基于SolidWorks Plastics软件的缩痕分析在注塑件加强筋设计中的应用

本文采用SolidWorks Plastics对某一注塑件进行了缩痕分析。通过分析,可以直观地观察到注塑件表面的缩痕,并分析出注塑件中容易产生缩痕的部位。通过比较不同的加强筋厚度、加强筋圆角以及拔模斜度等参数的计算结果,分析加强筋厚度、加强筋圆角和拔模斜度对注塑件缩痕的影响,对注塑件中加强筋的设计具有一     

阻尼座注塑模中的CAE技术

利用Moldflow软件流动模拟分析阻尼座零件不同浇口的位置。预测可能存在的气泡、熔接痕的位置,确定最佳浇口位置,并在此基础上设计模具。为了防止溢出飞边和刮伤凸模及固定型芯,推板和凸模型芯之间采用锥体配合,注射时不会因受注射压力影响而使型芯偏斜,从而保证塑件精度。     

基于灰色理论的顺序注射成型工艺参数优化

汽车保险杠是大型薄壁塑件,采用传统注射成型很难消除其表面的熔接痕,热流道顺序注塑是解决熔接痕,提高表面质量的一种很好的成型方法。以汽车保险杠为例,采用针阀式浇口,5点进浇,可以使熔接痕控制在产品边缘,但是其翘曲度偏大。根据分析,翘曲度的大小与针阀开启时机密切相关,以保压过程中的压力和针阀开启时刻为主要因素进行正交实验。运用灰色理论,计算出各试验的灰色关联度,并通过极差分析,获取最佳工艺参数值组合。将该最优参数组合在Moldflow软件中进行验证,该产品3个方向的最大翘曲度分别为0.973%,1.12%,1.33%,都小于1.5%,满足生产要求,这种热流道顺序注射成型方法成功的解决了塑件熔接痕的问题,同时对针阀开启时机的优化成功的控制了塑件的翘曲度的大小,这种成型优化方法可以在实际的生产中进行推广应用。     

不同类型光纤低损耗熔接的研究与实现

通过分析光纤熔接损耗产生的原因,得出可以调整熔接参数来改善模场失配,实现不同类型光纤的低损耗熔接。根据这样的理论分析,用普通商用的光纤熔接机进行手动熔接,实现不同种类光纤的低损耗熔接,降低光纤熔接成本,提高经济效益。     

DEFORM金属挤压成形工艺数值模拟技术

金属挤压成形是用压力机和模具对放置在模具腔内的金属坯料施加强大的压力使金属坯料产生定向塑性变形,从挤压模的模孔中挤出而获得所需断面形状、尺寸且具有一定力学性能的零件或半成品的塑性加工方法。挤压成形的种类很多,例如按照金属塑变流动方向可分为正挤压、反挤压、复合挤压及径向挤压。按照金属坯料温度分冷挤压、温挤压和热挤压等。     

挡泥板注射模具设计及制造

一、塑件工艺分析 材料为ABS,颜色为灰色,每件重202g,长350mm,宽90mm,最大壁厚为4．5mm,最小壁厚为1.5mm. 该产品成型后要求表面平整光洁,无影响外观的缩印、熔接痕、银丝、分色、缺料、飞边、裂纹和变形等工艺缺陷.     

降低光纤接头熔接损耗的方法

在光缆工程中，使用自动专用熔接器进行光纤接头熔接已经得到广泛应用。光纤接续后，光传输到接头处产生的熔接损耗，直接影响光传输质量。目前，测量熔接损耗有远端监测法、近端监测法、远瑞环回双向监测法等。为了降低或消除熔接损耗可以采取多种措施，例如，在接续施工中设法在光纤断开处进行熔接，以使光纤模场直径对熔接损耗的影响最小；避免光纤的扭转、弯折，尽可能降低光纤受损伤的几率，等等。     

DEFORM金属挤压成形工艺数值模拟技术

金属挤压成形是用压力机和模具对放置在模具腔内的金属坯料施加强大的压力使金属坯料产生定向塑性变形，从挤压模的模孔中挤出而获得所需断面形状、尺寸且具有一定力学性能的零件或半成品的塑性加工方法。挤压成形的种类很多，例如按照金属塑变流动方向可分为正挤压、反挤压、复合挤压及径向挤压。按照金属坯料温度分冷挤压、温挤压和热挤压等。     

Moldflow在光驱托盘模具设计中的应用

为制造出高质量高精度的模具,以某光驱托盘为研究对象,利用Moldflow MPI 6.0的填充、流动以及冷却-流动-翘曲分析模块对熔体在模具中的流动行为进行数值模拟.制品采用Pro/ENGINEER建模并进行自动网格划分.网格采用Fusion格式,尺寸为3 mm.根据模拟出的熔体流动前沿的推进速度、填充过程中的温度和压力变化、制品冷却时间等流动行为和工艺参数,确定最佳成型方案.示例表明该方法能基本满足产品的质量要求.     

