LASER PROCESSING SYSTEM AND OVERLAY WELDING METHOD

• US 20120145683A1
• Filed: 12/12/2011
• Published: 06/14/2012
• Est. Priority Date: 12/13/2010
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tsukamoto, Takeshi, MIYAGI, Masanori, Kawanaka, Hirotsugu
• Granted Patent: US 8,901,453 B2
• Time in Patent Office: Days
• US Class Current: 219/121.64
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/14 using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor B23K26/12 takes precedence
• CPC Class Codes: B23K 26/144 the fluid stream containing particles, e.g. powder
• CPC Class Codes: B23K 26/147 Features outside the nozzle for feeding the fluid stream towards the workpiece
• CPC Class Codes: B23K 26/34 Laser welding for purposes other than joining
• CPC Class Codes: B23K 26/342 Build-up welding
• CPC Class Codes: B23K 35/0244 Powders, particles or spheres; Preforms made therefrom
• CPC Class Codes: B23K 35/38 Selection of media, e.g. special atmospheres for surrounding the working area
• CPC Class Codes: B23K 35/383 mainly containing noble gases or nitrogen

Abstract

A laser processing system includes a laser processing head, a powder supply device, and a controller. The powder supply device supplies powder to the laser processing head. The laser processing head includes: a laser emission unit which irradiates a workpiece with laser light; and a powder supply unit which receives the powder supplied from a powder supply device to the laser processing head, and can supply the powder to a laser spot on the workpiece. The powder supply unit includes: a powder discharge unit which can discharge the powder toward the laser spot on the workpiece; and a powder-supply control mechanism which controls the amount of the powder to be supplied to the powder discharge unit, by distributing to the powder discharge unit at least a part of a flow of the powder supplied from the powder supply device. The controller controls the distributing by the powder-supply control mechanism.

Claims

1. A laser processing system comprising:

a laser processing head including,

a laser emission unit which irradiates a workpiece with laser light,

a powder supply unit which receives powder supplied from a powder supply device to the laser processing head, can supply the powder to a laser spot on the workpiece, and includes,

a powder discharge unit which can discharge the powder toward the laser spot on the workpiece, and

a powder-supply control mechanism which controls the amount of the powder to be supplied to the powder discharge unit, by distributing to the powder discharge unit at least a part of a flow of the powder supplied from the powder supply device;

the powder supply device which supplies the powder to the laser processing head; and

a controller which controls the distributing by the powder-supply control mechanism.

2. The laser processing system according to claim 1, further comprising a powder recovery container, wherein the powder-supply control mechanism includes,

a plurality of branches arranged on a downstream side of a powder supply channel through which the powder is supplied from the powder supply device to the powder-supply control mechanism,

a supply pipe arrangement which connects at least one of the plurality of branches to the powder discharge unit,

a return pipe arrangement which connects one or more of the plurality of branches other than the at least one of the plurality of branches to the powder recovery container, and

a distribution-ratio control mechanism which controls a distribution ratio between the plurality of branches.

3. The laser processing system according to claim 1, wherein the powder supply device includes a powder reservoir, and the powder-supply control mechanism includes,

a plurality of branches arranged on a downstream side of a powder supply channel through which the powder is supplied from the powder supply device to the powder-supply control mechanism,

a supply pipe arrangement which connects at least one of the plurality of branches to the powder discharge unit,

a return pipe arrangement which connects one or more of the plurality of branches other than the at least one of the plurality of branches to the powder reservoir, and

a distribution-ratio control mechanism which controls a distribution ratio between the plurality of branches.

4. The laser processing system according to claim 2, wherein the powder-supply control mechanism includes a supplemental-gas supply mechanism which can supply supplemental gas to the plurality of branches.

5. The laser processing system according to claim 3, wherein the powder-supply control mechanism includes a supplemental-gas supply mechanism which can supply supplemental gas to the plurality of branches.

6. A laser processing system comprising:

a laser processing head including,

a laser emission unit which irradiates a workpiece with laser light, and

a powder supply unit which receives a plurality of types of powders respectively supplied from a plurality of powder supply devices to the laser processing head, can supply the plurality of types of powders to a laser spot on the workpiece, and includes,

a powder discharge unit which can discharge the plurality of types of powders toward the laser spot on the workpiece, and

a plurality of powder-supply control mechanisms which respectively control the amounts of the plurality of types of powers to the powder discharge unit, by distributing to the powder discharge unit at least a part of a flow of each of the plurality of types of powders supplied from the plurality of powder supply devices;

the powder supply device which supplies the plurality of types of powders to the laser processing head; and

a controller which controls the distributing by the plurality of powder-supply control mechanisms.

7. The laser processing system according to claim 6, further comprising a plurality of powder recovery containers, wherein each of the plurality of powder-supply control mechanisms includes,

a plurality of branches arranged on a downstream side of a powder supply channel through which one of the plurality of types of powders is supplied from one of the plurality of powder supply devices,

a supply pipe arrangement which connects at least one of the plurality of branches to the powder discharge unit,

a return pipe arrangement which connects one or more of the plurality of branches other than the at least one of the plurality of branches to one of the plurality of powder recovery containers, and

a distribution-ratio control mechanism which controls a distribution ratio between the plurality of branches.

