Q
The steps of the CNC lathe tool setting?
A
The steps of the CNC lathe tool setting?
CNC lathe tooling method:
The lathe itself has a mechanical origin. You usually try to cut the knife. For example, after the outer diameter of the car, the Z-direction exits, measure the outer diameter of the car, and then find the tool number you used in the G screen to move the cursor. To X input X... According to the measuring machine, the position of the tool tip on this tool position is known. The inner diameter is the same, the Z direction is simple, and each knife is touched in a Z direction and then measured Z0.
In this way, all the knives have a record, and the machining zero point is determined to be inside the workpiece shift (offshift), and the workpiece origin can be determined by any knife.
In this way, remember to read the knife before the knife.
There is a more convenient method, which is to use the chuck to align the knife. We know the outer diameter of the chuck. The cutter can touch the input outer diameter. For the inner diameter, you can take a gauge block and press it on the chuck. The outer diameter of the chuck is fine.
If there is a tool holder, it is much more convenient. The tool holder is equivalent to a fixed tool setting test. When the tool touches it, it is recorded in the position.
Therefore, if it is a multi-class small batch processing, it is best to buy a tool holder. Save time.
I used the MAZAK lathe, I changed the new workpiece from the stop to the new workpiece. The intermediate time is usually 10 to 15 minutes. (including the change of the soft claw test)
Comparison of basic coordinate relationship of CNC lathe and several methods of tool setting
In the operation and programming process of the CNC lathe, it is very important to understand the basic coordinate relationship and the principle of tool setting. This is a great help for us to better understand the machining principle of the machine tool and to modify the dimensional deviation during the processing.
一, the basic coordinate relationship
Generally speaking, there are usually two coordinate systems: one is the mechanical coordinate system; the other is the workpiece coordinate system, also called the program coordinate system. The relationship between the two can be represented by Figure 1.
Relationship between mechanical coordinate system and workpiece coordinate system
A fixed reference point (assumed to be (X, Z)) is provided in the machine coordinate system of the machine. The role of this reference point is mainly used to position the machine itself. Because the position of the tool holder is set to (0,0) after each power-on, the system will set the current position to be inconsistent, so the first step of each power-on is reference point return (there is It is called the homing point, that is, the origin (0, 0) is determined by determining (X, Z).
For the convenience of calculation and programming, we usually set the program origin to the center of rotation of the right end of the workpiece, and try to make the programming reference coincide with the design and assembly basis. The machine coordinate system is the only reference for the machine tool, so you must figure out the position of the program origin in the machine coordinate system. This is usually done during the next tool setting process.
二, the knife method
1.Trial cutting
The trial cutting method is the most common method of tool setting in practice. The RFCZ12 lathe adopting the MITSUBISHI 50L numerical control system is taken as an example to introduce the specific operation method.
After the workpiece and the tool are clamped, the spindle is driven to rotate, and the tool holder is moved to the workpiece to test a section of the outer circle. Then keep the X coordinate unchanged and move the Z axis tool away from the workpiece to measure the diameter of the outer circle of the segment. Input it into the tool length in the corresponding tool parameter, the system will automatically subtract the diameter of the outer circle of the test cut from the current X coordinate of the tool, that is, the position of the origin of the workpiece coordinate system X. Then move the tool to test the end face of the workpiece, and input Z0 in the tool width of the corresponding tool parameter. The system will automatically subtract the value of the Z coordinate of the tool from the value just entered, that is, the position of the Z coordinate of the workpiece coordinate system.
For example, if the diameter of the outer circle of the 2# tool holder is 25.0 when the X is 150.0, the program origin X value when cutting the tool is 150.0-25.0=125.0; the end face of the tool holder when Z is 180.0 is 0, then the program origin Z value when cutting the tool is 180.0-0=180.0. The (125.0, 180.0) is stored in the X and Z of the 2# tool parameter tool length, and the workpiece coordinate system can be successfully established by using T0202 in the program.
In fact, finding the position of the workpiece origin in the machine coordinate system is not to find the actual position of the point, but to find the position of the tool holder when the tool tip point reaches (0, 0). In this way, the standard knife is generally not used for the knife, and all the tools of the knife to be used need to be aligned before processing.
2. Automatic tool setting for the tool
Many lathes are equipped with a tool setting tool. The tool setting tool can eliminate the error caused by the measurement and greatly improve the accuracy of the tool setting. Since the tool setting instrument can automatically calculate the difference between the tool length and the tool width of each tool and store it in the system, only the standard knife is needed when machining the other parts, which saves time. It should be noted that the tool is generally equipped with a standard tool for the tool, and the standard tool is used for the tool.
3.The following is an example of the WASINO LJ-10MC turning center in Japan using the FANUC 0T system. The working principle and usage of the tool setting tool are introduced. The working principle of the tool setting instrument is shown in Figure 3. The tool tip moves with the tool holder position detection point at the set position with the tool holder until it contacts the internal circuit to send an electrical signal (usually we can hear a click and an indicator light). When the 2# tool tip touches the a point, the X coordinate of the point where the tool is located is stored in the X of G02 shown in Fig. 2, and the Z coordinate of the point where the tool is located when the tool tip touches the b point is stored in the Z of the G02. . The tool setting of the other tools is operated in the same way.
