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Showing papers on "Material flow published in 1997"


Journal ArticleDOI
TL;DR: In this article, an experimental study was carried out with the objective of understanding and improving the predictive capabilities of the rheological behavior of granular materials in rotary cylinders, and the results of the experiments provided the necessary assumptions, constraints, and data for granular flows in partially filled rotating cylinders.
Abstract: Material flow in partially filled rotating cylinders (rotary kilns) is encountered in many practical applications of material processing, for example incineration, calcination, grain drying, etc. The flow behaviour in the cross-section is important to other transport mechanisms such as mixing and energy distribution within the bed material. The paper describes an experimental study which was carried out with the objective of understanding and improving our predictive capabilities of the rheological behaviour of granular materials in rotary cylinders. Measurement techniques similar to that used in chute flows have been employed to measure flow characteristics, e.g. particle velocities, granular temperature, and solid concentration (in the shear layer developed between the free surface and the bulk of the bed) for different materials having a wide range of coefficients of restitution. The results of the experiments provide the necessary assumptions, constraints, and data for granular flows in partially filled rotating cylinders.

133 citations


Journal ArticleDOI
TL;DR: In this article, the results of orthogonal cutting tests on electroplated nickel-phosphorus (15% phosphorus) and AISI 52100 bearing steel are presented and compared.

104 citations


Journal ArticleDOI
TL;DR: In this paper, the authors unify their contributions to material flow engineering and show how present day system design methodologies incorporate their ideas on best practice, particularly relevant to the product delivery process (PDP).
Abstract: The post World War II Industrial Revolution has driven production away from the old 'economies of scale' to the new 'economies of scope'. Apparently Japanese led, the associated roots of present good practice on material flow can be traced back in the USA to Jay Forrester and in the UK to Jack Burbidge. Specifically, in the supply chain scenario, Forrester exposed the importance of system structure in relating and integrating information flow with material flow. Similarly Burbidge led the way in exploiting cycle time reduction, synchronization of orders throughout the chain, simplified product structures, and streamlined component flows. This paper unites their contributions to material flow engineering and shows how present day system design methodologies incorporate their ideas on best practice. These principles are particularly relevant to the product delivery process (PDP) which governs material flow in supply chains.

94 citations


Journal ArticleDOI
TL;DR: In this paper, the use of pipeline feedback to ensure good control of material flow systems has been developed over the years on a pragmatic basis, which has led to recommendations for good parameter settings which may be used with confidence when applied to a particular generic decision support system (DDS) known as the To-Make model.
Abstract: The use of pipeline feedback to ensure good control of material flow systems has been developed over the years on a pragmatic basis. More recently, the mechanism by which the improved control is achieved has been the subject of theoretical analysis. In turn, this has led to recommendations for good parameter settings which may be used with confidence when applied to a particular generic decision support system (DDS) known as the “to make” model. One consequence of utilizing pipeline feedback is the enhanced damping capability of this system. In our experience, many supply chains may be represented by the coupling together of a series of To‐Make models. In this paper, we show that the use of supply chain feedback within each echelon greatly reduces the order amplification as it proceeds upstream from the market place. Using as an example a model of the Beer Game Supply chain, it is concluded that demand amplification is readily reduced by a factor of 2:1.

72 citations


Journal ArticleDOI
TL;DR: The modeling process and the methodologies employed to address the material flow issues in a large-scale manufacturing process, namely the assembly of automobiles in a highly automated plant in Italy are illustrated.

61 citations


Journal ArticleDOI
TL;DR: In this paper, a closed loop control which uses the friction force as control parameter and the blank holder force (BHF) as feedback parameter is used to realize the predetermined friction force curve over the stroke, even if the tribological conditions between the sheet metal and the upper and lower binder will change.

