注塑件模拟焊缝成形的实验验证外文文献翻译、中英文翻译

《注塑件模拟焊缝成形的实验验证外文文献翻译、中英文翻译》由会员分享，可在线阅读，更多相关《注塑件模拟焊缝成形的实验验证外文文献翻译、中英文翻译（20页珍藏版）》请在装配图网上搜索。

1、外文出处： Polymer Testing 29 (2010) 9109141外文资料翻译译文（约3000汉字）：注塑件模拟焊缝成形的实验验证J.G. Kovcs*, B. Sikl布达佩斯技术经济大学高分子工程系摘要：近几年来，由于对注塑件性能要求的不断提高，人们对注塑件的焊缝分析越来越感兴趣。当两个熔化前沿相互接触时形成焊缝。如果不修改零件的几何结构，就不可能完全消除焊缝，但可以将其对零件性能和外观的负面影响降到最低。这可以通过试错实验或模型预测来实现。后者的成本和时间效率使其成为焊缝分析的首选方法。注射成形计算机模拟软件包能够准确预测焊缝位置，但现有的软件包都不能定量预测焊缝接触角和力学

2、性能。本文对焊缝成形过程进行了分析，提出了改进有限元网格的方法，以获得较好的效果。关键词：焊缝；注塑成型；模拟；有限元网格1、 介绍注塑成型是用于成型塑料零件的最有效的工艺之一16。该方法的有效性取决于产品的质量，这可能会受到工艺设置不足或模具结构造成各种缺陷的阻碍。许多缺陷如焊缝、翘曲、喷射或凹陷等都会降低注塑件的质量，降低生产效率。在注塑件的设计中，焊缝的产生是一个重要的美学和机械问题。当两个熔化前沿相互接触时形成焊缝。在具有多个浇口的零件中，在模具填充过程中，可变壁厚、孔或型芯形成单独的熔体前沿，而分离的熔体前沿形成焊缝，从而在零件中造成许多故障7,8。它不仅恶化了局部的机械性能，而且会

3、产生光学缺陷，特别是在使用高光泽材料时。Chen等人在ABS拉伸钢筋上研究了感应加热在表面温度控制中的应用，消除了焊缝表面的痕迹 9。 的确许多参数对焊缝的性能有影响，这些因素已经从多个方面进行了研究。在力学性能方面，对焊缝强度和模量进行了分析，结果表明焊缝对拉伸模量没有显著影响10,11。一些研究人员12-15使用焊缝系数（WL factor），定义为：有焊缝的试样强度/没有焊缝的试样强度，来评估他们的实验。采用高熔体温度、高保压压力和低结晶器温度对未填充材料的影响系数最高。利用激光引伸计和声发射对焊缝进行了研究，得出的结论是焊缝不是材料中的简单不连续，而是应力应变分布的局部扩展扰动16。近

4、年来，由于对注塑件性能要求的不断提高，人们对注塑件焊缝分析的兴趣大大增加。如果不修改零件的几何结构，就不可能完全消除焊缝，但可以将其对零件性能和外观的负面影响降到最低。这可以通过试错实验或模型预测来实现。后者的成本和时间效率使其成为焊缝分析的首选方法。注射成型计算机模拟软件包能够准确预测焊缝位置，但现有的软件包都不能定量预测焊缝性能。这主要是因为迄今为止，焊缝特性的数学模型不可用17。在他们的文章中，周和李17提出了一个基于人工神经网络方法（ANN）的焊缝强度评估模型。对于网络的输入，选择了影响焊缝性能的因素，即材料的取向系数、相遇角和熔体流动历史系数。与试验结果的比较表明，该模型能够定量地预

5、测焊缝性能，为工程设计提供了依据。Zhou等人 18 研究了熔体温度和保压对焊缝试件力学性能的影响，发现随着保压和熔体温度的升高，焊缝试件的屈服强度和疲劳强度增加。他们解释了观察到的不同性质的皮肤核心形态，这是受熔体温度和保持压力的影响。Au 19使用几何方法来生成塑料部件的填充图案，并确定可能的焊接线的大致位置。Fathi和Behravesh20用可视化技术研究了焊缝成形过程中的流动动力学行为，而Zhou和Li17开发了一个人工网络来预测焊缝性能。为了确定网络的输入参数，对影响因素进行了详细的分析。对不可避免的焊缝非关键区域的形成和定位进行了仿真分析。多浇口零件焊缝定位的流量控制采用流道尺寸

