DE102005019756A1 - Device for treating cylindrical surfaces especially for bearing surfaces of cylindrical openings in combustion engine blocks passes laser beam through a beam shaper to give circular cross-section before diverting onto the surface - Google Patents

Abstract

A device for treating cylindrical surfaces (F), especially bearing surfaces of cylindrical openings in combustion engine blocks (M), comprises a rotating housing (8) with a drive (7) and containing rotationally fixed optics (14) directed so as to divert a laser beam (L) onto the surface to be treated. The laser beam is passed through a beam shaper (18) to produce a circular cross-section before passing to the diverting optics. An independent claim is also included for a method that uses the above device.

Description

The The invention relates to an apparatus and a method for treating of cylindrically shaped surfaces, in particular for treating the raceways of the cylinder openings of internal combustion engine blocks, by means of a laser beam.

devices and methods of the above-mentioned kind are, for example used to on surfaces, which are subjected in practice to a friction load, to create a layer that, due to its surface structure, its structure or their composition a particularly high resistance to wear has. Usually For this purpose, a laser beam of high energy density is used. directed by means of suitable deflecting mirror on the surface to be treated becomes.

If a particular surface structure is to be produced in this way, then, as for example in the German patent specification DE 197 11 232 C2 described, a laser beam as long directed to the respective surface bearing base material until the desired leveling or roughening is achieved.

According to the publication EP 1 041 173 A1 European Patent Application 00 105 126.7 it is also possible to melt so far with a laser beam struck by him each surface portion that specifically causes a change in the structure or a change in the composition of the base material can be done by adding hardening elements.

One fundamental Problem in the treatment of larger surfaces by means of a laser beam is that the laser beam to be processed area usually due to the limited available energy does not fully capture can, but that the processing is carried out in sections got to. In order to accomplish this, an exact guidance of the Laser beam guaranteed be.

In addition to be increased the to the beam guide requirements by the fact that the intensity and the Intensity distribution, with which the laser beam detects the respective surface section, exactly set and must be adhered to in order to achieve the desired work result achieve.

One typical application for Methods and devices of the type in question is the treatment the treads the cylinder openings of internal combustion engines. These surfaces are in practical use exposed to high frictional loads due to the relative movements, which is in the cylinder opening each up and down moving piston executes.

Around cylindrically curved surfaces With a laser beam to edit, the laser beam is usually so led, that it is coaxial with a coincident with the axis of curvature Rotary axis of a deflection optics incident in the respective cylinder opening. at a first known device of the type specified the laser beam then hits a deflection device which is in the Usually from a combined with a lens system deflection mirror is formed and the laser beam in the direction of the treatment area projected. Due to the rotation of the deflection optics is circulating respectively exposed a strip of the surface to be treated with the laser beam. As soon as the processing of the respective strip section of treating area is completed, the entire optics is shifted in the axial direction and the portion adjacent to the previously processed strip processed. Alternatively, it is also possible, the deflection optics continuously to move in the axial direction of each processed opening, so that the laser beam in a helical Strip course over the surface to be processed guided becomes.

Of the Advantage of the rotation of the deflection optics is that clearly lower masses must be accelerated and decelerated, higher speeds can be realized the change from one cylinder to another faster and several cylinders of a block can be processed simultaneously can. Also for the adjustment of the optics in the axial direction can be used adjusting devices due to the low moving masses in terms of their positioning accuracy can be optimized.

Around a uniform illumination of the respective processed surface section to ensure, the laser beam is in the known devices by a Guided aperture. The opening this aperture is adjusted so that the edge areas, in the energy density of the laser beam is lower, shielded become. In this way, only the beam center, in the a relatively uniform energy distribution present, to the deflection optics.

the The success achieved by using the bezel is more significant Disadvantage over that a large Part of the total energy of the laser beam is lost at the aperture. This loss results in a relatively low efficiency the known devices.

Further Known instruments for beam rotation are mirror combinations and so-called Dove prisms. These are however in the Usually characterized by a high adjustment sensitivity, which makes a use is made difficult in intensive moving constructions.

A different possibility the leadership of the laser beam in the treatment of cylindrical running surfaces from JP 56-05923, known. In this known device for Treatment of the area of holes of components that are in relation to the longitudinal axis the bore are formed symmetrically, the laser beam via a during the Machining stationary deflection optics directed to the surface to be treated, while the cylindrical member about an axis parallel to the longitudinal axis of machined bore aligned rotation axis is rotated. To this Way can that be for the leadership of the laser beam optimized for a maximum yield of laser energy become.

