DE102016221322A1 - Cutting gas nozzle with segmented sleeve - Google Patents

Abstract

In a cutting gas nozzle (1) for a laser processing head (2) with a nozzle body (5) having a nozzle opening (7) and with a sleeve (8) surrounding the nozzle opening (7), which is guided axially displaceably on the nozzle body (5) and at least protrudes beyond the nozzle body (5) in its front end position, the sleeve (8) according to the invention from several relative to each other axially displaceably guided sleeve segments (17) composed.

Description

The invention relates to a cutting gas nozzle for a laser processing head with a nozzle body having a nozzle body and a nozzle opening surrounding the sleeve which is guided axially displaceably on the nozzle body and projecting at least in its front end position on the nozzle body.

Such a cutting gas nozzle is, for example, JPH10216978A or WO 2014/072609 A1 known.

For the cutting of different materials (mild steel, stainless steel, aluminum, ...) in different material thickness with the help of a laser beam different cutting gas nozzles are required, which have different outer or inner contours, differently shaped nozzle openings and different nozzle diameters.

In order to reduce this variety and the frequency of a necessary nozzle change, JPH10216978A a cutting gas nozzle for a laser processing head is known, which directs a cutting gas through an inner nozzle and an auxiliary gas to the process site by an annular nozzle surrounding the inner nozzle. The annular gap nozzle can be pushed axially back and forth relative to the inner nozzle by means of a screw thread, in order to change the nozzle opening (the nozzle cross-sectional area) of the annular gap nozzle and thus influence the gas flow of the auxiliary gas. When laser cutting with a slanted cutting gas nozzle or when laser cutting workpieces with three-dimensional contours, however, a gap between the workpiece and sleeve is present, causing a high gas loss occurs.

From the WO 2014/072609 A1 is a cutting gas nozzle with a surrounding the nozzle opening sleeve is known, which is guided axially displaceably on the nozzle body. By the gas pressure, the sleeve is moved against the action of a return spring in its front end position, in which it projects beyond the nozzle body and rests all around tightly against the workpiece in non-inclined cutting gas nozzle. Here, too, a gap between the workpiece and the sleeve always remains during laser cutting with a slanted cutting gas nozzle or laser cutting of workpieces with three-dimensional contours, which leads to a high gas loss.

Finally, out of the DE 198 53 735 C1 a laser processing head is known in which a cutting gas nozzle with an inner nozzle and with an annular gap nozzle is arranged in a slidably guided hollow piston. During operation of the laser processing head, a gas cushion forms between the workpiece surface and the end face of the hollow piston. With the aid of the gas pressure, the gap between the workpiece surface and the end face of the hollow piston can be adjusted, wherein the inner nozzle and the annular gap nozzle can be acted upon with different pressures.

In contrast, the present invention has the object, in a cutting gas nozzle of the type mentioned during the laser cutting process to reduce the gas loss in the gap between the workpiece and sleeve.

This object is achieved in that the sleeve is composed of several relatively axially displaceable guided sleeve segments.

According to the sleeve segments can move independently of each other and rest against the workpiece, whereby - in contrast to a non-segmented sleeve - a gap between the workpiece and sleeve gap significantly reduced and thus the gas loss is reduced. Thereby, the absolute pressure of the cutting gas at the same time higher mass flow, which enters the kerf of the workpiece to expel the melt there, can be reduced. In other words, the segmented sleeve enables increased gas flow in the kerf even at reduced cutting gas pressures, as well as contour adaptation of the sleeve to three-dimensional contours or narrow contour radii of the workpiece.

Preferably, all sleeve segments are guided axially displaceable directly on the nozzle body. Alternatively, however, only some of the sleeve segments, e.g. only every second sleeve segment, guided axially displaceably directly on the nozzle body; At this sleeve segments then the other sleeve segments are guided axially displaceable, which are therefore only axially guided axially displaceable on the nozzle body.

More preferably, at least some of the sleeve segments, in particular all sleeve segments, each guided axially displaceable on their mutually facing peripheral sides, whereby the individual sleeve segments are secured against lateral tilting.

