Number Of Picks Research Articles

Geometrical modeling and experimental validation of 3D woven honeycomb fabric for lightweight aircrew helmet liner manufacturing

This research focused on the development of a honeycomb fabric by predicting the areal density suitable for aircrew helmet liner. The aim was to fulfill the requirements for the lightweight and mechanical properties of composite liner. The model was based on the structural characteristics of the preform, including the weave design and geometric parameters. The predicted areal density, based on varying yarn linear density and the number of picks in the free and bonded wall, was compared to experimental results and showed good agreement. A geometric model was derived to predict the areal density of 3D woven honeycomb preforms for producing the composite liner of aircrew helmet. The model was validated using experimental data from a variety of 3D woven honeycomb preforms, showing that it accurately predicts the areal density and can be used as a tool to design 3D woven honeycomb preforms for advanced composites.

Travel distance estimation of relation-based storage assignment policies in picker-to-part warehouses

<p>Relation-Based Storage Assignment (RBSA), also called the “family grouping method,” has garnered significant interest among researchers and practitioners looking for an intuitive means by which to arrange related Stock Keeping Units (SKUs) in nearby regions for simultaneous picking. However, there is no analytic model for picking distance estimation for RBSA. Most of the related studies have targeted specific cases and applied simulation or mathematical programming to validate the family grouping method’s superiority over traditional storage assignment methods including the random assignment policy. To explore the effects of RBSA, this current study develops a preliminary analytical model of travel distance estimation for low- level, picker-to-part, and pick-by-order warehouses. We use Frequency-Based Storage Assignment (FBSA) as a baseline for comparison. We consider both single-aisle warehouse layouts and two-block, multi-aisle warehouse layouts, with return and traversal picking policies. The skewed ABC distribution curve of SKUs, the number of picks (N) per picking tour, the number of SKUs (n1) in a family, and the number of families (n2) are also taken into account. Our results show that, in comparison with the FBSA method, the RBSA method decreases the picking distance by as much as 32%.</p> <p> </p>

Using an Improved Differential Evolution for Scheduling Optimization of Dual-Gantry Multi-Head Surface-Mount Placement Machine

The difference between dual-gantry and single-gantry surface-mount placement (SMP) machines is that dual-gantry machines exhibit higher complexity and more problems due to their additional gantry robot, such as component allocation and collision. This paper presents algorithms to prescribe the assembly operations of a dual-gantry multi-head surface-mount placement machine. It considers five inter-related problems: (i) component allocation; (ii) automatic nozzle changer assignment; (iii) feeder arrangement; and (iv) pick-and-place sequence; it incorporates a practical restriction related to (v) component height. The paper proposes a solution to each problem: (i) equalizing “workloads” assigned to the gantries, (ii) using quantity ratio method, (iii) using two similarity measurement mechanisms in a modified differential evolution algorithm with a random-key encoding mapping method that addresses component height restriction, (iv) and a combination of nearest-neighbor search and 2-opt method to plan each placing operation. This study reports an experiment that involved the processing of 10 printed circuit boards and compared the performance of a modified differential evolution algorithm with well-known algorithms including differential evolution, particle swarm optimization, and genetic algorithm. The results reveal that the number of picks, moving distance of picking components, and total assembly time with the modified differential evolution algorithm are less than other algorithms.

A dynamic storage location assignment model for a progressive bypass zone picking system with an S/R crane

We propose a storage location assignment (SLA) model that considers workload balance and recirculation reduction under a storage space restriction. The SLA model balances the weighted sum of the number of picks and the number of visits across zones to reduce the recirculation. We then extend it to a storage location reassignment (SLR) model for limited relocation capacity. When the zone picking system runs short of relocation capacity for a SLA, the SLR model moves some pairs of products, which are prioritised to maximise the SLR. Simulations of industry orders show that the SLA and SLR models reduce the order picking completion time by 9.2%∼13.6% and 5.9%∼8.9%, respectively. The results imply that the SLR model is preferable when management needs to make minimal changes to SLRs.

