A Study on Development of a Die Design System for Diecasting

Diecasting is one of the forming methods for manufacturing a large number of products with short lead time and a good surface by high injection pressure of cast alloy. Die design is composed of selection of cast alloy, design of product, runner and gate design, etc. In reality, however, die design for diecasting has been performed by a trial and error method, which causes economic and time loss. This paper describes the development of the computer-aided design of product and die design. The CAD system has been written in AutoLISP on the AutoCAD with a personal computer. In this study, the die design system for the die casting process has been developed and a flowchart is presented for the automation of die design, especially of the runner–gate system. As the generation process and die design system using 3D geometry handling are integrated with the technology of process planning, die design can be automated. In addition, specific rules and equations for the runner–gate system have been presented to avoid too much trial and error with expensive equipment. It is thus possible for engineers to make automatic and efficient die design for diecasting which will result in a reduction of the required cost and time. An example of a cap-shaped product, i.e. a motor pulley, is given using the proposed flowchart.     

An energy consumption prediction approach of die casting machines driven by product parameters

Die casting machines, which are the core equipment of the machinery manufacturing industry, consume great amounts of energy. The energy consumption prediction of die casting machines can support energy consumption quota, process parameter energy-saving optimization, energy-saving design, and energy efficiency evaluation; thus, it is of great significance for Industry 4.0 and green manufacturing. Nevertheless, due to the uncertainty and complexity of the energy consumption in die casting machines, there is still a lack of an approach for energy consumption prediction that can provide support for process parameter optimization and product design taking energy efficiency into consideration. To fill this gap, this paper proposes an energy consumption prediction approach for die casting machines driven by product parameters. Firstly, the system boundary of energy consumption prediction is defined, and subsequently, based on the energy consumption characteristics analysis, a theoretical energy consumption model is established. Consequently, a systematic energy consumption prediction approach for die casting machines, involving product, die, equipment, and process parameters, is proposed. Finally, the feasibility and reliability of the proposed energy consumption prediction approach are verified with the help of three die casting machines and six types of products. The results show that the prediction accuracy of production time and energy consumption reached 91.64% and 85.55%, respectively. Overall, the proposed approach can be used for the energy consumption prediction of different die casting machines with different products.     

Design optimization of clutch housing mold by fluid flow and solidification simulation

Aluminum die casting is so complex where flow momentum is critical matter in the mould filling process due the high velocity of the liquid metal. Actually, in complex parts the exact calculation of mould filling performance with using experimental knowledge is almost impossible. Aluminum die castings play a definitive role in the manufacturing of lightweight automobile bodies. Hence it is more essential today that these castings be produced with the high quality methods. In this condition the simulation is becoming more important in the designing procedure. This saves time and reduces the cost of the casting system design, which is an advantage of using simulation programs. Also, economical utilization of materials can be obtained when the quantity of test castings is decreased. This paper describes the advantages of the clutch housing die casting mold simulations to achieve better casting system design in High pressure die castings (HPDC). Filling analysis is used to determine the size and location of the gate as well as proper runner system design for ensuring a complete and balanced filling of the clutch housing part.

     

Die design optimization of die casting for fabrication of fuel cell aluminum bipolar plate with micro-channel through casting simulation and experimental investigation

In vacuum die casting, we require a high quality die design for fuel cell bipolar plates to prevent unfilled phenomena, turbulent flow, and porosity. We have designed a die for thin plate die casting using two geometric shapes. In addition, we propose a new overflow system based on numerical simulation, and conducted actual vacuum die casting experiments. An optimal die design consists of seven overflows at the end of the cavity and three overflows at each side wall of the cavity. In our experiment, the molten metal that passed the gate and reached the side wall flowed into the side overflow, no turbulent flow occurred, and the filling behavior and are uniform. In addition, partially solidified molten metal passing through the channel was perfectly eliminated by overflow without back-flow. To validate the proposed approach, a good quality sample was manufactured using the optimal die design with the proposed overflow system.     

