Showing papers on "Material flow published in 2013"

Creating Sustainable Fresh Food Supply Chains through Waste Reduction

Abstract: Purpose – The aim of this empirical paper is to study information sharing in fresh food supply chains, with a specific goal of reducing waste and facilitating sustainable performance. The study focuses on material and information flow issues, specifically on sharing demand and shelf‐life data.Design/methodology/approach – This work has been designed as an exploratory case study in three fresh food supply chains, milk, fresh fish, and fresh poultry, in the Nordic countries. The cases are based on interviews and data from the databases of the companies involved. Each case focuses on analyzing information flow, particularly the current order patterns and forecasting and planning process, and material flow, focusing on the supply chain structure. In two cases significant changes have been made to forecasting processes and material flow, while the third case intends to identify the most beneficial uses of shared information to create a sustainable fresh food supply chain.Findings – The performance of the peris...

Location and allocation decisions for multi-echelon supply chain network - A multi-objective evolutionary approach

Abstract: This paper aims at multi-objective optimization of single-product for four-echelon supply chain architecture consisting of suppliers, production plants, distribution centers (DCs) and customer zones (CZs). The key design decisions considered are: the number and location of plants in the system, the flow of raw materials from suppliers to plants, the quantity of products to be shipped from plants to DCs, from DCs to CZs so as to minimize the combined facility location and shipment costs subject to a requirement that maximum customer demands be met. To optimize these two objectives simultaneously, four-echelon network model is mathematically represented considering the associated constraints, capacity, production and shipment costs and solved using swarm intelligence based Multi-objective Hybrid Particle Swarm Optimization (MOHPSO) algorithm. This evolutionary based algorithm incorporates non-dominated sorting algorithm into particle swarm optimization so as to allow this heuristic to optimize two objective functions simultaneously. This can be used as decision support system for location of facilities, allocation of demand points and monitoring of material flow for four-echelon supply chain network.

Supply Chain Finance: Concept and Modeling

Abstract: In an era of globalization, it is almost impossible for a company to stay competitive with its supply chain locating in a single country ( A. Sabbaghi & N. Sabbaghi, 2004 , Global supply-chain strategy and global competitiveness. International Business & Economics Research Journal, 3 (7), 63–76). On the other hand, increasing global sourcing and selling brings substantial challenges on the material flow, information flow, and financial flow along lengthened supply chains. Many researches in the past decades have illustrated the benefits of supply chain visibility by streamlining information flow ( Eppen, 1979 , Effects of centralization on expected costs in a multilocation newsboy problem. Management Science, 25 (5), 498–501; Lee & Whang, 2000 , Information sharing in a supply chain. International Journal of Manufacturing Technology and Management, 1 (1), 79–93; Vickery, Jayaram, Droge, & Calantone, 2003 , The effects of an integrative supply chain strategy on customer service and financial performance: An analysis of direct versus indirect relationships. Journal of Operations Management, 21 (5), 523–539; Zhang & Zipkin, 1990 , A queueing model to analyze the value of centralized inventory information. Operations Research, 38 (2), 296–307). It is well known that an informational centralized supply chain outperforms its decentralized counterpart through reducing bullwhip effect (Chen, Drezner, Ryan, & Simchi-Levi, 2000, Qualifying the bullwhip effect in a simple supply chain: The impact of forecasting, lead times, and information. Management Science, 46 (3), 436–443; Lee, Padmanabhan, & Whang, 1997 , Information distortion in a supply chain: The bullwhip effect. Management Science, 34 (4), 546–558).

Finite Element Analysis of Material Flow in Mechanical Clinching with Extensible Dies

Abstract: An investigation of the material flow during the clinching process with extensible dies is carried out. Clinched joints were produced under different forming loads to evaluate the evolution of the jointsprofile experimentally. Tensile-shear tests were conducted to evaluate the influence of the forming load on mechanical strength of the clinched joint. Since the jointsstrength depends on the jointsprofile, which in turn depends on the punch-die cavity volume, an analysis of the forces acting on the extensible dies was carried out. A finite element model was developed and validated by comparing the predicted and measured material flow and quality criteria (e.g., neck thickness and undercut). Therefore, the FE model was utilized to analyze the evolution of contact forces acting on the die sectors during the joining process. Furthermore, the main causes of the asymmetry in the cross section of such joints have been studied. It turned out that the axial asymmetry due to material flow within the gap between consecutive die sectors increases with the punch force and the sheet thickness.

