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Comparison of Different Tool Setting Modes on CNC Lathes

It is very important to understand the principle of tool setting during the operation programming of the CNC lathe for inclined bed.

This is very helpful for us to better understand the machining principle of the machine tool and modify the dimensional deviation during the processing process.

The tool setting for the CNC lathe of the inclined bed has the following two methods:

★ Trial cutting method

Trial cutting method is the most widely used tool setting method in practice. After the work piece and the tool are clamped, the main shaft is driven to rotate, and the tool holder is moved to the workpiece for trial cutting of an outer circle. Then keep the x coordinate unchanged and move the z-axis tool away from the workpiece, and measure the diameter of the outer circle of the segment.

Enter it into the tool length in the corresponding tool parameters, the system will automatically subtract the diameter of the outer circle of the trial cut from the current x coordinate of the tool to obtain the position of the x origin of the workpiece coordinate system.

Then move the tool to try to cut the end of the workpiece. Enter z0 in the tool width of the corresponding tool parameter. The system will automatically subtract the value of the tool’s z coordinate at this time to obtain the position of the origin of the workpiece coordinate system z.

For example, the diameter of the outer circle of the 2 # tool holder when the x is 150.0 is 25.0, then the program origin x value when cutting with this 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 with this tool is 180.0-0 = 180.0. Save (125.0, 180.0) to x and z in 2 # tool parameter tool length respectively, and use t0202 in the program to successfully establish the workpiece coordinate system.

In fact, finding the position of the workpiece origin in the machine coordinate system is not the actual position of the point, but the position of the tool holder when the tool point reaches (0, 0). In this method, the standard tool is generally not used, and all the tools of the tool need to be aligned before processing.

★ Tool setting method

Now, many CNC lathes with inclined bed are equipped with a tool setting instrument. Using the tool setting instrument to set the tool can avoid the measurement errors 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 tool needs to be aligned when processing other parts, which greatly saves time. It should be noted that when using the tool setting tool, the tool setting generally has a standard tool. When setting the tool, the standard tool is set first.

The tip of the tool moves with the tool holder to the position detection point of the tool setter whose position has been set and contacts it until the internal circuit is connected to send out an electrical signal.

In fact, only the zero point of x and the difference between the tool and the standard tool in the x direction and z direction are set during the operation, and the zero point can be set when the workpiece is replaced for processing.

Since the position of the tool setting instrument in the mechanical coordinate system is always fixed, after replacing the workpiece, you only need to use the standard tool to set the origin of the z coordinate.
Raise the z-axis shift measurement button “z-axisshiftmeasure” during operation, manually move the x and z axes of the tool holder to make the standard tool approach the right end of the workpiece in the z direction, try cutting the end of the workpiece, press the “positionrecorder” button, the system will automatically Record the position of the cutting point of the tool in the z direction of the workpiece coordinate system, and add the difference between the other tool and the standard tool in the z direction to this value to obtain the z origin of the corresponding tool. The value is displayed on the workshift work screen.

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