52 citations


Journal ArticleDOI
TL;DR: In this paper, an allocation method for the cascade recycling system that considers both quality and quantity of a material used is proposed, where the quality of material as well as the material flow should be considered.
Abstract: Allocation in LCA is defined as partitioning the responsibility for environmental burdens from the economic activities to a reference flow or a reference life cycle system in some proper shares. The result of LCA study involving a multi-input/output system or an open loop recycling system is affected significantly by the choice of the allocation method. For the case of allocation in a cascade recycling system, the quality of material as well as the material flow should be considered. Therefore, environmental burdens from the primary material production, the recycling process and the waste management process have to be allocated in proportion to the quality degradation of a material and to the quantity of a material used in each life cycle system. This paper proposes an allocation method for the cascade recycling system that considers both quality and quantity of a material used.

48 citations


Journal ArticleDOI
TL;DR: In this paper, a due date assignment model (DDAM) was constructed by using the simulation method and queuing theory to find a suitable WIP level and then control the material release by fixed-WIP policy.
Abstract: High work-in-process (WIP) level, long manufacturing lead time, high lead time variation, and poor due date performance are the major problems for wafer fabrication factories. An order's due date relates to its releasing time and flow time. Due date performance will not be improved if WIP level is high and material flow is unstable. Too high WIP level cannot increase throughput but lengthens lead time. Find a suitable WIP level and then control the material release by fixed-WIP policy. In this paper, we construct a due date assignment model (DDAM) by using the simulation method and queuing theory. Observing the results of simulations, the lowest system WIP level corresponding to the desired up-time machine utilization rate of the bottleneck resource or the capacity constraint resource (CCR) and the shortest mean flow time can be found. To make the material flow stable, we also propose the methodology of determining a wafer's WIP level, daily moves, and flow time for each product type and for each circuitry layer; all of these can be used as the parameters for controlling flow time. Demonstration of the DDAM is provided with actual data. Comparing the performance of our DDAM with others, the results reveal that DDAM performs well in each performance criterion.

38 citations


Proceedings ArticleDOI
01 Jul 1997
TL;DR: In this article, the authors focus on modeling an industrial cement grinding circuit using physical arguments and experimental data, which consists in a mixed set of algebraic and partial differential equations, which can be used to gain some insight into the process dynamics and design control loops to achieve product specifications.
Abstract: This paper focuses on modeling of an industrial cement grinding circuit using physical arguments and experimental data. The resulting "gray-box" model, which consists in a mixed set of algebraic and partial differential equations, can be used to gain some insight into the process dynamics and design control loops to achieve product specifications. Several multivariable control schemes using the feed rate and the classifier speed as manipulated variables, and the circulating material flow rates and/or the fineness of the product as controlled variables, respectively, are compared and the influence of disturbances, i.e., variations in the material grindability, is investigated.

21 citations


Patent
10 Feb 1997
TL;DR: In this paper, a plate for reducing wear by a material flow, according to the present invention, includes a body having at least one surface exposed to the material flow and a rod which has a distal end and a proximal end.
Abstract: A plate for reducing wear by a material flow, according to the present invention, includes a body having at least one surface exposed to a material flow. At least one bore is formed in the body through the surface of the body exposed to the material flow. Also included is at least one rod which has a distal end and a proximal end. The rod is immovably secured in the bore. The distal end of the rod is positioned a distance beyond the surface of the body exposed to the material flow.

20 citations


Journal ArticleDOI
TL;DR: This paper looks at the MFA problem as a particularly structured system identification problem with special emphasis on the linear, static case, where a procedure for reconciliating the flow measurements and for estimating the unmeasured flows and the transfer coefficients by taking into account a priori restrictions such as balance equations.
Abstract: Material Flow Analysis (MFA) has become an important instrument in environmental science and pollution research. In this paper, we look at the MFA problem as a particularly structured system identification problem. Special emphasis is given to the linear, static case, where we describe a procedure for reconciliating the flow measurements and for estimating the unmeasured flows and the transfer coefficients by taking into account a priori restrictions such as balance equations.

Journal ArticleDOI
TL;DR: In this article, a movable container, which is axially driven by an actuator while the billet is squeezed by the punch, is employed to reduce the forming pressure of precision forging to a feasible level.

