Showing papers on "Material flow published in 1993"

Material management in decentralized supply chains

Abstract: A supply chain is a network of facilities that performs the functions of procurement of material, transformation of material to intermediate and finished products, and distribution of finished products to customers. Often, organizational barriers between these facilities exist, and information flows can be restricted such that complete centralized control of material flows in a supply chain may not be feasible or desirable. Consequently, most companies use decentralized control in managing the different facilities at a supply chain. In this paper, we describe what manufacturing managers at Hewlett-Packard Company (HP) see as the needs for model support in managing material flows in their supply chains. These needs motivate our initial development of such a model for supply chains that are not under complete centralized control. We report on our experiences of applying such a model in a new product development project of the DeskJet printer supply chain at HP. Finally, we discuss avenues to develop better ...

Vibrating tube densimeter

Abstract: A Coriolis effect densimeter which produces density output data of improved accuracy by embodying the principal that the natural frequency of a vibrating tube filled with material decreases with an increase in the material mass flow rate. High accuracy output data is achieved by measuring the natural frequency of the tube as material flows therethrough, correcting the measured frequency to compensate for the decrease in natural frequency caused the material flow (mass flow rate) and using the corrected natural frequency in the material density computation.

Two sequence-pattern, matching-based, flow analysis methods for multi-flowlines layout design

Abstract: In optimizing the layout design of a multi-product assembly environment, the analysis of the material flow is a vital ingredient. In a multi-product production environment, products are usually grouped together into families. Products of the same family group usually involve similar operations; however, it is common to see some difference in the operations and the operational sequences among these products. The design technique for the layout of multi-product flowlines should be able to resolve the difference among the operation sequence of these products. The ideal material flow in a good layout design should be mostly in-sequence flow. In-sequence flow usually has the benefits of smaller flow distance, easier control of the production process and easier material handling. This paper proposes two flow analysis methods that are designed to provide a better flow analysis for the design of multi-products flowline. The first method adopts the traditional line structure for analysis. The second metho...

Apparatus and methods for applying conformal coatings to electronic circuit boards

Abstract: Apparatus and methods 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.

Economical design of material flow paths

Abstract: In this paper, we suggest a branch-and-bound procedure for designing flow paths of fixed-path material handling systems. The method may be applied to automated monorail systems (AMS), automated guided vehicle systems (AGVS), flexible conveyor systems and other fixed-path material handling systems. We formulate an economic model which considers the construction cost of each path segment as well as the travel cost. A procedure is developed to determine the configuration of flow path and the direction of each flow path segment. A tight lower bound for the optimal objective function and an efficient search strategy are suggested. Computational performance of this procedure is compared with a procedure previously developed by Kaspi and Tanchoco for the special case of AGV systems.

Measuring and monitoring the size of particulate material

Abstract: Apparatus for monitoring a characteristic diameter of a flowing particulate material, comprises a chamber (31) having a particle size measurement outlet (33) of known dimensions through which the flowing material passes, means to determine the flow rate of the material, and means to determine the characteristic diameter of the material by reference to the dimensions of the particle size measurement outlet, the bulk density, and the flow rate of the material. The bulk density may be known or measured. The flow rate of material may be measured in a second chamber (34) having another outlet (37) through which the material flow also passes. The flow rate measurement outlet may be in the form of a slot (37). Flow rate is determined by reference to the height (h2) of material flow through the slot. Bulk density may be determined by maintaining a constant volume of material in the chamber with the particle size measurement outlet, and by reference to changes in the weight (31b) of the contents of this chamber.

Numerical simulation of non‐isothermal SMC (sheet molding compound) molding

Abstract: Design of molding tools and molding cycles for sheet molding compounds (SMC) is often expensive and time consuming. Computer simulation of the compression molding process is a desirable approach for reducing actual experimental runs. The focus of this work is to develop a computer model that can simulate the most important features of SMC compression molding, including material flow, heat transfer, and curing. A control volume/finite element approach was used to obtain the pressure and velocity fields and to compute the flow progression during compression mold filling. The energy equation and a kinetic model were solved simultaneously for the temperature and conversion profiles differential scanning calorimetry (DSC) was used to experimentally measure the polymer zation kinetics. A rheometrics dynamic analyzer (RDA) was used to measure the rheological changes of the compound. A series of molding experiments was conducted to record the flow front location and material temperature. The results were compared to simulated flow front and temperature profiles.

Improvements in and relating to applying coatings

Abstract: Apparatus and methods for producing intermittent, discrete patterns of coating material onto discrete irregular substrate areas, such as electronic circuit boards (10), where the patterns have sharp, square leading and trailing edges (13,16), as well as side edges (14,15). A slot nozzle die (32) has elongated air slots (61,62) along the slot extrusion opening (40). In the operation of the apparatus, the air flow is initiated from both air slots (61,62) 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 (10) for deposition in discrete areas thereon. The sharp cut-on and cut-off accommodate multiple discrete area coating or multiple automated circuit board coating.

