A computer-aided system for an optimal moulding conditions design using a simulation-based approach

Moulding conditions design refers to parameter settings of moulding conditions such as melt temperature, mould temperature and injection time. They are important factors in plastic injection moulding design. The determination of these parameters is a highly skilled job and has largely been dependent on injection moulding engineers' experience and intuitiveness. In this paper, the authors present a flexible computer-aided system to assist the designers by using simulation-based technology. One of the most prominent characteristics of the system is that it allows the designers to specify their intended quality measuring criteria such as minimum cavity pressure and shear stress, a uniform distribution of cooling time, end-of-fill temperature and volumetric shrinkage. The system uses weighted criteria as an objective function to determine optimal moulding conditions when multiple criteria are specified. Moldflow simulation results are used to compare different designs. A two-step exhaustive search strategy (from coarse to refined) is used to search for a near-optimal design.     

Investigation of complex rapid EDM electrodes for rapid tooling applications

This paper describes a collaborative research programme aimed at investigating the use of quick EDM electrodes obtained via appropriate rapid prototyping techniques in finishing laser-sintered tools. Two methods were employed in obtaining the EDM electrodes: copper coating of stereolithography models and copper coating of direct metal laser sintered (bronze) models.The amount of copper deposited on both electrode models proved problematic as the electroplating process was unable to deposit enough copper in the inner cavities of the electrodes, with very gradual reduction in copper layer thickness from the outer faces/surface to virtually no deposition in the inner walls and bottom face. Consequently, the electrodes were not suitable for the envisaged EDM process.     

Advances in micro assembly injection moulding for use in medical systems

In micro systems technology, the process of micro assembly injection moulding is used for the generation of hybrid micro systems. With this process, more functions are integrated in less space. In the field of medical technology, miniaturisation also means new methods of treatment with fewer side effects on the patient. New cures are developed by the miniaturisation of medical instruments, such as keyhole surgery. For detailed investigations a specific demonstration was developed to display the potential of micro assembly injection moulding in medical science. This part consists of a carbon-fibre reinforced PEEK puncture needle, which incorporates three lumens. The selected materials allow use of the needle during magnetic resonance imaging. In order to attach additional equipment a plastic connector needs to be overmoulded on the needle. The investigations focus on the injection moulding process by characterising the influences of temperature, moulding parameters and material combinations on the resulting bond strength between needle and connector.     

A computational system for process design of injection moulding: Combining blackboard-based expert system and case-based reasoning approach

The process design of injection moulding involves the selection of the injection moulding machine, mould design, production scheduling, cost estimation, and determination of injection moulding parameters. Expert system approaches have been attempted to derive the process solution for injection moulding in the past few years. However, this approach has been found to be incapable of determining the injection moulding parameters owing to the difficulty in setting the moulding parameters. In addition, the existing expert systems for process design lack the proper architecture for organising a heterogeneous knowledge source. In this paper, the combination of a blackboard-based expert system and case-based reasoning approach is introduced to make up the deficiencies of the existing expert-system approach to the process design, from which a computational system for process design of injection moulding, named CSPD, was developed and described. CSPD first derives the process solution including the selection of injection moulding machine and mould base, tooling cost, and processing cost estimation, and production scheduling based on the blackboard-based expert-system approach. It is then followed by the determination of the injection moulding parameters based on the case-based reasoning approach and the previously derived partial solution.     

A computational system for process design of injection moulding: Combining a blackboard-based expert system and a case-based reasoning approach

Process design of injection moulding involves the selection of the injection moulding machine, mould design, production scheduling, cost estimation, and determination of injection moulding parameters. An expert system approach has been used to derive the process solution for injection moulding over the past few years. However, this approach is found to be incapable of determining the injection moulding parameters owing to the fragile nature of the knowledge for setting the moulding parameters. In addition, the existing expert systems for process design lack proper architecture for organising heterogeneous knowledge sources. In this paper, the combination of a blackboard-based expert system and a case-based reasoning approach is introduced to eliminate the deficiency of the existing expert-system approach to process design, from which a computational system for the process design of injection moulding, named CSPD, has been developed. CSPD first derives the process solution including the selection of the injection moulding machine and the mould base, tooling cost, processing cost estimation, and production scheduling based on the blackboard-based expert-system approach. It is then followed by the determination of the injection moulding parameters based on the case-based reasoning approach and the previously derived partial solution.     