6、调整方法21。Mezghani22将模拟的焊缝位置结果与注塑件的实际位置进行了比较。Zhou和Li23提出了一种基于初始相遇节点特征的焊缝检测算法。Chen24在零件仿真模型中应用模糊理论，通过改变壁厚和浇口位置来控制焊缝位置。Chun25通过模拟研究了壁厚和浇口位置对焊缝形成和位置的影响。2、 实验实验在Arburg Allrounder 320C 600-250注塑机上使用双腔注射模（图1）进行。这种特殊的模具有可更换的插入件，可以用不同的浇口类型（标准、薄膜、特殊薄膜等）具有不同的模具表面光洁度（抛光、细腐蚀、粗腐蚀），并注入不同厚度的试样（0.54 mm）。样品的厚度是由一个移动的部分

7、来设置的，以定位空腔的深度。注射模的顶出系统不同于传统的顶出系统，它不包括顶出销，而是在整个零件表面积上工作，从而消除了试样的变形。浇口类型可以随插入型腔之间的嵌件的变化而变化，而无需从注塑机上拆下模具。实验中，采用了精细的腐蚀表面光洁度，并在模具中设置了双标准浇口镶块。每个零件的标称尺寸为80 mm80mm2mm，从两点注射成型（图2）。两个标准浇口位于腔的一侧，距零件边缘10 mm，相距60 mm。采用聚酰胺6（Durethan B30S，Lanxess）进行研究。在注射成型之前，材料在80注射工艺条件保持恒定，模具温度为90， 当熔体温度设定在280 使用不同的切换点设置（图3）使用短射

8、技术制作试样。在样品上测量熔体前沿的相遇角，作为流动距离的函数（图4）。测量结果绘制在图5上。从中可以清楚地看出，会合角随流长的增加而增大。在7毫米的流动距离，它达到了一个可测量的焊缝角约28，当距离为22毫米时，角度为100。在较长的流动中，由于熔体前沿的轮廓，无法测量会合角。通过在浇口位置中心使用同心圆对熔体前沿进行可视化，还构建了会合角。结果表明，拉伸会合角的增加没有测量值高（图5）。在理论流动距离为10毫米时，它很好地代表了测量值，但在较长的距离时，它低估了实验尺度。3、 分析有限元模拟注射成型是目前设计注射模最先进的技术。市场上有不同级别的节目。这些基础知识对产品设计有一定的帮助，可

9、以在不了解塑料制造的情况下使用。更复杂的程序能够模拟整个注射成型过程，这样人们就可以看到模具是否能够完美工作。这种软件覆盖了大量的材料和机械数据库，设计者必须具备塑料制造的专业知识。对于注塑模拟，在大多数情况下，采用二维三角形单元或三维四面体单元来描述型腔，其中两节点管单元用于流道、连接件和通道。用控制体积法计算了熔体前沿的变化。在每一步中都可以得到压力场、温度场和速度场。这些结果构成了应力和变形分析以及焊缝结果的基础。Moldflow Plastics Insight 6.2用于模拟分析实验中使用的零件模型（图6）。在分析过程中，使用了三种不同的中间平面网格类型：原始网格、理想网格和平滑网格

10、。每种网格类型在4个网格边长度中完成：1、2、2.5和5 mm。原始网格是指模型由等边三角形组成，沿估计焊缝的节点不产生直线。这种网格类型的优点是具有良好的长宽比。网格单元的长宽比非常重要，因为它影响结果的精度。比率定义了三角形的最长边与三角形面积之间的相关性，而中面网格的推荐最大纵横比为约6。可以看出，在每一条边的长度上，这种网格三角形的平均长宽比都大于1.5。理想网格由具有共线节点的等腰三角形构成。生成这种网格类型的优点是，它可以很好地自动化，但是，由于较差的纵横比，即2，它不如原始网格那样精确（图7）。在平滑网格的情况下，原始网格的节点收敛形成一条线，在预测的焊缝区域中创建网格三角形边的

