Control device for judging whether machining is possible

Abstract

The invention provides a control device for judging whether machining is possible. The control device (20) comprises a first ratio calculating unit (24) that calculates a maximum output value corresponding to the speed of a motor (11) , which is detected by a speed detecting unit (13) based on a first relationship, and calculates a first ratio of an actual output in relative to the maximum output value; a second ratio calculating unit (25) that calculates a continuous nominal output value corresponding to the speed of the motor (11) , which is detected by the speed detecting unit (13) based on a second ratio , and calculates a second ratio of the actual power in respect to the continuous rated output value; and a judging unit (26) that uses the first ratio and the second ratio as a basis to judge whether at least one of an intermittent machining and a continuous machining of a workpiece is possible.

Description

technical field [0001] The present invention relates to a control device for controlling a motor that drives a spindle of a machine tool. Background technique [0002] The main shaft of the machine tool is driven by an electric motor, and the tool installed in the main shaft cuts the workpiece. Figure 4A It is a graph showing such a relationship between the motor output and the motor speed. exist Figure 4A The maximum output characteristic PMC which shows the maximum output when a maximum electric current is supplied to a motor, and the continuous rated output characteristic PCC which shows the output characteristic which a motor can output for an infinite time are shown in . Japanese Patent Application Laid-Open No. 10-90011 discloses that, while visually displaying such motor characteristics, an indicator for a load gauge value to be described later is displayed together with the motor characteristics. [0003] Such as Figure 4A As shown, the maximum output characteris...

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Problems solved by technology

[0013] In this way, in the region where the ratio of the maximum output characteristic PMC to the continuous rated output characteristic PCC is not constant, even if the operator can grasp one load gauge value, it is difficult to simply predict the other load gauge value from one load gauge value.

[0014] So, for example, in Figure 5B Between the basic speeds V1 and V2, the operator cannot simply calculate the load meter value LM at the maximum output time based on the load meter value LC at the continuous rated output

In addition, in Figure 5C Between the basic speeds V1 and V2, the operator cannot simply calculate the load meter value LC at the continuous rated output based on the load meter value LM at the maximum output

Therefore, the operator cannot grasp at what level of load the intermittent operation and / or continuous operation of the motor can be performed.

As a result, the operator cannot grasp whether the workpiece can be cut intermittently and / or continuously

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