Advantageously, at least some of the sleeve segments, in particular all sleeve segments, each engage with their mutually facing peripheral sides, whereby the individual sleeve segments are mutually aligned. Particularly advantageous to engage behind the mutually facing peripheral sides of the sleeve segments each other in the circumferential direction. For example, the sleeve segments can be interlocked with each other or alternately engage behind each other, whereby the sleeve segments are held captive each other.

In a particularly preferred cutting gas nozzle is provided that at least some of the sleeve segments, in particular all sleeve segments, with each other in cross-section hook-shaped circumferential sides mutually intermeshed and are guided axially displaceable relative to each other. For example, the hook-shaped peripheral sides can be spirally rotated and engage in one another in a complementary manner, wherein the spiral shape can be formed with a round or angular contour periphery. The mutually engaging behind spiral arms of the sleeve segments prevent the sleeve from falling apart radially outward. Likewise, a mutual axial guidance of the sleeve segments is ensured by this gearing. It is possible to realize the toothing of the sleeve segments by other geometries of their peripheral sides. A coupling by a T-shaped, or widening in another way, contour and a complementary rail is an alternative embodiment.

Particularly advantageously, the sleeve is composed of identical sleeve segments, which allows the simple production of the sleeve segments by cutting an injection-molded semifinished product with the profile described above.

In an advantageous embodiment, the sleeve is formed of an electrically non-conductive sleeve material, e.g. made of a high performance plastic such as polyetheretherketone (PEEK), which is also used as a sealing material. But it can also be used as a sleeve material other electrically non-conductive ceramic and plastic compounds.

Preferably, the sleeve segments are each independently biased towards their forward end position, e.g. by spring force or pneumatically. In the latter case, that surface portion of the sleeve to which a cutting gas pressure in the forward direction acts during operation may be larger than the surface portion to which the cutting gas pressure acts in the reverse direction during operation. When passing through an inner or outer radius of a three-dimensional workpiece, the sleeve segments remain due to their bias on the workpiece and thereby ensure to keep the distance from nozzle to plate (ADB) as low as possible. Since the cutting speed of the laser processing head can not be kept constant in the radius range (for lack of sufficient machine dynamics), the cutting properties locally change there. This effect can e.g. be taken into account by contour switching.

To pass over light steps in the workpiece surface, as e.g. may occur due to the tilting of cut workpiece parts, without being able to slide away from damage, the front sleeve end face of the sleeve preferably has on the inside and / or outside a run-on slope, e.g. in the form of a 45 ° bevel, on.

A further advantageous embodiment relates to a cutting gas nozzle for a laser processing head with an inner nozzle for forming a core flow and with an annular nozzle surrounding the inner nozzle to form a ring flow. In this case, the segmented sleeve is arranged so that in the annular gap of the annular nozzle over the inner nozzle protruding sleeve is axially slidably guided between a rear and a front position to release the nozzle cross-sectional area of the annular gap nozzle in the two positions differently wide, in particular either lock or release.

Further advantages and advantageous embodiments of the subject invention will become apparent from the description, the claims and the drawings. Likewise, the features mentioned above and the features listed further can be used individually or in combination in any combination. The embodiments shown and described are not to be understood as exhaustive enumeration, but rather have exemplary character for the description of the invention.

• 1 eine erste erfindungsgemäße Schneidgasdüse mit einer verschiebbar geführten, segmentierten Hülse:
• 2a, 2b die in 1 gezeigte, segmentierte Hülse in einem Längsschnitt ( 2a) und einer Ansicht auf ihre untere Stirnseite (2b);
• 3 die in 1 gezeigte Schneidgasdüse beim Durchfahren einer innenliegenden Werkstückkontur, wobei die einzelnen Hülsensegmente der segmentierten Hülse unabhängig voneinander an der Werkstückkontur anliegen; und
• 4 eine zweite erfindungsgemäße Schneidgasdüse mit einer Ringspaltdüse und mit einer verschiebbar geführten, segmentierten Hülse, die in ihren beiden Endstellungen den Düsenquerschnitt der Ringspaltdüse unterschiedlich weit freigibt.