基于功能元耦合的注塑模机构设计方法研究

这里提出了基于功能元耦合的注塑模机构设计方法,分析了基于功能元的注塑模机构需求特征模型以及机构元特征模型,并在此基础上描述了注塑模机构的设计过程。研究以注塑模机构为对象,以功能元耦合为理论基础,开发了基于功能元耦合的注塑模机构设计原型系统。     

注塑机拉杆传动端梯形螺纹的应力分析与优化

针对注塑机拉杆在使用过程中易在其传动端梯形螺纹处早期断裂的问题,就梯形螺纹的特点,采用ANSYS软件内嵌的APDL语言建立拉杆传动端梯形螺纹的二维几何模型、有限元模型与优化模型.在对比分析弹性材料与弹塑性材料梯形螺纹受力特点的基础上,运用弹性材料的分析模型对梯形螺纹参数进行优化.对比优化前后拉杆梯形螺纹的弹性与弹塑性应力分析表明,拉杆梯形螺纹的承载能力得到大幅提高,并可确定拉杆梯形螺纹在与螺母配合处之外的合理牙型数.     

A user-friendly,interactive expert system for the injection moulding of engineering thermoplastics

An expert system for the injection moulding of engineering thermoplastics has been developed. The system performs off-line, on the factory floor, and can resolve operating deviations interactively with the user. The expert system is hierarchical and offers the corrective action which is easiest to achieve, rather than the most likely. This allows the operator the facility to attempt resolution of the deviation first, much the same as would occur currently. If the deviation persists then material changes will be offered. Finally, if the deviation is still present then mould changes will be offered. The corrective actions offered by the expert system are bounded by the recommended operating condition windows, but this restriction may be overridden by the user. Existing software packages are used to supplement the decision-making processes.     

瓶坯注射模冷却水路的改进

并联式冷却水路结构简单,加工方便,对于一般注射模来说是一种不错的选择, 可是对于冷却要求较高的瓶坯注射模来说,并不能达到理想的效果.通过分析,把并联式水路改为串联螺旋式水路,解决了常规方案中存在的问题,为同类产品的模具冷却系统设计提供一个新的思路.     

A systematic computer-aided approach to cooling system optimal design in plastic injection molding

Cooling system design is of great importance for plastic injection molding because it significantly affects the productivity and quality of the final products. In this paper, a systematic computer-aided approach is developed to achieve the cooling system optimal design. This approach expiates the trial and error process normally practiced in conventional cooling system design based on the designer's experience and intuition. Various aspects of the optimization process for cooling system design are investigated including cooling analysis using boundary element method (BEM), a perturbation-based approach to design sensitivity analysis, optimization problem formulation, and a novel hybrid optimizer based on Davidon–Fletcher–Powell (DFP) method and simulated annealing (SA). A case study shows that the proposed methodology for cooling system optimal design is efficient, robust and practical.     

应用软PLC技术构建全电子注塑机温度控制系统

基于德国3S公司软PLC产品CoDeSys,阐述应用软PLC技术构建温度闭环控制系统,充分发挥软PLC扫描精度高、运算能力强等优点,为注塑机温度控制提供了一套全新的方案.根据现场调试的结果表明,提供的控制方法行之有效,各控制段静态温控精度在±1℃,动态精度达到±2℃,而且系统鲁棒性好、可靠性高、抗干扰能力强,满足注塑机对温度控制的要求.     

The concurrent implementation of high velocity control performance and high energy efficiency for hydraulic injection moulding machines

A high servo control response and a high energy efficiency, which are difficult to achieve simultaneously, are requested in hydraulic servo systems of current hydraulic injection moulding machines. This investigation develops new solutions to concurrently implement energy-saving control and velocity control for simultaneously realising high velocity control response and high energy efficiency for injection moulding machines. Two different hydraulic pump systems, including a variable displacement pump and a variable rotational speed pump, are developed and in each one of them two different energy-saving control concepts, such as load-sensing control and constant supply pressure control, are implemented. Thus, for verifying the feasibility of the integrated control systems and comparing the energy-saving effects, velocity control of the hydraulic cylinder can be integrated with four different energy-saving control systems (ESCSs) and also the conventional hydraulic system without energy-saving control. A fuzzy sliding mode control that can simplify the complex fuzzy rule bases is used for solving the complex two-input two-output systems. The experimental results show the excellent performance of the integrated concurrent control systems.     

Process chain development for the rapid prototyping of microstructured polymer, ceramic and metal parts: composite flow behaviour optimisation, replication via reaction moulding and thermal postprocessing

Different variants of reaction moulding techniques exploiting the rapid light-induced photopolymerisation of reactive resins are widely used in microsystem technologies for the fabrication of plastic components or for rapid prototyping (RP) purposes. In this paper, the further development of micro reaction moulding with respect to a rapid prototyping of ceramic and metal parts will be described. As in powder injection moulding, the process sequence binder–filler–formulation, replication, debinding and sintering has to be passed. The mould filling and, hence, the accurate reproduction of surface details depend strongly on the composite’s viscosity, which is a function of the filler load. Especially, an improved process control of the composite formation prior to moulding and the thermal debinding is crucial for the realisation of microstructured ceramic or metal parts. The development of the whole process chain and some examples will be presented. This paper was originally presented at the International Conference on Multi-Material Micro Manufacture (4M), Karlsruhe, Germany, 29 June 2005 to 1st July 2005, and is extended for publication in this journal.     

