COMPACT LASER MACHINING HEAD

Abstract

An improved laser-machining head unit for fabric comprising a diagonal mirror assembly with a tubular sleeve extending downward to an internally threaded distal tip. An annular adapter is provided with an externally-threaded male fining at one end and an internally-threaded receptacle at an opposing end. The externally-threaded male fitting of the adapter is adjustably screw-threaded into the internally threaded distal tip of the tubular sleeve. A laser nozzle has a frusto-conical tip and an annular collar Cm attachment to the adapter, the collar being externally threaded and fixedly screw-inserted into the internally-threaded receptacle of the adapter. In addition, there is a gas inlet affixed to the collar of the laser nozzle for introducing gas at a 90-degree angle thereto. The screw-adjustable configuration ensures proper alignment at all times of the lens, the beam and the nozzle aperture, and air stream.

Claims

1. A laser-machining head unit, comprising: a diagonal mirror assembly having a housing with a laser inlet and an orthogonal laser outlet, a reflecting mirror seated inside the housing for directing laser light from said inlet into said outlet; a tubular sleeve in optical communication with said mirror assembly and extending downward from the outlet of said diagonal mirror assembly, and a laser nozzle in optical communication with said tubular sleeve and having an inlet and an interior channel leading to a frusto-conical tip for directing laser light along a linear path from said inlet onto a workpiece, and a gas inlet to the laser nozzle for introducing gas flow perpendicularly to said linear path.

2. The laser-machining head unit according to claim 1, further comprising one or more focusing lenses seated inside the laser nozzle.

3. The laser-machining head unit according to claim 1, wherein said laser nozzle is adjustably attached to said tubular sleeve.

4. The laser-machining head unit according to claim 3, wherein said laser nozzle is adjustably attached to said tubular sleeve by an adapter.

5. The laser-machining head unit according to claim 4, wherein said adapter is screw-threaded to said laser nozzle for screw-adjustment along said linear path

6. The laser-machining head unit according to claim 5 wherein said adapter is screw-threaded into said laser nozzle.

7. The laser-machining head unit according to claim 5, wherein said adapter is screw-threaded onto said laser nozzle.

8. The laser-machining head unit according to claim 5, wherein said adapter is screw-threaded to said laser nozzle by screw-threads having a pitch diameter within a range of from 0.2 mm to 0.8 mm.

9. The laser-machining head unit according to claim 5, wherein said adapter is screw-threaded to said laser nozzle by screw-threads having a pitch diameter within a range of from 0.2 mm to 0.5 mm.

10. The laser-machining head unit according to claim 5, wherein said laser nozzle is fixedly attached to said adapter.

11. The laser-machining head unit according to claim 5, wherein said laser nozzle is fixedly screw-threaded to said adapter.

12. The laser-machining head unit according to claim 5, wherein a height of said laser nozzle relative to a workpiece may be adjusted by rotating the adapter.

13. A laser-machining head unit, comprising: a diagonal mirror assembly having a housing with a laser inlet and an orthogonal laser outlet, a reflecting mirror seated inside the housing for directing laser light from said inlet into said outlet; a tubular sleeve in optical communication with said mirror assembly and extending downward from the outlet of said diagonal mirror assembly to an annular sleeve end configured with adjustment screw threads; an adapter ring having a first end configured with mating screw threads and adjustably engaged to the screw threads of the annular sleeve end; and a laser nozzle fixedly attached to an opposing end of said adapter and having an inlet and an interior channel leading to a frusto-conical tip for directing laser light along a linear path from said inlet onto a workpiece.

14. The laser-machining head unit according to claim 13, comprising at least one focusing lens mourned in said laser nozzle.

15. The laser-machining head unit according to claim 14, wherein said at least one focusing lens is adjustably mounted.

16. The laser-machining head unit according to claim 15, wherein a height of said laser nozzle relative to a workpiece may be adjusted by rotating the adapter.

17. The laser-machining head unit according to claim 12, consisting of a single focusing lenses seated inside the laser nozzle.

18. The laser-machining head unit according to claim 14, wherein said adapter is screw-threaded into said laser nozzle.

19. The laser-machining head unit according to claim 14, wherein said adapter is screw-threaded onto said laser nozzle.

20. The laser-machining head unit according to claim 14, further comprising a gas inlet to the laser nozzle for introducing gas flow perpendicularly to said linear path.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other objects, features, and advantages of the present invention ill become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which:

[0018] FIG. 1 is a front perspective view of a prior art laser machining head element 10,

[0019] FIG. 2 is a front perspective view of the laser machining head element 20 according to an embodiment of the invention.

[0020] FIG. 3 is a side cross-section of the laser machining head element 20 as in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021] The present invention is an improved laser machining head element 20 that ensures perfect alignment and eliminates yellowing, and yet makes lens cleaning simple and convenient.

