How to set tools on a CNC lathe without tool setter
I. Basic Coordinate Relationships
Generally speaking, two coordinate systems are commonly used: one is the Machine Coordinate System, and the other is the Workpiece Coordinate System (also referred to as the Program Coordinate System). A fixed reference point (assumed to be at coordinates (X, Z)) is established within the machine tool's Machine Coordinate System. The primary function of this reference point is to provide a positioning datum for the machine tool itself. Since the system automatically sets the current position to (0, 0) every time the machine is powered on-regardless of where the tool turret happens to be-this would inevitably lead to inconsistent positioning datums. Therefore, the very first operation performed after powering on is the "Reference Point Return" (sometimes referred to as "Homing" or "Returning to Zero"), a process that establishes the origin (0, 0) by locating the fixed reference point (X, Z). For the sake of computational and programming convenience, the Program Origin is typically set at the center of rotation on the right-hand face of the workpiece; this is done to ensure, as much as possible, that the programming datum aligns with the design and assembly datums. Since the Machine Coordinate System serves as the machine tool's sole absolute datum, it is imperative to accurately determine the position of the Program Origin within this Machine Coordinate System. This determination is typically accomplished during the subsequent "Tool Setting" process.
II. Tool Setting Methods
1. Tool Setting via Test Cutting: The test-cutting method is the most widely utilized tool-setting technique in actual practice. The following section outlines the specific operational procedures, using a lathe equipped with a GSK CNC system as an illustrative example.
Once the workpiece and cutting tool have been securely clamped, engage the spindle to initiate rotation. Move the tool turret to the workpiece and perform a test cut on a section of its outer diameter. Next, while maintaining the current X-coordinate value, move the tool along the Z-axis to retract it away from the workpiece. Measure the diameter of the section just cut. Enter this measured diameter value into the "Tool Length" parameter within the corresponding tool data settings. The system will then automatically subtract the measured diameter from the tool's current X-coordinate position to determine the location of the X-axis origin within the Workpiece Coordinate System. Subsequently, move the tool to perform a test cut on the end face of the workpiece. Enter "Z0" into the "Tool Width" parameter within the corresponding tool data settings; the system will then automatically subtract this entered value from the tool's current Z-coordinate position to determine the location of the Z-axis origin within the Workpiece Coordinate System.
For instance, if Tool #2 (mounted on the turret) is used to measure an outer diameter of Φ50.78 mm, the input for the X-axis tool setting would be: "X50.78". ...measurement." If the tool is set to zero at the workpiece face, then the Z-value of the program origin for cutting operations using this specific tool is 0.0. By storing the values (50.78, 0.0) into the X and Z fields of the length parameters for Tool #2, one can successfully establish the workpiece coordinate system within the program by simply calling T0202. In essence, locating the workpiece origin within the machine coordinate system does not entail determining the absolute physical position of that specific point; rather, it involves identifying the position of the tool turret at the precise moment the tool tip reaches the (0, 0) coordinate. When employing this method for tool setting, a standard reference tool is typically not utilized; instead, it is necessary to accurately set all the tools intended for use prior to commencing the machining process.
