Simultaneous two-axis numerical control method for an injection-molding machine and an apparatus therefor

A numerical control apparatus for an injection-molding machine having step feed conditions and including axes and servomotors for driving the axes, the apparatus comprising:

• a numerical control processing means for controlling the servomotors;
• a programmable machine controller means for sequentially controlling the injection-molding machine;
• and
• a memory means accessible by both said numerical control processing means and said programmable machine controller means;
• said programmable machine controller means including:
• first determination means for determining whether the
• step feed conditions are fulfilled, and
• memory control means for storing information specifying a step feed axis, step feed execution information including a displacement, a moving speed, and a moving direction of said step feed axis, and step feed command information in said memory means when said step feed conditions are fulfilled,
• said numerical control processing means including:
• second determination means for determining if said step feed command information is stored in said memory means and for determining whether said step feed conditions are fulfilled, and
• means for reading said step feed execution information from said memory means, and for alternately performing pulse distribution while said step feed conditions are fulfilled for said step feed axis, based on said step feed execution information, and pulse distribution for another one of the axes in response to said step feed command information, so that said numerical control processing means simultaneously drives said step feed axis and said another one of the axes are driven simultaneously in accordance with said step feed execution information stored in said memory means by said programmable machine controller means.