Material Flow During Compression Moldings of Long Fiber Reinforced Thermoplastic Composites

Abstract: Because of their many advantages, long fiber reinforced thermoplastic composites have been used in many industrial applications. However, because material flows during compression molding cause a large scatter in the mechanical properties of moldings, it is necessary to characterize the flow behavior during molding. A new experimental procedure, the “Mark Method”, was used to observe the flow in different layers during molding. Mold flow was found to be characterized by interlaminar slippage, which causes the core layer to flow to the edge of the panel.

Method and apparatus for monitoring the flow of solid materials

Abstract: A method and apparatus for monitoring the flow of bulk material in a bulk materials handling system is disclosed. A critical stage in the system is identified in which variations in flowability of the material might result in the entire system flow being impeded. Upstream from that critical stage, flow conditions in the critical stage are simulated so that the flow can be interrupted if unsatisfactory flowability conditions exist. A pivotable chute may be positioned at an angle to simulate the flow of particular materials at critical downstream points in a material handling system. If material conditions such as excess moisture impede the rate of flow of the material to a degree which would cause blockages in critical downstream points, the chute will pivot to a secondary position which will temporarily interrupt the material flow.

Arrangement and method for pressure treatment of granular material

Abstract: In the pressure treatment of granular material in the roller gap (15) of a two-roller machine, air (17) is pressed out of the bulk material and flows, counter to the material flow, through the bulk material and loosens the latter in the process. As a result of a widening of the lower part of the material feed shaft (12), the bulk material can form a slope (16) and is conveyed in a free flow to the roller gap (15), unhindered by the air flowing towards it and by friction against the shaft wall.

Computer controlled material flow system - has sources, sinks, bar=code scanner identifying transported material on rollertrack and system computer controller

Abstract: The material flow system includes sources (2 to 4), sinks (5 to 7), control and data capture elements (11,12,29,34) which read identifier bar codes on transported material, transport system components (8 to 10, 13 to 20, 22 to 27) and a system control computer which acquires these inputs. The links between sources (2 to 4) and sinks (5 to 7) are monitored, and the system capacity and availability statistics are generated. USE/ADVANTAGE - System capacity and availability statistics generation for material transport systems.

Solid material flow monitoring device

Abstract: The utility model discloses a solid material flow monitoring device used for unpacked solid materials, comprising a material flow monitoring part and an automatic vibration bin The material flow monitoring process is accomplished by a material measuring plate When the materials flow is broken, the material measuring plate can automatically start a limit switch of the automatic vibration bin Thus, the automatic vibration bin can ensure the continuous running of the material flow The utility model has the advantages of simple device, reasonable structure, low cost and convenient maintenance The solid material flow monitoring device is suitable for poor manufacturing environments of powder dust, high temperature, etc

Method for controlling discharge rate of coating material

Abstract: PURPOSE:To easily conduct the operation to control the discharge rate of a coating material. CONSTITUTION:A discharge control valve D is obtd. by computation equation D=(D0-k0)Xk+k0 when the reference value D0 corresponding to the kind of a material to be coated, the offset value k0 corresponding to the kind of a flow control valve (coating material flow rate regulator) 7 and the coefft. value k corresponding to the kind of the coating material are inputted by the operation of an operation board 13. Pressurized air is force-fed from an electro- pneumatic proportional valve 6 to the flow control valve 7 by the control signal based on this discharge control value D. The coating material is regulated to an optimum flow rate by passing the opened flow control valve 7 and is discharged from a coating gun 1. The coating material can be discharged at the flow rate optimum for the coating conditions by the labor- and time-saving operation of inputting the predetermined reference value D0, offset value k0 and coefft value k to the controller 10.

Innovations in Transfer Chute Design

Abstract: This paper looks at the control of material flow from one conveyor to another by projecting the material trajectory which minimises the loss of energy of the material caused by friction and impact.

Computer Aided Metal Flow Simulation and Die Design Optimization for Axisymmetric Forging Process

Abstract: A CAD system has been developed for closed die forging and optimization. This system includes rules for geometrical design of the die and a finite element package for metal flow simulation, based on the rigid plastic formulation. Using this system the initial shape of the die is predicted based on empirical guidelines. Then simulation of metal flow is carried out to check wether the material flow is taking place without any defect and to insure the completion of the die filling. Using the field variable of the metal flow-simulation at the final stage of deformation, the actual die is analyzed using an elastic-plastic finite element package resident in the same computer to see wether there is any likehood of die failure due to over stressing. If appropriate, the die is modified to prevent premature failure.