Showing papers on "Material flow published in 1998"

Time compression in the supply chain: information management is the vital ingredient

Abstract: Our total cycle time (TCT) compression strategy encompasses the whole system in the supply chain from consumer demand to customer satisfaction. TCT has two major components that are essential to meeting customer demand: information flow and material flow. Both are necessities and together make up the total supply chain lead‐time; the information activates the material pipeline. Therefore to optimise a time compression strategy TCT must include both the information and material flows. We show in the paper that a very effective way of achieving TCT is via access to EPoS data by all “players” in the supply chain. The tremendous benefits exhibited by TCT compression within the supply chain can be described as “squaring the dynamic response circle”. Not only are the stock dynamic responses improved via time compression, but the capacity dynamics are also radically improved. Therefore TCT compression avoids the dilemma frequently faced by companies when implementing change of having to trade off customer service level against capacity utilisation. Our results are verified using a simulation model of a common real‐world supply chain.

3D finite element method for the simulation of the filling stage in injection molding

Abstract: During the molding of industrial parts using injection molding, the molten polymer flows through converging and diverging sections as well as in areas presenting thickness and flow direction changes. A good understanding of the flow behavior and thermal history is important in order to optimize the part design and molding conditions. This is particularly true in the case of automotive and electronic applications where the coupled phenomena of fluid flow and heat transfer determine to a large extent the final properties of the part. This paper presents a 3D finite element model capable of predicting the velocity, pressure, and temperature fields, as well as the position of the flow fronts. The velocity and pressure fields are governed by the generalized Stokes equations. The fluid behavior is predicted through the Carreau Law and Arrhenius constitutive models. These equations are solved using a Galerkin formulation. A mixed formulation is used to satisfy the continuity equation. The tracking of the flow front is modeled by using a pseudo-concentration method and the model equations are solved using a Petrov-Galerkin formulation. The validity of the method has been tested through the analysis of the flow in simple geometries. Its practical relevance has been proven through the analysis of an industrial part.

Method and device for measuring the flow of bulk materials

Abstract: The disclosure relates to improved methods of designing surfaces whereby to minimize the effects of changes in the coefficients of friction between so-called bulk fluids and the surfaces. The disclosure also relates to surfaces designed in accordance with the methods. A device embodying the invention, for metering the mass flow of bulk material, such as grain or other crop material, comprises a sensor member with a curved surface installed adjacent the outlet of a conveyor. The sensor member is mounted for pivoting about a transverse axis and is subject to a moment resulting from the material flow along its surface. A spring means is provided to keep the sensor member in zero load position. The displacement of the sensor member is proportional to the mass flow rate. Changing friction coefficients μ between the bulk material and the surface will affect the flow pattern therealong, but an array of length and/or inlet orientation angles can be found relative to which the measured moments remain substantially insensitive to these flow changes. Such metering devices may be used in grain and forage harvesters, wherein they need less recalibration under varying harvesting conditions.

An heuristic for configuring a mixed uni/bidirectional flow path for an AGV system

Abstract: An heuristic methodology has been developed in the present work for configuring a mixed (hybrid) uni/bidirectional flow path for an AGV material handling system. The given unidirectional flow path layout, material flow intensities and vehicle travelling time matrix among various processing centres are taken as input information to this technique. A multiplicative function of material flow intensities between any two centres is used as a criterion for selectively configuring a path as a bidirectional one. The highest such product indicates that the shorter path between that pair of centres is a strong candidate for being configured as bidirectional. The heuristic has been applied to an illustrative FMS and various alternate flow path designs have been obtained. Simulation is then performed with the aim of comparing the productive potentials of the facility when it is operated on either unidirectional, or mixed uni/bidirectional, or allbidirectional flow path design alternatives. The benefits of bidirection...

Coriolis flowmeter having its flow calibration factor independent of material density

Abstract: A single tube Coriolis flowmeter of enhanced flow sensitivity in which material flow induces Coriolis deflections in a flow tube and Coriolis-like deflections in a balance bar vibrationally coupled to the flow tube. Both the Coriolis deflections and the Coriolis-like deflections have a phase shift determined by material flow and are used co-adjuvantly to derive material flow information. The flowmeter achieves a constant flow sensitivity over a range of changes in material density by 1) varying the flow sensitivity in a first direction under control of the ratio between the drive mode vibration amplitude of the flow tube and the balance bar and 2) varying the flow sensitivity in an opposite direction under control of the ratio between the Coriolis deflection amplitude of the flow tube and the Coriolis-like deflection of the balance bar. The drive mode vibration amplitude ratio varies with changes in drive mode frequency caused by changes in material density. The amplitude ratio of the Coriolis defection and the Coriolis-like deflection changes with changes in the magnitude of the separation of the drive mode frequency and the second bending mode frequency to the balance bar density which, in turn, is caused by changes in material density.