[0022] FIG. 2 is a front perspective view of the laser machining head element 20 according to an embodiment of the invention. In a traditional manner the laser machining head element 20 receives laser light from a source and redirects it by a diagonal mirror assembly 22 into a nozzle 26 having a gas inlet 28. The diagonal mirror assembly 22 includes a housing 42 that positions a reflecting mirror 21 at a 90 degree angle with respect to an inlet opening and an outlet opening. The beam is reflected off the adjustable diagonal 21 seated inside housing 42 and downward through a hollow tubular sleeve 23.

[0023] FIG. 3 shows the internal configuration. The reflecting mirror 21 redirects the laser light down through downwardly-extending sleeve 23 Sleeve 23 is cylindrical along, its length and may be permanently or removably attached to the housing of mirror assembly 22 as a matter of design choice. In a preferred embodiment sleeve 23 is 35 mm long and has an internal diameter of 22 mm. Importantly, sleeve 23 is internally or externally threaded along its distal tip with adjustment threads preferably having a pitch diameter within a range R.sub.1 of from 0.2 mm to 0.8 mm, and most preferably within a range R.sub.1 of from 0.2 mm to 0.5 mm. An adapter 25 is adjustably-screwed onto the threaded sleeve 23 extending from the mirror assembly 22, and may be micro-adjusted in or out as desired. The adapter 25 likewise has an internally or externally threaded upper neck with matching adjustment threads within said pitch range R.sub.1. The adapter 25 has a screw-threaded bottom orifice into which the nozzle 26 screws directly (this is a fixed non-adjustable screw-attachment). The thread pitch of the adapter 25 bottom orifice is preferably within a range R.sub.2 of from 0.2 mm-1 mm and is optimally 0.5 mm. Preferably, the exterior surface of adapter 25 is textured to provide a finger grip. The threaded sleeve 23 is hollow: there is no focusing lens assembly as per the prior art.

[0024] In accordance with the present invention, and as best seen in FIG. 3, the nozzle 26 includes an upper cylindrical collar containing the primary focusing lens assembly 30 and mount 32, and is equipped with a 90 degree gas inlet 28 directed at'the lens assembly 30. The conical tip of nozzle 26 may be configured as an industry standard sonic nozzle (see inset top). Alternatively the conical tip of nozzle 26 may be configured as a supersonic minimum length nozzle (inset bottom). The lens mount 32 may include conventional focusing/alignment optics which focuses the laser beam for passage through the nozzle 26 tip and to the cutting bed below, where the laser beam forms a point focus on the target. For example, the laser output may be focused to a spot using a single plano-convex lens mounted in an adjustable lens bed. In certain embodiments, the lens mount 32 is either air-cooled or water-cooled to reduce heating of the nozzle 26.

[0025] The gas stream from 90-degree gas inlet 28 impinges transverse to the laser beam to cause particles from the workpiece being machined to be blown away laterally from the outlet opening of the nozzle 26 and thus removed.

[0026] Given the foregoing configuration, the focusing lens(es) is/are located in the nozzle 26 effectively shortening the focal length to the nozzle, e.g., resulting in a 1-2 beam path through nozzle 26 that must be aligned and focused. This makes it easier for fabric applications. Moreover, the nozzle 26 height may be conveniently set by adjusting the distance that the adapter 25 is screwed into the threaded sleeve 23 extending from the mirror assembly 22. This screw-adjustment serves to maintain the precise height of the nozzle 26 and makes adjustment easier. This is important for fabric applications where the need for focusing/calibration is more acute, and more frequent and accurate focusing is required. The screw-fit assembly ensures the laser beam is always properly aligned with the lens assembly 30 and the nozzle opening eliminating the need to adjust the mirror 21 in the diagonal mirror assembly 22 for lens-to-beam-to-nozzle alignment. Preferably, a comparatively small 50 mm focal length lens is used, the lower focal length of the lens assembly 30 affording a much wider operating window and uniform laser settings across all fabric backing combinations.

[0027] In use, it was found that the optimum nozzle 26 height for most fabric backing combinations is 5 mm from the top of the fabric. One skilled in the art will understand that most cutting beds have a 1 mm or more variation across their surface and the 5 mm height setting is able to compensate for that variation adequately. If yellowing still occurs at the 5 mm setting it can be eliminated by lowering the nozzle two rotations (down to 4 mm).

[0028] It is important to ensure that the nozzle 26 is always screwed firmly into the adapter 25 and not loosened to lower the nozzle height. An operator should always adjust the nozzle height by adjusting the adapter 25 depth within the sleeve 23. If desired, a small amount of thread tape applied to the adapter 25 thread will create a tighter fit between the adapter 25 and the nozzle 26.

[0029] One skilled in the art will readily appreciate that the laser machining head 20 according to the invention has a smaller focal length and compact structure. Moreover, the nozzle 26 may be easily removed for lens assembly 30 cleaning. In addition, since the air front inlet 28 blows in horizontally it will not shoot back up into the sleeve 23.

[0030] It should be apparent that the foregoing results in a laser machining head element 20 that maintains proper alignment at all times between the lens assembly 30, the beam and the nozzle 26 aperture. This has been a description of the present invention and, the preferred embodiment