Implementation Method The concept of measurement control technology, now called intelligence, is a human-based neural network system that captures a variety of random, sensitive external stimulus signals and converts them into information that the brain can recognize.
If this concept is used in the error measurement and control technology caused by the deformation, wear and thermal expansion deformation of the tool during CNC machine tool processing, the machining accuracy of the existing closed-loop CNC machine tool will be further improved. The factors affecting the accuracy of tool machining are relatively random and require data to be collected from the dynamic cutting portion of the tool, which increases the difficulty.
An intelligent tool is being developed, which uses a special tool material with measurement function to coat the blade, as shown in 2. This material not only has the high hardness, high wear resistance and heat resistance required for cutting, but also changes the resistance of the coating when it deforms, wears or changes in temperature, so it can be collected randomly. This change in the electrical signal and its transmission back to the numerical control device, it has such a measurement function will make some of the most difficult problems.
The thermal expansion and contraction deformation of the double closed-loop control system principle causes the resistance of the coating to change. Theoretically, the resistance value Rx of the coating change has a one-to-one correspondence with the deformation δ of the tool, and the corresponding relationship is: Rx=F(δ), then, as long as the resistance value of the change is measured, it is measured. The error caused by the tool deformation.
Each resistance value Rx corresponds to a corresponding current or voltage value. The changed mode signal is relatively easy to detect, and the mode signal is converted into a digital signal μ by a corresponding circuit, and the relationship is: μ=G(Rx ), that is, μ = G [F (δ)]. When cutting, the current or voltage change value caused by the deformation of the blade is detected by the sensing technology on-line, and then converted into a digital signal by the A/D conversion circuit and input to the numerical control device. Then, the numerical control device can be changed according to the actual cutting time. The induced error δ is randomly calculated and controlled by the control program according to the μ value calculated by the relation μ=G[F(δ)]. The basic principle is as shown in 3. This is equivalent to adding a closed loop to the original closed loop system and becoming a double closed loop CNC machine.
Before writing its control program, it is necessary to establish a mathematical model of tool deformation and coating resistance change by means of experiments, that is, establish a correspondence between them, and their relationship can also be expressed by a list for Used when writing a control program for compensation calculations. This workload is large, and the content is complex, which is the key to directly affect the accuracy of these error control.
As a result, the error control range of the closed-loop system is extended to the end of the machining and cutting tools, so that the control accuracy of the CNC machine tool is further improved. Once the technology of the coated blade is mature, it can be used as a tool for CNC machine tools, and its prospects are very broad.
Scheme analysis (1) The control feed function is readily available, but it is necessary to consider the system program to compensate for these errors on the basis of the current closed-loop CNC machine tool. This compensation value should be the amount δ of the closed loop compensation. The sum of the amount δ' that the closed loop needs to compensate, and the value to be compensated by the system at this time is δ total = δ + δ '.
(2) The difficulty in breaking through this technology is that the coated blade must be matched with the system. That is to say, the data source processed by the system program must have a one-to-one correspondence with the basis for establishing the system program. Of course, once its technology is mature, the tool can unify its standards and the problem will be solved.
(Finish)
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