1. Technological characteristics of diamond tool grinding
The grinding of diamond tools has its own technological characteristics, especially the high hardness of materials, which leads to the rapid loss of grinding wheel and unstable size. Second, the majority of diamond tools are turning tools or blades, and the grinding position relative to the machine tool is uncertain (such as the change of blade thickness), causing the change of grinding point. Third, the high resistance of grinding makes the process system composed of grinding wheel, cutting tool, clamping tool and machine tool produce relatively large elastic deformation, thus producing relatively large "let the knife" phenomenon.
These three characteristics are the realization of automatic grinding of three "blocking land rover", directly affect the cutting tool after the die cutting dimensional accuracy. If not properly solved, it will inevitably lead to poor consistency of grinding size accuracy and roughness, low grinding efficiency and unsuitable for mass production. The application of voice control technology in diamond tool grinder can effectively solve these three problems.
2. Application of adaptive control technology in rough grinding
The main tasks of rough diamond grinding are: to improve the grinding efficiency, that is, to set the safe distance as little as possible, and to reduce the time of "grinding" air; Remove the grinding allowance as soon as possible within the range of machine tool stiffness. Find out as soon as possible that the grinding allowance has been removed (the sign is that the grinding resistance has been reduced to the minimum).
The intense acoustic wave generated by the friction between the grinding wheel and the diamond tool is propagated on the process equipment. The monitoring of the acoustic wave can accurately reflect the grinding condition, such as whether the tool is in contact with the grinding wheel, whether the pressure between the tool and the grinding wheel (i.e. grinding resistance) is eliminated, etc. If the control system can collect and analyze these information in real time, and make the machine tool control system adapt to it, it is no different from installing a sensitive ear to the machine tool, making the machine tool controller become a more intelligent adaptive system. In fact, the development of the system was also inspired by on-site workers sharpening knives.
In normal grinding, there are two situations in which the acoustic frequency has obvious characteristics, one is the moment of contact between the cutter and the grinding wheel, and the other is when the grinding reaches the final size (the grinding resistance decreases to the minimum), which is easy to understand. The former can be used as the end of fast feed and the dividing line of grinding feed; The latter can be used as a sign of grinding completion.
Even in cutting tools and grinding wheel in the process of "close contact", the change of the sound wave frequency can also reflect the resistance between cutter and grinding wheel, the "information feedback" to machine controller, adjust the servo feed speed, the grinding in a relatively "constant" under the force of complete, for improving the grinding efficiency, extend the life of the machine tool has great significance.
3. Application of "knife grinding" in fine grinding
The main task of diamond fine grinding is to control the final size precision of grinding accurately and stably. Grinding wheel wear, accurate positioning of edge tip grinding point and grinding resistance will eventually affect the machining accuracy. These factors have nothing to do with the movement accuracy of the machine tool, but are related to when to start grinding (that is, to the point of the tool), what degree to finish grinding and other issues, and the monitoring of grinding state is closely related.
Although grinding wheel wear is difficult to measure and the height of the blade (which affects the grinding point position) is difficult to measure within a certain range, the control system with the voice control device can easily record the exact position of the blade tip and the grinding wheel surface at the moment of contact. Taking this as a starting point, relative feed can accurately control the size accuracy, we call this "knife grinding". Of course, the premise of "knife grinding method" is that the previous process has an accurate reference, or can be accurate measurement of the size before grinding, which can be done by CCD system online measurement system. In the industry, hand machine tools are used to grind knives. The grinding process of the first back Angle of PCD tool (i.e. polishing edge) is as follows: on the basis of the size of rough grinding, grind down 0.02~0.03mm to form the blade belt of 0.05~0.1mm. This and "knife sharpening method" also happens to coincide.
In the grinding process, the grinding wheel is still wearing away, and the system can timely detect and compensate the wear, reducing the time of "grinding air" to nearly zero, greatly improving the grinding efficiency.
Voice control technology is widely used in the whole grinding industry, because this technology can resolve the common contradictions in grinding. This contradiction is particularly prominent in diamond grinding.