二板式注塑机合模结构系统刚性分析

注塑机合模机构系统刚性设计非常重要。目前二板式注塑机已经越来越成为大型注塑机的主流趋势,而对二板机合模系统刚性的研究依旧较少。文章从二板合模机构的机械刚性和液压刚性两方面进行解析,研究后发现合模机构在合模-注射过程中的力学特性并不相同,模具的不可逆回弹也会影响到机构的二次延伸。在设计二板式合模机构系统刚性时,机械、液压构成的串联刚度考虑非常重要。     

基于关联特性的注塑机合模机构运动特性研究

针对目前在合模机构的研究中广泛采用多刚体动力学系统模型,未考虑开合模运动过程中合模机构各零件弹性变形的影响,难以解释开模瞬间动模板运动特性的问题。通过对合模机构锁模状态的形变分析,基于弹性力学理论,建立了锁模力的数学模型,揭示了合模机构刚度、机构变形和锁模力三者之间的关系,并通过合模机构刚性模型和刚柔祸合模型的仿真对比,得到了动模板的速度和位移曲线,研究了开模瞬间动模板的运动特性及其对成型制品品质的影响。     

二板式液压注塑机锁模力能参数及增压回路的研究

介绍了二板式液压注塑机合模机构的基本结构,建立了锁模力能参数数学模型,分析了锁模力的特性,确定了锁模力能参数的取值极限范围。针对合模机构中的锁模液压缸一方面受注塑机整体尺寸限制,另一方面又要提供足够锁模力的特点,给出了高压锁模回路基本油路形式,利于实现注塑机自身轻量化。     

内循环二板注塑机液压合模系统的能耗分析及优化

应用AMESim软件建立了内循环二板直压式注塑机液压合模系统的模型,并对其能耗进行了分析。通过减少合模系统的单向阀、改变液压油缸活塞杆杆径和添加蓄能器等措施对注塑机合模系统进行了改进,并模拟计算了每种改进措施对系统能耗的影响。模拟结果表明:注塑机合模系统的最大能耗部分为锁模过程和泄压过程,锁模油缸的工艺参数对注塑机能耗的影响很大;通过减少单向阀系统能耗降低了26.7%,当液压油缸活塞杆杆径为95 mm时,系统能耗最低,使用蓄能器可使系统能耗降低26.3%。     

七支点合模机构及其液压驱动的两者互联关系的分析设计

双曲肘斜排列七支点合模机构是一种创新发明的新颖的合模机构,液压驱动系统基于肘杆机构的特性进行设计,两者之间相辅相成使机构的性能得到进一步提高。研究了液压驱动系统与机构的运动学、力学的性能之间的关系,提出了系统的主要技术参数的计算理论和设计准则,并通过实例验证了设计计算理论和公式的可行性,为机构的开发和应用提供了理论基础和工程设计方法。实例研究表明,双曲肘斜排列七支点合模机构同比双曲肘斜排列五支点合模机构,行程比大1倍,液压驱动节能35%,系统液压驱动装载功率下降40%。     

四板注压式合模机构的研究

设计了一种新型四板注压式合模机构,该机构由肘杆机构完成第一次合模,由增压板完成第二次压缩成型,并对增压板及动模板进行有限元分析。结果表明,增压板及动模板的受力及变形在合模机构允许范围内,分布较均匀,能提高制品的成型精度。     

注塑机合模机构分析及发展综述

从注塑机合模机构的功能、结构及性能特点出发,对其按照模板数目、驱动源、传动形式、合模架构等特点进行了详细分类,再选取双曲肘式、全液压直压式、无拉杆式、二板复合式4种典型的合模机构进行分析,总结出各自的结构特性及应用情况。最后又探讨了此4种典型合模结构各自的发展趋势。     

注射成型机五孔斜排合模机构的优化设计

介绍了从合模机构的强度和刚度要求出发进行注射成型机五孔斜排合模机构优化设计的方法。提出了等功效系数法的概念,并介绍了它在优化设计中的应用。由于综合处理强度和刚度,并简化处理目标函数,既达到了优化搜索方案的目的,又降低了编程难度,缩短了计算机运行时间,且能得到整个合模机构的结构尺寸。应用计算公式简洁、明了,具有明显的使用价值。     

全自动塑料正压热成型机

一种全自动塑料正压热成型机,包括送片机构、加热机构、合模冲剪机构、收卷机构。合模冲剪机构设有导柱、固定模板,以及可沿导柱上下滑动的活动模板,在活动模板的下方中间位置设有推动板,活动模板的两端分别通过一组肘杆机构与推动板连接,该合模冲剪机构还设有丝杆,丝杆由伺服电机驱动,丝杆与推动板上的螺母构成螺旋副。     

1140液压硫化机液压原理的设计

与机械式硫化机进行比较，介绍了液压硫化机的优越性。液压技术在液压硫化机中具体应用在横梁升降，加合模力，中心机构，活络模操纵装置，介绍了各部位液压原理的设计。     

再生聚酯纤维在不同夹持方式下的拉伸性能研究

分别测试了再生聚酯纤维和普通涤纶在三种夹持方式(直接、结节和钩接)下的拉伸断裂性能,从而研究了夹持方式对两种纤维拉伸断裂性能的影响。测试结果表明:两种纤维在直接拉伸方式下的拉伸断裂性能都要优于其它两种方式,这是由纤维弯曲伸直差异、应力集中现象以及弱环定律的原因造成的,且在钩接方式下进行拉伸时应力集中现象更为明显;再生聚酯纤维和普通涤纶的拉伸断裂性能存在一定的差异,特别是断裂伸长率和断裂功差异较大,且再生聚酯纤维的断裂强度受夹持方式的影响更大。     

