Showing papers on "Material flow published in 1995"

Facilities layout design optimization with single loop material flow path configuration

Abstract: Here we formulate the facilities layout design optimization problem for a single loop material flow path configuration. Because of the NP-bard nature of the overall search space, we employ a genetic approach to sample the decomposed search spaces. In addition we analyse the following features of the problem: (1) we estimate lower bounds for the unidirectional flow problem along the loop by analysing the bidirectional flow problem; (2) we intelligently sample the search space by designing a knowledge-augmented genetic operator for layout cases with very low flow path dominance because the regular genetic search does not perform very well in such cases; and (3) we exploit qualitative constraints for reducing travel distances in highly circuitous flow paths.

Literature review of material flow control mechanisms

Abstract: We review mechanisms which control the flow or material into and within a manufacturing line. These material flow control (MFC) mechanisms address the problem of when to release material into a manufacturing line and when workcentres should be authorized to produce. The MFC mechanisms reviewed include: Kanban, CONWIP, workload regulating, starvation avoidance, BORA, maximum load limit, MRP, the base stock system, workload control, and production authorization cards.

An introduction to the segmented flow approach for discrete material flow systems

Abstract: Due to increases in versatility and the complexity of demands in modern manufacturing systems a growing need has evolved t0 simplify the control of these systems while maintaining a high degree of efficiency and flexibility in operation. The segmented flow approach (SFT) suggested in this paper is a possible solution to these needs. This structure simplifies the control task by reducing the need for dispatching and by eliminating the need for routeing material handling devices and scheduling traffic at intersections. Each task involves only one material handling device and one possible route. This structure maintains a high degree of efficiency by operating material handling devices in a bidirectional mode and eliminates congestion and blocking by operating them on mutually exclusive tracks. This paper introduces a design procedure for an SFT implemented system using a minimum cost objective, and compares the throughput and time in system performance of this system to a conventional system and a tandem ty...

Network design models for discrete material flow systems: A literature review

Abstract: The effectiveness of a material handling system depends on several factors, among them a well-thought-out flow-path design. The flow path has a significant effect on the travel time, the operating expenses, and the installation costs of the system. Moreover, the flow-path configuration has a significant impact on the complexity of the system's control software. The literature review presented in this paper describes several approaches to the design of material flow networks, including conventional type systems and more recent developments like the single-hoop, tandem configuration, SBSL, and SFT.

Precision cold die forging of a ring gear by divided flow method

Abstract: The process utilizing divided material flow is applied to working a ring gear. When the specimen is of a larger height and the ratio of the height to the radial thickness is large, the central material flow in the radial direction produces a time lag in both the upper and a lower material flow which causes a product defect. The theoretical calculation suggests that the above phenomenon can be eliminated when the side shppe of a specimen is swollen at the central portion. Various experiments are carried out based on the above estimate. The experiment makes clear that it is useful to swell the side shape. When the side shape is that of a beer-barrel with a small radius of curvature, the working pressure is reduced. A ring gear of high accuracy can be forged under the mean pressure of about 2.6 times the final uni-axial compressive yield stress of the worked material.

Infrared wood product dryer

Abstract: An infrared wood product dryer apparatus (10) constructed in accordance with the invention broadly includes enclosure structure (12) defining an interior (20), a conveyor assembly (14) configured for conveying a particulate material along a material flow path through the interior (20) substantially between an inlet (22) and an outlet (24), an array of infrared radiant energy sources (22) configured for exposing the material to infrared radiant energy while it is conveyed along the path (38), and a series of agitators (18) configured for agitating the material in order to increase the exposure of the material to the infrared radiant energy A gas recirculation assembly (52) is provided to direct a heated interior gas onto the material in order to convection-dry the material An exhaust assembly (62) reduces the moisture content of the interior gas by drawing a quantity of the gas from the dryer (10) so that fresh gas having a lower moisture content may be drawn into the dryer (10) A method of drying a particulate cellulosic material includes conveying the material along a material flow path, exposing the material to infrared radiant energy during the conveyance along the path, and agitating the material during the conveyance along the path

The mechanical behavior of zinc during machining

Abstract: It is well known that a nonzero force is obtained when cutting forces measured at different feed rates but otherwise constant cutting conditions are extrapolated to zero feed rate. In the literature, this nonzero intercept has been attributed to a ploughing effect associated with the finite sharpness of the cutting tool. However, the standard extrapolation method does not account for other variables such as strain, strain rate and temperature which also vary with feed rate and influence the work material flow stress. In this paper, the apparent flow stresses measured in high and low speed machining tests on zinc are compared with the flow stresses measured in compression tests. The results show that the flow stress measured in cutting is consistent with that measured in compression when all deformation variables are properly accounted for and that, contrary to the results obtained using the extrapolation approach, the ploughing force is negligible.