汽车仪表板注射成形浇注系统方案及翘曲分析

针对汽车设计中的轻量化需求,分析不同浇口模型下汽车仪表板的注射成形过程.分析3种浇注模型下模具型腔的充填情况,发现熔接痕的数量不仅与浇注系统的布局有关,还受产品结构影响;分析3种浇注模型下的充填压力,发现浇口数量越多,充填压力损失越小,但浇口数量的增加会导致熔接痕数量增多;4浇口模型与5浇口模型对应的制品收缩率分布基本一致,3浇口模型的收缩率略高;采用高性能有限体积法（High Performance Finite Volume Method,HPFVM）分析3种浇注模型下制品的翘曲情况,发现3浇口模型的总翘曲变形量分布最宽,5浇口模型的总翘曲变形量分布最窄.     

Influence of processing parameters on micro injection molded weld line mechanical properties of polypropylene (PP)

As a hot fabrication technology for micro scale parts, micro injection molding is receiving increasing market attention. Improving mechanical properties of micro parts should be an important issue in the micro injection molding process. The relation between weld line strength in micro injection molding parts and processing parameters is investigated. A visual mold with variotherm unit is designed and constructed, in which the micro tensile specimen with weld line are prepared. Polypropylene (PP) is used as the research material in this study, and six processing parameters were chosen as investigating factors, which were melt temperature, mold temperature, injection pressure, packing pressure, ejection temperature and injection speed. In order to achieve optimized processing parameters and their order of significance, Taguchi experiment method was applied in this presented study. The prediction formulation of the strength of micro weld line was built up by multiple regression analysis based on Chebyshev orthogonal polynomial. The results showed the influencing significance order of parameters from strong to week separately are mold temperature, melt temperature, injection speed, ejection temperature, packing pressure and injection pressure. And the tolerance of micro weld line prediction formulation was found to be lower than 21% through confirmation experiments.     

A visual mold with variotherm system for weld line study in micro injection molding

In order to study the weld line developing process and its influence on mechanical properties in micro injection molding, a visual mold with variotherm system mold was designed and fabricated. In this mold, a visualization design and a rapid heating/cooling system were integrated, and specimens with different cross section shape and micro dimensions could be molded for weld line study. The building process for the visual and variotherm mold was presented and the experiments were executed. The specimens for weld line study of micro injection molding were produced applying different processing parameters. A problem of flash in molded specimens needs to be solved.     

热轧带钢层流冷却控制方法

针对热轧带钢层流冷却终冷温度范围的扩大以及控制精度提高的要求,通过分析影响层流冷却过程的关键性因素如,速度、厚度、喷水量对终轧温度的影响,以及各因素之间相互的作用关系,合理制定出层流冷却的初始值,并建立起层流冷却温度控制的数学模型。运用前馈控制、速度补偿控制的思想以及针对层流冷却特点的线性叠加控制对层流冷却过程进行实时控制。所提出的方法成功运用于某层流冷却生产模型中,实现了终冷温度范围扩大以及控制精度提高的目标。     

Effect of micro tensile sample’s cross section shape on the strength of weld line in micro injection molding process

As a suitable mass and cost efficiency fabrication method, micro injection molding is doing a very good performance in micro plastic parts production. The mold design is an important part affecting micro parts properties. In this study, a micro injection mold with multi cavities of micro tensile bar is used. These micro cavities are fabricated by a micro milling process in different cross section shapes (semicircle R = 0.5 mm, equilateral triangle D = 0.3 mm, and trapezoid D = 0.336 mm t = 0.2 mm bottom angle = 95°). With an Arburg^® 320C injection molding machine, micro tensile test sample are prepared in different processing parameters so that a correlation between the cross section shapes with micro weld line strength in different conditions could be investigated by tensile test. Final results show that when the cross section shape is different, their corresponding weld line strength is also different. Equilateral triangle cross section is leading to strongest weld line, and then followed by trapezoid, semi-circle is the last. By analysis of these tensile test results, the quantitative factor a is defined as the ratio of perimeter to area of cross section shape, and higher a value is corresponding stronger weld line. After weld line strength comparison in different processing conditions, the results show that higher injection pressure induced to lower weld line strength whatever the cross section shape is. By higher mold and melt temperature, equilateral triangle cross section gives improved weld line strength. But mold and melt temperature affect weld line strength negative for other cross section shapes.     

Effect of physical vapor deposition metallic thin films on micro injection molded weld line mechanical properties

Micro injection molded polymeric parts coated with functional thin films/layers show off the promising applications in microsystems area. But the unfavorable and unavoidable defect of weld line in micro injection molding part leads to detrimental mechanical and surface properties. The possibility of the functional thin film for enhancing micro injection molded weld lines was investigated. Two typical coating materials (aluminum and titanium) with various film thicknesses (400, 600, 800 nm) were deposited on one side of the micro injection molded weld line tensile sample via physical vapor deposition (PVD) method. The coated micro weld line samples were characterized by tensile tests. The results show that PVD films of aluminum and titanium can reinforce the strength and stiffness of micro injection molded weld line, even at thin thickness levels. But when the film thickness is increasing, the weaker adhesion between metallic films and polymers decreased the PVD films’ enhancing performance for micro weld line mechanical properties due to the degradation of polymers related to longer time exposure under high temperature.     

