant Shigeo Shingo. Argues that under the interpretation and widespread adoption of the single minute exchange of dies (SMED) philosophy, substantive design‐based solutions are being overlooked in favour of incremental, low cost, team‐based approaches which emphasize organizational changes to the changeover. Identifies difficulties which can arise with existing approaches to changeover improvement and the relative merits of emphasis on design or organization are discussed. Pays particular attention to the problems which have been observed in sustaining levels of improvement.

Late customisation: issues of mass customisation in the food industry

The strategy of mass customisation is being increasingly adopted as companies seek to exploit market trends for greater product variety and individualisation. The implications of changing to mass customisation practice are considerable, where traditional contradictions of high volume and extensive product variety require being reconciled. The literature discusses the need for an integrated approach to mass customisation across all business functions if micro-segmentation of markets is to be profitably pursued, and the current paper investigates extending the paradigm of mass customisation into the, until now, poorly represented sector of food processing. Product design and manufacturing system design for mass customisation are reviewed and contrasted with good practice in more traditional mass customisation industries.

Changeover Improvement: Reinterpreting Shingo's “SMED” Methodology

A rapid changeover capability is widely acknowledged as an essential prerequisite to flexible, responsive small batch manufacturing. Its importance in mass customization is recognized, where minimal losses need to be incurred as manufacture switches between differing products. Retrospective improvement of existing changeover practice is often undertaken, arising from pressure to respond better to customer demands, wherein improvement personnel frequently engage Shigeo Shingos Single Minute Exchange of Die (SMED) methodology to achieve better performance. Irrespective of the improvement methodology that is employed this paper assesses two fundamental mechanisms by which better changeovers might be achieved. First, improvement can occur by altering when tasks are conducted. Better allocation of tasks to the resources necessary to conduct them is sought, where the tasks themselves remain essentially unchanged. The second mechanism is to seek structural change to existing tasks, thereby intrinsically enabling them to be completed more quickly. These two mechanisms are described in relation to use of the SMED methodology, where it is argued that, by reinterpreting Shingos work, greater clarity of potential improvement options can be gained

Changeover improvement: A maintenance perspective

Abstract The current paper assesses on-machine maintenance in the context of recent work to improve changeover performance. It is argued that techniques employed to improve changeovers equally might be applied in maintenance situations. With brief reference to case studies from the authors’ research, it is further argued that focused maintenance activity can also directly influence changeover performance, particularly by ensuring that items involved during a changeover (change parts, product, fixed machine components and consumables) are in satisfactory condition. The role of design to improve either changeover or maintenance performance is also discussed. Design rules that might be employed are introduced.

Set-up reduction (SUR) beyond total productive maintenance (TPM)

Abstract There is a growing awareness of the importance of set-up performance in multiproduct manufacturing environments. This paper contrasts the potential business contribution of conducting set-up reduction (SUR) as an initiative in its own right with the contribution SUR will make as a component part of a rigorously conducted total productive maintenance (TPM) initiative. It is argued that under TPM a business can easily fail to recognize the global impact of SUR and fail to take the opportunities afforded by improved setup times. It is demonstrated that in the nature of TPM, and in the manner in which it is implemented and measured, there is pressure to move away from responsive, small-batch manufacture that SUR promotes. While there is a growing awareness of SUR benefits, there are relatively few reported cases in which sustained long-term improvements have been seen. One reason for this is that although faster changeovers are perceived as a ‘good thing’, there is little in-depth analysis of their impact on overall business performance. A classification is proposed against which the potential SUR benefits may be assessed and the commercial opportunities that can arise through having a more responsive manufacturing system are also highlighted.

A new-generation automated warehousing capability

A novel and highly adaptable concept is presented whereby automated warehouses can be built based on a series of simple modules with their inherent feature of scalability and reconfigurability. A potential application example of such a warehousing system is modelled to indicate the level of capability that the concept can provide. Physical infrastructure and operational control events within the system are illustrated in the paper. Simulation results demonstrate that this type of automated warehousing system can simultaneously deliver large numbers of items from storage modules to assigned collection locations with minimal delay. The concept is readily applicable within the wider logistics sector. The system performance can be enhanced by deploying an integrated warehouse control and management mechanism using automatic identification and data capture techniques and wireless communication networks. A framework on application of these emerging technologies in order to achieve the desired coordinated functionality of automated warehouse operations is proposed in the paper.

A formal design for changeover methodology. Part 1: theory and background

Abstract A rapid changeover capability is central to todays thinking in respect of responsive, small batch manufacturing. Mass customization and other modern manufacturing paradigms have prompted companies to adapt swiftly to market turbulence and at the same time avoid the traditionally high unit costs associated with custom-made or small-volume products. Historically, an operation-focused approach has been adopted in reducing changeover times; however, it is argued that there is a significant benefit if there is a focus on equipment design. There is a considerable challenge to design and build cost-effective changeover-capable equipment. This challenge would be greatly assisted by the availability of a coherent design for changeover (DFC) methodology. The authors have been researching the changeover area for many years and present their latest thinking in two parts. In the first part of this paper the basic concepts for a formal DFC methodology are introduced. Drawing lessons from various existing DFX methodologies, including design for assembly and design for variety, these concepts set out the basics for a novel DFC methodology. The debated DFC methodology is presented in the second part alongside an illustrative case study [1].

Review of fast tool change systems

Abstract The key to success in many manufacturing businesses is a move toward a leaner, more flexible, more responsive manufacturing environment. The ability of a company to change over rapidly from one product to another is essential if this move is to be achieved. There is a significant amount of information in the literature on specific ideas that have been used to reduce changeover times, but in the vast majority of cases this rich source of data is ignored by companies undertaking changeover reduction programmes. Research has shown that, although some companies have a genuine desire to ‘reinvent the wheel’, the main reason why companies fail to tap the information source is that it lacks structure and focus. This review brings together information from research literature, journals, conferences, industrial collaborations and trade and technical literature. The information has been classified, and is presented here as an overview of the state of the art techniques for reducing changeover times.

Sustaining changeover improvement

Abstract The role of rapid changeover in todays manufacturing environment is widely acknowledged. Tools to improve changeovers—typically Shingos ‘SMED’ methodology—are well known. However, little work has been done to establish whether changeover gains have been sustained in differing industrial environments once initial improvement has been achieved. This paper investigates sustaining changeover improvement, investigating factors that contribute to this outcome.