Study On Soft Abrasive Wheel Preparation And Properties Of Sapphire Substrate Grinding

Single crystal sapphire has a range of excellent performance, its Moh's scale of hardness is up to 9, and has broad uses in the field of military and civilian. Because of its hardness, the formation of the traditional processing methods (grinding and polishing) have shortcomings as follows: low processing efficiency, difficult to automate and pollution environmental, therefore, domestic and foreign experts and scholars have been committed to how to achieve high efficiency and no damage surface of ultra-precision processing technology research on single crystal sapphire substrates. Among them, ultra-precision grinding technology using bonded abrasive is a hot research current, and has achieved remarkable results, but inevitably the traditional diamond wheel grinding will damage the surface of sapphire substrates, so it needs the follow-up of the chemical-mechanical polishing to remove the damage layer, thus reduced the substrate processing efficiency.To solve the above issues, in order to efficiently process single crystal sapphire in non-destructive manner, this paper presents a processing method using soft abrasive grinding wheel grinding single crystal sapphire, using solid-state reaction between grinding wheel abrasive, additives and single crystal sapphire and the soft abrasive's mechanical friction to achieve ultra-smooth sapphire substrate, low-damage grinding. According to the physical and chemical properties of single crystal sapphire, this paper design and manufacture soft abrasive grinding wheel for ultra-precision grinding sapphire substrates, design the composition of two soft abrasive grinding wheel, carry out the conduct of repression and soft abrasive grinding wheel manufacturing, and through the grinding and dressing test, the practicability of the two soft abrasive grinding wheel is verified; carried out solid-phase chemistry simulation between the abrasive and single crystal sapphire to simulate the probably solid phase chemical reactions in grinding process, tests showed that, MgO and Fe₂O₃ abrasive can occur solid state reaction with single crystal sapphire, thus provides theoretical basis of soft-abrasive grinding mechanism; conduct a soft abrasive grinding wheel grinding sapphire substrate performance, test results show that the use of soft abrasive grinding wheel can achieve ultra-precision machining on the single crystal sapphire, the processing performance of soft abrasive wheel is better than diamond grinding wheel on grinding sapphire, after processing of soft abrasive wheel the sapphire surface quality the surface roughness is up to Ra 1.365nm, and the soft-abrasive grinding wheels can achieve smaller surface materials removal, realize damage-free grinding; at the end of the paper, angle polishing tests is carried out, by series processes of cutting, sticking film, grinding, polishing, corrosion the single-crystal sapphire substrate, verify the single-crystal sapphire after grinding of soft-abrasive grinding wheel is a non-destructive sub-surface, single-crystal sapphire substrates.