Numerical controller for controlling five-axis machining apparatus

A numerical controller for controlling a five-axis machining apparatus provided with three linear axes and two rotary axes for moving a tool relative to a workpiece mounted on a table, according to a machining program, said numerical controller comprising:

• command reading means that successively reads a motion path command for the linear axes, a relative velocity command for designating a velocity of the tool relative to the workpiece, and a tool orientation command designating an orientation of the tool relative to the table, from the machining program;
• tool orientation command correcting means that successively corrects the tool orientation command to obtain corrected tool orientation command;
• interpolation means that determines respective axes positions at every interpolation period based on the corrected tool orientation command, the motion path command and the relative velocity command such that an end point of the tool moves along the commanded motion path relative to the workpiece at the commanded relative velocity;
• and
• means that drives motors for the respective axes to the respective axes positions determined by said interpolation means,
• wherein said tool orientation command correcting means corrects the tool orientation command in each block such that a ratio between each rotary axis motion amount in a block and linear axis motion amount in the corresponding block is constant, for the motion path command.