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.

IMPROVE THE KINETIC PERFORMANCE OF THE PUMP CONTROLLED CLAMPING UNIT IN PLASTIC INJECTION MOLDING MACHINE WITH ADAPTIVE CONTROL STRATEGY

The kinetic characteristics of the clamping unit of plastic injection molding machine that is controlled by close loop with newly developed double speed variable pump unit are investigated. Considering the wide variation of the cylinder equivalent mass caused by the transmission ratio of clamping unit and the severe instantaneous impact force acted on the cylinder during the mold closing and opening process, an adaptive control principle of parameter and structure is proposed to improve its kinetic performance. The adaptive correlation between the acceleration feedback gain and the variable mass is derived. The pressure differential feedback is introduced to improve the dynamic performance in the case of small inertia and heavy impact load. The adaptation of sum pressure to load is used to reduce the energy loss of the system. The research results are verified by the simulation and experiment, The investigation method and the conclusions are also suitable for the differential cylinder system controlled by the traditional servo pump unit.

Hydraulic cylinder control of injection molding machine based on differential evolution fractional order PID

Injection molding machine,hydraulic elevator,speed actuators belong to variable speed pump control cylinder system.Because variable speed pump control cylinder system is a nonlinear hydraulic system,it has some problems such as response lag and poor steady-state accuracy.To solve these problems,for the hydraulic cylinder of injection molding machine driven by the servo motor,a fractional order proportion-integration-diferentiation(FOPID)control strategy is proposed to realize the speed tracking control.Combined with the adaptive differential evolution algorithm,FOPID control strategy is used to determine the parameters of controller on line based on the test on the servo-motor-driven gear-pump-controlled hydraulic cylinder injection molding machine.Then the slef-adaptive differential evolution fractional order PID controller(SADE-FOPID)model of variable speed pump-controlled hydraulic cylinder is established in the test system with simulated loading.The simulation results show that compared with the classical PID control,the FOPID has better steady-state accuracy and fast response when the control parameters are optimized by the adaptive differential evolution algorithm.Experimental results show that SADE-FOPID control strategy is effective and feasible,and has good anti-load disturbance performance.

A New Type Machine of Mixing-molding for Polyblends

This paper introduces a new type machine for polyblends with excellent mixing capabilities of internal mixer and continuous molding character of extruder.The machine includes two functions - mixing and extrusion molding that have been composed together by rational design,so a tandem production mode - "batch + continuous" are opened up.The mathematical model of continuous mixing molding was established and verified availably by experimental research.The main physical mechanical property of vulcanizate,which had met national waterproof material standard,verified the machine practicability.The essential difference from other similar type machines is that this machine is not only suitable in producing granular and powder rubbers but also lumpish rubbers.

Kansei Engineering Applied to the Form Design of Injection Molding Machines

This study investigated the relationship between a subject’s evaluation of injection molding machines (IMMs) and formal design features using Kansei engineering. This investigation used 12 word pairs to evaluate the IMM configurations and employed the semantic differential method to explore the perception of 60 interviewees of 12 examples. The relationship between product feature design and corresponding words was derived by multiple regression analysis. Factor analysis reveals that the 12 examples can be categorized as two styles—advanced style and succinct style. For the advanced style, an IMM should use a rectangular form for the clamping-unit cover and a full-cover for the injection-unit. For the succinct style, the IMM configuration should use a beveled form for the safety cover and a vertical rectangular form for the clamping-unit cover. Quantitative data and suggested guidelines for the relationship between design features and interviewee evaluations are useful to product designers when formulating design strategies.

Model evolvement and reuse technology of injection molding machine based on performance knowledge

To illuminate the necessity of model evolvement and reuse, dynamics of injection molding machine＇s product models are analyzed. The performance knowledge is used to support the model evolvement and reuse. The driven factors of mechanical product model are concluded. The dynamic characteristics of reuse. Finally, HT1800X1N series injection molding machines are taken as examples to illuminate that the arithmetic is correct and practical.