To be able to use this possibility also in the processing of cylindrical surfaces of engine blocks for internal combustion engines, whose mass distribution is not symmetrical with respect to the longitudinal axis of the bore is in the DE 197 11 232 C1 has been proposed to compensate for imbalances, which occur during the rotation of the engine blocks to the stationary with respect to the rotation Umlenkoptik by counterweights. In this way, despite the large centrifugal forces occurring during the rotation of the component, a smooth, trouble-free circulation of the component during processing is to be ensured.

The devices in the DE 197 11 232 C1 described type with respect to the rotation of stationary deflection optics makes it possible to operate such a device speed-oriented. If at the same time the table on which the engine block is mounted can be raised and lowered, then a spiral contour can be traced on the cylinder surface to be machined, the slope of which depends on the axial extent of the laser spot imaged on the surface and the desired overlap of the individual strip sections.

The Advantages of the known, with a silent in relation to the rotation standing deflection optics equipped device is a disadvantage opposite that for the Turning the respective machined workpiece complex and powerful drives needed become. These must to be able to handle the respective workpiece at high speeds to rotate the axis of rotation defined by the position of the optics. Furthermore, the flexibility the plant regarding clock time adjustment and workpiece compatibility at a clearly limited such arrangement.

outgoing from the above Prior art, the object of the invention was to provide a Device and to provide a method with which at high efficiency the machining of cylindrically shaped surfaces, in particular the running surfaces of cylinder openings of internal combustion engines, possible is.

In Referring to a device for treating cylindrically shaped surfaces, in particular for treating the raceways of the cylinder openings of internal combustion engine blocks, by means of a laser beam, with a rotatably mounted and through a rotary drive about a rotation axis driven housing, in a deflecting optics for deflecting the laser beam from a in longitudinal direction of the housing directed direction in a deviating from this, to the working surface directionally fixed direction is the above solved this task that the laser beam, before it hits the deflection optics, passes through a beam shaping device, which preferably to him forms a jet with a substantially circular cross-section.

Accordingly is the above object also by a method for Treatment of cylindrically shaped surfaces, in particular for treatment the raceways of the cylinder opening of internal combustion engine blocks, by means of a laser beam, in which the laser beam with the aid of a Deflection optics from a longitudinal direction the surface to be processed directed direction in a deviating from this, directed to the surface to be machined Direction is deflected, with a relative movement between the to be machined surface and the deflection optics is generated by the deflection optics a rotation axis is rotated, thereby solved that the laser beam is formed into a jet having a circular cross-section having.

Becomes for generating the laser beam, a laser beam source, for example an excimer laser used, the design of a steel produced with non-round cross-section, so the rotation of the deflection optics leads to a change the beam position on the surface to be processed in dependence on the angle of rotation the consequence that the energy output and the orientation of the each captured by the laser beam surface portion is not constant are. This can be prevented in a conventional manner, that placed in the beam path in front of the deflection optics, a diaphragm is, which deals with the deflection optics about a common axis of rotation rotates.

By having existing if necessary Aperture and the deflection optics are illuminated by a circular cross-section, laser beam, an optimized efficiency is achieved. This is achieved by means of an imaging beam guidance system which, in conjunction with the components "if necessary existing diaphragm" and "deflection optics" rotating in the housing, permits the generation of a field which rotates about the cylinder center axis but is geometrically constant. In this way, it is ensured that the optical process parameters do not change during the machining of the respective cylinder surface.

Prefers For this purpose, the laser beam in the beam shaping device is reshaped, that he has a field with defined, i. predetermined energy distribution, maps. Dependent For this purpose, the beam-shaping optics can Reshape the laser beam so that it has an energy distribution, in certain areas of each of the laser beam detected Section of the surface to be machined has a deliberately increased intensity. Depending on however, it may also be appropriate for the respective processing task To transform the laser beam so that it has a homogeneous energy distribution having.

in the Case that a laser beam generating a non-circular cross-section Laser source is used, forms the inventively used beam shaping device in contrast to the conventional cylindrical lens arrays a round field, so especially in combination with a square aperture the losses are minimized by the hidden at the aperture Proportion of cross-sectional area of the laser beam. In a mechanical coupling of this Cover with the housing rotates the aperture in the round field at the same rotation speed like the case itself. Because with this concept the round field is not directly on the Cylinder surface but on a screen is generated and its location remains unchanged, takes over which also in the housing Integrated deflection optics, the projection of the aperture on the cylinder surface.