8. The laser processing system according to claim 6, wherein the plurality of powder supply devices respectively include a plurality of powder reservoirs, and each of the plurality of powder-supply control mechanisms includes,

a plurality of branches arranged on a downstream side of a powder supply channel through which one of the plurality of types of powders is supplied from one of the plurality of powder supply devices,

a supply pipe arrangement which connects at least one of the plurality of branches to the powder discharge unit,

a return pipe arrangement which connects one or more of the plurality of branches other than the at least one of the plurality of branches to one of the plurality of powder reservoirs included in the one of the plurality of types of powders, and

a distribution-ratio control mechanism which controls a distribution ratio between the plurality of branches.

9. The laser processing system according to claim 7, wherein each of the plurality of powder-supply control mechanisms includes a supplemental-gas supply mechanism which can supply supplemental gas to the plurality of branches.

10. The laser processing system according to claim 8, wherein each of the plurality of powder-supply control mechanisms includes a supplemental-gas supply mechanism which can supply supplemental gas to the plurality of branches.

11. An overlay welding method executed in a laser processing system including a laser processing head and a powder supply device which supplies powder to the laser processing head, where the laser processing head includes a laser emission unit which irradiates a workpiece with laser light and a powder discharge unit which can discharge the powder to a laser spot on the workpiece, the overlay welding method comprising the steps of:

supplying, by the powder supply device, the powder to a powder-supply control mechanism arranged in the laser processing head;

controlling, by the powder-supply control mechanism, the amount of the powder to be supplied to the powder discharge unit by distributing to the powder discharge unit at least a part of a flow of the powder supplied from the powder supply device; and

discharging, by the powder discharge unit, the powder the amount of which is controlled by the powder-supply control mechanism, to the laser spot on the workpiece.

12. The overlay welding method according to claim 11, wherein in the controlling by the powder-supply control mechanism, the flow of the powder supplied from the powder supply device to the powder-supply control mechanism is split, at a position on a downstream side of a powder supply channel through which the powder is supplied from the powder supply device to the powder-supply control mechanism, into a first part which is to be distributed to the powder discharge unit and a second part which is to be distributed to a powder recovery container, and the amount of the powder to be supplied to the powder discharge unit is controlled by controlling a distribution ratio of the powder between the first part and the second part.

13. The overlay welding method according to claim 11, wherein in the controlling by the powder-supply control mechanism, the flow of the powder supplied from the powder supply device to the powder-supply control mechanism is split, at a position on a downstream side of a powder supply channel through which the powder is supplied from the powder supply device to the powder-supply control mechanism, into a first part which is to be distributed to the powder discharge unit and a second part which is to be distributed to a powder reservoir arranged in the powder supply device, and the amount of the powder to be supplied to the powder discharge unit is controlled by controlling a distribution ratio between the first part and the second part.

14. The overlay welding method according to claim 12, wherein the powder is sent out, together with carrier gas, from the powder supply device to the powder supply channel.

15. The overlay welding method according to claim 13, wherein the powder is sent out, together with carrier gas, from the powder supply device to the powder supply channel.

16. The overlay welding method according to claim 14, wherein supplemental gas is added to the first part before distributing the powder to the powder discharge unit.

17. The overlay welding method according to claim 15, wherein supplemental gas is added to the first part before distributing the powder to the powder discharge unit.

18. An overlay welding method executed in a laser processing system including a laser processing head and a plurality of powder supply devices which respectively supply a plurality of types of powders to the laser processing head, where the laser processing head includes a laser emission unit which irradiates a workpiece with laser light and a powder discharge unit which can discharge the plurality of types of powders to a laser spot on the workpiece, the overlay welding method comprising the steps of:

supplying the plurality of types of powders from the plurality of powder supply devices to a plurality of powder-supply control mechanisms arranged in the laser processing head, respectively;

controlling, by the plurality of powder-supply control mechanisms, the amounts of the plurality of types of powders to be supplied to the powder discharge unit, by distributing to the powder discharge unit at least a part of a flow of each of the plurality of types of powders supplied from the plurality of powder supply devices, respectively; and

discharging, by the powder discharge unit, the plurality of types of powders the amounts of which are controlled by the plurality of powder-supply control mechanisms, to the laser spot on the workpiece.

19. The overlay welding method according to claim 18, wherein in the controlling by each of the plurality of powder-supply control mechanisms, the flow of one of the plurality of types of powders supplied from the powder supply device to one of the plurality of powder-supply control mechanisms is split, at a position on a downstream side of a powder supply channel through which the one of the plurality of types of powders is supplied from one of the plurality of powder supply devices, into a first part which is to be distributed to the powder discharge unit and a second part which is to be distributed to a powder reservoir arranged in the one of the plurality of powder supply devices, and the amount of the one of the plurality of types of powders to be supplied to the powder discharge unit is controlled by controlling a distribution ratio between the first part and the second part.

20. The overlay welding method according to claim 18, wherein the one of the plurality of types of powders is sent out, together with carrier gas, from the one of the plurality of powder supply devices to the powder supply channel.

21. The overlay welding method according to claim 19, wherein the one of the plurality of types of powders is sent out, together with carrier gas, from the one of the plurality of powder supply devices to the powder supply channel.

22. The overlay welding method according to claim 20, wherein supplemental gas is added to the first part before distributing the one of the plurality of types of powders to the powder discharge unit.

23. The overlay welding method according to claim 21, wherein supplemental gas is added to the first part before distributing the one of the plurality of types of powders to the powder discharge unit.