Showing papers on "Material flow published in 1990"

Successful Supply‐Chain Management

Abstract: The supply chain is the flow of both information and material through a manufacturing company, from the supplier to the customer. Traditionally the flow of material has been considered only at an operational level, but this approach is no longer adequate. It is now essential for businesses to manage the supply chain in order to improve customer service, achieve a balance between costs and services, and thereby give a company a competitive advantage. Managers must work to integrate the supply chain – i.e. to ensure that all the functions and activities involved in the chain are working harmoniously together. To develop an integrated supply chain means managing material flow from three perspectives: strategic, tactical and operational. At each of these levels, the use of facilities, people, finance and systems must be co‐ordinated and harmonised as a whole. The article describes how this can be achieved in practice by working through three phases: (1) evaluation of the competitive environment; (2) diagnostic review of the supply chain; (3) development of the supply chain, which involves functional integration, internal integration and finally external integration. Companies which develop an integrated supply chain, with all that this involves, will benefit hugely in the marketplace. Those that do not will get left behind in the struggle for survival.

Extrusion Through Controlled Strain Rate Dies

Abstract: The workability of a material during deformation processing is determined by (a) the die geometry which, in turn, determines the flow field during deformation, and, (b) the inherent workability of the material under the imposed processing conditions of strain rate and temperature. Most common alloys have good inherent workability and can be successfully formed over wide ranges of temperature and strain rate. Products can be successfully formed from these alloys even with dies which impose large variations in strain rate during deformation. However, many of the new alloys and composites can be deformed only in very narrow processing regimes, and control of the strain rate during deformation of such materials becomes important. For example, extrusion of a whisker-reinforced aluminum alloy composite is possible only when the strain rate is controlled to within one order of magnitude. This paper describes the development of a method for obtaining preliminary shapes of controlled strain rate extrusion dies, a special case being the constant strain rate die. The theoretical basis for such die design processes is presented, followed by some examples of die geometries. Since this design procedure ignores the material flow properties, the designed die shapes must be verified using the finite element method or physical modeling. Results of simulations with the program ALPID are also presented.

Apparatus for controlling material flow in a fluid dispensing process

Abstract: A fluid dispensing apparatus is provided with a controller for modifying a tool speed signal from a robot and to generate a corrected signal to the dispenser nozzle flow controller which compensates for non-linear flow characteristics of fluids, such as non-Newtonian adhesive fluids, to maintain uniform bead size as the tool speed varies. The corrected tool speed signal is generated by computing the ideal flow for the tool speed signaled, comparing the computed flow with actual flow data stored in a memory using linear interpolation of data between the stored values, and generating a control signal modified in accordance with the comparison. The stored data is acquired by operation in a calibration mode wherein a series of standard signals is sent to the fluid controller while the actual flow at each signal level is measured and stored in a table. The method of operation corrects non-linear flow phenomena such as the shear-thinning effect.

Machining and material flow system design for minimum cost production

Abstract: SUMMARY In many manufacturing organizations, batch production is an everyday occurrence. Usually, the batch size may range from less than ten parts to thousands. The majority of batch manufacturing in the US is in batches of 100 parts or less. Unless adequate control is exercised, potential sources of operational improvements on batch manufacturing systems can be easily overlooked. Two main time consuming activities encountered in batch manufacturing are operations at the workstation level and material handling. Parts can be handled individually or in small lots. In this paper, a methodology for selecting the machining parameters at each workstation and the material flow plan in a multi-stage production system is presented. The model objective is to minimize total production cost. A forward dynamic programming algorithm imbedded within a unidimensional search algorithm is used in seeking a solution to the model. The procedure can be easily computerized for use as a regular shop planning system.

Material flow management in cellular configurations for small-lot, circuit card assembly†

Abstract: SUMMARY This paper addresses questions which arise in analysing the practices that might be effective in managing material flow in cellular systems that assemble circuit cards, including the potential effect of cell design, the role of buffers, the relative effects of traditional management policies, and the influence of material handling equipment. The paper provides a structured method for analysing circuit card assembly systems and suggests guidelines expected to be useful in actual systems.

Process network theory

Abstract: A set of logically consistent, systems-theoretic concepts, principles, and postulates, called process network theory (PNT), for partitioning the physical and biological production processes of economic enterprises into networks of technology-specific elemental processing components is presented. These processing components convert material resources of a given technical form into technically specific products and byproducts at a unit technical cost, through the application of dissipative resources. The transformation is expressed in terms of two distinct classes of performance variables, namely, the material flow rates and their associated technical cost. Specific technologies and the scale of operation appear as parameters in the transformation equations. The material flow rates and technical costs satisfy, respectively, the continuity and compatibility postulates of systems graph theory, thereby providing a theoretical and analytical framework for characterizing the technical and cost performance of the overall production system in terms of the elemental processing components and their interconnection. >

Diaper constitution of sprayed adhesive

Abstract: PURPOSE: To enable a positioning to be carried out accurately in the cross direction of an adjacent semi-cycloidal pattern and to be formed its accurate arrangement by controlling a supplying means and a gas introducing means, and by bringing each associated material flow to a selected track in the direction of a moving body. CONSTITUTION: A nozzle assembling body 10 forms a continuous flow 11 of a hot melt adhesive 12, and a gas jet forms a gas flow and gives a spiral motion to the material flow 11. A pump and a pressure control valve control each material flow 11 and gas flow rate, and bring the material flow 11 to a selected track in the direction of a base body 14. A base body web 14 moves at a selected speed forming a cycloidal pattern on the base body 14 depositing the material. The side fringe 94 of semi-cycloidal adhesive pattern has a change in the cross direction not exceeding about ±0.125 inches to a specified and desired position along the cross direction preventing substantially the interference between the air flow produced by each nozzle unit and the flow of adhesive.

Nonferrous extrusion process control system

Abstract: A control system is provided for coordinating and monitoring material flow through a nonferrous extrusion facility. The system maintains first-in/first-out queues between stations within the facility to improve tracking of the material through the process. The extrusion equipment is controlled in response to the queues and to stored job information to move the material efficiently and automatically through each station within the facility.

Information material flow mapping

Abstract: During recent years integration has been the key issue for many manufacturing organisations The authors review recent developments and ongoing research work and propose a methodology based on existing tools and techniques which would allow integration of the material flow system with the supporting information system

Method and equipment for compressing material consisting of particles

Abstract: A method and a pressing machine for compressing material (7) consisting of particles so that the material is feeded between press surfaces (1, 1'), whereby the cross-sectional area of the material flow decreases in feeding direction of the material. At least one of the pressing surfaces is formed by parallel transfer elements (1, 1'), like balks, moving back and forth in feeding direction, the larger part of the total pressing surface of which is moving in the feed direction at a time than moving backwards. The speed of return motion of the transfer elements is higher than that of the feed motion.