By doing also according to the invention the existing existing aperture and the deflection optics together to be rotated about a rotation axis, it is achieved that the aperture always is in an optimal position to the deflection optics.

simultaneously are in a device according to the invention drastically reduces the masses moving in the operation, where the deflection optics during the editing while resting the workpiece is turned. Due to the low moving masses, the deflection optics, an optional deflection and the like If necessary, rotate existing aperture at higher speeds, thereby also higher Repetition rates are possible. Those in the prior art, in which the workpieces are rotated, required Safety precautions are no longer required to this extent. Due to the much smaller dimensions and lower moving Masses can Simple and effective security elements are integrated.

in the Result enabled it the invention thus, with reduced technical complexity and increased flexibility surfaces to work with a laser beam. The integration of redundant Systems are supported by the invention. In this case, the device according to the invention operates practically independent from the illumination optics. This means that with the lighting optics creates a square field in the aperture plane and the aperture even running around can be. Due to its inventive design, the efficiency the device according to the invention even better than conventional devices of this type, where a rectangular box and a rectangular panel with each other be combined.

According to one first advantageous embodiment of the invention, if necessary existing aperture a right-angled, in particular square aperture on. With such a shaping of the aperture can be in a simple manner a uniform coverage the strip-shaped Ensure areas in which the laser beam is the one to be treated Surface overrun.

Based on a rectangular, in particular square aperture can the loss of laser beam energy at the diaphragm thereby additionally be minimized that the aperture has a polygonal aperture Form has. This can for example be formed by that at a rectangular in the basic form aperture Corner areas through short side pieces bevelled are. The chamfers in the corner areas it, the one swept from the aperture Area even closer to the cross-sectional shape of the striking on the panel To adapt to laser beam.

Depending on the cross-sectional shape of the laser beam generated by the laser source can be further improved, the adjustment of the aperture the cross-sectional shape of the laser beam and thus the energy yield in that the aperture polygonal or complete is designed around.

The deflection of the laser beam in the direction of the surface to be machined advantageously takes place via a monolithic system composed of, for example, a prism and a plano-convex spherical lens. This variant offers the advantage that the focus of the deflection optics is between the prism and the surface to be machined. In this way, the load of the prism is given only by the cross section of the incoming beam.

alternative however, a combination can also be used for a monolithic system from a deflection mirror and a lens or a plurality of lenses as deflection optics taking into account the position of the lens focus under consideration the damage threshold the deflection unit selected should be.

Around a far-reaching decoupling of the movement of the aperture and deflection system from the others for the leadership and reshaping the laser beam used optical elements to ensure it is convenient when the beam shaping device rotatably outside the housing is arranged. It transforms the laser beam in such a way that he hits the screen as a static lighting field.

Of the Diameter of the cross section of the laser beam after the Leaving the illumination optics illuminated illumination field is preferably sized to illuminate the largest diagonal of the aperture. For this purpose, the cross-sectional diameter can be adjusted so that it is essentially equal to the largest diagonal the aperture is, if necessary, a slight oversize is chosen, even in the case of Tolerances always the safe illumination of the aperture guarantee. By the diameter of the laser beam cross section on the largest diagonal the aperture is tuned even with a quadrangular, rectangular, in particular square shape of the aperture of the "lost" proportion of laser beam energy reduced to a minimum. Which in this way already opposite the Prior art achieved improvement in the efficiency can be further optimized that the corner areas of the aperture cut By making the aperture an aperture with a rectangular basic shape has, whose corner regions bevelled by short side pieces are. In this way, an even narrower diameter of the Laser beam generated lighting field produced and the on the aperture "lost" proportion of laser beam energy be further minimized. The capping of the corner areas of the aperture should be expediently so on the shape of the aperture be tuned that remains a flawless, well-defined and even coverage scored in each case on the machined surface exposed strip becomes.

A see further particularly practical embodiment of the invention vor, that in the beam path of the laser beam in front of the deflection optics translucent and rotatably with the housing connected deflection unit with plane-parallel to each other and obliquely to the longitudinal axis of the housing arranged passage surfaces for the Laser beam is arranged. If there is an aperture, it will be Diverter Conveniently arranged so that the deflection between the aperture and the deflecting optics is arranged. For this it may be advantageous, aperture, Position the deflection unit and the deflection optics together in a housing.

