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坑的新工艺。具有暴露区域的掩模覆盖表面，使得被覆盖的区域不能被机加工。因为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中形成锥形，使得研磨浆料可以到达暴露表面。磨料浆与由低压泵供应的水在水射流喷嘴中混合。当磨料水垂直地流到锥形掩模之间的表面上时，在喷嘴的正下方形成停滞。由于滞止时流速较低，加工表面不会发生脆性断裂。垂直流动也以高速从停滞区转向水平方向。因此，磨料颗粒在水平方向上以高速加工表面。喷嘴沿着曝光区域来回移动数次。在熔石英表面加工出深2.5 μm、宽20 μm的V形槽。制作了一台微加工机，用于在指定的位置和角度加工微槽。在一些实例中，表明该机器可以很好地在表面上制作微纹理。另一台机床被建立起来，以制造具有在板上曝光的图案的掩模的微图案。利用具有微孔的板加工微凹坑。在控制流场的作用下，可以在凹坑内加工出三维结构。加工实例证明，计算流体动力学可以预测加工形状。

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.