基于层次分析法的级进模工序排样影响因子权重的计算

分析了级进模工序排样的特点,总结了级进模设计基本原则,建立了工序排样的评价指标体系。根据层次分析法的基本原理和步骤计算出级进模工序排样影响因子的权重。该方法模拟出设计专家在工序排样过程中考虑众多影响因素的模糊性和综合性思维过程,将思维过程中的定性指标转化为定量指标,为模糊综合评价法在级进模工序排样中的应用奠定了基础,为设计人员进行工序排样方案的最优选择提供了定量科学的参考数据。     

Development of a Practical Blank Layout Optimisation System for Stamping Die Design

Blank layout is one of the most important processes in stamping die design. As the major cost in sheet metal stamping is the material cost, any efforts to minimise the scrap may result in substantial savings not only in strip material, but also in overall production. This paper is mainly targeted at establishing a practical blank layout optimisation system for stamp ing die by using AutoCAD’s ObjectARX toolkit. The basic principles of blank layout optimisation are first described, and then the general structure of the system is proposed. Not only a suitable algorithm for layout calculation, but also the manufacturing requirements and user operation are fully considered in this system. Finally, an algorithm for blank shape offsetting is proposed to solve the problem of self-intersection in offset curves, and the traditional ‘1-step tranzlation’ algorithm for the calculation of layout parameters is improved to eliminate the conflict between precision and efficiency in the layout optimisation.     

An elitist strategy genetic algorithm for integrated layout design

While designing the layout of any manufacturing organizations, the primary objective is to decide an optimal arrangement of their departments (machines or cells) in a two-dimensional shop floor (facility) satisfying desired objectives, which is termed facility layout problem (FLP). In traditional layout design philosophy, the inter-cell layout and flow path layout design of material handling system (MHS) was carried out step by step in a sequential manner. This results in sub-optimal solutions for FLP. In this paper, an integrated approach is adopted to design the inter-cell layout and the flow path layout of MHS simultaneously. The quality of the final layout is evaluated by minimizing the weighted sum of two distance-based cost objectives namely, (1) total material handling cost. (2) Distance-weighted cost of total closeness rating score. Sequence-pair (SP) representation is used for layout encoding. The translation from SP to layout is efficiently done by longest common subsequence methodology. Due to NP-hard nature of the proposed problem, an elitist strategy genetic algorithm (ESGA) is developed and tested with three test problem instances available in the literature. It is found that the proposed ESGA algorithm is able to produce the best solutions consistently, twice faster than the standard GA for the test problem instances.     

Concurrent cell formation and layout design using scatter search

Two key decisions in designing cellular manufacturing systems are cell formation and layout design problems. In the cell formation problem, machine groups and part families are determined while in the facility layout problem the location of each machine in each cell (intra-cell layout) and the location of each cell (inter-cell layout) are decided. Owing to the fact that there are interactions between two problems, cell formation and layout design problem must be tackled concurrently to design a productive manufacturing system. In this research, two problems are investigated concurrently. Some important and realistic factors such as inter-cell layout, intra-cell layout, operations sequence, part demands, batch size, number of cells, cell size, and variable process routings are incorporated in the problem. The problem is formulated as a mathematical model. Three different methods are described to solve the problem: multi-objective scatter search (MOSS), non-dominated genetic algorithm (NSGA-II), and the ε-constraint method. The methods are employed to solve nine problems generated and adopted from the literature. Sensitivity analysis is accomplished on the parameters of the problem to investigate the effects of them on objective function values. The results show that the proposed MOSS algorithm performs better than NSGA-II and produces better solutions in comparison to multi-stage approaches.     

An investigation of an expert system for shearing cut progressive die design

The purpose of this paper is to develop an expert system for shearing cut progressive die, with the aim of enhancing the design of shearing cut progressive dies. This study is different from previous research on shearing cut die design by the author in that the design of one station was extended into a progressive die design. The major research objectives achieved in this study can be summarised as follows:

1. This study presents a pattern recognition method called the new combined structural approach to let the user interpret blanks by a better and more direct method, thereby achieving the goal of communicating with this expert system.
2. The layout of the strip can affect the material cost shared by the press-worked pieces. This study presents the near optimal method for seeing a better layout of the strip in order to save material.
3. Owing to the great variety of blank shapes which cause the variations in pressing procedures, this study proposes a matching combination learning method, which is a learning conscious system for pressing procedures, in order to obtain the optimal number of operation stations in shearing cut progressive die design.
4. The establishment of the knowledge-base system for shearing cut progressive die should improve the efficiency for die design problems.