Apparatus for applying conformal coatings to electronic circuit boards

Abstract: Apparatus for producing intermittent, discrete patterns of coating material onto discrete irregular substrate areas, such as electronic circuit boards, where the patterns have sharp, square leading and trailing edges, as well as side edges. A slot nozzle die has elongated air slots along the slot extrusion opening. In the operation of the apparatus, the air flow is initiated from both air slots prior to the initiation of the coating material flow. Also, the air flow is continued beyond that point in time, when the coating material flow ceases. The delays between the operations of the air flow and the hot melt flow are on the order of micro seconds. Alternatively, the lead and lag air start and stop times on each side of the film of coating material are different to control the exact disposition of the square cut-on and square cut-off coating edge on the circuit board. The air flow carries the film coating material to the circuit board for deposition in discrete areas thereon. The sharp cut-on and cut-off accommodate multiple discrete area coating or multiple automated circuit board coating. Methods are disclosed.

Mass flow generator

Abstract: An insert system for changing the pattern of material flow in a bulk storage hopper during the discharge process, from a form where a channel flow develops within a mass of smile material into a form where the entire stored contents are caused to flow. This change is affected by the provision of insert members supported within the hopper, which modify the stress pattern in the flowing contents to allow the bulk material to deform more readily and for slip to take place on all contact surfaces between the material and the hopper walls.

Work-in-process space allocation: a model and an industrial application

Abstract: This paper presents a model for allocating storage space to inventory in a way that minimizes the cost of material handling. The space allocation problem is modeled as a generalized transportation problem; however, transporting material within the facility is the focus. The basic formulation of the model considers material type, material flow transitions, and distance transported. The model is extended to determine production levels for multiple products such that additional material handling costs (i.e., load/ unload times) are minimized. Applications of the just-in-time (JIT) concept and material handling in the job shop environment are discussed. Finally, an industrial case study is presented.

Dual flow divider with diverter valve

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, i.e., 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.

Design and implementation of a hybrid manufacturing facility

Abstract: A method for the design of hybrid, cellular/functional, facilities is presented in this paper. This method targets the minimization of inter-cell material handling and the maximization of intra-cell directional material flow. Furthermore it develops a shop redesign plan that maximizes the net benefit obtained from the facility rearrangement.

Cycling residues. Potential for increased transportation demands due to recycling of materials in Sweden

Abstract: This paper discusses in general terms the potential risk that increased recycling of materials in the technosphere may lead to significant changes in freight transportation demands. Such cyclic, as opposed to linear, material flows are proposed as one step towards an environmentally sustainable use of resources. Total volume of transported annual material flows in Sweden are estimated in order to provide a background for the analysis of transport demands: • Raw material 210 Mton • Products 165 Mton • Residues from production 20 Mton • Residues from consumption 10 Mton The difference in volume between raw material and products is explained by foreign trade, generation of residues and indefinite data. The difference in products compared to residues can primarily be explained by an increasing stock of materials in society, large pollution flows (e.g., CO 2 ), and that resources have a higher water content than residues. On a qualitative basis, it can be argued that a drastic increase of transportation demand can not be expected by increased recycling. A decrease of transported raw material is expected for some sectors, while only limited increase of residue transports. Furthermore, it should also be observed that the problem of residue/waste transportation is very small compared to the environmental impact of the total transportation sector. The main conclusion is therefore that the expected changes in transportation demand due to increased reuse and recycling, are not a general hindrance against introducing a more cyclic material management.

System for calibrating measurement of material flow on agricultural working machine

Abstract: The system has a material flow deflection system (22). The material flow after passing a measuring unit (28) is deflected by the deflection system selectively, for diverting the flow to a calibration unit (24), where it is weighed. The calibration operation is automatically and/or manually introduced, e.g. at selected time rates, with the switching on of the amount measuring, with a change of the conveyed medium. The material flow deflection depends on the positions of the individual conveyor elements, the conveyor speed and/or results for a selected time cycle.