A methodology for designing cutting drum of surface miner to achieve production of desired chip size

The size of coal chips, produced during coal cutting operations, is of prime importance from the viewpoint of feed size desired by power plants. Proper chip size in cutting can eliminate primary crushing and in-turn save energy. Achieving a designated size of chip is intimately linked with the drum design inter alia the wrap angle, line spacing of picks and pick size. Operating parameters namely cutting speed and drum speed also influence the output. Considering the increased need to produce a sized product for cost-effective mining, a design methodology was developed to achieve a required chip size for surface miners with a middle drum configuration. Various pick, drum and operational parameters were taken into account for the development of drum design, namely drum width, drum diameter, pick size, clearance angle, rake angle, cutting angle, lacing pattern, angle of wrap, depth of cut, indented depth of cut and pick spacing. Limiting factors for drum design such as the number of picks, pick temperature, strength of pick, depth of cut and dust generation were discussed. A new drum configuration for achieving 100 mm chip size was validated which showed close agreement with the output produced using 2200SM model surface miner.

Analysis of Statistics on Methane Release in High-Production Coal Faces in Kuzbass

The statistical analysis results on methane release in coal faces in Kuzbass are presented. The parabolic curves of methane release have maximums as regard to feed velocity and productivity of shearer. Methane release from broken coal is an inverse proportional function of linear hyperbolic dependence and has maximum as regard to feed velocity and productivity of shearer. The analysis of the found methane release from broken coal shows that methane release reduces as a quadratic dependence with decreasing drum rotation speed and number of picks per cutting line, and increases also as a quadratic dependence with growing thickness of coal seam and shearer web width.

The Anti-Resonance Criterion in Selecting Pick Systems for Fully Operational Cutting Machinery Used in Mining

Abstrat This article discusses the issue of selecting a pick system for cutting mining machinery, concerning the reduction of vibrations in the cutting system, particularly in a load-carrying structure at work. Numerical analysis was performed on a telescopic roadheader boom equipped with transverse heads. A frequency range of the boom’s free vibrations with a set structure and dynamic properties were determined based on a dynamic model. The main components excited by boom vibrations, generated through the process of cutting rock, were identified. This was closely associated with the stereometry of the cutting heads. The impact on the pick system (the number of picks and their arrangement along the side of the cutting head) was determined by the intensity of the external boom load elements, especially in resonance zones. In terms of the anti-resonance criterion, an advantageous system of cutting head picks was determined as a result of the analysis undertaken. The correct selection of the pick system was ascertained based on a computer simulation of the dynamic loads and vibrations of a roadheader telescopic boom.

The Effects of Manual Material Handling Equipment on Loading and Unloading Time of a Case in a Pallet

In this study, we mainly investigate the impacts of usage of a raisable turntable as a material handling equipment in forward-picking area of the warehouse with respect to the loading and unloading operation of a box in a pallet. For unloading, we evaluate expected time to pick (extract) cases from a pallet. We develop a varying picking time expression with respect to the human factors and the positions of cases in a pallet to formulate expected picking time. We also conduct a detailed experimental design to investigate the effects of several important parameters such as pick list size and number of cases in a pallet on picking time. We show that human factors and picking from different positions, as well as number of picks, have an important impact on extracting time of cases. Therefore, we present that using turntable for picking or loading operation offers time savings over traditional manual material handling in most cases.

Ultra-violet Protection and Easy- care Children Garments by Nanotechnology

This research focuses on nanotechnology in finishing of cotton/polyester fabrics. Treatment of cotton / polyester fabrics 75/25% were done by using Arcofix as anti-crease agent and ZnO (Zinc oxide) nanoparticle as UV protection agent in children garments (middle childhood) 6-9 years. The used fabrics have the following specifications: Three weaves structures (plain 1/1- twill 2/2- stain 5) with weft density (16-24-28) picks/cm. The fabrics were treated with Arcofix, 80g/l and ZnO nanoparticle at different concentrations (0.001-0.002-0.003)g/l then curing at 150°C for three minutes, some investigations, such as ( meter square weight – crease recovery angle –tear strength- UPF) were done for treated and untreated fabrics. Scanning electron microscope (SEM) was used to detect the changes in surface characteristics, the obtained results found that the best weave structure for all performance properties was the stain5 with the pick 28pick/ cm which treated by ZnO nanoparticle 0.003g/l , quality factor (94.16)% ,while the plain 1/1with 16 pick/cm was the least by a quality factor (50.55)% . The fabrics with stain 5 design structure used for design of five shirts for middle childhood (6-9) years . The statistics showed that the fifth design is the best design for all proposed designs . Aims of research: Ultra-violet protection and easy-care in children clothes by nanotechnology. Achievement of optimum conditions for weave structure, number of picks and concentration of ZnO nanoparticles. Make some shirts designs suggested to children from the best treatment fabrics and choose the best one. Results: The impact of study factors on the functional properties of the fabrics produced under research . Analysis of variance (ANOVA) has been made to study the impact of study factors (weave structure, numbers of picks, ZnO nanoparticles concentration) of the fabrics produced under research.Hence the importance of this research to shed light on the reciprocal relationship between the mother and her female child and the extent of the Girls' link and attachment to their mothers, through innovate fabric designs of ladies clothes and their formats for the children.We cannot ignore the world fashion trends and the importance of guide with it to make a printing product with an Egyptian identity and at the same time fits the latest fashion trends in taste, color, shape and quality. And on the other side, and in technological terms, the product has to be environmentally friendly and safe to the young consumer (children).