11、更均匀路径。它是从原始网格类型生成的，并在焊缝区域进行了修改。将焊缝上的节点靠近理想焊缝位置。模拟分析的工艺设置与实验注射成型相同，模具恒温，熔体温度为90和280。焊缝分析结果与实验结果进行了比较。在大多数情况下，理想的网格类型最适合测量结果。在边长为1mm的情况下，采用理想和平滑网格类型的分析接近于流量长度为7-10mm之间的测量结果（图8）。原始网格类型计算的值沿整个检测流长在测量结果周围波动，不接近测量值，而其他网格类型与流动开始时的测量值不同。同时观察到，在距离为10 mm后，所有网格都预测出焊缝角急剧增加。当网格长度为2 mm且流动距离较短时，振动再次明显（图9）。与测量结果相比，

12、原始网格给出的结果最不准确。角度值变化较大：计算出焊缝角为0距离10.6毫米但14712毫米。除原始网格外，在较长的流动路径下与测量结果的差异小于在边缘长度为2 mm时的差异。边缘长度增加到2.5mm，测量结果和模拟结果之间的相似性降低（图10）。在流动距离为1520 mm的区域，用理想网格模拟计算的焊缝线角与实测值接近，但其它网格变化不符合实测值的变化趋势。使用5 mm的边缘长度，曲线之间的一致性很弱（图11）。尽管分析结果显示出一些相似性，但出乎意料的是，结果仅在少数流动长度下接近测量值。比较每个边缘长度处的不同网格类型，可以注意到在每种情况下，理想网格与测量数据的相关性最好，在0.95和

13、0.98之间变化（图12）。结果还表明，理想网格的最佳相关度在高边长处，即5mm处，但随着边长的减小，相关度降低的幅度相对较小。对于原始网格类型，相关性最低，但随着边缘长度的增加，相关性显著提高，但这种网格类型并没有达到理想的相关性值。使用平滑网格，相关度随着边缘长度的增加而提高，但也没有达到理想网格类型的值。参考文献1 T. Tbi, J.G. Kovcs, Examination of injection molded thermoplastic maize starch. Express Polym. Lett. 12 (2007) 423.2 L. Mszros, T. Tbi, J.

14、G. Kovcs, T. Brny, The effect of EVA content on the processing parameters and the mechanical properties of LDPE/ground tire rubber blends. Polym. Eng. Sci. 48 (2008) 868.3 E. Lafranche, P. Krawczak, J.P. Ciolczyk, J. Maugey, Injection moulding of long glass fibre reinforced polyamide 6-6: guidelines

15、 to improve flexural properties. Express Polym. Lett. 7 (2007) 456.4 G. Dogossy, T. Czigny, Modeling and investigation of the reinforceing effect of maize hull in PE matrix composites. Polym. AdvanTechnol. 17 (2006) 825.5 S. Hashemi, Effect of temperature on tensile properties of injection moulded s

16、hort glass fibre and glass bead filled ABS hybrids. Express Polym. Lett. 7 (2008) 474.6 K. Banik, Effect of mold temperature on short and long-term mechanical properties of PBT. Express Polym. Lett. 2 (2008) 111.7 J. Shoemaker, Moldflow Design Guide. Carl Hanser Verlag, Munich,2006.8 R.A. Malloy, Pl

17、astic Part Design for Injection Molding. Hanser Publishers, 1994.9 S.-C. Chen, W.-R. Jong, J.-A. Chang, Dynamic mold surface temperature control using induction heating and its effects on the surface appearance of weld line. J. Appl. Polym. Sci. 101 (2006) 1174.10 S. Hashemi, Y. Lepessova, Temperatu

18、re and weldline effects on tensile properties of injection moulded short glass fibre PC/ABS polymer composite. J. Mater. Sci. 42 (2007) 2652.11 S. Hashemi, Thermal effects on weld and unweld tensile properties of injection moulded short glass fibre reinforced ABS composites. Express Polym. Lett. 1 (

