Developing a Piercing Technique for Ceramic and Glass Sheets by Utilizing a High Impulsive Pressure

近年来，精细陶瓷和高性能玻璃等新材料的显著发展提出了新的制造问题。它们具有硬而脆的质量，并且难以加工。虽然已经开发了各种加工工艺，但它们都具有生产率低和设备成本高的共同缺点，因此适用性有限，本研究试图开发一种新的穿孔技术，利用粘塑性压力介质的脉冲压缩下产生的高压，而不存在上述问题。该方法被称为VIP工艺，并从理论和实验上验证了其适用性。实验结果表明：（1）用原变截面杆对四种脆性材料进行了穿孔试验，结果表明，原变截面杆可以成功地穿孔。例如，两种无机玻璃、GC复合材料和氧化铝片。(2)提出了一种利用线性粘弹性模型估算冲击压力的方法，并验证了该方法的有效性。(3)通过有限元分析，阐明了穿孔机理。(4)对原方法进行了改进，提高了穿孔成功的概率。因此，提出了两种新的方法，并被证明是有用的。(5)从实际应用的角度出发，提出了一种利用液压机进行低速压缩的方法，称之为VM工艺，并验证了其有效性。(6)介绍了原子力显微镜的加工工艺，并对提高孔的加工精度进行了试验研究。(7)最后，提出了VM/AFM或VIP/AFM工艺的组合方法，并通过无机玻璃片实现了各种特殊应用：一次穿孔多个孔，穿孔非圆孔和圆形小孔。

Recent, remarkable development of new materials, such as fine ceramics and high-performance glasses, presented a new manufacturing problem. They have hard and brittle quality, and are difficult to work. Though various working processes available for such materials have been developed,they have the common disadvantage of low productivity and high equipment cost, and thus limited applicability.The present research attempted to develop a new piercing technique with no such problem as aforementioned by utilizing a high pressure caused under the impulsive compression of a viscoplastic pressure medium. The method was referred to as VIP Process, and its applicability was examined theoretically and experimentally. Results obtained may be summarized as follows :(1) The original VIP was shown to be successful in piercing a circular hole through four kinds of brittle materials, i. e., two inorganic glasses, GC composite and alumina sheets.(2) A method for estimating the impulsive pressure was presented using a linear viscoelastic model, and its validity was confirmed.(3) The piercing mechanism was clarified by the FEM analysis.(4) An improvement in the probability of successful piercing was given to the original method. As a result, two new methods were proposed, and shown to be useful.(5) From the viewpoint of practical use, a low speed compression method using a hydraulic press machine, referred to as VM Process, was proposed, and its validity was confirmed.(6) The AFM Process was introduced, and shown to be effective for improving the accuracy of the formed holes.(7) Finally, the combined method (VM/AFM or VIP/AFM Process) was proposed, and various special applications were accomplished through inorganic glass sheets : one-shot piercing of plural holes and piercings of noncircular holes and circular fine holes.