Modification and Development of a Blow Molding Machine

This study is based on the modification and development of a two-liter plastic container blow molding machine into a five-liter one provided with a translucent view stripe. This study considers some objectives including reducing the total cost, increasing the amount of plastic recovery, and raising the desired plastic materials. Proper designs were prepared and directly applied on spot. Tangible results were obtained. Among others, the modification of some components of the machine, e.g. the extruder, has led to the possible reuse of the milled (recovery) and extra material from the manufacturing processes. That was also conducive to an effective reduction in the cost of production to 50% in some cases. Prior to its modification, this old machine was used to produce polyvinyl chloride (PVC) containers that have become prohibited these days for their damaging effect on man’s life. For now, and after modification, it has become possible to use High Density Polyethylene (HDPE) material, a fact that has improved labor conditions, too.

Improvement of machining quality of copper-plated roll mold by controlling temperature variation

Micro prism film used in LCD industry can be manufactured by roll to roll method with copper-plated roll mold. As copper-plated roll mold is getting larger, pitch error is getting severer. The pitch error drops the quality of micro prism film. The main cause of the pitch error was investigated during machining large roll mold whose machined length was 1 200 mm. The temperature of machining system was elevated during machining roll mold, and this elevation induced thermal expansion of the system. The temperature variation around the roll mold also made thermal expansion of the roll mold. The amount of thermal expansion had strong relationship to the amount of pitch error. Therefore, the roll mold was machined after warming-up of machining system and precise temperature controller around copper-plated roll mold was installed, which minimized the temperature variation. Finally, precise micro prism patterns without pitch error were machined on the large roll mold.

Theoretical modeling of cutting temperature in high-speed end milling process for die/mold machining

A parametric model of cutting temperature generated in end milling process is developed according to the thermal mechanism of end milling as an intermittent operation, which periodically repeats the cycle of heating under cutting and cooling under non-cutting. It shows that cutting speed and the tool-workpiece engagement condition are determinative for tool temperature in the operation. The suggested model was investigated by tests of AlTiN coated endmill machining hardened die steel JIS SKD61, where cutting temperature on the flank face of tool was measured with an optical fiber type radiation thermometer. Experimental results show that the tendency of cutting temperature to increase with cutting speed and engagement angle is intensified with the progressing tool wear.

Computer Aided Design of Heat Treatment for AISI P20+Ni Mold Steel with Good Machinability

Computer aided design of heat treatment for AISI P20 mold steel with good machinability is attempted to proceed by the commercial software package Thermo-Calc (TCP+DICTRA). Through experimental and theoretical analysis of phase transformation during heat treatment, further knowledge of designing proper heat treatment is obtained. Then the machinability of AISI P20+Ni steel under given heat treatment condition is studied and the influencing factors to their machinability are analyzed. It is shown that heat treatment designed by computer simulation of carbide transformation is applicable to AISI P20+Ni steel with good machinability; AISI P20+Ni steel with tempered sorbite treated by quenching & tempering has optimal machinability; normalizing at the temperature of 910°C & tempering can avoid cracking and result in acceptable machinability in small thickness module.

Optimization strategy in end milling process for high speed machining of hardened die/mold steel

An optimization strategy for high speed machining of hardened die/mold steel based on machining feature analysis was studied. It is a further extension of the previously presented study on the thermal mechanism of end milling and constant cutting force control. An objective function concerning machining cost and associated optimization algorithm based on machining time and cutting length calculation was proposed. Constraints to satisfy specific machining strategies when high speed machining the hardened die/mold steel, trochoid tool path pattern in slot end milling to avoid over-heat and feed rate adaptation to avoid over-load, were also discussed. As a case study, the tool selection problem when machining a die part with multiple machining features was investigated.