Patent
Craig R. Gustin1
18 Mar 1997
TL;DR: In this article, a paving machine with a screed assembly has at least one pivotally mounted flow control gate operably connected to a selectively controllable actuator for actuating the gate to a flow preventing position and flow permitting position.
Abstract: Material flow management apparatus for a paving machine having a screed assembly, including at least one pivotally mounted flow control gate operably connected to a selectively controllable actuator for actuating the flow control gate to a flow preventing position and flow permitting positions, the flow control gate mounted immediately adjacent the outer edge of the main body of the screed assembly to variably control the volumetric flow of paving aggregate from the main material reservoir preceding the screed main body and ensure a suitable volumetric material supply to the secondary material reservoir preceding the variably extensible screed extension body.

Journal ArticleDOI
TL;DR: In this article, the authors developed a model of the economic system to account for every production process and derived carbon embodiment functions that evaluate the embodied carbon emissions of an arbitrary product in terms of material content.

Patent
10 Jun 1997
TL;DR: In this article, methods and apparatuses for manufacturing a semiconductor device package utilizing a lead frame which has one or more encapsulant material flow diverters are presented. But the lead frame having material flow diversters includes a multiplicity of leads and at least one material flow flow diverter.
Abstract: Disclosed are methods and apparatuses for manufacturing a semiconductor device package utilizing a lead frame which has one or more encapsulant material flow diverters. The lead frame having material flow diverters includes a multiplicity of leads and at least material flow diverter. The material flow diverter is arranged in such a manner as to control the amount of encapsulant material which is directed both above and below an attached die during the encapsulation process.

Journal ArticleDOI
TL;DR: In this paper, the flow of material during injection forging of solid billets is quantified and an approach for the design of preforms to eliminate the development of flaws is proposed.
Abstract: During injection forging, the ratio of axial and radial deformation of each section of billet in the diecavity prescribes the pattern of material-flow, thereby determining the scope of the process and the quality of the product. To date, research on the quantification of the pattern of material-flow has been superficial; the models which were used invariably referred to particular conditions. FE simulation and corresponding experimental analyses were conducted with a view to characterising the flow of material during Injection Forging of solid billets and enabling the definition of the practical process range and a proposal for an approach for the design of preforms to eliminate the development of flaws.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a solution for the analysis of polymer flow processes in extruder screws that will consider the slip condition of polymer melt, avoiding additional and lengthy determinations of material data from the user's side.
Abstract: The analysis of polymer flow processes in extruder screws is usually based on the wall-sticking behaviour of these materials. There are however some materials, among them the ultra high molecular HOPE and the polyvinylchloride (PVC), which may be wall-slipping plastics under certain conditions. The existing theories for the flow calculation of these materials are difficult to apply in screw design, due to the highly sophisticated material data to determine the slipping velocity at the wall. This paper therefore tries to suggest a solution which will consider the slip condition of polymer melt, avoiding additional and lengthy determinations of material data from the user's side. The target is not to do research work in the detailed analysis of wall-slipping, but to introduce this kind of material behaviour in the normal flow analysis for screw design. The theory in this paper needs only the results of measuring the temperature and shear-rate dependent viscosity. It is assumed that the critical wall shear stress that marks the beginning of wall-slipping is only a function of the temperature and not related to the flow channel geometry. Equations are performed for the throughput and temperature behaviour. They were included in the software package REX for the computer-aided simulation of single-screw extrusion processes. The experimental verification was done by comparing the theoretical results with experimental data from a 45 mm single screw extruder processing various PE-HD. The results show a satisfying accuracy, taking into account the target of the work. The process behaviour of wall-slipping materials can be determined with the same accuracy as that of wall-sticking materials.

Patent
30 Jan 1997
TL;DR: In this paper, a process sequence in a subprocess is subdivided into four steps, referred to as quarter cells, with each quarter cell containing a point in time, a time range to describe possible process time fluctuations, the name of the previous quarter cell, and a marker of whether the process time fluctuation of this subcell is influenceable or non-influenceable.
Abstract: A process and a device for comprehensive control of a basic industry plant, such as a steel plant or an integrated iron works, which includes subprocesses that are critical with regard to continuous material flow, eg, casting processes The invention optimizes the material flow through the system and prevents the interruption of the material flow prior to the start of subprocesses that are critical with regard to continuous material flow The process sequence in a subprocess is subdivided into four steps, referred to as quarter cells with each quarter cell containing a point in time, a time range to describe possible process time fluctuations, the name of the previous quarter cell, ie, the name of the previous substep of a subprocess, as well as a marker of whether the process time fluctuation of this subcell is influenceable or non-influenceable