Simultaneous material flow analysis of nickel, chromium, and molybdenum used in alloy steel by means of input-output analysis.

Abstract: Steel is not elemental iron but rather a group of iron-based alloys containing many elements, especially chromium, nickel, and molybdenum. Steel recycling is expected to promote efficient resource use. However, open-loop recycling of steel could result in quality loss of nickel and molybdenum and/or material loss of chromium. Knowledge about alloying element substance flow is needed to avoid such losses. Material flow analyses (MFAs) indicate the importance of steel recycling to recovery of alloying elements. Flows of nickel, chromium, and molybdenum are interconnected, but MFAs have paid little attention to the interconnected flow of materials/substances in supply chains. This study combined a waste input–output material flow model and physical unit input–output analysis to perform a simultaneous MFA for nickel, chromium, and molybdenum in the Japanese economy in 2000. Results indicated the importance of recovery of these elements in recycling policies for end-of-life (EoL) vehicles and constructions. Im...

A Coupled Thermal/Material Flow Model of Friction Stir Welding Applied to Sc-Modified Aluminum Alloys

Abstract: A coupled thermal/material flow model of friction stir welding was developed and applied to the joining of Sc-modified aluminum alloy (7042-T6) extrusions. The model reveals that surface material is pulled from the retreating side into the weld zone where it is interleaved with in situ material. Due to frictional contact with the shoulder, the surface material is hotter than the in situ material, so that the final weld microstructure is composed of bands of material with different temperature histories. For this alloy and the associated FSW heating rates, secondary phase dissolution/precipitation temperatures are in proximity to the welding temperatures. Therefore, depending on the surface and in situ material temperatures in relation to these transformation temperatures, disparate precipitate distributions can develop in the bands of material comprising the weld nugget. Based on the numerical simulation and on thermal analysis data from differential scanning calorimetry, a mechanism for the formation of onion rings within the weld zone is presented.

Vertical Wall Formation and Material Flow Control for Incremental Sheet Forming by Revisiting Multistage Deformation Path Strategies

Abstract: In this article, multistage deformation path strategies for single point incremental forming (SPIF) are revisited with the purpose of controlling material flow (improving sheet thickness distribution) and forming a vertical wall surface for cylindrical cups. It is noted that stretching and thinning are two main deformation modes during SPIF. How to control material flow in an optimal way is a key point for successful forming. Multistage incremental forming shows more advantages than single-stage forming, especially dealing with shapes with steep walls. In this study, three basic multistage deformation path strategies have been proposed, that is: A. incremental part diameter; B. incremental draw angle; and C. incremental part height and draw angle. Those strategies and their combinations have been evaluated in terms of formability and compared in order to understand the material allocation mechanism and optimize the multistage forming process. In addition, approximate plane-strain analysis models have been...

Optimization of the material flow in a manufacturing plant by use of artificial bee colony algorithm

Abstract: To survive in today's competitive global market, companies must perform strategic changes in order to increase productivity, eliminating wasted materials, time, and effort This study will examine how to optimize the time and effort required to supply raw material to different production lines in a manufacturing plant in Juarez, Mexico by minimizing the distance an operator must travel to distribute material from a warehouse to a set of different production lines with corresponding demand The core focus of this study is similar to that of the Vehicle Routing Problem in that it is treated as a combinatorial optimization problem The artificial bee colony algorithm is applied in order to find the optimal distribution of material with the aim of establishing a standard time for this duty by examining how this is applied in a local manufacturing plant Results show that using this approach may be convenient to set standard times in the selected company

On the microstructure of micro-pins manufactured by a novel progressive microforming process

