注塑产品工艺参数的计算机管理

介绍了一个注塑工艺参数管理软件的实际开发过程.随着工艺参数记录的增加,可将此作为以后开发注塑工艺参数专家系统的知识库,实现注塑工艺参数的智能给定.     

A study of gate location optimization of plastic injection molding using sequential linear programming

A gate location is one of the most important design variables controlling the product quality of injection molding. In this paper, the numerical simulation of injection mold filling process is combined with the design optimization method to find the optimum gate location to achieve balanced flow. The objective function is expressed in terms of the difference between the maximum and minimum times of boundary filling. The coordinates of gate are chosen as design variables, and a constraint is employed to limit the clamp force lower than the reference value. The optimization problem is solved with the sequential linear programming algorithm, and design sensitivities are evaluated via the finite difference approximation. Finally, numerical examples are given to demonstrate the effect of proposed methods.     

注射成型橡胶制品的自动脱模装置

用于输变电线路的硅橡胶绝缘子大多采用注射成型工艺生产。由于注射时的压力较大,成型后的制品与模腔挤压得非常紧,目前尚无法使制品自动脱离模具,一般采用人工脱模。存在这种现状的主要原因是复合绝缘成型技术应用时间较短,目前一次成型的绝缘子产品长度不超过1．5m。由于长度较小,脱模所需的力尚在人力所及范围,因而人工脱模一直沿用至今。     

Virtual plastic injection molding based on virtual reality technique

Virtual reality (VR), as a new technology, is integrated with software systems for engineering, design, and manufacturing. The integration has given a new impetus to the field of computer-aided engineering. This paper presents a research effort aimed at creating a virtual plastic injection molding (VPIM) environment, which is designed and implemented based on techniques such as VR, multidiscipline simulation, and scientific visualization. The VPIM system includes two parts: designing in VPIM and evaluation in VPIM. It is the first system to scrutinize virtual prototype mock-ups of new products, machines and production processes in interactive graphic simulation. During the evaluating phase, coupled to appropriate computer-based reasoning and decision-support tools and driven by data from the real manufacturing environment, a realistic impression of the process of plastic injection molding and manufacture can be achieved and can be changed interactively, and it is possible to thoroughly examine the planned system and eventually detect and remove any defects and inadequacies. The construction approach and key techniques (FEA, virtual assembly, stereoscopic display, a triangulated boundary-representation of an approximating polyhedron, collision detection, etc.) of the system are described in detail. The overall system is a powerful new approach for highly relevant industrial application of VPIM which focuses on the construction and assessment of alternate manufacturing sequences and mold design in an early design stage. Improvement of the design and manufacturing process will lead to better design and reduced development time and cost.     

现代双组份产品用注射成型工艺的可能性

当前,对一种产品总是提出多种要求,例如,汽车结构。为此,要考虑开发新的技术领域,但首先要从经济性、安全性、适用性及费用等着手考虑,从而导致要快速了解有关知识,即只有对不同材料进行组合利用才能满足这些要求,多种材料组合产品的一个典型的实例是汽车轮胎。该产品包括许多不同的材料,这些材料以不同的几何形状、布置及物理特性获得了理想的应用。还有些例子,如输送带、胶管或轴承部件等。     

浅析注射成型塑料件结构设计

从注射成型塑料件结构设计的角度出发,结合材料本身特性及注塑生产的工艺特点,总结了注射成型塑料件结构设计上的一些要点和注意事项,列举了若干设计中经常采取的结构形式和改进方法,为注射成型塑料件的结构设计给出了参考。     

An integrated parameter optimization system for MISO plastic injection molding

This paper presents the development of a parameter optimization system that integrates mold flow analysis, the Taguchi method, analysis of variance (ANOVA), back-propagation neural networks (BPNNs), genetic algorithms (GAs), and the Davidon–Fletcher–Powell (DFP) method to generate optimal process parameter settings for multiple-input single-output plastic injection molding. In the computer-aided engineering simulations, Moldex3D software was employed to determine the preliminary process parameter settings. For process parameter optimization, an L₂₅ orthogonal array experiment was conducted to arrange the number of experimental runs. The injection time, velocity pressure switch position, packing pressure, and injection velocity were employed as process control parameters, with product weight as the target quality. The significant process parameters influencing the product weight and the signal to noise (S/N) ratio were determined using experimental data based on the ANOVA method. Experimental data from the Taguchi method were used to train and test the BPNNs. Then, the BPNN was combined with the DFP method and the GAs to determine the final optimal parameter settings. Three confirmation experiments were performed to verify the effectiveness of the proposed system. Experimental results show that the proposed system not only avoids shortcomings inherent in the commonly used Taguchi method but also produced significant quality and cost advantages.     

Intelligent methods for the process parameter determination of plastic injection molding

Injection molding is one of the most widely used material processing methods in producing plastic products with complex geometries and high precision. The determination of process parameters is important in obtaining qualified products and maintaining product quality. This article reviews the recent studies and developments of the intelligent methods applied in the process parameter determination of injection molding. These intelligent methods are classified into three categories: Case-based reasoning methods, expert system- based methods, and data fitting and optimization methods. A framework of process parameter determination is proposed after comprehensive discussions. Finally, the conclusions and future research topics are discussed.     

