CNC machine having interactive control of corner tolerance that is programmed to vary with the corner angle

In a positioning device, a method of moving a tool relative to a workpiece along a programmed path, the method comprising the steps of:

• (a) specifying a tolerance;
• (b) executing the programmed move to generate a sequence of move command signals, each move command signal indicating a desired position of the tool relative to the platform along the programmed path;
• (c) moving the tool relative to the platform through a sequence of incremental moves in accordance with the move command signals, wherein, if the desired position indicated by a current move command signal is a corner on the programmed path, moving the tool relative to the platform along the programmed path until the position of the tool relative to the platform is within an allowable distance from the corner, and once the position of the tool relative to the platform is within the allowable distance from the corner, moving the tool relative to the platform in accordance with a next move command signal;
• and
• (d) interactively modifying the specified tolerance during the step of moving, wherein the allowable distance is larger than the specified tolerance, and
• wherein the allowable distance is derived as a function of the specified tolerance and an angle of the corner.

In a positioning device, a method of moving a tool relative to a workpiece along a programmed path, the method comprising the steps of:

• (a) specifying a tolerance;
• (b) executing the programmed move to generate a sequence of move command signals, each move command signal indicating a desired position of the tool relative to the platform along the programmed path;
• (c) moving the tool relative to the platform through a sequence of incremental moves in accordance with the move command signals, wherein, if the desired position indicated by a current move command signal is a corner on the programmed path, moving the tool relative to the platform along the programmed path until the position of the tool relative to the platform is within an allowable distance from the corner, and once the position of the tool relative to the platform is within the allowable distance from the corner, moving the tool relative to the platform in accordance with a next move command signal,
• wherein the allowable distance is larger than the specified tolerance, and wherein each step of incremental moving includes the steps of producing a position correction signal based on a difference between a current position of the tool relative to the platform and the desired position indicated by the current move command, and moving the tool relative to the platform to a desired velocity based on the position correction signal.

In a positioning device, a method of moving a tool relative to a workpiece along a programmed path, the method comprising the steps of:

• (a) specifying a tolerance;
• (b) executing the programmed move to generate a sequence of move command signals, each move command signal indicating a desired position of the tool relative to the platform along the programmed path;
• (c) moving the tool relative to the platform through a sequence of incremental moves in accordance with the move command signals, wherein, if the desired position indicated by a current move command signal is a corner on the programmed path, moving the tool relative to the platform along the programmed path until the position of the tool relative to the platform is within an allowable distance from the corner, and once the position of the tool relative to the platform is within the allowable distance from the corner, moving the tool relative to the platform in accordance with a next move command signal;
• and
• (d) interactively modifying a programmed feed rate during the step of executing, wherein programmed feed rates are adjusted in accordance with the modified programmed feed rate and the adjusted programmed feed rates are employed during the step of executing,
• wherein the allowable distance is larger than the specified tolerance.

A CNC machine for cutting a corner portion of a workpiece, comprising:

• a tool;
• a platform;
• a programmable control unit programmed to control the movement of the tool relative to the platform along a programmed path;
• a drive assembly connected to at least one of the tool and the platform to move the tool relative to the platform along the programmed path,
• wherein, once the drive assembly moves the tool relative to the platform to a position that is within an allowable distance from a corner of the programmed path, the tool is moved relative to the platform towards a point on the programmed path beyond the corner,
• wherein the allowable distance varies with respect to an angle of the corner.

A method of machining a workpiece within a specified tolerance by moving either a tool or a workpiece platform relative to each other along a programmed path, the method comprising the steps of:

• (a) generating a sequence of move command signals, each move command signal indicating a desired position of the tool relative to the platform along the programmed path;
• and
• (b) moving the either the tool or the platform relative to each other through a sequence of incremental moves in accordance with the move command signals, characterized in that,
• if the programmed path includes a corner, following the current move command signal until the position of the tool relative to the platform is within an allowable distance from the corner, and then deviating from the programmed path in a linear direction towards a position on the programmed path beyond the corner to follow the next move command signal, wherein the allowable distance varies in accordance with the angle of the corner.