The compatibility of durable goods with contingent generic consumables

Many durable products provide value only when used together with contingent services or consumable components, e.g. light fixtures (bulbs), printers (ink), electronics (batteries). Consumers need only have access to the contingent consumable components to continue to derive service from a durable. In fact, many firms rely primarily upon the revenues generated from the contingent services or consumables as the primary source of profitability, e.g. giving away the razors to make money on the blades. Such firms often invest considerable effort into making sure that consumers of their durables are held captive to their own branded consumables by impeding their access to generically available consumables. They do so by designing their products in such a way that they are not readily compatible with the generic consumables. We consider the implications of competition from third-party manufacturers that can provide generic consumables and the manufacturer’s production decisions of a durable good under such contingencies. This allows us to draw managerial insights about how a firm should decide on his product compatibility and production quantity when the generic contingent consumables enter the market.     

A comment on: A note on the EOQ-JIT relationship

In a recently published note in this journal the need for independent control of the production rate (R) and production time (L) was established in order to adapt the economic production quantity (EPQ) model in JIT settings. In this comment we aim to improve the relevance of EPQ in a JIT environment. We focus on two issues, namely, modelling the production rate as a decision variable and also deriving an expession for the optimal number of batches (n* ) for the raw materials and/or subcomponents needed.     

Inspection of an unreliable flexible manufacturing system: with repairable parts and non-negligible inspection times

The purpose of this paper is to address the problem of quality control and repair in an FMS which is described by an open queuing network. We consider two cases: first, all detected defective parts are directed to a special repair facility; second, a defective part is repaired within the machine group where it is detected. Using numerical analyses, we provide some managerial insights regarding the role, position, and distribution of the inspection effort in an FMS, and draw some inferences regarding the design of such FMS when both quality and quantity issues in the FMS are considered.     

Manpower planning for maintenance jobs in process industries

This paper describes a model for allocating the weekly requirement of manpower for maintenance jobs in the process units. We develop a simple procedure for the solution of the manpower allocation problem which has to deal with planned and unplanned jobs during a planning period. The solution procedure is illustrated by a numerical example. Possible extensions of this model are also discussed.     

An industrial application for total productivity optimization

Abstract. This paper presents four strategies for total productivity optimization of a real-life manufacturing company. These strategies are developed to attain overall growth, cost reduction, upgrading of technical efficiency and management effectiveness. Such strategies have been modelled mathematically by using a nonlinear mathematical programming approach. The model base and the data base used in implementing the strategies can serve as decision support to management for optimizing total productivity.     

One-machine scheduling to minimize mean tardiness with minimum number tardy

In this paper the one-machine scheduling problem with the objective of minimizing the mean tardiness subject to maintaining a prescribed number of tardy jobs is analysed. An algorithm for solving this problem is presented. It is proved that the schedule generated by the proposed algorithm is indeed optimal.     

Rough-cut capacity planning for remanufacturing firms

Capacity planning is a critical element of any successful production planning and control system. A method of rough-cut capacity planning is developed, based on the bill-of-resources approach, that can be used to plan for capacity required for firms in a remanufacturing including overhaul repair operations environment. The modified bill-of-resources approach developed takes into account two major stochastic elements inherent in this environment; probabilistic material replacement factors and probabilistic routing files. A detailed example from an actual repair overhaul operation is presented to illustrate the technique.     

An assessment of GRAI Grids and their use in the Strathclyde Integration Method

The purpose of this paper is to present a critical assessment of GRAI Grids as a tool for improved manufacturing integration. GRAI Grids, a key component of the GRAI approach, form an integral part of the Strathclyde Integration Method SIM for manufacturing integration. The contribution of the paper is thus to provide a 'third party' view of the effectiveness of GRAI Grids as a modelling tool. The paper presents a brief overview of the GRAI approach, concentrating particularly on the Grids, and an overview of SIM, showing how GRAI Grids are used. The main section of the paper presents an assessment and critique of GRAI Grids. Several benefits and limitations of the Grid as used in SIM and some suggestions for extensions are presented. The paper concludes that the use of the GRAI Grid, within a methodology, provides a unique insight into the behaviour and design of manufacturing information systems and that those who criticize the technique perhaps do so from a lack of awareness of its concepts, principles and advantages.