A particularly simple design of this deflection results in the process when the deflection unit is designed as a plate. When passing through the deflecting unit, the laser beam is transversely offset, so that its longitudinal axis offset after leaving the plate relative to the longitudinal axis of the housing runs. The measure of Offset is dependent from the angle at which the deflecting element against the longitudinal axis of the housing aslant is arranged, and the thickness of the respective deflection unit. The Use of such a deflection unit has the advantage that despite the rotating movement the deflection optics at a greater distance from the treated area can be arranged. In this way, especially in the Processing of interior surfaces of cylinder bores with small diameters a maximum distance between the deflection optics and the respectively processed surface section produce. Dependent from the spatial Circumstances, this may be appropriate excessive pollution to avoid the deflection optics. This pollution is a consequence Ablation of particles from the surface to be machined and the resulting, directed against the deflection optics particle flow. The ablation products move very much on one side high speed on the deflection optics too. On the other hand, they cool but also relatively fast. By the laser beam through the Deflection unit in accordance with the invention is deflected and the deflection optics with a correspondingly greater distance to each processed surface section can be arranged, is thus the largest possible distance between the last optically effective surface the deflection unit and the machined surface.

following the invention is based on a two embodiments performing Drawing closer explained. Each show schematically:

1 a device for laser-illuminating the running surfaces of cylinder openings of a Ver internal combustion engine in a partially cutaway view;

2 in the 1 shown device in a cross section along in 1 specified section line AA;

3 in the 1 shown device in a cross section along in 1 indicated section line BB;

4 a second apparatus for laser-illuminating the treads of cylinder openings of an internal combustion engine in a partially longitudinally sectioned view;

5 in the 4 shown device in a cross section along in 4 specified section line AA;

6 in the 4 shown device in a cross section along in 4 specified section line BB.

The in the 1 to 3 illustrated device 1 for laser imaging has a laser 2 which may, for example, be a so-called "excimer laser" of a type known per se. The one from the laser 2 generated laser beam L is via an optical guidance system 3 to a deflecting mirror 4 passed, by which the laser beam L is deflected with its central axis L _M in a direction parallel to the respective surface F to be processed. The leadership system 3 with the deflection mirror 4 is arranged at a distance above a further not shown clamping table of a clamping device, also not shown, on which the motor block M to be machined is fixed, of which in the figures only a small portion is shown. The engine block M may, for example, be a six-cylinder engine block for a passenger car internal combustion engine.

Furthermore, the device comprises 1 a rotary and actuator 7 , on whose output side a tubular, directed in the direction of the engine block M housing 8th is attached. By means of the rotary and actuator 7 can the case 8th with the elements contained in it in each case about a rotation axis D rotated and adjusted along the axis of rotation D.

The outer diameter D _{aG of} the tubular housing 8th is smaller by a suitable undersize than the diameter D _{iB of} the cylinder _opening Z to be machined of the engine block M. The length of the housing 8th is dimensioned so that the housing 8th can be moved with its free end portion in the cylinder opening Z over the entire height H, via which the surface F of the cylinder opening Z is to be processed. Here is the case 8th aligned in the cylinder opening Z such that its axis of rotation D coincides with the central longitudinal axis L _{Z of} the cylinder opening Z.

The housing 8th indicates at its upper, the deflection mirror 4 associated end face an inlet opening 10 on, through which the laser beam L in the housing 8th entry. Basically, directly in the entrance opening 10 be arranged a diaphragm. In the embodiment shown, however, is only shortly below the inlet opening 10 in the case 8th a panel 11 positioned, rotatably with the housing 8th connected is. The aperture 12 the aperture 11 is square and aligned so that its center with the axis of rotation D of the housing 8th coincides.

At a distance below the aperture 11 is designed as a plane-parallel plate, translucent deflection 13 arranged, which also rotatably with the housing 8th is connected and at an angle β is held at an angle to the rotational axis D angled. The through the aperture 12 with a coaxial with the axis of rotation D aligned central axis L _M passing, on the deflection 13 the incident laser beam L is passing through the deflection unit 13 so deflected that he leaves the diverter unit 13 offset with its central axis L _M relative to the axis of rotation D, but still axially parallel to the axis of rotation D from the deflection 13 exit.

Further below under the deflection unit 13 sits a preferably monolithically formed deflection optics 14 , which also rotatably with the housing 8th connected is. The deflection optics 14 is through a mirror 15 and a convex lens 16 formed, the focus between their curved end face and the surface to be machined F is located.

Adjacent to the lens 16 is in the peripheral wall of the housing 8th an outlet opening 17 formed by the of the deflection optics 14 deflected laser beam L free from the housing 8th exit.

