CNC lathe thread processing principle

      1, in the ordinary lathe thread processing, the spindle and the feed mechanism between the existence of mechanical fixed ratio transmission relationship, is by the complex mechanical transmission chain to ensure that the
The proof of the complex mechanical transmission chain. CNC lathe in the design, simplify the transmission chain, cancel the spindle box, spindle generally use frequency conversion speed control. In the thread processing of CNC lathe, there is no mechanical fixed ratio transmission relationship between the spindle and tool holder, but rely on the CNC system to control the servo feed motor to ensure that the Z-axis feed rate and spindle speed to maintain - linear proportionality. Only understand the principle of CNC lathe thread processing, use CNC lathe in accordance with operating procedures, analyze the common failure phenomenon in thread processing, "according to the reasoning analysis of the elephant", in order to solve the actual processing of some of the problems that arise in production, improve processing efficiency.high speed punch press

        CNC lathe thread cutting, spindle work in the state of rotary feed, in essence, the spindle angular displacement and Z-axis feed interpolation between the CNC lathe, generally use photoelectric encoder as the spindle angular displacement measurement element, through mechanical components and spindle connection, the transmission ratio of 1:1, the encoder's Z pulse (also known as the "one-turn signal") as the spindle position. The Z pulse of the encoder (also called "one-turn signal") is used as the spindle position signal, which is processed by the numerical control system to drive the movement of the tool holder. The spindle pulse generator sends out two groups of signal pulses, one group is counting pulse, CK6140 CNC lathe is equipped with 1200 lines spindle encoder, i.e., 1200 counting pulses are sent out per revolution, and the other group is the spindle reference pulse, which sends out a synchronized pulse signal per revolution. When turning threads, the CNC system detects the arrival of the spindle reference pulse synchronization signal and starts cutting, otherwise it is in a waiting state. This ensures that the initial position of each cutting is at the same position on the circumference of the workpiece to ensure that the threads of each cutting coincide with each other, preventing the phenomenon of multiple cutting and messy buckling. In the CNC system, the elements to complete the thread processing are: spindle speed n and thread lead t, feed rate F = n * t;. That is, every turn of the spindle, Z-axis feed a lead, spindle rotation and feed axis must maintain a strict proportional relationship. Benchmark pulse synchronization signal is extremely important, it is to ensure that the initial position of each cutting in the thread processing in the workpiece of the same bit on the bitter, to prevent the phenomenon of "chaotic buckle" occurs.high speed punch press

    2, CNC lathe thread machining cutting principle analysis
Can we find a way to overcome the lack of CNC lathe processing? After careful observation and analysis, found that CNC lathe thread processing is synchronized by the spindle position encoder and spindle speed to process the thread, why change the spindle speed in the processing of threads to be chaotic buckle it? Usually, thread cutting is repeated along the same tool trajectory from rough cutting to fine cutting. Because thread cutting is started when the position encoder on the spindle outputs a signal, thread cutting starts from a fixed point and the tool trajectory on the workpiece remains unchanged while thread cutting is repeated. As the thread cutting system has a response time, and in the same response time, the speed of the spindle is different, the cutting angle is also different, so the spindle speed from rough cutting to fine cutting must be maintained at a constant level, otherwise the threads are not buttoned.

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