# US 10,108,174 B2 · Numerical controller controlling a laser processing machine

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- Number: US 10,108,174 B2
- Document ID: US10108174B2
- Status: Granted
- Kind: B2
- Application number: 14/629,524
- Filed: 2015-02-24
- Published: 2015-08-27
- Granted: 2018-10-23
- Earliest claimed: 2014-02-25
- Assignees: Fanuc Corporation
- Applicants: FANUC Corporation
- Inventors: Takayoshi Matsumoto
- Web page: https://patentgrep.com/patent/US10108174B2

## CPC

- G05B 19/402: characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position (G05B19/19 takes precedence)
- B23K 26/03: Observing, e.g. monitoring, the workpiece
- B23K 26/048: {by controlling the distance between laser head and workpiece}
- B23K 26/0876: {in at least two axial directions}
- B23K 26/0892: {Controlling the laser beam travel length}
- B23K 26/38: by boring or cutting
- G05B 2219/45041: Laser cutting
- G05B 2219/50131: Setup as function of tool position in manufacturing center
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM

## Abstract

The gap control axis following speed calculating unit of a numerical controller controlling a laser processing machine calculates a gap control axis following speed based on a displacement amount obtained from a separation distance and a reference distance between a nozzle tip and a workpiece, and a gap control gain. A first determining unit determines that the nozzle tip has entered an approach side when the separation distance becomes smaller than the reference distance. A first changing unit changes the gap control gain continuously in accordance with the displacement amount.

## Claims

### Claim 1

A numerical controller controlling a laser processing machine, the numerical controller including a processor configured to perform a method comprising:
specifying a reference separation distance between a nozzle tip and a workpiece as a reference distance;
detecting a separation distance between the nozzle tip and the workpiece;
obtaining a displacement amount from the specified reference distance and the detected separation distance;
calculating a gap control axis following speed based on the obtained displacement amount and a stored gap control gain G;
determining that the nozzle tip has entered an approach side when the detected separation distance between the nozzle tip and the workpiece becomes smaller than the specified reference distance;
changing the gap control gain G using a function G(x) continuous at the approach side closer to the workpiece than the specified reference position to an approach side gap control gain G′ continuously and increasingly in accordance with the obtained displacement amount when the nozzle tip is determined to have entered the approach side;
controlling a position of the nozzle tip of the laser processing machine based on the obtained displacement amount; and
determining that emergent abnormal closeness is present when the detected separation distance between the nozzle tip and the workpiece becomes smaller than a predetermined abnormally close distance;
changing the approach side gap control gain G′ to a fixed-value gap control gain G″ for emergency when the emergent abnormal closeness is present to return the nozzle tip to the specified reference position, the fixed-value gap control gain G″ being higher than the approach side gap control gain G′;
determining that the nozzle tip has returned from the approach side to the specified reference position after changing the approach side gap control gain G′ to the fixed-value gap control gain G″; and
switching to a normal gap control gain when the nozzle tip is determined to have returned to the specified reference position.

### Claim 2 (depends on 1)

The numerical controller controlling a laser processing machine according to claim 1, wherein the gap control gain for the approach side is a function that is any one of an N-order function with N being a natural number, a trigonometric function, an exponential function, and a logarithmic function and is continuous at the approach side from the specified reference position.