A Tool Path Re-generation Algorithm for Die & Mold Machining

Facing the challenges of a shorter product design a nd manufacturing lead-time, many mold companies are using 3-D CAD/CAM software s ystems in design and manufacturing. A new product file is often issued to the mo ld design department before it is completely finalized and the design may have t o be iterated many times during the mold design and making processes. In practic e, if a mold has been modified, all the tool paths that cover the modified regio n must be re-generated, no matter how small the modified region may be. With th e available tool path generation systems, if a tool path needs to be re-generat ed, all the cutter location (CL) points must be re-calculated, and none of the original CL points can be re-used. It would require as much time to re-gen erate the modified tool path as in the original case. On the other hand, the mod ified region is usually quite small compared with the entire mold. The complete re-generation process is therefore highly unproductive and time-consuming. This paper proposes an efficient tool path re-generation approach for 3-axis d ie and mold machining. It is assumed in this research that a gouge-free too l path has been generated for the original mold and the same ball end-mill is to be used to generate the tool path for the modified mold. It is shown in th is work that if the boundary of the modified region is interference-free, the a ffected CL points are enclosed by a set of CL points which correspond to the poi nts on the boundary of the modified region. An efficient tool path re-generatio n algorithm was developed in this research. With this algorithm, a closed CL cur ve is first generated from the boundary of the affected region. The CL points fo r the original mold are then analyzed by comparing the x and y values with the b oundary of the affected CL points. If the CL points are not affected by the modi fication, they are output to the new CL file directly. Otherwise, they are remov ed and replaced by the new CL points. The algorithm has been tested using severa l industrial parts, and results show that it is efficient, robust, and the re-g enerated tool path is gouge-free and smooth.

Development of Online Machining and Measurement System in Die and Mold Manufacturing： Concept and Fundamental Experiments

The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining has an influence on accuracy and efficiency and is an important factor. The measurement system for measuring the forms of die and mold at all times is essential in order to machine the die and mold with high accuracy and efficiency. However, the problems of management and operation errors are found in compensating process of die and mold machining. In this paper, an online machining and measurement system in die and mold manufacturing is developed in order to overcome these problems. In this online system, 2-axis control system is added to a surface roughness measuring instrument, and both NC machining program and measured data are linked and controlled using a same computer. Therefore, the machining and measurement can be recognized for consistent process, and can be realized on the machine. This system has the advantages such as the high accuracy, low-price, and online convenience and so on. The possibility of practical use of this online system was investigated by fundamental experiments.

Computer aided design of free-machinability prehardened mold steel for plastic

In order to improve the machinability but not to impair other properties of the prehardened mold steel for plastic, the composition was designed by application of Thermo-Calc software package to regulate the type of non-metallic inclusion formed in the steel. The regulated non-metallic inclusion type was also observed by SEM and EDX. Then the machinability assessment of the steel with designed composition under different conditions was studied by the measurement of tool wear amount and cutting force. The results show that the composition of free cutting elements adding to mold steel for plastic can be optimized to obtain proper type of non-metallic inclusion in the aid of Thermo-Calc, compared with the large volume fraction of soft inclusion which is needed for promoting ductile fracture at low cutting speeds, the proper type of inclusion at high cutting speeds is glassy oxide inclusion. All those can be obtained in the present work.

多策略改进黏菌算法阶段优化HSVM变压器故障辨识

为解决变压器故障诊断精度较低的问题,提出了一种多策略改进黏菌算法(ISMA)阶段优化混合核支持向量机(HSVM)的变压器故障诊断新方法。首先,利用主成分分析(PCA)来消除变量之间的信息冗余并降低数据集维度。其次,引入黏菌算法(SMA),并结合Logistic混沌映射、二次插值、自适应权重多策略改进SMA,以提高SMA算法收敛速度和局部搜索能力;然后,与原始SMA、WHO和GWO算法进行寻优测试,对比验证改进后SMA算法的优越性;最后,使用改进SMA算法分阶段对混合核支持向量机参数寻优,构建ISMA-HSVM变压器故障诊断模型。将降维后的特征数据输入HSVM模型与BPPN、ELM和SVM进行比较,HSVM模型的诊断准确性分别提高了5.55%、8.89%、5.55%。使用ISMA优化HSVM模型参数,与WHO、GWO、SMA算法优化效果比较,结果准确性提高了13.33%、12.22%、5.55%。其中,ISMA-HSVM模型的诊断精度为93.33%。实验结果表明,所提模型有效提升故障诊断分类性能,且具有较高的故障诊断精度。

