Multi-scale analysis of void evolution in large-section plastic mold steel during multi-directional forging

The void evolution of large-section plastic mold steel during multi-directional forging(MDF)was investigated using multiscale analysis.To simulate the forging process of the plastic mold steel(SDP1 steel)and realize micro-void reconstruction in a representative volume element(RVE),MDF experiment and void-characteristic evaluation of the SDP1 steel were carried out.Traditional upsetting and stretching forging(TUSF)and MDF were simulated to comparatively analyze the evolution of temperature,effective stress,and effective strain.By embedding RVE with a micro-void and using boundary condition by point tracking into the forging process,the single-void evolution in TUSF and MDF was studied.The effect of void orientation on single-void evolution was also investigated.The multi-scale analysis revealed the following results.(1)Compared with TUSF,MDF achieved a higher efficiency in void closure.(2)The closing efficiency of the void increased with the increase in angle h(the angle between the Z and long axes of the void).(3)The closing efficiency increased with the increase in the orientation angle during the forging process.On the basis of the important role of the main stress in each forging step on the void closure,an integral formula of the main stress was proposed.When main compressive-stress integration reached-0.4,the closed state of the void could be accurately determined.

基于Moldflow软件的短射法气辅成型数值分析及优化

使用数值成型对短射法气辅成型进行分析及优化。依据经验设计,对塑料扶手设计了3种进气方案,仿真结果表明:设置进气点位于浇口位置附近(方案3),气体虽未能充满所有部位熔体内部,但气道质量最佳。以方案3为基础,优化工艺参数,得到最佳方案为熔体注射量40%,气体延迟时间2.5 s,此时气体充满熔体内部,熔体壁厚减小且壁厚均匀,气道质量较好。以翘曲变形量为考察对象,运用正交试验法继续优化其他工艺参数,得到了最佳工艺方案为:熔体温度240℃,模具温度60℃,保压压力3 MPa,保压时间10 s。

基于Moldflow技术的塑料缸盖罩成型过程及模流数值分析

为解决传统人工鉴定塑料缸盖罩瑕疵产品的方式效率低下、成本高,以及传统的直流道数学模型不适用于弯流道的问题。对塑料制品的成型原理及过程进行了阐述,基于Moldflow对塑料缸盖罩成型过程进行了模流分析,建立了熔体在弯流道中流动的理论模型,采用Moldflow在不同的注射速率条件下进行数值模拟。实验结果表明:采用的塑料缸盖罩的生产工艺有制品内、外温差大,冷却不均的问题;塑料熔体在弯流道内的流动速度、剪切速率以及温度都随着注射速率的增大而增大,熔体粘度随着注射速率的增大而降低;熔体在流经弯流道时外侧与内侧熔体的指标差值较直流道更大。

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.

Warpage prediction of the injection-molded strip-like plastic parts

For most strip-like plastic injection molded parts,whose cross section size is much smaller than their length,the traditional Hele-Shaw model and three-dimensional model do not work well in the prediction of the warpage because of their special shape.A new solution was suggested in this work.The strip-like plastic part was regarded as a little-curved beam macroscopically,and was divided into a few one-dimensional elements.On the section of each elemental node location,two-dimensional thermal finite element analysis was made to obtain the nonuniform thermal stress caused by the time difference of the solidi fication of the plastic melt in the mold.The stress relaxation,or equivalently,strain creep was dealt with by using a special computing model.On the bases of in-mold elastic stress,the final bending moment to the beam was obtained and the warpage was predicted in good agreement with practical cases.

Computer Aided Alloy Design of High Performance Prehardened Mold Steel for Plastic

prehardened mold steel for plastic, Thermo-Calc ＆ DICTRA software package, machinability, heat treatment technology, free cutting phase.

Development of a plastic injection molding training system using Petri nets and virtual reality

In this study, Virtual Reality (VR)-based plastic injection molding training system (VPIMTS), which can be modeled as an integrated system with a task planning module, an intelligent instruction module, a simulation module, and virtual envi-ronment (VE) module, was developed. Presented in this paper are an architecture of VPIMTS, a practical knowledge modelling approach for modelling the training scenarios of the system by using Petri nets formalism and key techniques (FEM, injection molding procedure modelling) which have been developed independently. The utilization of the Petri net model realized the environment where the trainee can behave freely, and also made it possible to equip the system with the function of showing the next action of the trainee whenever he wants. The overall system is a powerful approach for highly improving the trainee’s comprehension and injection molding study-efficiency by building digital, intelligent, knowledgeable, and visual aids.

