A NC Modification Of Super-hard Cutting Tool Grinding Machine Based On Microcontroller

Super-hard cutting tools, with their unique properties, are playing a more and more important role in modern processing technology. Since cutting tool material is a key factor in realizing high-speed, dry and hard-state cutting, especially when high precision or ultra-high precision cutting is needed, increasing attention is paid to the investigation of super-hard cutting tool manufacturing and grinding equipments.With their excellent combination of high hardness and good wear resistance, super-hard cutting tools are the ideal ones for modern machining. However, all these favorable properties also contribute to their extremely poor machinability. Currently exported grinding machines such as RS-12 and FC-200D are usually used to grind super-hard cutting tools. These kinds of machine hold high rigidity and good precision, but due to their high prices, moderate and small enterprises can not afford generally. In light of this issue, this study tries to realize super-hard cutting tools grinding using a general tool grinder, which is fairly cheap. But most tool grinders can't satisfy the strict qualifications needed to grind super-hard cutting tools either because of the inherent drawbacks of their hydraulic mechanisms, or because that they can't realize auto-reciprocating. In order to solve this problem, a general tool grinder was modified, and the function of auto-reciprocating was achieved.The modification of a general grinding machine was introduced in this paper as the following three parts: mechanical design, control system and grinding experiment. Firstly, a connecting mechanism between the control system and the work table of tool grinder was designed. Secondly, an AT89S52 microcontroller was used as the core to form an open-loop control system, in which a stepper motor was employed as the actuator and a LCD and a keyboard were used as the interface. As to the software of the system, a discrete control method for accelerating and decelerating process of stepper motor was introduced, and the speed and position of the work table were controlled through C language program. Finally, a series of grinding experiments were conducted on the post-modified grinding machine. By means of SEM micrograph analysis, it was found that high quality cutting edge can be achieved using this post-modified grinding machine. It shows that the modified general grinding machine can run smoothly with very small vibration, and it can satisfy all the specific qualifications needed for super-hard cutting tools manufacturing.