Investigating the mechanical behavior of composites made from textile industry waste

Recycling the waste for environmental protection has been an important challenge for the mankind. The fibrous waste in textile industry accounts for approximately 15% of the amount of fibers used, leading to a lower yield %. The current study focused to use this waste as reinforcement to produce a fiber-reinforced polymer composites. Reinforcements were woven in 3/1 S twill, using yarn produced from noil waste and knitting waste in the weft direction. The weft yarn count, type of waste material and number of picks were the variables of study. Laminated composites were fabricated from these reinforcements and the mechanical properties (tensile, bending and impact) were compared to the conventional glass fiber composites. The specific mechanical properties of these composites were found comparable or less than that of glass fiber composites.

Order Batch Formations for Less Picker Blocking in a Narrow-Aisle Picking System

This paper analyses the best batch formations for order picking throughput in narrow-aisle order picking systems. Our analytical comparison finds that a high pick density variation leads to a heavy picker blocking. Simulation experiments show that a distance-based batching algorithm reduces picker blocking by decreasing the number of aisles visited and stabilizing the variation in number of picks per aisle by packing orders tightly, and that the solution quality and mechanism for determining the batch size dictated by the sorting strategy causes varying amounts of blocking. We conclude that combining a distance-based batching method with an appropriate batch sizing strategy will reduce picker blocking and shorten travel in narrow-aisle picking systems.

Development of pallet pattern placement strategies in robotic palletisation

Purpose – This paper presents an investigation on the development of different pattern placement strategies in robotic palletisation of box packages in the packaging industry with practical implementations for one, two, four and five block patterns with the aim of improving the operational efficiency in robotic palletisation. Design/methodology/approach – The work involves considering the gripper design and maximum number of picks and various process parameters that affect the robotic implementation of pallet patterns and develops a methodology to form different patterns for a given pallet size. Findings – The proposed methodology represents an efficient approach for pallet pattern implementation and results in reduced number of placements required for a given number of boxes per layer and reduced time for palletisation. Originality/value – The paper introduces a novel technique for pallet loading problem (PLP) considering the physical aspects and restrictions encountered when using the robot and the gripper size to generate the pattern on the pallet. Traditional solutions of PLP do not consider these aspects in pattern placements.

A note on picker blocking models in a parallel-aisle order picking system

This note develops analytical picker blocking models to simply and accurately assess picker blocking in parallel-aisle order picking systems when multiple picks occur at a pick point. The Markov chain--based models characterize the two bounding walking speeds for modeling picker movement: unit walk time and instantaneous walk time. The unit walk time model has a state-space transition matrix that is reduced by a factor of 16 for both narrow-aisle and wide-aisle systems. Additionally, the model improves upon the existing literature by providing a closed-form expression for the narrow-aisle system with instantaneous walk time. Experimental results are provided to demonstrate how picker blocking is influenced by pick density in a variety of scenarios under varying assumptions regarding the maximum number of picks at a pick point. These results broaden those previously presented in the literature, as well as demonstrate the improved efficiency of the proposed model.1

Taguchi analysis of fabric shrinkage

This article reports on the effects of fabric constructional factors such as fabric sett, warp tension, back rest position, and pick insertion rate, on the warp-way and weft-way shrinkages of a three-up-one-down twill woven fabric using a Taguchi design of experiments. It was observed that the fabric shrinkage in the warp direction was mostly affected by the change in the number of picks per inch, followed by warp tension, number of ends per inch, number of picks per minute, and back rest position, respectively. The fabric shrinkage in the weft direction was found to be mostly affected by the change in number of ends per inch, followed by number of picks per inch, back rest position, number of picks per minute, respectively and least affected by warp tension. It was observed that the aforesaid five factors were able to explain 99.02 % and 82.81 % of the total variation of fabric shrinkage in the warp and weft directions, respectively.