     

制造系统智能布局设计

阐述了制造系统智能布局设计的总体结构及主要功能 ,深入探讨了该布局设计系统中面向对象的知识表示方法和知识库的构成 ,提出了面向对象的制造系统布局设计推理机制和基于目标驱动的反向推理策略 ,并进行了实例研究。     

Design and Verification of an Auxiliary System for High Vacuum Die Casting

Vacuum die casting is the optimal method to produce high quality aluminum alloy components.At present,there are still very few systematic studies on vacuum die casting theory and equipment design.On the basis of the existing theories of the vacuum die casting pumping and venting systems,a simplified model is established in this research.The model has an aggregate unit consisted of "vacuum pump + buffer tank" and a cylindrical container(including the shot sleeve,cavity and exhaust channel).The theoretical analysis is carried out between the cavity pressure and the pumping time under different volume models.An auxiliary system for high vacuum die casting is designed based on the above analysis.This system is composed of a vacuum control machine and a new vacuum stop valve.The machine has a human-computer control mode with "programmable logic controller(PLC) + touch screen" and a real-time monitoring function of vacuum degree for buffer tank and die cavity.The vacuum stop valve with the "compressed gas + piston rod + labyrinth groove" structure can realize the function of whole-process vacuum venting.The new system shows great advantages on vacuuming the cavity with a much faster speed by making tests on an existing die casting mold and a 250 t die casting machine.A die cavity pressure less than 10 kPa can be reached within 0.8 s in the experiment and the porosity of castings can be greatly decreased.The systematic studies on vacuum die casting theory and equipment have a great guiding significance for high vacuum die casting,and can also be applied to other high vacuum forming in related theoretical and practical research.     

A Parametric-Controlled Cavity Layout Design System for a Plastic Injection Mould

Today, the time-to-market for plastic products is becoming shorter, thus the lead time available for making the injection mould is decreasing. There is potential for timesaving in the mould design stage because a design process that is repeatable for every mould design can be standardised. This paper presents a methodology for designing the cavity layout for plastic injection moulds by controlling the geometrical parameters using a standardisation template. The standardisation template for the cavity layout design consists of the configurationsfor the possible layouts. Each configuration of the layout design has its own layout design table of all the geometrical parameters. This standardisation template is pre-defined at the layout design level of the mould assembly design. This ensures that the required configuration can be loaded into the mould assembly design very quickly, without the need to redesign the layout. This makes it useful in technical discussions between the product designers and mould designers prior to the manufacture of the mould. Changes can be made to the 3D cavity layout design immediately during the discussions, thus saving time and avoiding miscommunication. This standardisation template for the cavity layout design can be customised easily for each mould making company to their own standards.     

Development of an automated progressive design system with multiple processes (piercing, bending, and deep drawing) for manufacturing products

This paper describes the research work involved in developing an automated progressive design system with multiple processes such as piercing, bending, and deep drawing for manufacturing products. This approach to make a progressive, flexible working system is based on knowledge-based rules. The knowledge required for this system is formulated from plasticity theories, experimental results, and the empirical knowledge of field experts. The system consists of three main modules: shape treatment, strip layout, and die layout modules. The system is founded on knowledge-based rules and is designed in consideration of several factors, such as the material and thickness of a product, the piercing, bending and deep drawing sequence, and the complexities of blank geometry and punch profiles. The system then generates the strip layout drawing for an automobile product. The die layout module carries out the die design for each process from the results of the strip layout module. The results obtained using the modules enable the designers of manufacturing products with multiple processes to be more efficient in this field.     