19、2007) 688.12 R. Seldn, Effect of processing on weld line strength in five thermoplastics. Polym. Eng. Sci. 37 (1997) 205.13 S. Hashemi, Influence of temperature on weldline strength of injection moulded short glass fibre styrene maleic anhydride polymer composites. Plast. Rubber Compos 31 (2002) 318

20、.14 C. Lu, S. Guo, L. Wen, J. Wang, Weld line morphology and strength of polystyrene/polyamide-6/poly(styrene-co-maleic anhydride) blends.Eur. Polym. J. 40 (2004) 2565.15 N. Merah, M. Irfan-ul-Haq, Z. Khan, Temperature and weld-line effects on mechanical properties of CPVC. J. Mater. Process. Tech.

21、142 (2003) 247.16 C. Biergel, W. Grellmann, T. Fahnert, R. Lach, Material parameters for the evaluation of PA welds using laser extensometry. Polym.Test. 25 (2006) 1024.17 H. Zhou, D. Li, Computer evaluation of weld lines in injectionmolded parts. J. Reinf. Plast. Comp. 24 (2005) 315.18 Y. Zhou, P.K

22、. Mallick, Effects of melt temperature and hold pressure on the tensile and fatigue properties of an injection molded talcfilled polypropylene. Polym. Eng. Sci. 45 (2005) 755.19 C.L. Au, A geometric approach for injection mould filling simulationInt. J. Mach. Tools Manuf 45 (2005) 115.20 S. Fathi, A

23、.H. Behravesh, Visualization analysis of flow behavior during weld-line formation in injection molding process. Polym. Plast. Technol. 47 (2008) 666.21 M. Zhai, Y. Lam, C. Au, Runner sizing and weld line positioning for plastics injection moulding with multiple gates. Eng. Comput. 21(2006) 218.22 K.

24、 Mezghani In: The 6th Saudi Engineering Conference, Dharan,2002, pp. 335347.23 H. Zhou, D. Li, Modelling and prediction of weld line location and properties based on injection moulding simulation. Int. J. Mater. Prod. Technol. 21 (2004) 526.24 M.-Y. Chen, H.-W. Tzeng, Y.-C. Cheng, S.-C. Chen, The ap

25、plication of fuzzy theory for the control of weld line positions in injection molded part. ISA T 47 (2008) 119.25 D.H. Chun, Cavity filling analyses of injection molding simulation:bubble and weld line formation. J. Mater. Process. Tech. 89-90 (1999) 177.2外文资料原文（与课题相关，至少1万印刷符号以上）：Experimental valida

26、tion of simulated weld line formation in injection moulded partsJ.G. Kovcs*, B. SiklAbstract：The interest in weld line analysis of injection-moulded parts has increased in the past few years, mainly because of the ever-increasing requirements for the performance of injec- tion-moulded items. Weld li

27、nes are formed when two melt fronts come in contact with each other. Whereas the total elimination of weld lines is not always possible without modifying the part geometry, their negative inuence on part performance and appear- ance can be minimized. This can be done by trial and error experiments o

28、r by model prediction. The cost and time efciency of the latter makes it a preferred route for weld lines analysis. Computer simulation packages of injection moulding are capable of accu- rately predicting the weld line location, but none of the current ones can predict the weld line contact angle o

29、r mechanical properties quantitatively. This paper focuses on the analysis of weld line formation and suggests ways to modify the nite element mesh to get better results.Keywords：Weld line ；Knit line；Injection moulding ；Simulation；Finite element mesh1.IntroductionInjection moulding is one of the mos

30、t productive processes used to form plastic parts 16. The effectiveness of the method depends on the quality of the product, which can be hindered by inadequate process settings or mould construction causing various deciencies. Many kind of defect such as weld lines, warpage, jetting or sink marks c

31、an reduce the quality of the injection moulded parts, worsening productivity. The occurrence of a weld line means a signicant problem both aesthetically and mechanically in the design of injection moulded parts.Weld lines are formed when two melt fronts come in contact with each other. In a part wit