Multi-Objective Optimization Design for Cutting Head of Roadheader

Aiming at load fluctuations and energy consumption of cutting head, a novel optimization strategy is presented in this paper, which is making every pick loaded uniformly and keeping number of picks in cutting section constant at every moment. It also considers the coal compression-tension effect and the action of pick tilt angle to pick force. The mathematical model of multi-objective optimization design for pick arrangement parameters and motion parameters of cutting head is established firstly, and then the sequential quadratic programming method (SQP) is chosen to compile the program of optimization design. The optimization example shows that in the premise of outline dimensions of cutting head unchanged, the load torque fluctuation decreases for 92%, which reduces the torsional vibration of transmission system of roadheader effectively. The swing force fluctuation also decreases for 83%, which enhances the stability of swing feed. Although the mean value of cutting head’ load decreases a little, all the load peaks decline after optimization, which avoid the single pick overload. And, the specific energy consumption decreases for 21%, which improves the energy utilization of roadheader.

Analysis on Cutting Ability of Picks on Continuous Miner

In order to obtain the continuous miner cutting ability of picks and its adaptability to coal, the average cutting force of continuous miner is got by means of the cutting electromotor power, and the cutting impedance is got compared with the single cutting resistance. It calculated and analyzed roller diameter, roller rotating speed, cutting power and the influence of the number of picks at work at the same time to the single cutting resistance.

An evaluation of routing policies for order-picking operations in low-level picker-to-part system

This paper evaluates the performance of three routing policies in the order-picking process, i.e. return, traversal, and midpoint policy. It is assumed that items are assigned to storage locations on the basis of the cube-per-order index (COI) rule in a low-level picker-to-part warehousing system. First, for the three policies, analytical models are developed for the total expected travel distance of the order picker considering the number of the stocking aisles is even or odd. Then the developed models are compared with simulation results to show the validity. Finally, the performance of the three policies is examined by varying the parameter value of the COI-based ABC curve, number of picks in the pick list, and ratio of the length to the width of the warehouse.

Experimental results of a low-power roadheader driving a gallery with different types of rock at the face

In this paper, the experimental results of a 45-kW and 15-t roadheader excavating a gallery with two different types of rock at the face using two different cutting heads are shown. It is proved that the roadheader works properly with both cutting heads. In comparison with other results in the literature, the principal parameters, i.e. specific energy, cutting rate and tool wear, are at a level that can be considered satisfactory taking into account the low power of the roadheader. On the other hand, the influence of the number of picks, which is the main difference between the two cutting heads, on the operational parameters is shown.

Layout design in manual picking systems: a simulation approach

Manual picking system productivity is greatly influenced by layout design (i.e. the layout scheme and the number of aisles). In fact, layout plays an important role in determining the expected length of pickers’ tours which is itself a relevant component of the time required to complete a given set of orders. This paper presents a simulation approach to efficient layout design of the picking area in picker‐to‐part systems using random or cube per order index (COI)‐based storage policies. The optimal number of aisles depends on both strategic/long‐term and short‐term decisions. Indeed, layout is a function of the total storage length which, in turn, is related to strategic decisions concerning the forward/reserve problem, i.e. the choice of the fraction of items to be located in the picking (forward) area. Moreover, layout preferences seem to be strongly affected by operating decisions concerning batch size, i.e. number of picks in a tour, and the adoption of a COI‐based storage policy. Some design guidelines are provided for both stable environments where the operating conditions are well defined, and for unstable contexts where conditions may vary.

13—ASPECTS OF STARTING ALLOCATIONS AND BOX-PLANNING ON 4 × 4 BOX LOOMS

There is a general algorithm for the determination of practicable starting allocations of colours to the two sides of a 4 × 4 box pick-at-will loom, but its convenience in use varies greatly. An improvement is indicated, but a simpler and more efficient algorithm is suggested for the one-empty-box case, for which the general algorithm is least satisfactory. Two of the constraints of weft patterning on such 4 × 4 box looms are examined, largely by using the general algorithm. First, the maximum number of practicable starting allocations is determined for any given number of weft colours and any smaller number of box-pairs. Next, it is shown that there is a possibility that a weft repeat may be unweavable with one shuttle per colour if the number of picks in the reduced repeat is not less than the number of shuttle boxes in use. In contrast to the genera! case, if there is only one empty shuttle box, the box plan that minimizes the number of large box movements for a given weft repeat can rapidly be determined by using a microcomputer.