Integrated control of clamping force and energy-saving in hydraulic injection moulding machines using decoupling fuzzy sliding-mode control

The objective of this research is to implement a novel parallel control of clamping force and energy-saving in hydraulic injection moulding machines (HIMMs) in order to simultaneously achieve accurate force control response and high energy efficiency. In order to verify the feasibility of the integrated control system and compare energy-saving effects, the clamping force control of HIMMs can be integrated with two different energy-saving control systems or integrated with a conventional hydraulic system without energy-saving control. The overall control system is a coupled two-input two-output system. Therefore, a decoupling fuzzy sliding-mode control (DFSMC) strategy, which can reduce the fuzzy rule numbers and counteract the coupling effects, is developed for the integrated control of HIMMs. The experimental results show the outstanding performance of the parallel control in HIMMs with DFSMC .     

注射模冷却系统中的CAE技术应用

因塑件所用塑料的性能、塑件的结构以及成型工艺参数不同,注射模对其冷却系统的要求也不相同.塑料注射模冷却系统的设计不但关系到塑件质量而且也关系到注射成型生产效率.以碗厨上盖塑料制件为倒,阐述了CAE技术在注射成型冷却系统中的应用与模拟分析,并根据冷却分析的结果提出了相应的优化方案,最终获得了良好的冷却效果.     

基于神经网络和遗传算法的薄壳件注塑成型工艺参数优化

建立基于神经网络和遗传算法并结合正交试验的薄壳件注塑成型工艺参数优化系统.正交试验法用来设计神经网络的训练样本,人工神经网络有效创建翘曲预测模型;遗传算法完成对影响薄壳塑件翘曲变形的工艺参数(模具温度、注射温度、注射压力、保压时间、保压压力和冷却时间等)的优化,并计算出其优化值.按该参数进行试验,效果良好,可以有效地减小薄壳塑件翘曲变形,其试验数值与计算数值基本相符,说明所提出的方法是可行的.     

Conceptual design support system in a collaborative environment for injection moulding

The shortened time-to-market of new products requires experts from multiple disciplines to cooperate in product development. In this collaborative product development environment, an Internet-based conceptual design support system for Injection moulding is developed. It can help designers to put forward feasible design solutions quickly and provide strong support for collaborative design. The architecture, implementation and evaluation of this system are discussed in this paper. The proposed system makes fully use of component-based web technology and has a flexible distributed architecture. A hybrid neural network and genetic algorithm approach is also adopted for more accurate and efficient retrieval. Experiment results indicate it is superior to conventional systems in accuracy and time.     

并行工程在注塑模具设计制造中的应用

介绍了CE理论,针对现行传统的串行注塑模具设计模式存在的问题,提出引入CE设计方法,从管理与技术两个方面,提高企业产品设计能力、缩短产品开发周期、提高产品质量,降低成本,从而提高企业的竞争力,并给出了实施方法。     

Structural scheme optimization design for the stationary platen of a precision plastic injection molding machine

The current development of precision plastic injection molding machines mainly focuses on how to save material and improve precision, but the two aims contradict each other. For a clamp unit, clamping precision improving depends on the design quality of the stationary platen. Compared with the parametric design of stationary platen, structural scheme design could obtain the optimization model with double objectives and multi-constraints. In this paper, a SE-160 precision plastic injection molding machine with 1600 kN clamping force is selected as the subject in the case study. During the motion of mold closing and opening, the stationary platen of SE-160 is subjected to a cyclic loading, which would cause the fatigue rupture of the tie bars in periodically long term operations. In order to reduce the deflection of the stationary platen, the FEA method is introduced to optimize the structure of the stationary platen. Firstly, an optimal topology model is established by variable density method. Then, structural topology optimizations of the stationary platen are done with the removable material from 50%, 60% to 70%. Secondly, the other two recommended optimization schemes are given and compared with the original structure. The result of performances comparison shows that the scheme II of the platen is the best one. By choosing the best alternative, the volume and the local maximal stress of the platen could be decreased, corresponding to cost-saving material and better mechanical properties. This paper proposes a structural optimization design scheme, which can save the material as well as improve the clamping precision of the precision plastic injection molding machine.     

Countercurrent plunge cooling: A new approach to increase reproducibility in the quick freezing of biological tissue

Conditions fulfilling all the accepted criteria for optimum cryoquenching are realized for the first time in a plunge freezing device. Samples are plunged down through a smoothly rising cryogen stream that is maintained within ± 0.25 K of a preselected temperature. Dry nitrogen gas at ambient temperature removes evaporated cryogen molecules from the plunging path immediately above the liquid coolant to prevent pre-cooling of the sample. Symmetrical instrument design and conditions of flow ensure symmetrical freezing under optimum conditions in a totally repeatable fashion. The device has been used with halocarbons, propane and ethane. It provides consistent cooling rates comparable with the best so far obtained by any other plunging method.