Method for dispensing a viscous solution

Abstract: A method for substantially dynamic flow control when dispensing a substantially viscous material by means of a dosing system, including at least one dosing unit controlled by means of a computer unit, which dosing unit consists of at least one pressure part, a material container for containing the material to be applied, a nozzle and a pressure member displaceable in the material container. A test sequence is run before the dispensing operation and during the test sequence data is collected mainly about the dosing unit including the pressure within at least one pressure part, the position of the pressure member of the dosing unit, and a material feed pressure by the computer unit, a set value is determined for a material feed pressure and a material flow substantially with regard to the collected data and the material is dispensed with regard to the set value for flow controlled by means of a regulator, as a direct value of the set flow value and at the same time the application flow is controlled.

An Analysis of Variables Influencing the Material Composition of Automobiles

Abstract: The use of materials is studied broadly, because of the environmental problems related to extraction, production, consumption and waste treatment. The use and substitution of materials in products is therefore a relevant issue for environmental policy making. Studies have been done to describe the material flow or to measure the impact of materials or products on the environment. However, these studies do not often consider economic, substitution and dynamic aspects of material flows. Other studies on material flows analyse the relationship between the use of materials and economic growth, but they do not consider substitution between materials. For environmental policy making economic, technological and environmental aspects of the use of materials need to be considered. Especially, substitution of materials is important. In various countries material and product policies are imposed on a variety of materials and products. For evaluation of these policies their environmental and economic effects need to be examined in detail. This study aims to analyse the economic and technological factors influencing the use of materials and the substitution between different materials dynamically. The goal is to obtain an insight in the effect that material levies may have on the use and substitution of materials. The statistical analysis is performed on a specific product-group because decisions on the use of materials are taken on a product-level. The case study is performed on automobiles. The results show that the material use is largely an autonomous development. The price of aluminium has a positive, significant effect on the use of that material. The price of plastics has a positive, but not significant effect on the use of plastics. Reasons may be that the costs of a raw material are small relative to the processing costs, and that the production process can only be changed slowly. Other factors, like competitiveness and consumers' tastes, may be more important for substitution. This implies that levies or subsidies on certain materials is not a promising policy to change the use of materials. Besides time, there are two other factors that have a positive and significant relationship with the use of aluminium and plastics: the fuel efficiency, which is the distance driven divided by the energy used; and, the road tax, which depends on the weight of a car. However, these effects are caused by their positive relationship with time. The main conclusion of the case study is that imposing a levy on materials may not have the desired or expected effect of reduction in material use.

Material flow accounts indicating environmental pressure from economic sectors

Abstract: The environmental performance of human activities is largely determined by the quantity and quality of the associated material flows The extraction of raw materials, on the one hand, and the emissions of waste materials on the other, exert pressures on the environment The material input to the economy (from nature) and the material output to the environment (from the economy) can be accounted for in a balanced manner Based on recent data on the overall material flow account of Germany, the policy relevant information that can be derived from such kinds of physical satellite accounts is described In order to avoid a shifting of environmental problems to other regions, the linkage of material flows with the production of imports and exports (their ‘ecological rucksacks’) have to be considered

Some Drying Aspects of Multistage Fluidized Beds

Abstract: Multistage fluidized beds with and without downcomers to the horizontal perforated plates are used to dry food materials under different experimental conditions. The influence of various operating parameters such as inlet temperature of the heating medium, flow rate of the heating medium, material flow rate, and number of stages have been investigated. The performance of multistage fluidized beds with and without downcomers is compared and the difference in performance is explained based on stagnancy and short-circuiting of materials in each stage.

Identification of material flow systems: Extensions and case study.

Abstract: The paper consists of two main parts. The first part is concerned with different aspects of mathematical modeling of material flow systems for the linear static case. The problems considered are the description of the model class, data reconciliation, identification of subsystems and the analysis of system properties relevant e.g. for simulation. In the second part an application of the modeling tools proposed in the first part to a study on the metabolism of phosphorus in an Austrian region is given.

