Tool changing method

A method for generating a numerical control program, comprising the steps of:

• (a) inputting a first numerical control program defining processes, each process including a tool change command followed by at least one machining command;
• and
• (b) converting the first numerical control program into a second numerical control program by converting the tool change command in each process into a combined tool change command identifying a first tool to be used during machining controlled by the at least one machining command following the tool change command and a second tool to be held in a stand-by position until a following process is performed, said converting including the substeps of:
• (b1) determining whether a command input in step (a) is a tool change command;
• (b2) storing a tool number included in an initial tool change command in the first numerical control program in a temporary storage area;
• (b3) repeating step (b1) until a next tool change command is identified;
• (b4) adding a delimiter and the tool number in the next tool command after the tool number in the tool command corresponding to the tool number stored in the temporary storage area;
• (b5) storing the tool number of the next tool command in the temporary storage area;
• and
• (b6) repeating steps (b3)-(b5) until all tool commands have been input in step (a).

A method for performing numerical control processing, comprising the steps of:

• (a) inputting a numerical control program defining processes, each process including a tool change command followed by at least one machining command, the tool change command containing first and second tool numbers identifying first and second tools, respectively, the first tool to be used in the process and the second tool to be used in a next process;
• (b) storing the second tool number in a standby register when the tool change command is executed;
• (c) comparing the first tool number of the tool change command with the second tool number of an immediately previous tool change command stored in the standby register;
• (d) storing the first tool number in an execution register and indicating that a tool change must occur when said comparing in step (b) determines that the first tool number of the tool change command is different from the second tool number of the immediately previous tool change command;
• (e) indicating that the second tool corresponding to the second tool number of the immediately previous tool change command should be used as the first tool of the process including the tool change command when said comparing in step (b) determines that the first tool number of the tool change command matches the second tool number of the immediately previous tool change command;
• (f) performing machining using the first tool under control of the at least one machining command included in the process;
• (g) controlling selection of the second tool for holding in a stand-by position during machining using the first tool;
• and
• (h) repeating steps (b)-(g) for all processes in the numerical control program.