Turning controller

A turning controller using a turning device, the turning device comprising:

• a spindle to be rotated together with a workpiece held thereon;
• a tool holding unit to hold a tool to turn the workpiece;
• a Z-axis driver to displace at least one of the spindle and the tool holding unit in a Z-axis direction which is a direction parallel to a rotation axis of the spindle;
• an X-axis driver to displace at least one of the spindle and the tool holding unit in an X-axis direction orthogonal to the Z axis;
• and
• a B-axis driver to incline the tool holding unit around a Y axis orthogonal to both of the Z axis and the X axis,
• to rotate the workpiece held on the spindle and relatively feed the tool in at least the Z-axis direction in a cutting state in a predetermined cutting depth in the X-axis direction with respect to the workpiece, thereby performing turning work,
• the turning controller comprising:
• a storage configured to store a working program for defining the turning work and tool shape data indicative of a shape of the tool;
• a working program processing device configured to analyze the working program and to calculate and output command amounts for the Z-axis driver, the X-axis driver, and the B-axis driver;
• a command value setting processing device configured to set an approach angle command value for defining an approach angle which is an angle formed by a cutting edge of the tool and a direction orthogonal to a relative feeding direction of the tool with respect to the workpiece when performing the turning work;
• an approach angle setting command amount calculator configured to calculate, as an approach angle setting command amount, a B-axis command amount for controlling to cause the approach angle to have the approach angle command value based on the tool shape data;
• and
• a command processing device configured to output the approach angle setting command amount to the B-axis driver, wherein
• the working program includes cutting depth data for defining a cutting depth and approach angle data for defining the approach angle,
• the turning controller further comprises an approach angle calculator configured to calculate an approach angle at which an absolute value of a thrust force to be applied to the workpiece by the tool is equal to or smaller than a specified value when performing the turning work according to the cutting depth data of the working program,
• the approach angle calculator is configured to register the calculated approach angle as the approach angle data into the working program, and
• the command value setting processing device is configured to set the approach angle data to the approach angle command value.