Coating device using alrless autogun

Abstract: PURPOSE:To keep constant the coating material spray at all times by an inexpensive constitution even if the coating material is of high viscosity in a coating device using an airless autogun. CONSTITUTION:An airless autogun 10 with at least two coating material inlets 12 and 13 is used in a coating material inflow chamber, and one coating material inlet is used as an inlet for compression feeding the coating material from a coating material pump, while the other inlet 13 is used as an inlet for making the coating material flowing into the coating material inflow chamber bypass a spray outlet 11a and returning. A flowmeter 20 for sensing the feed flow line of coating material is set on a coating material path on the inlet side, while an automatic flow control valve 19 for controlling the return flow rate of coating material is set on a coating material flow path on the outlet side. Valve control means 21 and 22, for responding to sensing signals of the flowmeter 20 and controlling the opening degree of the automatic flow control valve 19 so that the spray amount of the airless autogaun 10 is constant to the variation of supplied flow rate, are attached.

A UBET-Simulation Meant for Basic Understanding of the Extrusion of Aluminum Profiles

Abstract: A plane strain UBET-model, meant for deeper understanding of the material flow in the extrusion of complex shaped aluminum profiles is presented In order to get the desired straight shape of the extrudate, every part of its cross-section must exit the die with the same velocity One intention of the present work is to imitate this problem and to analyze it in a simplified way This has been done by studying the extrusion through a two-hole die face The flow is balanced by determining the optimum lengths of the bearing lands, ie, those lengths which result in equal exit velocities of the extrudates Furthermore, the material flow, as influenced by the position of the die openings along the die face, has been investigated

Material flow analysis of automotive assembly plants using FactoryFlow

Abstract: When designing a new assembly plant or retrofitting an existing plant, it is critical to determine where all the materials will be received, stored and used Variable width and color material flow diagrams created by FactoryFLOW are especially useful for presenting this information FactoryFLOW automatically finds the shortest route from origin to destination along an aisle network for all materials/parts involved Once routes are determined FactoryFLOW draws the routes, outputs travel distances, times, and costs to report files and scales the thickness of flow lines according to the flow intensity of each part The input data required by FactoryFLOW is the kind of basic from-to information typically already available in a database or spreadsheet Among other output reports, FactoryFLOW generates detailed reports on manpower requirements by equipment type FactoryFLOW's from-to chart shows the flow intensities and distances between ail from-to locations analyzed The distance intensity chart plots each part's move intensity against its travel distance on an X-Y graph With the help of powerful personal computer systems and user friendly graphical environments, material flow studies of over 10,000 parts within facilities of over 5 million square feet can be accomplished by a novice user in under an hour

Method for monitoring material flow processes in manufacturing.

Abstract: Method for monitoring material flow processes by means of an automatic fault reporting system which, by means of speech output via a telephone, reports disturbances on-site to the person in charge of the installation and supports him/her in removing the disturbance.

A Dynamic Analysis of Interest Rate and Logging Factors in Reducing Saw Timber Procurement Costs

Abstract: Wood harvesting operations were controlled in terms of financial expenditure and material flow at three related steps in the wood procurement system — logging, roadside inventorying, and transportation. Wood flow from sawtimber to available sawlogs in the mill yard was evaluated using the technique of dynamic programming. This program was successfully linked with data processing (input) and interactive interpretation procedures (output). The power of the algorithm was increased by implementing separable programming. In this model a nonlinear transportation function was linked to linear logging and inventorying functions. The dynamic programming procedure was not as effective computationally as the Simplex procedure, but future trends in computer development can be expected to offer increasing computing capacity for dynamic procedures. Small tactical problems were solved more accurately as the model construction was closer to real-life systems. No interest rate effects on sawtimber allocation were observed in the sensitivity analyses conducted, but transportation allocation as a phase of material flow changed when the effect of varying volumes of logging was analyzed.

Method for manufacturing flat coated articles using grid-structure preforms.

Abstract: not available for EP0657265Abstract of corresponding document: US5525283A method for the production of laminated moldings, such as internal linings or panellings of motor vehicles and the like, and dimensionally stable parts in which a support part is provided with a surface lamination and in which initially a preform having the same volume as the support part, but not having the same surface area with respect to the final shaping, is produced. Utilizing the inherent production heat, the preform is then connected by pressure action to the lamination by back-embossing with the thermoplastic material of the support part and is given its final shape by material flow processes. The invention improves back-embossing in the production of laminated moldings in such a way that with reduced embossing forces the surface-unitary adhesion of the lamination to the support part is improved and the risk of bubble formation is eliminated. This is achieved in that preforms identical in volume to that of the support part and having the same contour shapes as the finished laminated molding and with a lattice-like structure at least in partial areas are subject to the material flow process so that the initially open lattice meshes of the preform are closed by local flow with the pressure application for the back-embossing process.

