Study on the double-sided grinding of sapphire substrates with the trajectory method

Efficient and Precise Grinding of Sapphire Glass Based on Dry Electrical Discharge Dressed Coarse Diamond Grinding Wheel

“…When the feed speed v f was 15 mm/min, the roughness values S a and R a of the ground surface reached minimum values of 0.736 μm and 0.194 μm, respectively. The R a of 0.194 μm was much less than the 0.392 μm value obtained by using fine-grained diamond grinding wheels [5]. Therefore, in the grinding of sapphire glass using a dressed coarse diamond grinding wheel, the suitable feed speed should be set as 15 mm/min.…”

“…The main conclusions can be summarized as follows: Using the dry electrical discharge dressing technique, the grain protrusion height of #46 coarse diamond grinding wheel can reach 168.5 μm, which is about 48% of the theoretical diamond grain size. The large grain protrusion height and sharp micro-grain cutting edges can ensure efficient grinding machining for hard and brittle materials.The minimum roughness R a of ground sapphire glass surface is 0.194 μm using the proposed coarse diamond grinding method, which is much less than the obtained R a of 0.392 μm using fine-grained diamond grinding wheels [5]. At this point, the normal grinding force reaches a minimum value of 0.38 N and the grinding force ratio achieves a maximum value of 1.64.The depth of cut is controlled within 7 μm, and the wheel speed and feed speed are maintained between 3000–5000 r/min and 10–20 mm/min respectively, which can realize high efficiency and quality grinding of sapphire glass.The change of the grinding process parameters will cause the changes of grinding force and grinding force ratio, thus affecting the ground surface quality of the workpiece.…”

“…Sapphire glass is a typical hard and brittle material. Although the smooth surface can be obtained by grinding and polishing techniques [4,5,6], it is very difficult to ensure the overall size and shape accuracy of the workpiece due to long polishing time.…”

Removal Characteristics of Sapphire Lapping using Composite Plates with Consciously Patterned Resinoid-Bonded Semifixed Diamond Grits

“…The trajectory of lapping/grinding grits plays a determinant role in the material removal characteristics, surface quality, and dimensional accuracy of lapped workpieces. It has been revealed that the more uniform the trajectory of grinding grits, the higher the MRR and surface integrity of ground and lapped surfaces of sapphire [14,15]. Hence, trajectory analysis not only promises an understanding of the difference in the performance of abrasive tools during sapphire lapping, but also provides a useful reference for the design of lapping plates, especially the arrangement of abrasive blocks.…”

Evaluation of Double-Sided Planetary Grinding Using Diamond Wheels for Sapphire Substrates

“…In general, both TTV and Ra have no significant variation under different rotation speeds, but have an obvious increase at the rotation speed of 90 rpm. The fluctuation of TTV and Ra is considered to be relative to the uniformity of trajectory distribution that was left on the sapphire substrate surface [28]. Under the same grinding pressure, the MRR increases approximate linearly with the increase of rotational speed, as shown in Figure 7.…”