Show it:

• 1 a first cutting gas nozzle according to the invention with a slidably guided, segmented sleeve:
• 2a . 2 B in the 1 shown, segmented sleeve in a longitudinal section ( 2a ) and a view on its lower end face ( 2 B );
• 3 in the 1 cutting gas nozzle shown when passing through an internal workpiece contour, wherein the individual sleeve segments of the segmented sleeve rest independently of each other on the workpiece contour; and
• 4 a second cutting gas nozzle according to the invention with an annular gap nozzle and with a displaceably guided, segmented sleeve which releases the nozzle cross-section of the annular gap nozzle to different degrees in its two end positions.

In the following description of the drawing, identical reference numerals are used for identical or functionally identical components.

In the 1 cutting gas nozzle shown 1 is on a laser processing head 2 arranged and serves to a cutting gas on a by means of a laser beam 3 machined workpiece (eg sheet metal) 4 to judge.

The cutting gas nozzle 1 includes a nozzle body 5 with a central nozzle bore 6 and a nozzle opening 7 the nozzle bore 6 surrounding sleeve 8th on the outside of the nozzle body 5 is guided axially displaceably between a front and a rear end position and at least in its front end position on the nozzle body 5 protrudes. The front end position is through a on the nozzle body 6 screwed union nut 9 defines an outer ring collar 10 the sleeve 8th in the forward direction 11 engages and thereby the sleeve 8th on the nozzle body 5 holds.

The nozzle bore 6 is connected to a cutting gas supply (not shown), so that the cutting gas 12 and the through the nozzle hole 6 going laser beam 3 from the nozzle opening 7 leak out and onto the workpiece 4 be directed. Upstream of the nozzle opening 7 has the nozzle body 5 several of the nozzle bore 6 outgoing connection holes 13 which is in an annulus 14 lead in the forward direction 11 through the rear sleeve end face 15a is limited. Due to the cutting gas pressure, the sleeve 8th in the forward direction 11 moved until it's in the front end position with its collar 10 at the union nut 9 is applied. The rear sleeve end face 15a is significantly larger than the front sleeve end face 15b so that the pressure difference between the nozzle interior and the environment advancing the sleeve 8th in the forward direction 11 and already on the workpiece 4 attached sleeve 8th a contact force of the sleeve 8th on the workpiece 4 causes, which is proportional to the cutting gas pressure. Through this pressure-proportional suspension of the sleeve 8th is a lifting of the sleeve 8th prevented by the workpiece surface. Pushing back the sleeve 8th in reverse direction 16 up to the rear end position takes place by varying widely lowering the cutting gas nozzle 1 to the workpiece 4 , causing the sleeve 8th on the workpiece 4 and then pushed back.

As in 2a and 2 B shown is the sleeve 8th from several, in each case identical sleeve segments 17 assembled, which are guided axially displaceable relative to each other. The sleeve 8th or the sleeve segments 17 are formed from an electrically non-conductive sleeve material, in particular polyetheretherketone. The individual sleeve segments 17 can each be independent of each other and relative to each other on the nozzle body 5 move axially. The sleeve segments 17 grip with in cross-section hook-shaped peripheral sides 18 each mutually engage with each other and thereby engage behind each other in the circumferential direction of the sleeve 8th , whereby on the one hand they are held captive against each other and on the other hand are each guided axially displaceable relative to each other. The sleeve segments 17 be by their hook-shaped peripheral sides 18 to the sleeve 8th put together, on the nozzle body 5 pushed on and with the union nut 9 secured. As in 2 B The hook-shaped peripheral sides can be shown 18 as helical or semi-annular arms 19 be formed, the complementary mesh. In any case, grip the sleeve segments 17 both in the circumferential direction and in the radial direction in such a way that they can not be separated from each other by a radially outward force, such as the applied process gas pressure.

The segmented sleeve 8th closes a gap between cutting gas nozzle during the laser cutting process 1 and workpiece 4 better than a non-segmented sleeve. This results in an increased gas flow in the laser-cut kerf of the workpiece 4 also possible with reduced cutting gas pressures.