Below the deflecting mirror 4 but before the laser beam L enters the housing 8th , is stationary a beam shaping device 18 arranged, which transforms the laser beam L so that it has a round cross section with a substantially defined energy distribution.

The position of the deflection optics 14 and their imaging behavior are tuned so that the region of the strongest focusing of the laser beam L preferably in the region of the outlet opening 17 is located, through which the laser beam L, the housing 8th leaves before it hits the surface F to be processed. This allows the width of the exit opening 17 on to reduce a minimum. The so narrow passage opening 17 protects the deflection optics 14 additionally in front of the ablation products dissolving from the surface F during processing.

The in the 4 to 6 illustrated device 100 for laser exposure is basically the same structure as the device described above 1 so that in the 4 to 6 for matching components and features the same reference numerals as in FIGS 1 to 3 used and subsequently only those between the devices 1 and 100 existing differences are described.

In the in the 4 to 6 The device shown is the housing 8th from a rotary drive 107 worn, the housing 8th can rotate about the rotation axis D, in contrast to the rotary and actuator 7 the device 1 however, it is not suitable for the housing 8th also to move in the axial direction along the axis of rotation D. To a relative movement between the engine block M and the housing 8th the device 100 to accomplish, the engine block M is stretched on a lifting table, not shown here, which raises the engine block M via a corresponding drive and lowers.

The aperture 111 the device 100 points in contrast to the aperture 11 the device has a circular aperture 112 on whose diameter D _B is smaller by a small undersize than the diameter D _L of the diaphragm 111 striking laser beam L.

In the beam direction below the aperture 111 sits like the device 1 a plate-shaped deflecting unit 113 leading to a greater offset compared to the baffle 13 the device 1 leads. This results in a larger distance between the last optical element and the processing surface.

In the device 100 is in the lower section of the case 8th in which the deflection optics 14 is disposed in the inner surface of the peripheral wall of the housing 8th a recess 119 formed. In this recess 119 is the deflection optics 14 set with their the peripheral wall side assigned. This way is in the device 100 a maximum distance of the lens 16 the deflection unit 14 made to the surface F to be processed. At the same time, the deflection unit 14 oriented in this way, that their incident surface 14a is aligned centrally to the central axis L _{M of} the laser beam L.

For exposure of the surface F to be processed, the housing 8th and the respective cylinder opening Z of the engine block M positioned to each other so that the longitudinal axis L _{Z of} the cylinder opening Z with the axis of rotation D of the housing 8th flees. Subsequently, the housing 8th at the device 1 by lowering the housing 8th and at the device 100 immersed by lifting the engine block M to the initial position of the machining in the cylinder port Z. By this time at the latest, the case 8th set in rotation about the axis of rotation D. The then in the housing 8th guided laser beam L strikes the aperture first 11 respectively. 111 ,

In the device 1 corresponds to the diameter of the illuminated by the laser beam L illumination field B of the diagonal of the square aperture 12 so that the size of the front panel 11 hidden edge portions of the laser beam L is reduced to a minimum. The one of the aperture 12 as a result of the rotation of the housing 8th swept area is in 3 by a dashed representation of different rotational positions of the aperture 12 indicated. The through the aperture 12 passing portion of the laser beam L has a square cross-sectional area.

The one through the aperture 11 respectively. 111 passing laser beam L falls through the entrance surface 14a on the mirror 15 the deflection optics 14 , From the mirror 15 the laser beam L is projected in the direction of the surface F to be processed and by the subsequently passed through lens 16 focused so that a clearly defined, clearly defined section of the incident on the surface F to be processed laser beam L is illuminated.

After the first circumferential strip of the surface F to be processed is finished, the housing becomes 8th further inserted into the cylinder opening Z until the deflection optics 14 is positioned relative to the surface F to be machined such that the circumferential strip of the surface F adjoining the first strip is swept by the laser beam L. Alternatively to a stepwise adjustment in the axial direction, the axial adjustment of the housing 8th also take place continuously relative to the engine block M, so that the laser beam L sweeps over a continuous, helical strip course.

The risk of leakage of a laser beam from the device according to the invention 1 respectively. 100 can be countered that the respective device is operated within a telescopically closable and openable, not shown here Umhausung.

