The Technology Of Abrasive Cluster With Controlled Distribution And Development Of Its Grinding Wheel

Grinding is one of most extensively and efficiently used precision and ultra-precision machining methods. Nowadays, the materials of workpiece have extended not just the traditional metals but also some difficult-to-grind nonmetal-materials, such as ceramics, silicon, crystal and composite materials. With the conventional abrasives, especially the electroplated abrasive tools, it is very possible to happen that the surface of the abrasives easy to block, which would result in thermal damage, shorten the life of abrasive tools, cause the bad surface quality and reduce the efficiency because the grit is too small.For resolving these problems, a technology of electroplated grinding wheel with controlled and distributed abrasive-cluster is brought out in this paper, which uses a mask to make pattern of the abrasives, that is to say, abrasive distributed in cluster with designed dimension, shape and density. It is indicated that grinding tools with controlled or optimized abrasive distribution pattern are of excellent grinding performance in improving grit cutting ability or material removal rate, and minimizing heat generation or thermal damage.The mask with small cavities fabrication is one of the key technologies for this kind of grinding wheel. Based on the screen printing technology, the light-sensitive photogravure technology and the laser boring technology, the mask fabrication are trialed. It is indicated that the mask of PET film or soft PVC paster made by laser boring is suit for demand with accurate shape and pattern. However, the masks made by screen printing and light-sensitive photogravure are too thin to keeping the shape of cluster, which will become mushroom-like shape or even link up. The composite mask is created in this paper to solve the problem, which means that the outside mask is made by light-sensitive photogravure or laser boring, and adding a middle mask with design thickness. And it is approved that the composite mask is feasible by electroplated copper as the middle mask.The experimental system for electroplated grinding tools is developed. In order to ensure the combinative intensity between the cluster and substrate and the abradability of the electroplated alloy, the Watts bath by adding cobalt (Co) is chosen as the plating solution in this paper, and the effects of the plus plating processing parameters for the electroplated layer is analyzed by orthogonal test. These provide the optimized processing parameters for fabricating the electroplated wheel with controlled and optimized abrasive cluster. Moreover, the test for fabrication of this grinding wheel is processed under the upwards parameters and masks based on the three technologies. Some samples are successfully fabricated and the initial grinding test is carried. The results reveal that the processing feasibility is confirmed.At last, aiming to check the combinative intensity between the cluster and substrate and the block and abrasion of grains, the single cluster scratching test have been carried out on a 45 steel specimen. SEM and microscope observation of the cluster and marks show that there are no chips at the side grits of the scratching oriental on the single cluster sample but there are some clogging in the center of the cluster. It is concluded that the space between clusters cause chips exiting easily and these topography will keep sharpness of the grinding wheel.