32、h multiple gates, variable wall thicknesses, holes or cores form separate melt fronts during mould lling and the separated melt fronts create weld lines, causing numerous troubles in the part 7,8. It not only worsens the local mechanical properties, but creates optical imperfections, especially when

33、 using high gloss materials. The surface marks of weld lines can be eliminated by the application of induction heating in surface temperature control, which was investigated on ABS tensile bars by Chen et al. 9.Many parameters have an effect on the properties of a weld line and these factors have be

34、en investigated from many aspects. As regards mechanical properties, analysis of weld line strength and modulus was performed and showed that the weld line did not have a signicant effect on tensile modulus 10,11. Several researchers 1215 used the weld line factor (WL-factor), dened as: strength of

35、specimens with weld line/strength of specimens without weld line, to evaluate their experiments. Highest WL- factors were obtained for unlled materials and using high melt temperature, high holding pressure and low mould temperature. Weld lines were studied using laser exten- someter and acoustic em

36、ission, and the conclusion was that a weld line is not a simple discontinuity in the material, but a locally extended disturbance of the stress and strain distribution 16.The interest in weld line analysis of injection-moulded parts has increased greatly in the past few years, mainly because of the

37、ever-increasing requirements for the performance of injection-moulded items. Whereas the total elimination of weld lines is not always possible without modifying the part geometry, their negative inuence on part performance and appearance can be minimized. This can be done by trial and error experim

38、ent or by model prediction. The cost and time efciency of the latter makes it a preferred route for weld line analysis. Computer simulation packages of injection moulding are capable of accurately predicting the weld line location, but none of the current ones can predict the weld line prop- erties

39、quantitatively. This is mainly because a mathematical model for weld line properties is, to date, unavailable 17.In their article, Zhou and Li 17 presented an evaluation model for weld line strength based on the articial neural network method (ANN). For the input of the network, the factors affectin

40、g weld line properties were chosen; those are the orientation coefcient of the material, the meeting angle and the melt mobility history coefcient. Comparison with experimental results shows that the presented model is capable of predicting weld line properties quantitatively for engineering design.

41、 Zhou et al. 18 examined the effects of melt temperature and hold pressure on the mechanical properties of specimens with weld lines and found that the yield and fatigue strengths of the specimens increased with increasing hold pressure as well as increasing melt temperature. They explained the obse

42、rved differences in properties in terms of a skin-core morphology, which was inuenced by both the melt temperature and the holding pressure.Au 19 used a geometrical approach to generate the lling patterns of plastic parts and determine the approx- imate location of possible weld lines. Fathi and Beh

43、ravesh20 studied the kinematical behaviour of the ow during weld formation with a visualization technique, while Zhou and Li 17 developed an articial network to predict weld line properties. The affecting factors were analyzed in detail in order to identify the input parameters for the network. The

44、formation and positioning in noncritical areas of unavoidable weld lines are also investigated with simula- tion analyses. The controlling of the ow for weld line positioning for multi-gated parts was carried out with a runner resizing method 21. Mezghani 22 compared the simulated weld line location

45、 results with the real position on injection moulded parts. Zhou and Li 23 presented a weld detector algorithm, which is based on the characteristics of the initial meeting node. Chen 24 applied fuzzy theory for controlling the weld line position by varying the wall thickness and the gate location i

46、n part simulation models. Chun 25 showed by simulation the effect of wall thickness and gate location on the formation and position of weld lines.2.ExperimentalThe experiments were performed on an Arburg Allrounder 320C 600-250 injection moulding machine using a two cavity-injection mould (Fig. 1.).