A CAD/CAE-integrated injection mold design system for plastic products

Mold design is a knowledge-intensive process. This paper describes a knowledge-based oriented, parametric, modular and feature-based integrated computer-aided design/computer-aided engineering (CAD/CAE) system for mold design. Development of CAx systems for numerical simulation of plastic injection molding and mold design has opened new possibilities of product analysis during the mold design. The proposed system integrates Pro/ENGINEER system with the specially developed module for the calculation of injection molding parameters, mold design, and selection of mold elements. The system interface uses parametric and CAD/CAE feature-based database to streamline the process of design, editing, and reviewing. Also presented are general structure and part of output results from the proposed CAD/CAE-integrated injection mold design system.     

注塑工艺设计中模具CAE技术与正交试验的综合应用

模具CAE技术与正交实验、数据处理与分析技术的综合应用,可以有效地优化工艺参数方案,缩短模具设计周期、提高模具设计质量、降低模具制造成本。本文为注塑成型工艺方案的优化及模具设计提供了一种可行方案和技术路线。     

Recalling of the growth of Bohai plastic injection molding market

The rapid development of many industries has brought great opportunities to rubber and plastic injection molding industry, although rubber and plastic injection molding market of Bohai Sea economic zone is smaller than Yangtze River Delta and Pearl River Delta economic zone.     

Prediction of warpage in plastic injection molding based on design of experiments

In terms of injection processing parameters, a mathematical model for prediction of warpage was formulated based on design of experiments (DOE). First, the five most influential parameters were screened by using fractional factorial design (FFD): melt temperature, coolant temperature, injection time, V/P switch over and mold temperature. Second, considering the other four principal processing parameters except the melt temperature, the predicting mathematical model was founded by using central composite design (CCD) of experiments and FE simulation. Finally, the results of statistical analysis were collected from software Moldflow. The results suggested that the mathematical model can be used to predict warpage with adequate accuracy. Hence, it indicated that corrective and iterative design steps can be initiated and implemented for better quality of products without resorting to physical trials in plastics injection mold by using this predicting mathematical model.     

In-situ density measurement for plastic injection molding via ultrasonic technology

Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure−volume−temperature (PVT) method, have the shortages of time-delay and high cost of sensors. This study is the first to propose an in-situ density measurement method using ultrasonic technology. The analyses of the time-domain and frequency-domain signals are combined in the proposed method. The ultrasonic velocity is obtained from the time-domain signals, and the acoustic impedance is computed through a full-spectral analysis of the frequency-domain signals. Experiments with different process conditions are conducted, including different melt temperature, injection speed, material, and mold structure. Results show that the proposed method has good agreement with the PVT method. The proposed method has the advantages of in-situ measurement, non-destructive, high accuracy, low cost, and is of great application value for the injection molding industry.     

基于Moldflow的汽车大型覆盖件注射成型工艺研究

以汽车后保险杠为例,利用Moldflow软件直观地模拟出注射过程中的熔体流动过程.针对后保险杠的结构特点及品质要求,提出了一种针阀控制顺序进料延时保压的热流道浇注系统,分析了填充时间、填充/保压转换点压力、锁模力、翘曲变形、熔接痕分布等情况,消除了该类塑件易存在的熔接痕、翘曲变形大等缺陷,为实际生产提供了理论指导.     

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.     

基于Moldflow对突变壁厚塑件的注塑成型优化方案的研究

利用Mold flow/MPI技术对摩托车外壳进行CAE注塑模拟分析,预测了成型过程中的填充流动情况,并对型腔的填充时间、压力分布、锁模力大小等进行计算分析,掌握了翘曲变形产生的原因。根据注塑模拟分析结果优化了浇口、冷却系统设计方案和成型工艺参数,使模具设计更趋合理。优化后的成型方案用于实际生产,缩短了试模周期。     

An integrated parameter optimization system for MIMO plastic injection molding using soft computing

This study proposes an integrated optimization system to find out the optimal parameter settings of multi-input multi-output (MIMO) plastic injection molding (PIM) process. The system is divided into two stages. In the first stage, the Taguchi method and analysis of variance (ANOVA) are employed to perform the experimental work, calculate the signal-to-noise (S/N) ratio, and determine the initial process parameters. The back-propagation neural network (BPNN) is employed to construct an S/N ratio predictor and a quality predictor. The S/N ratio predictor and genetic algorithms (GA) are integrated to search for the first optimal parameter combination. The purpose of this stage is to reduce the process variance. In the second stage, the quality predictor is combined with particle swarm optimization (PSO) to find the final optimal parameters. The quality characteristics, product length and warpage, are dedicated to finding the optimal process parameters. After the numerical analysis, the optimal parameters can meet the lowest variance and the product quality requirements simultaneously. Experimental results show that the proposed optimization system can not only satisfy the quality specification but also improve stability of the PIM process.     

An experimental study on ejection forces of injection molding

In injection molding, the ejection forces decrease when the surface roughness of mold decreases. However, the ejection forces increase contrary in the area of surface roughness is less than 0.2 μmRa. Several kinds of PVD films are coated on the mold cores to prevent the increasing of ejection forces. Some of these PVD films showed effective prevention of increasing of ejection forces.