Tool path preparing method and machining method

Abstract

The movement position of the roughing tool is calculated, in S109, by adding the finishing allowance to the movement position of the finishing tool so that the path of the roughing tool is shifted in the direction perpendicular to the rotation center axis of the main spindle rotation motor from the path of the finishing tool by the finishing allowance. Then, a gap between the movement position of the roughing tool in the direction of the rotation center axis of the main spindle rotation motor and the workpiece W is calculated, and when the gap is not larger than a predetermined value G, in S113, the movement position of the roughing tool is corrected in the direction perpendicular to the rotation center axis of the main spindle rotation motor so that the roughing tool does not cut in the inside of the finishing portion of the workpiece. The movement position of the roughing tool is corrected so that the movement speed of the roughing tool in the direction perpendicular to the rotation center axis of the main spindle rotation motor is a predetermined value.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to a tool path preparing method for preparing a tool path to simultaneously conduct a roughing and finishing operations, and to a machining method employing the tool path preparing method.[0003] 2. Description of the Related Art JP-A-63-200943 discloses a tool path preparing method and a machining method employing the tool path preparing method, for example. According to JP-A-63-200943, controlling a position of a finishing tool automatically controls another tool to operate simultaneously at a rough-cut position having a smaller depth of cut by an arbitrarily given finishing allowance. In other words, only the position of the tip of the finishing tool is programmed, and the roughing tool is automatically controlled at a rough cut position leaving only the finishing allowance.[0004] However, there are the following problems in the tool path preparing method and machining method as disclosed in JP-A-63-200943.[0005]...

AI Technical Summary

Benefits of technology

[0011] In the tool path preparing method according to the present invention, after shifting the path of the finishing tool by a finishing allowance in the direction perpendicular to the predetermined axis to calculate the path of the rouging tool, the calculated path of the roughing tool is corrected so that a predetermined gap is formed between the workpiece and the roughing tool when viewed in the axis direction of the predetermined axis, therefore, the cut-in into the inside of the finishing portion by the roughing tool can be prevented without stopping the feed of the finishing tool. As the result, the machining time of the workpiece by the roughing tool and the finishing tool can be reduced. Further, because the feed of the finishing tool is not stopped, it can be suppressed that the cutter mark is formed on the surface of the workpiece by the finishing tool.

[0012] It is preferable that the path of the roughing tool is corrected so that the moving speed of the roughing tool in the direction perpendicular to the predetermined axis is a predetermined value. In such the manner, when the path of the roughing tool is corrected, by correcting the path of the roughing tool so that the movement speed of the roughing tool in the direction perpendicular to a predetermined axis is a predetermined value, the roughing tool can be smoothly moved, and the cutting load by the roughing tool can be decreased, and the variation of the cutting load can be suppressed.

[0013] It is preferable that the path of the roughing tool is corrected so that the roughing tool moves at a predetermined acceleration from a position, at which the gap between the workpiece and the roughing tool in the axis direction of the predetermined axis becomes a predetermined value, in the direction perpendicular to the predetermined axis. In this manner, when the path of the roughing tool is corrected, by correcting the path of the roughing tool so that the roughing tool is moved at a predetermined acceleration in the direction perpendicular to a predetermined axis from a position at which a gap between the workpiece and the roughing tool in the axis direction of the predetermined axis becomes a predetermined value, the path of the roughing tool can be easily corrected. Further, the variation of the cutting load by the roughing tool can be more suppressed.

[0019] Because, in the processing method according to the present invention, according to the tool path prepared by the tool path preparing method described in the first to the third aspects of the present invention, because the roughing and the finishing operations are simultaneously conducted by the roughing tool and the finishing tool, the cut-in into the inside of the finishing portion by the roughing tool can be prevented without stopping the feed of the finishing tool. As the result, the machining time of the workpiece by the roughing tool and the finishing tool can be reduced. Further, because the feed of the finishing tool is not stopped, it can be suppressed that the cutter mark is formed on the surface of the workpiece by the finishing tool.

Problems solved by technology

However, there are the following problems in the tool path preparing method and machining method as disclosed in JP-A-63-200943.

If the path of the roughing tool is prepared by shifting the finishing tool in the direction of the main spindle by an offset distance between the roughing tool and the finishing tool, and further shifting it in the direction perpendicular to the main spindle by the finishing allowance, a cutting which includes the shape perpendicular to or approximately perpendicular to the main spindle (for example, a stepped portion) would be impossible, because the roughing operation cuts in to the inside of the finishing portion.

In order to prevent the cut-in by the roughing tool, it is necessary that a feed of the finishing tool is stopped, and the roughing tool is retreated to a position at which the cut-in is not caused,which results in along machining time.

Further,because the feed of the finishing tool is stopped, a scar (cutter mark) is generated on the workpiece at a position the finishing tool is stopped.

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