【作者】 刘志明；

【导师】 王敏杰；

【作者基本信息】 大连理工大学 ， 机械制造及其自动化， 2005， 硕士

【摘要】 随着塑料门窗在我国的建筑行业的广泛应用,极大的推动了塑料异型材挤出模技术的发展。然而,由于缺乏设计、制造和试模经验,我国挤出模的设计和制造水平与国外相比还有较大差距。因此,研究塑料异型材挤出模制造技术具有重要的研究价值和迫切的现实意义。针对塑料异型材挤出模具正向设计难度大的问题,本文提出了基于反求工程曲面重构技术的塑料异型材挤出模具制造新技术,重点研究了数据采集、半径补偿、数据对齐、曲面重构等关键技术。 在挤出模模腔数字化时,针对存在的测头半径补偿问题进行了深入的研究,给出了三角网格化方法。在不需要重建曲面模型的情况下,找到每一个数据点的法矢,在该法矢方向上补偿一个球头半径实现了测头半径的三维补偿.该方法具有简单方便、准确性高的特点。在对复杂的模腔进行数据采集时,有时需要通过多次测量才能全部实现。本文采取了基于三个基准点对测量数据直接对齐的方法。在实际应用中,该方法是一种简单、快速、有效的手段。根据异型材挤出模模腔制造特点,采用几何造型中的扫掠曲面造型技术。通过两条横截面曲线沿一条导引线移动形成的扫掠曲面,对挤出模头模腔进行曲面重构。 最后,应用本文的方法对挤出模模腔最复杂部分机颈段进行反求制造。通过对机颈段数据采集、半径补偿、数据对齐、CAD模型重建、CAM模拟与加工,总结了挤出模具的反求制造流程。经过实践证明,本文提出的基于曲面重构技术的塑料异型材挤出模具制造技术,改变了挤出模具依靠手工测绘的传统设计制造工艺,缩短了挤出模具的开发周期,提高了模具质量,对提高国内挤出模设计制造水平有一定借鉴意义。更多还原

【Abstract】 With the wide application of plastic doors and windows in architecture industry in China, the technology development of extrusion dies was highly promoted. However, due to the lack of design, manufacture and testing experience, the design and manufacturing level lag behind a lot compared with foreign countries. Therefore, there are significant research values and urgent realistic meaning to study the technology of extrusion dies. Aimed at the difficulty of the traditional design of extrusion die, a new manufacturing technology of extrusion die base on surface reconstruction in reverse engineering is given in the paper. Some key technologies are studied deeply, which are data capture, probe radius compensation, data registration, surface reconstruction, etc.When the cavity of extrusion die is measured, the problem of probe radius compensation is studied, and the triangular net method is applied. The normal vector of each data point is calculated without reconstructing surface, and then realizing radius compensation with probe radius by going along normal vector. The method is simple, convenient and high accuracy. When the points of extrusion die are captured, many measurements are needed sometimes. In the paper, the registration method base on the three points is applied, m practical application, the method is simple, fast, effective. According to the manufacturing feature of extrusion die, the sweep surface is adopted to reconstruct surface which is formed by sweeping two cross-section curves along a profile curve.Finally, the most complicated part- neck section of extrusion die is manufactured by the method in the paper. The manufacturing procedure of the reverse engineering of extrusion die have been summarized, such as capturing data of neck section, compensating probe radius, data registration, CAD model reconstruction, simulating CAM and manufacture, etc. Application shows that, the manufacturing technology of plastic profile extrusion die which base on surface reconstruction technology has changed the traditional design pattern that depends on the drawing by hand, shorten the development period of extrusion die, improved the quality of the mould and the design and manufacture level of extrusion die in China.更多还原