逆向工程技术在塑料模具设计中的应用

介绍了一种基于反求工程技术的注塑模具快速设计方法,并以手电钻外壳为例对其流程进行了详细说明。在此过程中,先利用三维激光扫描仪采集了电钻外壳曲面的点云数据,并对数据进行了拼合、去噪和重采样等处理,然后应用Pro/e软件的逆向造型功能重构了电钻壳的CAD模型,最后利用重构完成的三维模型,设计了电钻外壳的注塑模具。结果表明,此方法能够实现注塑模的快速设计,缩短产品的开发周期,尤其对曲面形状复杂、缺失原始几何数据等产品的设计与制造极具潜力。     

逆向工程在塑料产品及其模具设计中的应用

介绍了一种基于逆向工程技术的塑料产品模具数字化设计方法,分析了塑料产品在逆向造型过程中应遵循的基本原则和要点,然后以某车灯反射器为例对其进行了说明。此过程中,先借助三维激光扫描仪采集了反射器曲面的点云数据,然后利用Geomagic Studio软件进行了数据处理和快速曲面重构,最后将曲面模型导入Pro/E软件中进行反射器的三维模型重建并分模,形成模具型腔。实践表明,此方法能够实现注塑模的快速设计,缩短产品的开发周期,尤其对曲面形状复杂、缺失原始几何数据等产品的设计与制造具有参考意义。     

逆向工程技术探讨

探讨了逆向工程技术产生的背景,逆向工程主要涉及的技术问题,包括测量技术,表面数字化技术,数据处理技术,三维曲面造型技术,曲面的描述方式,曲面重构技术以及重构技术以及常用的CAD/CAM系统的曲面功能等关键技术。     

基于逆向工程的曲面建模与创新设计

对于复杂曲面物体创新设计周期较长的问题,提出了基于逆向工程对复杂曲面进行重建和二次创新,并结合有限元分析和3D打印对创新实物进行理论和实物验证的方法。以鼠标曲面为例,利用Geomagic Studio对鼠标点云进行处理,创建出鼠标原始曲面,导入Rhino软件中进行创新设计,并以此为对象,导入abaqus对其进行跌落实验。实验结果表明:经过逆向创新设计的鼠标,在跌落过程中的最大Mises应力值下降了9.32%,利用3D打印机打印出实物。     

基于Imageware和UG技术的逆向曲面重构及模具设计方法

采用逆向辅助技术,对一款结构较为复杂的某制品进行快速而精确的模具设计,先利用三维激光扫描仪得到其点云数据,再使用Imageware软件进行点云处理和曲面重构,然后在UG软件中进行三维造型及相应的优化设计,最终以最合理的设计方法得到完整的模具图,用于后续的模具加工与生产。结果表明,此方法既能提高模具及产品的精度,又能大大缩短设计周期,节约成本。尤其对一些具有结构复杂、曲面要求高或者缺失原始几何数据的制品,此方法更能发挥其优势。     

玩具狗头的自由曲面重构

针对复杂曲面数据测量及曲面重构的要求,以玩具狗头为例,介绍使用三维激光扫描仪的自由曲面反求过程中产品点数据的处理方法,以及CAD模型的重构技术,分析了反求建模中存在的问题。实践表明,该建模方法可以得到满意的产品曲面模型。     

人机工程学鼠标底壳双色注塑模具设计

通过具有人机工程学复杂曲面造型的双色鼠标底壳零件,介绍了双色注塑零件可注塑性工艺分析方法,利用UG6.0对双色注塑的鼠标底壳模具进行了结构设计,比较详细地论述了在复杂曲面和双色成型双重特点下模具设计的考虑因素,着重介绍了双色模具内外抽芯机构设计过程和热塑性弹性体TPE外层包覆粘合的双色模具设计特点和成型方法。试模结果表明,该模具设计合理,制造方便,实现全自动双色注塑成型操作,成型过程能力指数Cpk大于1.33, 成型周期仅43 s,完全满足了鼠标底壳高品质和高效率的注射成型要求。     

油井钻头外形轮廓的反求造型

根据反求工程的原理,采用激光非接触式扫描测量方法．通过合理选择主要测量面,合理利用激光测头旋转或／和摆动角度,合理选择数据采集精度,加快了油井钻头外形轮廓几何数据的采集。通过选择功能强、操作方便的计算机软件,对点云数据进行平滑和精简预处理,选用高效率的曲面重构理论方法,简捷地完成了油井钻头的反求造型,并弄清楚它与其原始造型的差别,证明实际加工钻头中出现位置偏差的原因,在于毛坯铸造时未能控制住尺寸偏差。     

基于三坐标测量的产品自由曲面反求

通过分析产品自由曲面反求的技术,介绍了自由曲面数据的获取方法、CAD模型的重构技术,分析了自由曲面重构中存在的问题。以工艺品塑料树叶为例,详细介绍了基于三坐标测量的产品自由曲面反求技术,实践表明该建模方法可以得到实际生产中满意的曲面模型。     

基于Geomagic软件的汽车缸盖气道芯子逆向工程设计

针对汽车缸盖气道芯子的特点,利用光栅结构光扫描仪,测出点云数据。然后将测量的点云数据用Geomagic软件进行各项优化处理,创建多边形网格及NURBS曲面,然后利用CATIA软件的曲面造型功能,做出CAD模型。实现了汽车缸盖气道芯子由实物到点云、再由点云到三维模型及模具的快速逆向设计。     