Method for controlling with precision a process for separating constituents of a mixture, in a simulated moving bed separation system

Abstract: Method for controlling with precision a permanent in-line process for separating constituents of a mixture in a simulated moving bed separation system from concentration and flow rate measurements. The system comprises a set of columns forming a closed loop comprising several zones between fluid injection and draw-off points. Control of the process (linear or nonlinear) is performed from a knowledge model and from a certain number of operating variables at a plurality of measuring points along the loop (concentrations and flow rates for example) and characteristic measurements of the fluids injected and drawn off. Ratios respectively indicative of the ratio, in each of the different zones, between the fluid flow rates and the simulated adsorbent material flow rates, are determined from actual values of controlled variables depending on the measured operating variables (purity of the constituents, system yield, etc.). Values to be given to the operating variables in order to bring or to bring back the controlled variables to predetermined set values are determined from these ratios. The method can be applied for stabilizing separation processes, notably for aromatic hydrocarbons, in the presence of notable feedstock flow rate or quality variations.

An Integrated Model of the Material Handling System and Unit Load Design Problem

Abstract: Material flow system design problems (i.e. facility layout, material handling equipment selection and specification, flow path design, unit load sizing, cell design, warehousing, routing, etc.) have been predominately modelled independently in the past, Independent consideration of each design problem has reduced the solution complexity, but in the process has caused a loss in problem reality. This paper reviews recent developments in integrated approaches to material flow design and presents a model which integrates material handling equipment selection and specification (including material handling interface equipment) and path/load dependent unit load size. The formulation is solved using the meta-heuristic procedure of tabu search to find good solutions to the more realistic (and more complex model formulation.

Qualitative and quantitative testing of flow properties of bulk goods

Abstract: In an apparatus and method, a variable-speed electric stirrer is provided in a run-out funnel (1). A measuring device (2) is connected to the stirrer to detect the torque present during stirring. An electronic weighing device (4) is placed under the run-out funnel for measuring the run-out speed of the bulk material flow.

Modelling of friction in the simulation of metal machining

Abstract: Realistic characterisations of the frictional behaviour at the chip-tool contact region and material flow properties are most critical for successfully simulating metal machining. This paper deals with the former aspect and it describes some recent experimental and theoretical research on the modelling of friction for use in metal cutting simulations. It presents four such models, one obtained from continuous development of the other. The models have been tested against experiment and each other by implementing them in an existing finite element simulation of machining. It has been shown that different friction models used to represent the same friction data yield different simulation results, in particular, the temperature distributions and contact lengths. It has also been shown that friction modelling can be effective up to a certain stage where the information about material flow characteristics at levels observed in machining becomes important. Further exploration of this should be one of the prime areas of machining research.

Material flow and pressure prediction when extruding through bridge dies

Abstract: Extrusion of the alloy 6063 through bridge dies producing hollow shapes is a problem common in the aluminiums industry. This communication reviews previous work on the extrusion of both hollow and solid shapes and presents methods to determine the pressure requirements and assess the difficulty of extrusion of shaped extrusions in general. Material flow through the bridge die is investigated by optical macroscopy and by use of a finite element program. It is shown that the pressure may be predicted by upper bound techniques and that the process has the same thermally activated features as that for rod extrusion. The finite element program appears to predict all the major characteristics of the flow observed macroscopically.

Quench mixing device

Abstract: The utility model relates to a quench mixing device for a fixed-bed reactor in oil refining industry and petrochemical industry, composed of a cold air pipe, a material flow guiding disc, a restrictor, a mixing tank, etc. The utility model is characterized in that two arc inlets A of the mixing tank are arranged on the material flow guiding disc of the quench mixing device; cold air form the cold air pipe and hot material flow from the top enter the inlets A of the mixing tank after mixed; a baffle plate is arranged in the middle of the quench mixing device; the material flow guiding plate is arranged on the baffle plate to cause the material flow to annularly rotate and flow in the mixing tank; meshes D are uniformly arranged on a material flow dispersion disk of the quench mixing device.

How to manage your supply network to get better results

Abstract: The paper aims at providing a network diagnosis tool for the management of supply chains which can be very successful in evaluating and optimizing the performance of supply networks. Therefore, first of all, this paper gives an indication how variances within a supply chain can create great disturbances in the material flow over the own interorganizational boundaries. Analyses have shown that the standard deviation of the material flow of representative A-products can raise manifold along the supply chain. By investigating this phenomenon, also called the bull-whip effect (Lee, 1997), schedule instability was discovered as the root cause. To manage networks and to control the material flow over various links of the supply chain, a methodology, called network diagnosis system has now been developed. Experiences with the application of this methodology have shown that not only the variances can be diminished, but also the cooperation between the different organizations can be significantly improved. Moreover, first results have also revealed, that the awareness of the involved members about the subsequent consequences and effects of local single actions within the supply chain is one of the most critical factors for a successful network management.