Abstract: Microforming is defined as the process of production of metallic micro-parts with at least two dimensions in sub-millimeter range. Many of these microforming processes have been investigated in laboratory-scale, which is not suitable for industrial applications. In this work, the feasibility of producing copper micro-pins using a novel progressive microforming process is demonstrated. This process has a good potential for mass production of micro-parts. The material flow behavior and the microstructure of the formed micro-pins were investigated by means of optical microscopy and simulation. From this study of material flow behavior with respect to different process conditions (die diameter, die design and punch diameters used), it will be shown how the respective material flow behavior in the progressive forming process influenced the microstructure evolution in the formed micro-pin. It was found in the experimental results that there is a soft zone on the micro-pins surface under specific process conditions. The microhardness results were consistent with the microstructural observations. Simulation was employed to understand the material flow direction under the punch during the microforming process and evaluate the position of the neutral zone in the disk-shape head of the micro-pin produced. This understanding of the neutral zone position with relation to the metal dead-zone as well as the material flow behavior was necessary to explain the dead-zone leakage in the microstructure and the occurrence of the soft zone. By decreasing the punch to die diameter ratio, and also choosing a die without entrance fillet radius, it was shown that the soft zones at the pin surface could be either minimized or entirely removed.

Green Manufacturing Process for Helical Pinion Gear Using Cold Extrusion Process

Abstract: In this research, a cold extrusion process that can replace conventional machining process is developed for sustainable production. The cold extrusion method requires an analytical design process to assure desired dimensional accuracy of the final product. Therefore, the design must consider the material flow during the process in order to avoid product defects such as folding and underfilling. The forming load and material flow were analyzed using a commercial finite element code, DEFORM3D. To improve the dimensional accuracy, the shape of die and initial billet were designed using minimum distance analysis via FE simulation. Also the developed process included ejection for improving dimensional accuracy, and it was verified by a gear accuracy test. Isothermal annealing and spheroidizing were applied for increasing the formability of high strength workpiece. Finally a helical pinion gear was manufactured using the developed process and the product was compared to the simulation results. In conclusion, the developed process is a scrap reducing and energy saving method for manufacturing extrusion product with high dimensional accuracy.

A study on material flow pattern in friction stir welding using finite element method

Abstract: In this article, numerical modelling of friction stir welding of copper plates is presented. The aim of this study is to implement DEFORM-3D for developing the numerical simulation. Material flow p...

Method and system for acoustically treating material

Abstract: Methods and systems for acoustically treating material using a continuous process in which material may be caused to flow in a continuous or intermittent fashion into/out of an acoustic treatment chamber where the material is exposed to focused acoustic energy. The methods and systems may be arranged to permit continuous processing for extended periods while an acoustic energy source operates at a relatively high power output. Treatment chambers may include features such as an acoustic window, a heat exchanger, inlet/outlet flow arrangements, an inspection window, insert elements that define a treatment volume size or shape, etc. Treatment system configurations relating to arrangements of a treatment chamber relative to an acoustic source and coupling medium, material flow paths, and others are provided.

Mechanism of Weld Formation during Friction Stir Welding of Aluminum Alloy

Abstract: The present work aims at identification of process parameters for sound weld and to understand the mechanism of material matrix movement and weld formation in friction stir welding (FSW) of aluminum alloy. FSW experiments were conducted on 6 mm thick AA6061-T6 plates using various rotational and welding speeds. The welded plates were cut along the transverse direction to examine the macro defects. The defect size as a function of welding and rotational speed has been studied, and three parameter zones were identified. They are insufficient material flow zone, defects free zone, and excessive material flow zone. The sound zone is identified in the moderate rotational speed range for each welding velocity that occurs between the insufficient and excessive material flow zone. In the insufficient material flow zone, the defect size is found to be inversely proportional to rotational speed, whereas in the case of excessive material flow zone the defect size is directly proportional to rotational speed. As weld...

Grain size and workpiece dimension effects on material flow in an open-die micro-forging/extrusion process

Abstract: The interactive effect of grain size and specimen dimensions on the material flow and microstructural evolution was studied in a progressive open-die microforming process Particular interest was p

Analysis of tool geometry in dissimilar Al alloy friction stir welds using optical microscopy and serial sectioning

Abstract: The influence of tool geometry on material flow during friction stir welding of dissimilar aluminium alloys is investigated. Sheets of Al 2024 and Al 6061 alloys are friction stir welded in lap and butt configurations using different welding conditions. Optical microscopy with serial sectioning is utilised to systematically study material flow when small variations are made to the tool pin. It is shown that three flat features on the pin impose vertical material flow which can promote intermixing. When a threaded tool is used, the material flow and formation of the intermixed region depends on the orientation of the base materials, since the differences in viscosity of material on the advancing versus retreating side of the tool will inhibit intermixing. Decreasing the travel speed will promote intermixing by increasing the residence time to compensate for the differences in material viscosity that otherwise limit intermixing.