47、 This special mould has changeable inserts to be able to inject with different gate types (standard, lm, special-lm, multi gates, etc.), with different mould surface nishes (polished, ne eroded, rough eroded) and to inject different thickness specimens (0.54 mm). The thickness of the samples is set

48、by a moving part to position the depth of the cavities. The ejection system of the injection mould differs from the conventional one; it does not include ejector pins but operates on the whole part surface area, so eliminating deformation of the sample. The gate type can be varied with the change of

49、 an insert interposed between the cavi- ties without dismounting the mould from the injection moulding machine. For the experiments, a ne eroded surface nish was used and an insert with double standard gates was set in the mould.Each part, having nominal dimensions of 80 mm 80 mm 2 mm, was injection

50、 moulded from two points (Fig. 2.). The two standard gates are located on one side of the cavity 10 mm from the part edge and 60 mm apart.Polyamide 6 (Durethan B30S, Lanxess) was used for the investigations. Before injection moulding, the material was dried at 80 C for 4 h. The injection processing

51、conditions were kept constant; the mould temperature was 90 while the melt temperature was set at 280 C. The speci- mens were produced with short shot technology using different switch-over point settings (Fig. 3.). The meeting angle of the melt front was measured on the samples as a function of the

52、 ow distance (Fig. 4.).The results of the measurement are plotted on Fig. 5. It can be clearly seen that the meeting angle increased with the ow length. At a ow distance of 7 mm, it reached a measurable weld line angle of about 28, while at a distance of 22 mm the angle achieved was 100. At longer o

53、ws the measurement of the meeting angle was not possible because of the prole of the melt front.The meeting angles were also constructed from the visualization of the melt fronts using concentric circles centred at the gate locations. The results showed that the increase of the drawn meeting angle w

54、as not as high as the measured values (Fig. 5.). At a theoretical ow distance of 10 mm it represented the measured values well but at a longer distance it underestimated the experimental scale.3、AnalysisInjection moulding simulation with the nite element method is the most advanced technique for des

55、igning injection moulds. There are different levels of program available on the market. The basic ones are helpful in product design, which can be used without having deep knowledge of plastic manufacturing. The more complex programs are able to simulate the whole injection moulding process so one c

56、an see whether the mould will be able to work perfectly or not. Such software cover enor- mous databases of materials and machines and the designers must have professional knowledge of plastic manufacturing.For an injection moulding simulation, in most cases two-dimensional triangular elements or th

57、ree-dimensional tetrahedron elements are used to describe the cavity, with two-node tube elements for the runners, connectors and channels. The melt front advancements are calculated by the control volume method. The pressure, temperature and velocity eld can be obtained in each time step. These res

58、ults constitute the basis of the stress and deformation analysis as well as results for weld lines.Moldow Plastics Insight 6.2 was used for the simulation analyses with a model of the part used in the experiments (Fig. 6.). During the analyses, three different mid plane mesh types were used and comp

59、ared: original mesh, ideal mesh and smoothed mesh. Each mesh type was completed in 4 mesh edge lengths: 1, 2, 2.5 and 5 mm.Original mesh means that the model consists of equilateral triangles and the nodes along the estimated weld line did not produce a straight line. The advantage of this mesh type

60、 is the good aspect ratio. The aspect ratio of the mesh elements is important because it affects the accuracy of the results. The ratio denes the correlation between the longest side of the triangle and the triangle area, and the recommended maximum aspect ratio for a mid plane mesh is about 6. It c

61、an be seen that at every edge length this type of mesh triangle was greater than an average aspect ratio of 1.5.Ideal mesh is made up of isosceles triangles with collinear nodes. The advantage of the generation of this mesh type is that it can be well automated, however, because of the worse aspect

62、ratio, namely 2, it was not as accurate as the original mesh (Fig. 7). In the case of thesmoothed mesh, the nodes of the original mesh are converged to form a line creating a more uniform path of the mesh triangle sides in the area of the predicted weld line. It was generated from the original mesh

63、type with modication at the weld line region. The nodes positioned on the weld line were made nearer to the ideal weld line position.The process settings for the simulation analyses were identical to the experimental injection moulding, constant mould temperature and melt temperature namely 90 and 2

64、80 。The weld line analysis results were compared to the experimental. In most cases, the ideal mesh type best tted the results of the measurements. At an edge length of 1 mm, the analyses with ideal and smoothed mesh type came close to the measurement results between flow lengths of 7 and 10 mm (Fig. 8.). The values calculated with original mesh type flucated around the measured results along the whole examined flow length and did not approach them, while the other mesh type