Cooperative Research on Precision Machining

在我们的剪切(延性)磨削试验结果中，有两个严重的问题阻碍了它的发展。一种是去除速度受到砂轮与工件接触面积的限制，可能会产生热量。在试验过程中，磨削表面出现了烧损产生的裂纹，不可能采用剪切方式磨削。根据这一结果，我们推测，较大的接触面积限制了冷却剂的感应，并促进了产生热量的冷却剂区域的高温。在某些类型的磨削几何中，很难避免较大的接触面积。因此，我们已经提出了一种替代方案，即在超声波频率下激励砂轮，同时在砂轮和工件之间引入冷却液，结果表明，在剪切模式下，磨削力低于无振动(常规)磨削得到的磨削力值。此外，通过激励砂轮在接触区引入冷却液，可使磨削率提高2倍。另外，磨削表面被砂轮表面的各种磨粒划伤。因此，要保持高质量的磨削表面是非常困难的，因为使用砂轮不可能使磨粒的大小、形状、密度和取向均匀。因此，我们得出结论，我们需要一个新的金刚石工具来代替砂轮。这是一种“工程工具”。该工具在单晶钻石表面(1，0，0)上有许多小柱子。钻石尺寸为2*2*1 mm。这些柱子是用准分子激光精密加工而成的，彼此之间相距15克。每个柱子大小为5亩见方，高10亩米。这代表着具有恒定和已知间距的非常高密度的活性钻石。我们期待着。与传统加工相比，“工程工具”技术有利于发展硬脆材料的高精度加工。

In our experimental results of shear(ductile) mode grinding, there are two serious problems as obstacles to its development. One is that the removal rate is limited by the contact area of wheel to workpiece which might cause heat generation. During the experiment, cracks caused by burning appeared on the ground surface ; shear mode grinding was impossible. From this result, we guessed that a large contact area limits the induction of coolant and promotes high temperatures in the coolant zone where heat is generated. In some types of grinding geometry a large contact area is difficult to avoid. Therefore, we already suggested that an alternative is to excite the wheel at ultrasonic frequency, which also admits coolant between wheel and workpiece, The results showed that the grinding force value was lower than that obtained with no vibration (conventional) grinding in shear mode. Further, exciting the wheel to induce a coolant in the contact zone, it was found possible that removal rate is increased 2 times.Another is that the ground surface is scratched by various abrasive grits on the grinding wheel surface. Therefore, it is very difficult to keep a high quality ground surface, because, it is impossible to uniform the grits size, form, density, and orientation, using the grinding wheel. Thus, we were led to the conclusion that we need a new diamond tool instead of the grinding wheel. It is "Engineered Tool" . This tool has many small posts on the single crystal diamond surface (1,0,0). The diamond size is 2*2*1mm. Those posts was precisely machined 15 g in apart from each other, using Excimer Laser. Each post size is 5 mu m square, 10 mu m height. This represents a very high density of active diamond with constant and known spacing. We expect. that the "Engineered Tool" technique contrivutes to the development of high precision machining of hard and brittle materials, as contrasted with conventional machining.