Influence of friction on the material flow during precision forging of helical gears

Abstract: At the Institute of Metal forming and Metal forming machine tools (IFUM), University of Hannover, helical gearwheels are produced from cylindrical billets using single state precision forging processes. For a process integrated heat treatment, the workpiece materials need to be carburized already before the forming operation. Thus, in contrast to conventional manufacture, an inhomogeneous case depth distribution is obtained resulting from the material flow during forming. A numerical process simulation with the finite element method (FEM) enables to predict this distribution along the shape of the teeth. The performed experimental and numerical investigations illustrate the influence of friction conditions on the material flow and thus its influence on the case depth distribution.

Material flow accounts: definitions and data

Abstract: The author explains that material flow accounts represent an important tool for cataloging and calculating the apparent and hidden movements of bulk materials through the economy. He also argues that MFA information can be used to design indicators that show the relation between flows and environmental impacts. MFA’s can thus indicate the opportunities for policy improvement at the meta or megascale.

Improving the efficiency and effectiveness of production by materials management

Abstract: The primary objective of this study is to develop a new model for materials management in a case company. The new model improves on-time-deliveries by preventing the lack of material in production and improving the delivery promptness of suppliers. The secondary objectives of the model are to decrease inventories and time spent on the operative purchasing. The first section reviews the importance of logistics in purchasing and subcontracting, and reviews different methods for controlling material flow. The theory of the push system, mainly MRP II (Manufacturing Resource Planning) is compared with the Japanese pull system. Finally, the importance of forecasting and different classification methods of material are described. The second section presents the case company and the main problems of its purchasing process. The task of the study is also specified. The causes of material shortages, material and information flow, inbound logistics, time used by the purchasers, ability of the stock to serve the produ...

Production of building material and apparatus therefor

Abstract: PROBLEM TO BE SOLVED: To provide a process for producing a building material and device capable of discharging even a high-viscosity coating material at a high speed and drawing high-fineness patterns on the surface of a planar material for buildings having rugged patterns without the sag of ink drops. SOLUTION: This process for producing the building material comprises transporting the planar material 8 and discharging the coating material supplied from a coating material tank 1 from a coating material discharge nozzle 5 onto the surface of the planar material 8. A flow passage disposed between a valve 4 and the discharge nozzle 5 hole is pressurized to discharge the coating material from the discharge nozzle 5 when a valve 4 for opening and closing the flow passages disposed in the coating material flow passages to the discharge nozzle 5 is held closed by the valve 4 described above and a pressurizing device for pressurizing the flow passages described above.

Macroscopic modelling of two-phase metal materials

Abstract: Microscopic phenomena of the deformation of two-phase metal materials, material flow, formation and propagation of cracks, motion of broken particles of the secondary phase in the matrix or of the matrix flow in situ are very difficult to be traced. The solution of that problem is presented by macroscopic models enlarged for few orders of magnitude in comparison to the microstructure of real materials. Properties of the single model components are relatively very well comparable to those of the real materials. Two types of models have been made: the first one considered by the tensile deformation, and the second one by more complex way of the rolling deformation.

Vacuum coating device for coating all flanks of base material by turning base material within material flow

Abstract: PROBLEM TO BE SOLVED: To provide a vacuum deposition system which is capable of particularly evenly coating a substrate having intricate shapes with metallic surface film. SOLUTION: A base material holder 6 is formed of a hollow shape material divided to three leg parts 7, 8, 9 extending by forming angles with each other. The base material 3 is held at the end of the third leg part 9. This base material holder is turntable around the ordinate line 1 of the first leg part 7 and is movable back and forth toward this ordinate line. The base material is relatively nonturnably coupled to a driving shaft 12. The free end of this driving shaft is action connected to one motor 21.

Vibration speed change feeder

Abstract: The utility model discloses a vibration speed change feeder for quantitative package or other material feeding occasions The utility model comprises a material slot, an outer housing and a vibration exciter The lower end of the material slot is provided with a material flow regulating plate, and one side of the material slot is provided with a plurality of layers of vibrating plates Gaps are arranged among the vibrating plates The utility model has the advantages of simple and reasonable structure, favorable material feeding performance, uniform exported materials, high precision, high speed, wide material adaptive range, large flow amount variation, no deposition and clogging, etc

Effect of low cost press tool materials on formability of sheet steel

Abstract: The trend to increase the number of vehicle model variants has led to the need for low cost press forming tooling techniques and materials. These materials represent a radical change from traditional tool materials, such as cast iron. The use of such tool materials may significantly alter the behaviour of the material being pressed. The interaction between the sheet and the tool has an effect on the amount of material flow and the level of strain in the formed panel. The results of testing low cost tool materials, with coated and uncoated sheet steel, are presented here and are compared with those obtained using a traditional tool material. The effect of each tool material on the relative level of friction is established, along with the associated change in the strain level and distribution.