生物质成型技术及LH-600型生物质颗粒成型机设计

针对大型养殖场固体粪污、生物质秸秆、茶园茶梗、果园枝条、木屑及蘑菇渣等农业固体废弃物资源化利用过程中,生产生物质颗粒存在产量过低、设备故障率高、易堵塞模孔和成型率差等问题,研发设计了LH-600型生物质制粒成型机。对成型机喂料装置、颗粒成型装置、动力传动机构进行了创新设计,并利用Solidworks软件进行辅助设计。试验、工程实践应用表明,成型机具有使用寿命长、维护成本低、传动机构润滑降温效果好及高效节能等优点,适合大中型饲料加工厂、养殖场及有机肥厂使用。

食品包装热成型机电动八杆开合模机构的运动及受力分析

目的:解决热成型机的核心部件开合模机构相关杆件设计及其分析技术难题。方法:运用解析法阐述了一种热成型机的电动八杆开合模机构的运动和受力分析。结果:基于实例计算得到执行滑块位移与曲柄转角关系曲线,并进一步推导了速度和加速度变化规律;同时还揭示了片材挤压阶段的理论合模力和各杆件受力变化趋势及特点。结论:实现了在不具备专业软件的条件下对电动八杆开合模机构的分析,缩短了设计和试制周期。

考虑模具约束和开机成本的并行机调度问题研究

受企业实际的注塑排产问题启发,本文研究了一类考虑模具约束和开机成本的相同并行机调度问题,目标是最小化加权延迟成本、换模成本和开机成本之和。构建了混合整数规划模型,证明了问题必定存在无机器空闲的最优解,提出了新的工作分配规则以确保产生的解都无机器空闲。在此基础上,设计了修改的ATCS算法(ATCS-MOD)和基于列表调度的遗传算法(GA-LS)两种算法。大规模数值实验证明GA-LS求解效果优于CPLEX和ATCS-MOD,更显著优于传统ATCS算法,同时也证明了新工作分配规则相比传统ATCS规则的优越性。

基于STM32的动态注塑信号调节器设计

文中设计了一种基于STM32芯片与UCOSIII操作系统的动态注塑信号调节器。采用DDS芯片AD9833与数字电位器MCP41010配合实现了P/Q信号的发生与调幅;采用运算放大器OP07组成的加法器实现P/Q振动信号与P/Q静态信号的合成;基于RS485接口与Modbus通讯协议实现动态注塑信号调节器与上位机的实时通讯;基于emWin图形库设计了人机交互界面,可以在触摸屏上设定选定注塑参数。试验测试表明:动态注塑信号调节器能够根据上位机反馈的通讯信息在不同工序下输出不同波形、频率与幅值的P/Q动态注塑信号,满足泵控液压激振系统与动态注塑的应用需求。

安装扭矩对抱箍式锁模力仪测试结果影响的研究

注塑机锁模力监测系统主要用于在三板式注塑机中对锁模力的实时监测,以控制产品质量和防止设备的损坏。其中抱箍安装方式的锁模力实时监测仪由于价格低,安装可靠性高等特点,被广泛采用。在实际使用中,抱箍式注塑机锁模力传感器信号的准确度,在一定范围内与所施加的抱紧力(安装扭矩)有一定相关性,对后期维护会有较大影响。对抱箍式传感器在使用中的受力情况进行了分析,根据硅胶需要满足和格林柱之间无滑移的测试条件,分析了硅胶上的拉伸摩擦力以及正压力必须满足的条件,并根据传感器头的安装结构,推导了满足硅胶受力条件时,抱箍收紧时所需的理论最小扭矩公式,最后基于自行研发的抱箍式注塑机锁模力监测仪,进行了实验。实验结果表明,在扭矩较小时(100%理论最小扭矩),抱紧力的大小对测试结果影响很大;当抱紧力达到一定阶段后(150%最小理论扭矩),测试结果趋于稳定;当抱紧力达到一定值后(≥200%最小扭矩),测试结果的精度基本不再变化。