NUMERICAL CONTROL METHOD AND NUMERICAL CONTROL DEVICE OF MACHINE TOOL

• US 20130173045A1
• Filed: 10/26/2011
• Published: 07/04/2013
• Est. Priority Date: 10/27/2010
• Status: Active Grant

• Current Assignee: Makino Milling Machine Company Limited
• Original Assignee: Makino Milling Machine Company Limited
• Inventors: Mori, Norio, Oda, Mitsunari, Kawana, Akira
• Granted Patent: US 9,477,218 B2
• Time in Patent Office: Days
• US Class Current: 700/186
• CPC Class Codes: G05B 19/182 characterised by the machine tool function, e.g. thread cutting, cam making, tool direction control G05B19/21 - G05B19/40 take precedence
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/41078 Backlash acceleration compensation when inversing, reversing direction
• CPC Class Codes: G05B 2219/41083 Upon reversing direction, lower, change gain
• CPC Class Codes: G05B 2219/41155 During reversing, inversing rotation, movement
• CPC Class Codes: G05B 2219/41206 Lookup table, memory with certain relationships
• CPC Class Codes: G05B 2219/42039 Select servo parameter set from table for fixed linear working points
• CPC Class Codes: G05B 2219/49182 Tapping, overshoot after reversal, elasticity compensation

Abstract

A numerical control device which controls a feed axis of a machine tool (10) has a storage unit (92) which divides a range of movement of the feed axis into a plurality of regions and stores a plurality of control parameters corresponding to said divided plurality of regions in advance, a position detection unit which detects a position of a feed axis at the time of machining a workpiece, a parameter selection unit (90) which reads out control parameters corresponding to a divided region to which the detected feed axis position at the time of machining a workpiece belongs, and a servo control unit (52) which controls the feed axis using said read control parameters. Due to this, it is possible to provide a numerical control method of a machine tool which realizes stable machining precision without regard as to the feed axis position and a numerical control device which conducts that method.

Claims

1. A numerical control method which controls a feed axis of a machine tool, said numerical control method of a machine tool comprising steps of:

dividing a range of movement of the feed axis into a plurality of regions and storing in advance a plurality of control parameters corresponding to said divided plurality of regions,

analyzing a machining path from a machining program of said machine tool,

reading out control parameters corresponding to a divided region determined in accordance with said machining path from said stored plurality of control parameters, and

controlling the feed axis using said read control parameters.

2. The numerical control method of a machine tool as set forth in claim 1, wherein said control parameters are read out while the feed axis is moving toward a machining start position and are set to said control parameters immediately after reaching said machining start position.

3. The numerical control method of a machine tool as set forth in claim 1, wherein, when said machining path extends across a plurality of regions, control parameters corresponding to said region in which said machining path is included longest are read out.

4. The numerical control method of a machine tool as set forth in claim 1, wherein, when said machining path is an arc, control parameters corresponding to said region including a center of said arc are read out.

5. The numerical control method of a machine tool as set forth in claim 1, wherein said control parameters include at least one of an acceleration/deceleration time constant, feedback gain, feed forward gain, stick motion correction parameters, and filter constant of said feed axis.

6. A numerical control device which controls a feed axis of a machine tool, comprising:

a storage unit which divides a range of movement of the feed axis into a plurality of regions and stores a plurality of control parameters corresponding to said divided plurality of regions,

an analysis unit which analyzes a machining path from a machining program of said machine tool,

a parameter selection unit which reads out control parameters corresponding to a divided region determined in accordance with said machining path from said stored plurality of control parameters, and

a servo control unit which controls the feed axis using said read control parameters.