1

contraption for laser imaging

2

laser

3

optical guidance system

4

deflecting

7

rotary and actuator

8th

casing

10

inlet opening

11

cover

12

aperture

13

Return unit

14

deflecting

14a

Incidence surface of the deflection optics 14

15

mirror

16

lens

17

outlet opening

18

Beamformer

100

contraption for laser imaging

107

rotary drive

111

cover

112

aperture

113

Return unit

119

recess

B

illumination field

D

axis of rotation

D _aG

Outer diameter of the tubular housing 8th

D _i

diameter the cylinder opening to be machined Z

D _B

Diameter of the aperture 112

D _L

diameter of the laser beam L

F

to working surface

H

Height above the the area F the cylinder opening Z

processed shall be

L

laser beam

L _M

central axis of the laser beam L

L _Z

longitudinal axis the cylinder opening Z

M

block

β

angle

Z

cylinder opening

Claims (19)

Apparatus for treating cylindrically shaped surfaces (F), in particular for treating the raceways of the cylinder openings (Z) of internal combustion engine blocks (M), by means of a laser beam (L), with a rotatably mounted and by a rotary drive ( 7 ) about a rotation axis (D) driven housing ( 8th ), in which a deflection optics ( 14 ) for deflecting the laser beam (L) from a longitudinal direction of the housing ( 8th ) directed direction in a deviating from this, in a direction directed to the surface to be machined (F) is rotationally fixed, characterized in that the laser beam (L), before being applied to the deflection optics ( 14 ), a beam-shaping device ( 18 ), which forms it into a jet of substantially circular cross-section. Apparatus according to claim 1, characterized in that between the beam shaping device ( 18 ) and the deflection optics ( 14 ) an aperture ( 11 . 111 ) is arranged. Device according to claim 2, characterized in that the diaphragm ( 11 ) a right-angled aperture ( 12 ) having. Device according to claim 3, characterized in that the aperture ( 12 ) is square. Device according to claim 2, characterized in that the diaphragm ( 11 ) an aperture ( 12 ), which is designed as a polygon. Device according to claim 1, characterized in that the diaphragm ( 111 ) a circular aperture ( 112 ) having. Device according to one of the preceding claims, characterized in that the beam-shaping device ( 18 ) outside the housing ( 8th ) is arranged stationary. Device according to one of the preceding claims, characterized in that the beam-shaping device ( 18 ) transforms the laser beam (L) such that it acts as a static illumination field on the diaphragm ( 11 ) meets. Device according to one of the preceding claims, characterized in that the diameter of the laser beam (L) after leaving the beam shaping device ( 18 ) is dimensioned such that it the aperture ( 12 ) completely illuminates. Device according to one of the preceding claims, characterized in that the housing ( 8th ) is tubular. Apparatus according to claim 9, characterized in that the axis of rotation (D) of the housing ( 8th ) is aligned coaxially with the longitudinal axis (L _Z ) of the cylinder opening (Z). Device according to one of the preceding claims, characterized in that in front of the deflection optics ( 14 ) a translucent and non-rotatable with the housing ( 8th ) connected deflection unit ( 13 ) with plane-parallel to each other and obliquely to the axis of rotation (D) of the housing ( 8th ) arranged passage surfaces for the laser beam (L) is arranged. Apparatus according to claim 12, characterized in that the deflection unit ( 13 . 113 ) when Plate is formed. Device according to one of the preceding claims, characterized in that the deflection optics ( 14 ) a mirror ( 15 ) for deflecting the laser beam (L) in the direction of the respective surface to be machined (F). Method for treating cylindrically shaped surfaces, in particular for treating the raceways of the cylinder opening (Z) of internal combustion engine blocks (M), by means of a laser beam (L), in which the laser beam is deflected by means of a deflection optics ( 14 ) is deflected from a directed in the longitudinal direction of the surface to be machined surface (F) in a deviating from this, directed to the surface to be machined (F) direction, wherein a relative movement between the surface to be machined (F) and the deflection optics ( 14 ) is generated by the fact that the deflection optics ( 14 ) is rotated about a rotation axis (D), characterized in that the laser beam (L) to a beam (L) is formed, which has a circular cross-section in the diaphragm plane. Method according to claim 15, characterized in that that the laser beam (L) is reshaped so that it over its Cross-section has a defined distribution of its energy density. Method according to claim 16, characterized in that that the laser beam (L) after forming a substantially homogeneous distribution of energy density has. A method according to claim 16 or 17, characterized in that the laser beam (L) is reshaped so that when it hits the diaphragm ( 14 ) forms a static illumination field. Method according to one of claims 15 to 18, characterized in that the laser beam (L) before its impact on the deflection optics ( 14 ) is deflected such that its central axis is arranged axially parallel to the axis of rotation (D), but offset from this.