TOOL PATH GENERATION METHOD AND MACHINE TOOL

• US 20170300029A1
• Filed: 10/29/2014
• Published: 10/19/2017
• Est. Priority Date: 10/29/2014
• Status: Active Grant

• Current Assignee: Makino Milling Machine Company Limited
• Original Assignee: Makino Milling Machine Company Limited
• Inventors: ODA, Mitsunari, FURUTA, Megumi, SHINONE, Akihiro, KAWAI, Toshimune
• Granted Patent: US 10,248,101 B2
• Time in Patent Office: Days
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05B 19/4093 characterised by part programming, e.g. entry of geometrical information as taken from a technical drawing, combining this with machining and material information to obtain control information, named part programme, for the NC machine
• CPC Class Codes: G05B 19/4103 Digital interpolation
• CPC Class Codes: G05B 2219/35097 Generation of cutter path, offset curve
• CPC Class Codes: G05B 2219/36221 Entry of chamfer, beveling, rounding of corner shape
• CPC Class Codes: G05B 2219/45202 Edge finishing

Abstract

A tool path generation method for generating a second tool path by performing a smoothing process on a first tool path for processing a work with a machine tool includes a change rate calculation step of calculating a curvature change rate of the first tool path at a plurality of moving points (P_n) of the first tool path. The tool path generation method includes: a weight calculation step of calculating a moving average weight on the basis of the curvature change rate of the first tool path at each of the moving points (P_n); and a step of calculating coordinate values of the moving average of the moving points (P_n) using the weight at each of the moving points (P_n), and setting the coordinate values of the moving average of the moving points (P_n) as moving points of the second tool path.

Claims

1. A tool path generation method for generating second tool path by performing smoothing treatment with respect to first tool path that machines a workpiece with a machine tool, the tool path generation method comprising:

a step of setting movement points in the first tool path;

a rate-of-change calculation step for calculating a rate of change in curvature of the first tool path at each of the movement points;

a weight calculation step for calculating a weight of moving average based on the rate of change in the curvature of the first tool path at each of the movement points; and

a step of calculating a coordinate value of the moving average of the movement points by using the weight at each of the movement points and setting the coordinate value of the moving average of the movement point as the movement points of the second tool path.

2. The tool path generation method according to claim 1, wherein the rate-of-change calculation step includes a step of calculating a moving average value in the curvature at each of the movement points of the first tool path, and

a step of calculating a rate of change in the curvature based on a calculated moving average value in the curvature.

3. The tool path generation method according to claim 1, wherein the weight calculation step includes

a step of calculating a standard deviation of a normal distribution based on the rate of change in the curvature, and

a step of calculating the weight of the moving average based on the normal distribution including a calculated standard deviation.

4. The tool path generation method according to claim 1, wherein

an allowable value of a dimensional error of a machined workpiece is determined in advance, and

the weight calculation step includes a step of setting the number of movement points to be used for calculation of the moving average based on the allowable value.

5. A machine tool comprising a control device that generates second tool path by performing smoothing treatment on first tool path set by a first machining program, wherein

the control device includes:

a movement point setting part that sets a plurality of movement points based on the first tool path;

a rate-of-change calculation part that calculates a rate of change in curvature of the first tool path at each of the movement points;

a weight setting part that calculates a weight of moving average based on the rate of change in the curvature of the first tool path at each of the movement points;

a movement point correction part that calculates a coordinate value of the moving average of the movement points using the weight at each of the movement points and sets the coordinate value of the moving average of the movement points as the movement points of the second tool path; and

a program generation part that generates a second machining program based on the movement points of the second tool path.