Increment pulse coder
The rotary position measuring element is installed on the motor shaft or the ball screw, and when it rotates, it sends out pulses at equal intervals to indicate the displacement. Since there is no memory element, it cannot accurately represent the position of the machine tool. Only after the machine tool returns to zero and the zero point of the machine tool coordinate system is established, the position of the workbench or the tool can be expressed. When using, it should be noted that there are two ways for the signal output of the incremental encoder: serial and parallel. Individual CNC systems have serial interface and parallel interface corresponding to this.
Absolute pulse coder
The rotary position measuring element has the same purpose as the incremental encoder, and has a memory element, which can reflect the actual position of the machine tool in real time. The position after shutdown will not be lost, and the machine tool can be immediately put into processing operation without returning to the zero point after startup. As with the incremental encoder, attention should be paid to the serial and parallel output of pulse signals.
Orientation
In order to perform spindle positioning or tool change, the machine tool spindle must be positioned at a certain corner in the circumferential direction of rotation as the reference point of the action. Generally, there are the following 4 methods: orientation with position encoder, orientation with magnetic sensor, orientation with external one-turn signal (such as proximity switch), orientation with external mechanical method.
Tandem control
For a large workbench, when the torque of one motor is not enough to drive, two motors can be used to drive together. One of the two axes is the master axis and the other is the slave axis. The master axis receives the control commands from the CNC, and the slave axis increases the driving torque.
Rigid tapping
The tapping operation does not use the floating chuck but is realized by the rotation of the main shaft and the synchronous operation of the tapping feed axis. When the spindle rotates once, the feed of the tapping shaft is equal to the pitch of the tap, which can improve the accuracy and efficiency. Metal processing WeChat, the content is good, it is worthy of attention. To realize rigid tapping, a position encoder (usually 1024 pulses/revolution) must be installed on the spindle, and corresponding ladder diagrams are required to be programmed to set relevant system parameters.
Tool compensation memory A, B, C
The tool compensation memory can generally be set to any one of A type, B type or C type with parameters. Its external performance is: Type A does not distinguish between the geometric compensation amount and the wear compensation amount of the tool. Type B separates geometry compensation from wear compensation. Type C not only separates geometry compensation and wear compensation, but also separates tool length compensation code and radius compensation code. The length compensation code is H, and the radius compensation code is D.
DNC Operation
It is a way of working automatically. Connect the CNC system or computer with RS-232C or RS-422 port, the processing program is stored on the hard disk or floppy disk of the computer, and is input to the CNC in sections, and each section of the program is processed, which can solve the limitation of CNC memory capacity.
Advanced preview control (M)
This function is to read in multiple blocks in advance, to interpolate the running path and to preprocess the speed and acceleration. In this way, the following error caused by acceleration and deceleration and servo lag can be reduced, and the tool can more accurately follow the contour of the part commanded by the program at high speed, which improves the machining accuracy. The pre-reading control includes the following functions: linear acceleration and deceleration before interpolation; automatic corner deceleration and other functions.
Polar coordinate interpolation (T)
Polar coordinate programming is to change the Cartesian coordinate system of the two linear axes into a coordinate system in which the horizontal axis is the linear axis and the vertical axis is the rotary axis, and the non-circular contour processing program is compiled with this coordinate system. Typically used to turn straight grooves, or to grind cams on a grinder.
NURBS Interpolation (M)
Most industrial molds such as automobiles and aircrafts are designed with CAD. In order to ensure accuracy, non-uniform rationalized B-spline function (NURBS) is used in the design to describe the surface and curve of Sculpture. Metal processing WeChat, the content is good, it is worthy of attention. Therefore, the CNC system has designed the corresponding interpolation function, so that the expression of the NURBS curve can be directly instructed to the CNC, which avoids the use of tiny straight line segment approximation to process complex contour surfaces or curves.
Automatic tool length measurement
Install the touch sensor on the machine tool, and compile the tool length measurement program (using G36, G37) like the machining program, and specify the offset number used by the tool in the program. Execute this program in automatic mode, make the tool contact with the sensor, thus measure the length difference between the tool and the reference tool, and automatically fill this value into the offset number specified in the program.
Cs Contour control
Cs contour control is to change the spindle control of the lathe into position control to realize the positioning of the spindle according to the rotation angle, and it can interpolate with other feed axes to process workpieces with complex shapes.
Manual absolute ON/OFF
It is used to determine whether the coordinate value of manual movement after the feed pause is added to the current position value of automatic operation during automatic operation.
Manual handle interruption
Shake the handwheel during automatic operation to increase the moving distance of the motion axis. Correction for stroke or size.
Axis control by PMC
Feed servo axis controlled by PMC (Programmable Machine Tool Controller). The control instructions are programmed in the PMC program (ladder diagram), because of the inconvenience of modification, this method is usually only used for the control of the feed axis with a fixed movement amount.
Cf Axis Control (T series)
In the lathe system, the rotation position (rotation angle) control of the spindle is realized by the feed servo motor like other feed axes. This axis is interlocked with other feed axes to interpolate to process arbitrary curves. (common in older lathe systems)
Location Tracking (Follow-up)
When the servo off, emergency stop or servo alarm occurs, if the machine position of the table moves, there will be a position error in the position error register of the CNC. The position tracking function is to modify the machine tool position monitored by the CNC controller so that the error in the position error register becomes zero. Of course, whether to perform position tracking should be determined according to the actual control needs.
Simple synchronous control
One of the two feed axes is the master axis, and the other is the slave axis. The master axis receives the motion command from the CNC, and the slave axis moves with the master axis, thereby realizing the synchronous movement of the two axes. The CNC monitors the moving positions of the two axes at any time, but does not compensatethe error between the two. If the moving positions of the two axes exceed the set value of the parameters, the CNC will issue an alarm and stop the movement of each axis at the same time. This function is often used for double-axis drive of large worktables.
Three-dimension tool compensation (M)
In multi-coordinate linkage machining, tool offset compensation can be performed in three coordinate directions during tool movement. Compensation for machining with the tool side face and compensation for machining with the end face of the tool can be realized.
Tool nose radius compensation (T)
The tool nose of the turning tool has an arc. For precise turning, the tool nose arc radius is compensated according to the direction of the tool during processing and the relative orientation between the tool and the workpiece.
Tool life management
When using multiple tools, group the tools according to their lifespan, and pre-set the tool usage order on the CNC tool management table. When the tool used in machining reaches the life value, the next tool in the same group can be replaced automatically or manually, and the tool in the next group can be used after the tools in the same group are used up. Whether the tool replacement is automatic or manual, a ladder diagram must be programmed.
Post time: Aug-23-2022