4.In fact, in the previous step, only the zero point of X and the difference between the X direction and the Z direction of the tool relative to the standard tool are better, and the Z zero point can be used when the workpiece is replaced. Since the position of the tool setting tool in the machine coordinate system is always constant, after replacing the workpiece, it is only necessary to use the standard tool to the Z coordinate origin. When the Z-axis function measurement button "Z-axis shift measure" 。
5。Manually move the X and Z axes of the tool holder so that the standard tool approaches the right end of the workpiece Z direction. Trial the end face of the workpiece. Press the “POSITION RECORDER” button. The system will automatically record the position of the tool cutting point in the Z coordinate direction of the workpiece coordinate system. And the difference between the other tool and the standard tool in the Z direction is added to this value to obtain the Z origin of the corresponding tool, and the value is displayed on the WORK SHIFT work screen.
cnc lathe
Fanuc system CNC lathe tool setting and programming instructions
Fanuc system CNC lathe setting method of workpiece zero point
一, try to cut the knife directly with the tool
1. Test the outer garden with the outer garden cutter, remember the current X coordinate, measure the diameter of the outer garden, reduce the diameter of the outer garden with the X coordinate, and input the value into the X value of the offset interface.
2. Test the outer end of the outer garden with the outer garden cutter, remember the current Z coordinate, and enter the Z value of the geometry of the offset interface.
二, set the workpiece zero point with G50
1. Test the outer garden with an outer garden cutter. After measuring the diameter of the outer garden, retract the knife in the positive direction of the Z axis and cut the end surface to the center (X axis coordinate minus the diameter value).
2. Select MDI mode, input G50 X0 Z0, start START button, set the current point to zero.
3. Select MDI mode and input G0 X150 Z150 to make the tool leave the workpiece for machining.
4. At the beginning of the program: G50 X150 Z150 .......
5. Note: With G50 X150 Z150, your starting point and ending point must be the same as X150 Z150, so as to ensure that the repeated processing does not confuse the knife.
6. If the second reference point G30 is used, it can guarantee that the repetitive machining is not chaotic. At this time, the program starts with G30 U0 W0 G50 X150 Z150
7. In the FANUC system, the position of the second reference point is set in the parameter. In the Yhcnc software, press the right mouse button to display the dialog box, and press the left mouse button to confirm.
三, set the workpiece zero with the workpiece shift
1. In the Offset of the FANUC0-TD system, there is a workpiece shift interface, which can input the zero offset value.
2. Use the outer garden cutter to test the end face of the workpiece first. At this time, the position of the Z coordinate is as follows: Z200, directly input into the offset value.
3. Select “Ref” to return to the reference point mode, press the X and Z axes to return to the reference point, and the workpiece zero coordinate system is established.
4. Note: This zero point is always maintained. It is only cleared if the offset value Z0 is newly set.
四, set the workpiece zero point with G54-G59
1. Test the outer garden with the outer garden knife. After measuring the diameter of the outer garden, retract the knife in the positive direction of the Z axis and cut the end surface to the center.
2. Input the current X and Z axis coordinates directly into G54----G59, the program directly calls: G54X50Z50.......
3. Note: G54-----G59 workpiece coordinate system can be cleared by G53 command.
The FANUC system has three methods for determining the workpiece coordinate system.
The first is to obtain the workpiece coordinate system by writing the tool offset value to the tool. This method is simple in operation and good in reliability. He is closely related to the mechanical coordinate system through the tool offset. As long as the power is constantly changed and the tool offset value is not changed, the workpiece coordinate system will exist and will not change, even if the power is turned off, restart. After the reference point is returned, the workpiece coordinate system is still in the original position.
The second is to set the coordinate system with G50. After the tool is moved, move the knife to the position set by G50 to process. For the reference knives first, the knives of the other knives are relative to the reference knives.
 
The third method is the MDI parameter. With G54~G59, six coordinate systems can be set. This coordinate system is constant with respect to the reference point and has nothing to do with the tool. This method is suitable for mass production and the machining of workpieces with a fixed clamping position on the chuck.
The workpiece coordinate system of the aerospace numerical control system is determined by setting the coordinate value of the current position of the tool through G92 Xa zb (similar to FANUC's G50) statement. Before machining, the tool needs to be calibrated first. The reference tool is used to achieve the correctness. After the tool is set, the coordinate will be cleared. When the other tool is displayed, the coordinate value will be written into the corresponding tool compensation parameter. Then measure the tool diameter Фd, move the tool to the position where the coordinate display X=a-d Z=b, and run the program (the programmed coordinate system origin of this method is at the center of the right end face of the workpiece). Pressing reset or emergency stop during machining can return to the set G92 starting point to continue machining. However, if there is an accident such as: X or Z axis has no servo, tracking error, power failure, etc., the system can only be restarted, and the workpiece coordinate system set later will disappear, and the tool needs to be re-paired. If it is mass production, after processing one piece, return to G92 starting point to continue processing the next piece. If there is a slight mistake in the operation process, it is possible to modify the workpiece coordinate system and need to re-align the tool.

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