Patent
18 Nov 1997
TL;DR: A machine for compacting organic material such as silage and inserting the compacted material into an elongate elastic bag is described in this article, where a rotor positioned at an inlet of a tunnel propels and compacts the material, and a barrier positioned in the tunnel strategic to the rotor restricts the flow of material directly into the bag.
Abstract: A machine for compacting organic material such as silage and inserting the compacted material into an elongate elastic bag. A rotor positioned at an inlet of a tunnel propels and compacts the material. A barrier positioned in the tunnel strategic to the rotor restricts the flow of material directly into the bag. The barrier forces the material to flow through the barrier and upwardly over the barrier to insure complete filling of the bag. The barrier may be immovable or may be arranged to be pivoted to alter the resistance to the material flow.

Patent
Siegfried R. Wissmann1
10 Jan 1997
TL;DR: In this paper, a dual flow divider is configured to separate the melt stream received from the extruder at a central entry into two flow channels, the respective channels being formed as nearly to identical (mirror image) as possible.
Abstract: The present invention provides a dual flow divider for use on an extruder The flow divider is configured to separate the melt stream received from the extruder at a central entry into two flow channels, the respective channels being formed as nearly to identical (mirror image) as is practically possible The relative flow in the respective channels can be varied by rotating a diverter valve that extends to a position adjacent the central entry of the flow divider, ie, where the flow begins to divide The flow channels and control end of the diverter valve are specially configured to avoid any shape or surface conditions that would impose heat-generating restrictions to material flow, and/or allow areas of stagnation in the flow stream More specifically, the flow channels are machined to provide smooth, streamlined transitions at all points along the flow path The surfaces of the flow channels which intersect with the diverter valve do so at a sharp edge; this geometry blends the surfaces of the channels and valve while also serving as a "wiper" when the valve is rotated


Patent
30 Oct 1997
TL;DR: In this article, an improved methods of designing surfaces (53,453) were proposed to minimize the effects of changes in the coefficients of friction between so-called bulk fluids and the surfaces.
Abstract: The disclosure relates to improved methods of designing surfaces (53,453) whereby to minimise 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 (21) embodying the invention, for metering the mass flow of bulk material, such as grain or other crop material, comprises a sensor member (51) with a curved surface (53) installed adjacent the outlet of a conveyor (12). The sensor member (51) is mounted for pivoting about a transverse axis (P) and is subject to a moment (M) resulting from the material flow along its surface (53). A spring means (66) is provided to keep the sensor member (51) in zero load position. The displacement of the sensor member (51) is proportional to the mass flow rate. Changing friction coefficients µ between the bulk material and the surface (53) will affect the flow pattern therealong, but an array (70) of length and/or inlet orientation angles can be found relative to which the measured moments (M) 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.

Patent
02 Oct 1997
TL;DR: In this article, the heat content and the temperature profile of a slab are calculated by means of a mathematical-physical model, proceeding from the known temperature of the liquid phase at the mold exit, the known physical slab parameters, the convective spreading of the heat within the slab, and the time-dependent inhomogeneous heat transfer to the respective surrounding media.
Abstract: The heat content and the temperature profile of the slab are calculated by means of a mathematical-physical model, proceeding from the known temperature of the liquid phase at the mold exit, the known physical slab parameters, the convective spreading of the heat within the slab, and the time-dependent inhomogeneous heat transfer to the respective surrounding media. The calculation result, possibly in combination with the measured surface temperature, is used to control the material flow in an existing installation.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the relationship between material flow patterns in a manufacturing system and the distribution of the volume distance values associated with all possible solutions to a line layout problem.
Abstract: An empirical investigation is focused on the relationship between material flow patterns in a manufacturing system and the distribution of the volume distance values associated with all possible solutions to a line layout problem. Volume distance distribution for line layout problems are shown to follow roughly normal distribution for some common material flow patterns. Based on this result, sampling procedures are described for estimating the parameters of volume distance distributions and proposed as a basis for formulating satisficing criteria for use with heuristic line layout procedures. Subsequent empirical studies suggest relatively low levels of error are observed in the estimation of volume distance parameters for most material flow patterns. These results suggest that volume distance sampling and material flow analysis procedures may have practical value in the development of cost effective stopping criteria for heuristic line layout methods.