Novel Plastic Encapsulation Holding Method for Automobile Glass Using Injection Molding Process

Glass positioning and holding is difficult in the process of injection molding encapsulation of automobile glass. A suction cup or soft resin is always introduced in this process. However,these materials cannot hold glass tightly,thus resulting in the unsteady quality of toughened glass and encapsulated plastic. To solve this problem,a novel holding method called magnetic high-pressure holding with twin bags is proposed to address the features of toughened glass and the encapsulation injection process. Firstly,a pair of permanent magnets is introduced as energy source,followed by the magnetization of a couple of magnetic particle bags. Contact between the single bag and the glass surface will enable the couple of magnetic particle bags to hold glass tightly and to self-adapt the freeform of the glass. Secondly, an experimental system with mechanical and control systems is designed. This system is controlled by the opening and closing force of the mold,which turns the magnetic field on or off to hold or loosen the glass. The magnetic field distributions are measured at important positions of the permanent magnets and in the magnetized particles in the experiments to determine the holding performance. Finally, the process of determining the parameters of the magnet and its attenuation is analyzed, including the minimum friction force between the glass and the particle bag during injection molding,the magnetic energy product and the magnetized filed distributions,and the re-checking method for these parameters. The theoretical analysis and the experimental result show that this flexible holding system may produce sufficient holding force,which not only protects glass but self-adapts the glass freeform as well. The production practice meets the technical requirements of injection molding with a defect-free surface,with no scratches and cracks on the glass and no slight glass movements in the mold cavity.

基于Moldex3D汽车配件注塑成型工艺优化

注塑成型生产某种汽车配饰过程中会出现翘曲、缝合线、包封等缺陷,对汽车配饰件的装配以及使用产生影响。通过Moldex3D分析某种汽车装配件的注塑成型过程,采用PA66材料对产品的浇口位置、冷却水路、成型参数3方面进行模拟仿真,综合分析汽车配饰的翘曲程度和产生翘曲的主要原因,根据实验结果设立对照组进行优化处理,最终优化结果较原始方案翘曲优化率达到11.3%。

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.

UG和MoldFlow在《塑料成型工艺学》教学中的应用

《塑料成型工艺学》课程是材料科学与工程专业的重要专业课程,是一门应用于工业生产的理论和实践课程,本课程改变了传统的仅仅依靠课堂授课的教学模式,引入模具三维设计软件UG和模流分析软件MoldFlow作为重要的辅助手段,利用UG软件中的3D模型设计和模具设计和MoldFlow中的注射模流分析,可以给现有的教学过程提供有效的帮助,使学生能够更为深入的理论联系实际,更好、更直观地帮助学生理解塑料成型过程中的演化,也更好地适应企业对人才技能的需求。

基于抽真空系统的继电器线圈BMC热固性塑料模具结构设计

对于原有BMC继电器线圈模具的外观较差、线圈断线丝、生产效率及合格率较低等问题,设计了一种1模16腔布局的上、下双顶出系统的压注模具,通过抽真空系统结构的设计将注塑压力从原充填压力19~42 MPa降低至22~25 MPa,成型件采用电加热及电阻测温方法,上模镶件的温度控制在148~151℃之间,下模镶件的温度控制在148~151℃之间,通过实际生产验证抽真空系统的效果。该改进方案使不合格品率从0.08%降低至0.015%,生产效率提高了20%。结果表明,该模具通过抽真空系统的应用提高了模具的可靠性及稳定性,满足自动化数字化生产线的要求,并且,提高了生产效率与产品的合格率。