Fabrication of abrasion-resistant micro-nano hierarchical structure on glass surface by a hydrothermal corrosion method

When applying an additional coating method to fabricate micro-nano hierarchical structure required for superhydrophobic function on glass surface, the hierarchical structure does generally not have good abrasion resistance, due to the weak adhesion between coating and glass surface. However, glass itself is a material with good abrasion resistance. A micro-nano hierarchical structure with honeycomb-shaped micro-armor protection on glass surface by a two-step hydrothermal corrosion method has been constructed: the first step of hydrothermal corrosion in water to construct micro-armor structure, and the second step of hydrothermal corrosion in sodium citrate aqueous solution to fabricate micro-nano hierarchical structure. The advantages of this new method are: the treatment process is simple, and there is no need to apply additional coatings. The micro-nano hierarchical structure constructed on glass surface by this method has a great abrasion resistance. After 1,000 cycles of abrasion under harsh conditions, the nano-structure on glass surface can still be remained intact. It provides a new method for fabricating abrasion-resistant micro-nano hierarchical structure on glass surface, as well as a new approach to the preparation of abrasion-resistant superhydrophobic glass.     

Modification of the glass surface by titanium dioxide films synthesized through the sol–gel method

The glass surface has been modified by titanium dioxide films synthesized using the sol-gel method. The sol-gel synthesis has been optimized by the experimental design with the use of the Latin square method. The film composition has been evaluated using X-ray powder diffraction analysis and optical measurements. The photoinduced hydrophilicity of the modified glass has been investigated.     

短切玻璃毡增强聚碳酸酯基复合材料研究

本文研究了短切玻璃纤维毡增强聚磷酸酯(PC)复合材料。采用正交回归设计的试验方法优化复合材料工艺,所制得的复合材料性能优异,纤维与基体界面粘接良好。     

Limiting Subcritical Crack Growth in Glass-Matrix Composites

Subcritical crack growth measurements were made in borosilicate glass/Fe-Ni-Co particulate composites, in which the metal particles were used both as-received and also with a surface oxidation treatment. No crack growth was observed in the composites containing the partially oxidized particles before catastrophic failure ensued. The composites containing nonoxidized particles did exhibit measurable growth. Fracture surface observations identify strong bonding between the particles and matrix as the main reason for significantly increasing the slow crack growth resistance. This method of "effectively" eliminating subcritical crack growth may be a means by which the design threshold of glasses is raised, thus opening new areas of applications for glass systems.     

太阳能玻璃专用防霉隔离粉研究思路

针对太阳能玻璃这一特殊玻璃品种的特殊化学成分特性和表面形貌特性,在其专用防霉隔离粉配方设计中提出了设计原则和理念：匹配于太阳能玻璃化学成分的更强力的分子防霉设计、匹配于太阳能玻璃表面形貌的更充分的空间隔离设计、匹配于太阳能玻璃表面形貌的更有效的粉体流动性设计。研制成功符合太阳能玻璃这一特殊玻璃品种的新型防霉隔离粉。     

浮法玻璃设备可靠性分析与设计方法

运用可靠性相关理论对浮法玻璃设备进行了可靠性分析,总结出了浮法玻璃设备的主要失效形式。通过传统机械设计方法与可靠性设计方法的对比,指出可靠性设计方法的重要性,并给出了在工程设计中常用的几种可靠性设计方法。最后提出了一些提高浮法玻璃设备可靠性的方法以供设计人员参考。     

酸处理及有机涂层对玻璃力学性能的影响

采用氢氟酸基溶液对玻璃进行腐蚀,研究酸腐蚀对玻璃强度的影响。对新鲜玻璃表面施加有机涂层,研究了玻璃表面的微观结构及力学性能。结果表明,酸腐蚀可以提高玻璃的强度,处理10 min后强度达到最大,但是强度稳定性差,表面易受损伤,在酸处理后的表面施加有机涂层可以极大提高玻璃的强度。其增强机制是,涂层填充了玻璃裂纹空隙,起到治愈损伤的效果,同时泊松抑制效应也对玻璃强度的增加起了作用。与物理钢化及化学钢化相比,这种综合增强方法明显提高了玻璃的力学性能,同时降低了成本。     

Statistical interference of material strength and surface prestress in heat‐treated glass

It is customary to assume that the characteristic design value for heat‐treated glass is represented by the sum of the characteristic values of the annealed glass strength and of the heat‐induced surface prestress, even though experiments have provided evidence that the resulting strength may be much higher. Here, we investigate the statistical interference between an assumed two‐parameter Weibull distribution for the annealed glass strength and a Gaussian distribution for the surface prestress. We show how the compound distribution confirms the experimental findings and, in particular, that the type of stress induced by the applied loads, ie, uniaxial vs biaxial, has an important role. This effect, which is more relevant for “weak” than for “strong” glasses, is the mechanical counterpart of the well‐known principle of diversification of investments in economy, and leads to a critical consideration of the design approach commonly suggested by structural standards.     

Maintenance repair of the refractory lining of glass furnaces

The problem of increasing the service life of glass furnaces with the aim of reducing expenses is solved most effectively by using the method of depositing refractory powders onto the internal surface of fractured regions by an oxygen torch. The high efficiency of the facing has been confirmed by the service life of glass furnaces of different design, output, and purpose with the thus repaired roofs, walls, and other parts. The repair is performed using domestic equipment and powders. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 6, pp. 44–45, June, 2000.