Mechanical Response of a Large Fuel Cell Stack to Impact: A Numerical Analysis

Large fuel cell stacks usually undergo dynamic load (vibration and impact) during packing, transportation, and serving time, in particular for those used in the automobiles. This may cause the decay in the performance, and even structure damage of the stack. We numerically analyze the mechanical response of a large fuel cell stack clamped by steel belts to a violent impact in the present paper. It is found that the location of the clamping belts has a great effect on the anti‐impact performance of the stack. The results also indicate that the cells near the endplates have a worse anti‐impact performance than those far from the endplates. When subjected to a large impact in the direction parallel with the cells, the stack may give rise to interface slippage between cells, showing a downward bowing phenomenon. The relative slippage between cells is affected by the clamping force, impact acceleration and the friction coefficient between cells. A large interface friction coefficient and a reasonable high clamping force are expected in order to increase the anti‐impact performance.     

注塑机合模装置存在的主要问题及解决方法

根据全液压式,肘杆式合模装置的结构特点分析其存在的主要问题及解决办法,主要对拉杆,模板断裂以及模具的损坏等进行分析并探索减少其损坏的办法。     

注塑机双曲肘合模机构的优化设计研究

为提高合模机构的工作性能,提出运用Pro/E与ADAMS协同的方法建立合模机构的参数化模型,以力的放大比和行程比为目标函数进行优化的设计方法.通过对双曲肘合模机构的运动和力学特性进行分析,并推导了肘杆机构的几何尺寸及位置尺寸与模板行程、速度及力的放大比之间的关系,建立合模机构的优化模型,对目标函数进行优化.优化结果分析...     

全电动注塑机差动式合模机构的设计与分析

对全电动注塑机差动式合模机构进行结构设计,并对差动式齿轮机构的功率流向进行分析.差动式合模机构将异步电动机和步进电机生成的输入运动通过两个自由度的ZUWGW型2K-H差动轮系合成后,产生可编程的输出运动.同时异步电动机和步进电机混合驱动,其中异步电动机提供较大的功率,步进电机起调节的作用,二者的组合有效地代替了大功率步进电机,从而能实现高锁模力、高效率、运行速度快、低能耗、低成本.     

Development of dynamic mechanical methods to characterize the cure state of phenolic resole resins

We are interested in using dynamic mechanical analysis (DMA) to measure the degree of cure achieved by aqueous phenol-formaldehyde (PF) resole resins as a result of previous exposures to various temperature-humidity-time regimes. We developed procedures that permit the obtaining of data that properly characterize and quantify the DMA behavior of these aqueous systems. Particularly important factors are substrate selection, sample clamping geometry, and sample humidification prior to analysis. In this report, we illustrate the problems encountered and the steps that we adopted to resolve them. We also present preliminary DMA data that illustrate some approaches for measuring the degree of cure achieved during previous resin exposures. One especially promising approach employs the area under the tan delta curve during isothermal scanning as an inverse measure of precure. © 1993 John Wiley & Sons, Inc.     

Effect of sample geometry on the measurement of mechanical properties of anisotropic materials

Experimental observations have been made of the effect of sample geometry on the mechanical properties of anisotropic polymer systems. The non-uniform stresses at the sample ends, arising from the method of clamping are found to persist over much greater distances than in isotropic materials, as judged by their effect on the tensile and torsional modulus. The Principle of St. Venant does not appear to be applicable to anisotropic materials. This is further supported by results obtained using finite element methods. The results raise serious doubts concerning current practice in determining the mechanical properties of anisotropic materials.     

Tensile fracture and failure behavior of technical flax fibers

The apparent tensile strength of technical flax fibers was determined in single‐fiber tests at various clamping lengths (20, 40, and 80 mm) and the outcome was compared with literature data. It was demonstrated that the strength of flax at each clamping length obeyed the two‐parameter Weibull model. The failure mode and sequence were studied in situ (i.e., during loading) by SEM and acoustic emission (AE). The failure sequence (axial splitting of the technical fiber along its elementary constituents, radial cracking of the elementary fibers, multiple fracture of the elementary fibers) concluded reflected the hierarchical build‐up of the flax bast fibers. To the above failure events AE amplitude ranges were assigned. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3638–3645, 2003     

Mechanical Characterization of Si–C(O) Fiber/SiC (CVI) Matrix Composites witrTa BN–Interphase

The mechanical behavior of three CVT-processed 2D woven SiC/BN/SiC composite materials with different initial BN interphase thicknesses has been investigated by means of tensile and impact tests. The results have established the efficiency of a BN interphase in promoting a nonlinear/non–catastrophic tensile behavior and high impact resistance. The effect of the initial BN interphase thickness on the resulting mechanical behavior has also been demonstrated. Characterization of the fiber/matrix interfacial zones by AES and TEM has revealed the presence of a SiO₂/C double layer at the BN/fiber interface, which might result from a decomposition undergone by the Si–C(O) Nicalon fiber during processing. It has been suggested that the influence of the initial BN interphase thickness on the mechanical properties of the composites results from both changes occurring in the composition and morphology of the interfacial zones and modifications of the interfacial forces due to accommodation of the radial residual clamping stress.     

桌面型微注塑机锁模机构设计与分析

为了设计桌面型微注塑机的锁模机构,在对注塑机锁模肘杆机构的运动学特性和力学特性进行理论分析的基础上,确定了最佳的肘杆几何参数,对肘杆机构进行了运动学仿真分析和静力学分析.结果表明,设计的桌面型微注塑机的肘杆锁模机构能够满足慢—快—慢的理想速度特性,并且在能够提供100 kN锁模力的前提下,满足刚度和强度的要求.