The segmentation of the sleeve 8th allows a contour adjustment of the sleeve 8th even in narrow contour radii, as they often occur, for example, when laser cutting 3D body components. 3 shows such a workpiece 4 with a small inner radius 20 , The segments 17 the sleeve 8th move according to the contour of the workpiece surface to be machined so that the smallest possible gap between sleeve segment 17 and workpiece surface remains.

From the cutting gas nozzle 1 of the 1 is different in the 4 cutting gas nozzle shown 1' in that here the cutting gas nozzle 1' an inner nozzle 21 with the nozzle opening 7 for the formation of a core flow 22 and one the inner nozzle 21 surrounding annular gap nozzle 23 with an annular gap 24 to form a ring flow 25 having. The segmented sleeve 8th is with its outer ring collar 10 on the outside wall 26 of the annulus 14 guided axially displaceable between a front and a rear end position. The sleeve 8th forms a valve sleeve, which in its rear end position on the outer wall 27 the inner nozzle rests and thereby from the annulus 14 outgoing annular gap 24 locks and in all other positions the annular gap 24 releases.

As in the 1 to 4 shown, the front sleeve end face 15b the sleeve 8th inside and / or outside a run-in slope 28a . 28b , eg in the form of a 45 ° bevel, in order to be able to slide over slight steps in the workpiece surface, as can occur, for example, due to tilting of cut workpiece parts, without damaging them.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2014/072609 A1 [0002, 0005]
• DE 19853735 C1 [0006]

Claims (12)

Cutting gas nozzle (1, 1 ') for a laser processing head (2), with a nozzle body (5) having a nozzle opening (7), and with a sleeve (8) surrounding the nozzle opening (7), which is axially displaceable on the nozzle body (5) is and projects beyond the nozzle body (5), at least in its front end position, characterized in that the sleeve (8) is composed of a plurality of axially displaceably guided sleeve segments (17). Cutting gas nozzle after Claim 1 , characterized in that at least some of the sleeve segments (17), in particular all sleeve segments (17), are guided axially displaceably directly on the nozzle body (5). Cutting gas nozzle after Claim 1 or 2 , characterized in that at least some of the sleeve segments (17), in particular all sleeve segments (17), are guided on each of their mutually facing peripheral sides (18) in each case axially displaceable. Cutting gas nozzle according to one of the preceding claims, characterized in that at least some of the sleeve segments (17), in particular all sleeve segments (17), with their mutually facing peripheral sides (18) respectively interlock, in particular engage behind each other in the circumferential direction. Cutting gas nozzle according to one of the preceding claims, characterized in that at least some of the sleeve segments (17), in particular all sleeve segments (17), with hook-shaped in cross-section peripheral sides (18) each mutually engage and are guided axially displaceable relative to each other. Cutting gas nozzle according to one of the preceding claims, characterized in that the sleeve (8) is composed of identical sleeve segments (17). Cutting gas nozzle according to one of the preceding claims, characterized in that the sleeve (8) is formed from an electrically non-conductive sleeve material, in particular polyetheretherketone. Cutting gas nozzle according to one of the preceding claims, characterized in that the sleeve segments (17) are biased independently of one another in each case towards their front end position. Cutting gas nozzle according to one of the preceding claims, characterized in that the front sleeve end face (15b) of the sleeve (8) on the inside and / or outside a run-on slope (28a, 28b). Cutting gas nozzle according to one of the preceding claims, characterized in that that surface portion of the sleeve (8), on which a cutting gas pressure acts in the forward direction during operation, is greater than the surface portion on which the cutting gas pressure acts in the reverse direction during operation. Cutting gas nozzle according to one of the preceding claims, characterized in that the sleeve (8) in its two end positions, the nozzle cross-sectional area of the nozzle opening (7) surrounding annular gap nozzle (23) releases different levels. Cutting gas nozzle after Claim 10 , characterized in that the sleeve (8) in an annular gap (24) of the annular gap nozzle (23) for forming a ring flow (25) is arranged.

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