Micro Fabrication on Glass in The Abrasive Water Jet Process

提出了一种利用磨料水射流在玻璃表面加工微通道或微凹坑的新工艺。具有裸露区域的掩膜覆盖表面，从而覆盖的区域不能被加工。由于暴露区域的宽度比喷嘴的直径小得多，所以在掩模的横截面上制作了锥形，以便磨料浆可以到达暴露的表面。磨料浆在喷水嘴中与低压泵供应的水混合。当磨料水在锥形面罩之间垂直流入表面时，就会在喷嘴正下方形成停滞。由于停滞时流速较低，加工表面不会发生脆性断裂。垂直流动也从停滞状态下高速向水平方向转变。因此，磨料颗粒在水平方向上高速加工表面。喷射喷嘴沿暴露区域来回移动几次。在熔融石英表面可加工出深度为2.5μm、宽度为20μm的V型槽。制造了一台微加工机床，以在指定的位置和角度上加工微沟槽。实例表明，该机能很好地实现表面微观纹理的加工。另一台机床是用来制造带有掩模的微型图案，掩模的模板上有曝光的图案。微凹陷是用具有微孔的板来加工的。在控制流场的情况下，可以在压痕中加工出三维结构。加工实例证明，用计算流体力学方法可以对加工形状进行预测。

A new manufacturing process with abrasive water jet is proposed to fabricate micro channels or dimples on glass. Masks having exposed areas cover the surface so that the covered areas cannot be machined. Because the width of the exposed areas is much smaller than the diameter of the jet nozzle, tapers are made in the cross section of the masks so that abrasive slurry can reach the exposed surface. Abrasive slurry is mixed with water supplied by a low-pressure pump in a water jet nozzle. When abrasive water flows onto the surface vertically between the taper-shaped masks, stagnation is made right under the nozzle. Because the flow velocity is low in stagnation, brittle fracture does not happen on the machined surface. The vertical flow also changes to the horizontal direction at a high velocity out of the stagnation. Abrasive particles, therefore, machine the surface in the horizontal direction at a high velocity. The jet nozzle moves back and forth for several times along the exposed area. A V-shaped groove, which is a depth of 2.5 μm and a width of 20 μm, can be machined on the surface of fused silica. A micro fabrication machine is made to fabricate micro grooves at the specified positions and angles. It is shown that the machine works well to make micro textures on the surface in some examples. Another machine tool is built up to fabricate micro patterns with masks that have the exposed pattern on the plates. Micro dimples are machined with the plate having micro holes. Three-dimensional structure can be machined in the dimples with controlling fluid field. The machining example proves that the machined shape can be predicted with computational fluid dynamics.