Material Flow Tracking for Various Tool Geometries During the Friction Stir Spot Welding Process

Abstract: This study applied powder-tracing techniques to mount Cu and W powders on A6061-T6 aluminum sheets to investigate the material flow mechanism of friction stir spot welding (FSSW) using various geometric tools. The experimental results showed that the geometry of the tools plays a crucial role and determines the entrances of material flow during FSSW. It was believed that instantaneous voids were filled up with material flow in all directions for triangular pins, and the voids were located at the pin bottom for cylindrical pins. In accordance with the plastic rule of material flow, the pressure gradient is the necessary condition to cause material flow during FSSW; therefore, the transient constraint space (TCS) is required to generate pressure in this space. Enlargement of the TCS accompanies the evolution of the stir zone (SZ). A generated void causes a steep pressure gradient, which is regarded as the entrance of material flow. A tool with screw threads causes downward driving force, which determines the intermixing behavior between the upper and lower sheets, and also affects the size of the SZs.

Design of Friction Stir Welding Tool for Avoiding Root Flaws

Abstract: In order to improve material flow behavior during friction stir welding and avoid root flaws of weld, a tool with a half-screw pin and a tool with a tapered-flute pin are suggested. The effect of flute geometry in tool pins on material flow velocity is investigated by the software ANSYS FLUENT. Numerical simulation results show that high material flow velocity appears near the rotational tool and material flow velocity rapidly decreases with the increase of distance away from the axis of the tool. Maximum material flow velocity by the tool with the tapered-flute pin appears at the beginning position of flute and the velocity decreases with the increase of flow length in flute. From the view of increasing the flow velocity of material near the bottom of the workpiece or in the middle of workpiece, the tool with the half-screw pin and the tool with the tapered-flute pin are both better than the conventional tool.

Shape Effect of Angular Die External Wall on Strain Unevenness during Equal Channel Angular Extrusion

Abstract: The principal objective of the present article is to take into account the effect of deformation zone geometry on the deformation unevenness of material plastic flow in the Equal Channel Angular Extrusion (ECAE) of metals through the use of 2D Finite-Element Simulation. This approach allows us to analyze plastic material flow through the proposed generalized Iwahashi angular die with a variable external wall at the channel intersection zone. A varied set of quadratic curves has been used to define the possible external wall of the contact surface zone. The proposed approach allows us to extend ideas concerning the influence of the angular die deformation zone external wall on the energy-power parameters of the equal channel material flow. The results indicate that the preferred choice is to introduce the external die wall in the form of a hyperbola, which allows the achievement of high strain intensity 0.692 … 0.792, low strain unevenness 0.167 … 0.310, and low material waste 0.016 … 0.047 during one pass...

Optimal concentrations in transport systems.

Abstract: Many biological and man-made systems rely on transport systems for the distribution of material, for example matter and energy. Material transfer in these systems is determined by the flow rate and the concentration of material. While the most concentrated solutions offer the greatest potential in terms of material transfer, impedance typically increases with concentration, thus making them the most difficult to transport. We develop a general framework for describing systems for which impedance increases with concentration, and consider material flow in four different natural systems: blood flow in vertebrates, sugar transport in vascular plants and two modes of nectar drinking in birds and insects. The model provides a simple method for determining the optimum concentration copt in these systems. The model further suggests that the impedance at the optimum concentration μopt may be expressed in terms of the impedance of the pure (c = 0) carrier medium μ0 as μopt 2(α)μ0, where the power α is prescribed by the specific flow constraints, for example constant pressure for blood flow (α = 1) or constant work rate for certain nectar-drinking insects (α = 6). Comparing the model predictions with experimental data from more than 100 animal and plant species, we find that the simple model rationalizes the observed concentrations and impedances. The model provides a universal framework for studying flows impeded by concentration, and yields insight into optimization in engineered systems, such as traffic flow.