Input data sign determining method

In a method of creating NC machining data by entering a direction for each block of a part profile through use of a profile symbol key selected from the set of .uparw., , .fwdarw., , .dwnarw., , .rarw., , thereby to specify said part profile, followed by entering a dimension for each block of said part profile and using these entered data to create the NC machining data, an input data sign determining method having steps of:

• (a) entering, in the form of an incremental quantity along each axis, a part profile dimension in a predetermined block;
• (b) determining the sign of an entered incremental quantity on the basis of the direction of the part profile in said block by:
• determining the sign of an entered horizontal-axis incremental quantity as being plus if the part profile is directed rightward along a horizontal axis,
• determining the sign of an entered-horizontal-axis incremental quantity as being minus if the part profile is directed leftward along a horizontal axis,
• determining the sign of an entered vertical axis incremental quantity as being plus if the part profile is directed upwardly along a vertical axis, and
• determining the sign of an entered vertical axis incremental quantity as being minus if the part profile is directed downwardly along the vertical axis;
• determining the signs of entered vertical- and horizontal-axis incremental quantities as being plus if the part profile is directed upwardly toward the right,
• determining the signs of entered vertical- and horizontal-axis incremental quantities as being minus and plus respectively, if the part profile is downwardly toward the right,
• determining the signs of entered vertical- and horizontal-axis incremental quantities as being plus and minus, respectively, if the part profile is directly upwardly toward the left,
• determining the signs of entered vertical- and horizontal-axis incremental quantities as being plus if the part profile is directed downwardly toward the left;
• and
• (c) converting the incremental quantity into a signed quantity.