铜对4Cr16Mo塑料模具钢切削性能的影响

将4Cr16MoCu、4Cr16Mo和SDP136钢在1030℃保温4 h,冷却至室温后回火两次,第一次为540℃×4 h,4Cr16MoCu钢的第二次回火工艺为590℃×3 h,4Cr16Mo和SDP136钢为565℃×3 h,使其硬度达到35~36 HRC。采用扫描电子显微镜检测钢的显微组织,采用数控车床进行切削性能试验。分别采用SY-3F型应变式三维测力传感器、红外测温仪、TR200粗糙度测量仪和超景深显微镜测定切削力、刀尖温度、工件粗糙度和磨损刀具的形貌。结果表明:在相同的切削条件下,铜的添加能延长刀具的使用寿命;切削4Cr16MoCu钢的刀具温度比切削4Cr16Mo钢的刀具温度低50℃,切削试验的前、中期4Cr16Mo钢的切削力比4Cr16MoCu钢大43~94 N,但后期4Cr16MoCu钢的切削力上升至839 N,比SDP136钢大211 N。

基于Moldflow软件的塑料内饰件注射成型模拟

针对注塑件在实际生产中所产生的短射、气穴、翘曲、滞留、飞边及色差等问题,利用有限元理论,运用Moldflow软件对轿车塑料内饰件中央饰罩的3种浇注系统进行充型、熔接痕、翘曲分析的数值模拟,直观体现塑料在型腔内的变化过程.比较分析结果表明,选择充型均匀、平稳,熔接痕深度较浅,翘曲较小的浇注系统设计方案.

Moldflow软件在无绳电话机面板模具设计中的应用

在无绳电话机面板模具设计中,应用Moldflow软件分析了不同的浇口数量、位置及相应的保压压力、保压时间对制品的充模压力、熔接痕分布、翘曲变形量和缩痕缺陷等的影响。通过优化浇口数量、位置并辅助适宜的保压压力和保压时间,减少了注塑缺陷和制品变形,这对模具设计及注塑过程工艺参数的设定均有一定的实际意义。实践表明,Moldflow的分析结果与实际生产中通过试模所得到的方案非常相近,说明了Moldflow分析结果在塑料模具优化设计中具有很好的可靠性。

基于Moldflow的后盖CAE流动方案优化分析

以后盖为研究对象,阐述了产品的网格划分与MPI方案热流道的创建过程,介绍了MPI方案选材与基本成型条件,采用两种方案对产品的填充过程进行了模拟和分析,通过Moldflow软件对产品的变形和熔接痕进行了对比分析,最终选取方案2对产品成型进行优化分析,得到了一套切实可行的产品成型方案。研究表明,采用计算机辅助技术(CAE分析)对产品的成型优化具有较大的实用价值。

Moldflow软件在无绳电话机底盖模具设计中的应用

运用Moldflow软件,对无绳电话机底盖注塑成型过程的填充、保压、冷却进行模拟,详细分析了Moldflow软件在注塑模具优化设计中的应用。结果表明,Moldflow分析与实际生产中的成型工艺非常相近,其分析结果对塑料模具优化设计具有良好的指导作用。

基于Moldflow的薄壁注塑件成形工艺优化设计

基于Moldflow软件分析薄壁塑件的成形工艺,给出了通过调整模具温度、熔料温度、注射时间和注射压力等注塑工艺参数来实现成形工艺优化设计的方法,并得出了最佳成形工艺参数。

精密轴承用PEEK保持架结构及注塑工艺优化

针对原PEEK保持架兜孔无锁口,采用侧向抽芯机构进行注塑加工时外圆精度低的问题,将保持架兜孔分成内外两部分且设计为球面,注塑模具采用单分型面注塑模结构。并对注塑工艺浇口结构和浇口数量进行优化,基于正交试验得到最优工艺参数为模具温度180℃、熔体温度390℃、保压时间5 s和保压压力55 MPa。实际加工表明:外径面圆度不大于0.15 mm占86%;拉伸强度远高于65 MPa;200℃高温摩擦系数平均值为0.195,磨痕宽度平均值为0.9625 mm,磨损量平均值为0.1394 mm^(3);与相应公差等级套圈、球合套后,轴承旋转精度达到P4,振动值达到Z4。

基于Moldflow的注塑件翘曲优化及影响因素分析

结合Taguch i试验设计方法和注塑模拟Moldflow分析软件,对不同工艺条件下的塑件成型过程进行模拟分析,以减小翘曲量为质量目标对工艺参数进行优化。采用方差分析方法(ANOVA),分析了模具温度、熔体温度、注射时间、保压压力,保压时间等工艺参数对塑件翘曲变形的影响,并通过绘制因素水平影响趋势图,分析得出最优的注塑参数组合方案,并对该工艺组合方案进行模拟验证。