Improvements relating to airlocks

Abstract: An airlock comprising a duct 2 and valve means 4, 6, which valve means is/are operable to assume an open or closed condition in response to the flow of particulate material e.g. tobacco through the duct. During periods of continuous material flow, the rate of material supply and the rate of material removal are controlled relative to one another in order to ensure that a body of particulate material is maintained within the duct.

Flow properties of long fiber reinforced PP sheets

Abstract: Long glass fiber reinforced PP sheets, called stampable sheets, are attractive materials because of their light weight, high strength, high moldability, recyclability, and so on. Therefore, stampable sheets have been used in comparatively large products such as bumper beams or seat shells in the car industry. In order to design molds and select adequate molding conditions, flow patterns of stampable sheet must be characterized. In this paper, we carried out the finite element method of the flow of stampable sheet, using the lamination theory. One-ply sheet can be regarded as two PP resin layers and one reinforced layer. Large deformation analysis was performed with heat condition analysis, and the material was modeled as an elastic-perfect plastic material. In-plane and out-plane flow patterns were analyzed. In the former, the material flow occurred in the plane, as in the fabrication of plane sheet, and in the latter, the flow pattern was as in the case of ribs or boss parts. Numerical results suggested that in-plane flow was characterized by slippage flow, and out-plane flow was characterized by squeezing flow.

An environmentally desirable printed circuit and associated apparatus

Abstract: A process and apparatus for producing supported conductive networks (1) which can be flexible or rigid, having densely packed circuits (3). The process and apparatus for making the conductive network (1) involves forming a conductive material (8) supported on a 'dynamic pressure cushion' into a non-planar pattern defining the desired conductive circuits (3) in relation to a fixed reference plane (32). The 'dynamic pressure cushion' is a material having suitable viscosity and flow characteristics to flow out from under the conductive material (8) as it is being formed and fill up any voids. To ensure that the 'dynamic pressure cushion' properly flows without deforming the desired circuits (3), the die (6) used to form the conductive material (8) is provided with a material flow control grid and material expansion troughs. After forming the unwanted material is then mechanically removed in dimensional relation to the reference plane (32) leaving the desired conductive circuits (3).

Device for thermal treatment of fine-grained bulk materials

Abstract: of EP0770822The feed for the material has a throttle arrangement which brings about the pouring of material from a high-pressure chamber into a low-pressure chamber. The throttle arrangement is located beneath the high-pressure chamber to which it is coupled by an entry flange. The throttle arrangement has a steep, conical shaft for ensuring the material flow and a controlled feed flap which can close the shaft and regulate the delivery flow. An externally operable regulating thrust bar is fixed on the controlled feed flap. There is a conduit in the feed for material which is connected to a storage container for waste or residual material with a low heat value.

Method for applying afterpressure on injection molding compounds

Abstract: A method and an apparatus for applying afterpressure on injection molding compounds, particularly PET compounds in an injection molding machine including an injection mold and a screw connected to the injection mold through supply ducts. The injection molding material is conducted to the mold cavity by the screw in order to fill the injection mold. After the filling procedure has been concluded, the material flow is cutoff in the vicinity of the screw opening. During the phase of material shrinkage, the loss of volume is compensated by additionally conveying material present in the supply duct between the screw and the mold cavity. After cooling of the injection molding material, the continuous material flow of injection molding material into the mold cavity is separated from the material flow in the supply duct. After adjusting the pressure of the material in the supply duct to the pressure of the material in the screw, the separation from the screw is again opened and the material flow to the supply duct is released in order to once again form a continuous material flow. The material flow to the supply duct is again released without interruption of the material strand for an unimpaired injection procedure.

Auger Design for Uniform Unloading of Granular Material: II. Cylindrical Containers

Abstract: The analysis presented can be used to determine the design equations for augers that produce uniform vertical flow of granular material through containers with cylindrical cross-sections. The augers so designed have a constant outside diameter and a variable root or shaft diameter. Installed in cylindrical grain bins they could be used to convert a batch-in-bin dryer to a continuous flow dryer. The analysis is an extension of the work of Jones and Kocher (1995) who designed and tested such an auger for containers of rectangular cross-section, and determined flow to be uniform for practical purposes. The analysis follows the same concept used by Shivvers (1973) to develop augers with variable outside diameter to provide uniform vertical flow of granular material through containers with cylindrical cross-section.