Book ChapterDOI
01 Jan 1997
TL;DR: A tool flow system, TFS, is an integral part of a wider system within a Flexible Manufacturing System, FMS: the Material Flow System as mentioned in this paper, which also includes the Work Flow System.
Abstract: A Tool Flow System, TFS, is an integral part of a wider system within a Flexible Manufacturing System, FMS: the Material Flow System. This also includes the Work Flow System.

Patent
18 Jul 1997
TL;DR: In this article, a material flow control valve is constructed in the annular space around the air plenum by using a fixed plate and a rotatable plate, each with matching holes.
Abstract: An air plenum is located within a conduit forming a spout for a granular material supply tube, and air is fed through the air plenum while granular material flows around the plenum and out of the spout. The moving air carries the material away from under the spout and permits the receiving compartment to be completely filled. A material flow control valve is constructed in the annular space around the air plenum by using a fixed plate and a rotatable plate, each with matching holes. If material accumulates to a height blocking the spout, a level sensor within the spout activates a pneumatic cylinder which causes the material flow valve to close by misaligning the holes. The continuing air flow then distributes the material throughout the receiving compartment, and when the level sensor is free of material the flow valve reopens. A pressure sensor in the air system also controls the granular material flow to shut off the flow when the air pressure builds up because the receiving compartment is full.

Patent
24 Feb 1997
TL;DR: In this paper, a system and 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 (13, 113, 213, 313) controlled by a computer unit, is presented.
Abstract: A system and a method for substantially dynamic flow control when dispensing a substantially viscous material by means of a dosing system (10), including at least one dosing unit (13, 113, 213, 313) controlled by means of a computer unit (15), which dosing unit consists of at least one pressure part (20, 21, 120, 220), a material container (22, 122, 222, 322) for containing the material to be applied, a nozzle (24, 124, 224, 324) and a pressure member (25, 125, 225, 325) displaceable in the material container (22, 122, 222, 322). In the system, the data is collected substantially about the dosing unit (13, 113, 213, 313) from the computer unit (15) in a first stage, 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.

Journal ArticleDOI
TL;DR: In this article, a knowledge-based system was used to design the die angles and a multi-stage cold forming sequence process to manufacture the injector nozzle, which can provide higher strength and tighter dimensional tolerance.
Abstract: Higher strength and tighter dimensional tolerance is desired for the injector nozzles to attain high injection pressures for lower NOx and particulate emissions. Cold forming is an alternate method which can provide these characteristics replacing the present machining operation. Upset tests were carried out to study the flow stress properties for selecting a suitable material for this part. A knowledge-based system was used to design the die angles and a multi-stage cold forming sequence process to manufacture the injector nozzle. Finite Element Modeling was used to do the punch design and to optimize the punch loads and punch pressures for each stage of the forming process. Initial sequence design was modified based on the results of numerical modeling. The tooling was designed and experimentation was done to verify the formability and material flow.

Patent
10 Sep 1997
TL;DR: In this article, the authors proposed a utility model for a single-helical packing machine, where two parallel material pushing cavities are communicated under a hopper, each pushing cavity is respectively provided with a screw rod driven by an electric motor, and the front end of a material discharging cavity is provided with flow limiting board controlled by a weighing batcher.
Abstract: The utility model relates to a cement packing machine, two parallel material pushing cavities are communicated under a hopper, each material pushing cavity is respectively provided with a screw rod driven by an electric motor, and the front end of a material discharging cavity is provided with a flow limiting board controlled by a weighing batcher. Compared with the common double-nozzle single-helical type packing machine, the utility model has smooth material flow, little resistance and small vibration. The flow limiting board of a material discharging opening can accomplish the control of the dimension of the flow, and the stability and the reliability of weight measurement can be assured.