Runner sizing and weld line positioning for plastics injection moulding with multiple gates

Weld line and warping are two critical defects for injection-moulded part. If weld lines are unavoidable due to multiple gates in a moulding, they should be positioned in the non-critical region. Instead of using flow leaders and deflectors to control the locations of the weld lines, this paper presents an approach to specify the locations of the weld lines by sizing the runners in a multi-gated injection moulding with the optimum gate locations. The methodology consists of three steps: partitioning the moulding into sub-mouldings based on the specified weld line location, determining the optimum gate location in each sub-moulding by minimizing the injection pressure and repositioning the weld lines to the desired locations by varying the runner sizes. Two examples are used to illustrate the approach.     

利用OpenGL实现连铸模拟的可视化

连铸技术是借助有效的冷却控制,使钢水连续并逐渐转变为钢坯的工艺过程,连铸坯内钢液的流动和传热直接影响着铸坯的表面质量及内部质量。从可视化角度研究了连铸结晶器内温度场和流场的显示原理及方法,利用Visual C＋＋和OpenGL混合编程技术加以实现,并将屏幕上显示的图像保存为位图文件。     

Acquisition of Weld Seam Dimensional Position Information for Arc Welding Robot Based on Vision Computing

Recognition and identification of weld environment and seam dimensional position by computer vision is a key technology for developing advanced autonomous welding robot. Aiming at requirements for recognition of weld seam image characteristics, this paper first presents an improved algorithm of subpixel edge detection based on Zernike moments. Comparing with the Ghosal’s original algorithm, the improved algorithm deals with mask effect and first derivative model on edge gradient direction so that it has the strong robust to noise, self-thinning ability and higher locating precision. An algorithm based on ZMs to extract line is also proposed, the comparative results with SHT and RHT show the method has the highest calculation speed and accuracy. The stereovision technology is developed to identify dimensional position of weld seam by computing dimensional coordinates of the weld seam. According to characteristics of weld seam, view field scope model and stereovision model based on baseline are studied and a stereo matching method is presented. In order to evaluate the algorithms and models presented in this paper, a welding robot systems with single camera fixed on the weld torch end-effector has been established for the robot to identify the dimensional position of typical weld seam by one-item and two-position method. The experiment results on S-shape and saddle-shape weld seams show that the vision computing method developed in this paper can be used for acquiring weld seam dimensional position information in welding robot system. Thus the welding path is mapped before the welding operation is executed.     

Automated process parameter resetting for injection moulding: a fuzzy-neuro approach

Optimal process parameter setting for injection moulding is difficult to achieve due to a large number of factors involved. Current practice in industry is to adjust the parameters based on the products' defects of test-run through trial and error. This process, however, requires enormous experience and is often time consuming. This paper reports an intelligent system employing fuzzy sets and neural networks which is able to predict the process parameter resetting automatically to achieve better product quality. The system is designed to be used in the test-run of injection moulding. Seven commonly encountered injection moulded product defects (short shot, flash, sink-mark, flow-mark, weld line, cracking, and warpage) and two key injection mould parameters (part flow length and flow thickness) are used as system input which are described using fuzzy terms. On the other hand, nine process parameter adjusters (pressure, speed, resin temperature, clamping force, holding time, mould temperature, injection holding pressure, back pressure, and cooling time) are the system output. A back-propagation neural network has been constructed and trained using a large number of {defects} {parameter adjusters} expert rules. The system is able to predict the exact amount to be adjusted for each parameter towards reducing or eliminating the observed defects. Testing in several real cases showed that the system produced satisfying results.     

Evaluation of Si liquid cooling structure with microchannel and TSV for 3D application

The development of 3D integration has caused a major technology paradigm shift to all integrated circuit (IC) devices, interconnects, and packages. Despite the benefits of 3D integration, this process faces the key challenge of thermal management, especially for high power and high density IC devices. Due to the limitations of conventional thermal solutions, liquid cooling technology has become a field of great interest for IC thermal management. In this study, an on-chip liquid cooling module with three different through Si vias (TSVs) and a fixed microchannel structure has been fabricated on an Si wafer using deep reactive ion etching and anodic bonding, followed by a grinding and dicing process. Pressure drop, coolant flow, and temperature difference before and after liquid flow were experimentally measured. TSV depth and diameter have been shown to have little effect on the change of pressure drop; however, shallower TSV depth and larger TSV diameter led to improved liquid cooling performance. The trapezoidal TSV showed slightly more effective cooling than did the scalloped TSV or the straight TSV.