真空压铸设备升级改造研究与实践

针对普通真空压铸设备生产过程中出现的产品问题,提出了升级改造压铸机的解决方法并进行实践,为压铸产品质量改善提供一种途径。通过设计并比较不同的方案,经过多次实践实验,确定了升级改造用真空箱结构,并对相应的模具结构设计提出了经济可行的方法,经过试模验证了模具设计的合理性,产品质量更好,实现了有效可靠的压铸机控制系统,为压铸行业设备升级改造提供经济性和可靠性均较高的解决方案。     

Artificial immune system-based algorithm for the unidirectional loop layout problem in a flexible manufacturing system

Facility layout design is a significant aspect of designing any manufacturing setup and it has a huge impact on the performance of the manufacturing system. Reductions in operating expenses in a manufacturing system is greatly achieved by a good layout design. The problem of finding an optimal layout is hard and deterministic techniques are not suitable for large-sized problems. In this paper, a two-phase layout design is developed. As a first phase of layout design, an artificial immune system (AIS) algorithm is proposed for solving the unidirectional loop layout problem with the consideration of both min_sum and min_max objectives. The computational results showed that the AIS algorithm is efficient in solving layout problems and producing good-quality solutions. In the second phase, shortcuts are introduced in the flow path of the loop layout to enhance the performance of the system. The position of the shortcut in the loop which gives the minimum material handling cost is discovered.     

公理设计下基于功能的布局设计可行性研究

为了研究基于功能的布局设计的可行性,以公理设计理论为基础,结合多目标优化设计方法,首先探讨了布局设计问题的用户域向功能域的映射过程;其次,分析了功能域内的功能要求,并给出了功能域向物理域的映射关系;最后,以功能独立性公理为判据,讨论了基于功能的布局设计的功能要求之间的独立性。研究结果表明,基于功能的布局设计的功能要求能满足或经调整后能满足功能独立性公理,即基于功能的布局设计具有可行性。     

Development of a die design system for die casting

This paper presents a research work of a computer-aided die design system for die casting. The proposed system consists of seven distinct modules. Through these modules, the die designers are able to create a die casting die from a product part model. It is a user-friendly system that allows both experienced and novice die designers to easily accomplish the task of die design.The practical goal of this research is twofold: (1) to develop a system that integrates the different stages of die design process and (2) that at the same time facilitates the editing of die casting design during or after the course of the design process. The approach undertaken in this research includes (1) feature-based and constraint-based modelling, (2) parametric design and (3) a geometric and topological information extraction technique from a B-rep model. A prototype system has been developed using this approach and the system is able to aid the automation of the die casting die design process, thus improving the efficiency and quality of, and reducing the cost of die design for die casting.     

面向大型压铸模型腔壁厚的模糊优化设计

运用多目标模糊优化设计的原理,结合大型压铸模的工作条件,建立了逼近实际工况的型腔壁厚数学模型。采用最优水平截集法求解,并用复合形法进行优化。并给出了这种设计方法应用于潜望镜镜身铸件压铸模的工程实例。     

Solving cell formation problem in cellular manufacturing using ant-colony-based optimization

Grouping the machines and parts in a cellular manufacturing system based on similarities is known as the cell formation problem. It has been shown that cell formation problem is a NP-hard problem. In this paper, the ant colony optimization (ACO) method is used as an evolutionary approach to solve the cell formation problem. This model uses a P?=?[P _ij ] _{(C)?×?(M?+?P)} pheromone matrix in which C, M, and P are the number of cells, machines, and parts, respectively. In order to represent the sequence of operations, the machine–part incidence matrix entries are considered as positive integers. Performance of the proposed algorithm is tested on some benchmark problems existing in the literature to show the applicability and effectiveness of the proposed model. Comparison of the solutions obtained by the proposed algorithm with those reported in the literature indicates that application of the proposed algorithm has resulted in 5.73% improvement in the total number of intercellular movements and voids on average.     

Design of loop layout in flexible manufacturing system using non-traditional optimization technique

Layout arrangement is important to achieve high productivity in flexible manufacturing system (FMS). This paper discusses the design of loop layout in FMS. The objective of the loop layout problem is the determination of the ordering of machines around a loop, to minimize the total number of loop traversals for a family of parts. This paper details the design, development and testing of particle swarm optimization (PSO) technique to solve the loop layout problem. The proposed method is validated with bench mark problems. The clearance between the machines is also considered in the design of loop layout. This aspect aids in selecting the best layout.