DE202012007135U1 - Device for processing a workpiece with a laser beam - Google Patents

Abstract

Apparatus for processing cylindrical or tubular workpieces (W) by means of a laser (L) with: a rotary drive (M) with a chuck (30) for clamping and rotating the workpiece (W); a pair of rollers (20, 20) for rotatably supporting the workpiece (W); a laser device for processing the workpiece (W) while rotating the same.

Description

The invention relates to a device for processing a workpiece with a laser beam.

The laser machining of workpieces is a common manufacturing technique today. A known application is, for example, the precision machining of a tube with a jet tool. Processing methods are, for example, fineblanking, engraving, surface structuring or microwelding. In many known laser fine cutting systems in this case the workpiece to be machined is moved, wherein the beam direction of the laser beam remains fixed in the coordinate system of the machine. For machining a pipe, for example, it is displaced in the axial direction relative to the laser beam and rotated about its central longitudinal axis. In other words, the workpiece is moved under the laser beam. The outer contour of the workpiece is always formed on itself.

Such workpieces are thus cylindrical and extended in the longitudinal direction and the laser beam is aligned with a machining position on the workpiece, which is fixed with respect to the coordinate system of the machine in the circumferential direction of the workpiece with respect to its outer contour. In such a system, for example, a laser cutting of stents or other implants and instruments made of metals and plastics is performed, with accuracies of the sectional contour of well below 5 microns must be achieved. The type of workpiece guidance has a decisive influence on the achievable accuracy of the cutting contour.

An object in such a laser machining is therefore the centric and precise guiding of such workpieces of different diameters. To guide such workpieces different solutions are known.

It is known to guide the workpiece in a bushing guide, which has an opening whose inner diameter must correspond as exactly as possible to the outer diameter of the workpiece. Since such a bushing is not variable in diameter, it can not compensate, for example, tolerance-related changes in the outer diameter of the workpiece. The workpiece has play in the lead or blocks in this. Specially made bushings are required for each outer diameter of different workpieces.

A universal stent guide from ROFIN / Baasel Lasertechnik is also known, in which the workpiece is fixed in its longitudinal direction at the circumferential position on which the abovementioned machining position lies, on a stamp that is approximately 30 mm long and fixed relative to the machine is applied linearly. The stamp is associated with a relative to the machine (transverse to the workpiece) movably mounted prism, which presses the workpiece against the stamp. The prism is V-shaped, so that the workpiece abuts the prism again in the longitudinal direction along the length of the entire guide at two lay-up lines. The page centering is insufficient in the known guide, with a change in the pipe diameter results in an unwanted offset. The contact pressure is operator-unfriendly, not precise enough and only uniformly adjustable for the entire leadership. Due to the three investment lines, the guide pad is not clearly defined. Although the universal stent guide is within certain limits for pipes up to an outer diameter of about 1.5 mm, for pipe diameter from 2 mm, especially if these pipes are rather rigid, but the workpieces in the guide, resulting in a unwanted page offset leads.

From the US 2004/0004063 A1 a workpiece guide for stent applications is known. Here, V-shaped or cuboidal prisms are used for guiding, with two prisms each pushed into each other, resulting in a four-line support and thus to a static over-determination. A defined precise guidance is not possible with such an arrangement.

From the JP 2003 001 490 A For example, a tensioning device for butt welding joints is known in which a component is held by a punch in a V-shaped receptacle resulting in a three-line bearing.

Object of the present invention is therefore to provide an improved with respect to the leadership of the workpiece device for machining a workpiece with a laser beam.

This object is solved by the features of claim 1. Advantageous developments are defined in the dependent claims.

The invention is particularly aimed at workpieces that can be performed poorly with the known leadership principles.

On the one hand, these are workpieces which, due to the small diameter and / or the material properties, have too little flexural and torsional rigidity in order to be freely guided over a longer distance without assistance. The entrainment of the rollers here allows a continuous support of the workpiece, while in the principles described in the prior art at the beginning of machining a greater distance between the chuck in the rotatable drive shaft and the guide must exist, and the already machined workpiece is no longer performed ,

On the other hand, there are large diameter workpieces which have high flexural stiffness and, with the available diameter tolerances or slight distortion, cause high friction and shear forces in guide bushes or prisms. In these cases, the present invention offers the possibility of exerting high supporting forces on the workpiece via the rollers and pressure rollers without at the same time provoking high frictional forces in the contact points.

According to one aspect, there is provided an apparatus for machining cylindrical or tubular workpieces by means of a laser comprising:
a rotary drive with chuck or a rotatable chuck for clamping and rotating the workpiece;
a pair of rollers for rotatably supporting the (from the chuck projecting portion of the) workpiece;
a laser device for machining the workpiece during rotation thereof.

Preferably, further, a pressure roller or roller or ball is arranged as Andrückwälzkörper substantially opposite to the pair of rollers to press the workpiece with a defined force against the pair of rollers.

More preferably, the pair of rollers and / or the pressure roller or roller or ball is driven.

Preferably, the workpiece is pressed by means of the pressure roller or roller or ball with a contact pressure of about 0.1 N to about 50 N, preferably a contact pressure of about 1 N to about 20 N, against the pair of rollers.

More preferably, the rollers of the pair of rollers are interlocked.

Even more preferably, the rotatable chuck and the pair of rollers are arranged on a machine table which can be displaced relative to the laser device and / or the laser beam of the laser device is movable relative to the pair of rollers.

More preferably, the pair of rollers is driven via a coupled to the rotary drive of the chuck gear. Alternatively, the pair of rollers and the rotary drive may be directly driven by respective electric motors that are electronically coupled together.

Even more preferably, the pressure roller or roller or ball is pressed against the workpiece via a spring or a solid-state joint or a pneumatic cylinder.

1 shows a perspective view of the device.

2 shows another perspective view from a different angle.

3 shows a side view of the device.

4 shows front view of the device.

The invention relates to a workpiece guide for cylindrical components (ie pipes or solid material) of metals or plastics to be used in a laser processing machine. This is possible in different versions.

All versions have in common:
The device consists essentially of two parallel, about its own longitudinal axis rotatable rollers 20 , These rollers 20 are on a movable together with a rotation axis under the laser beam L at least in the X direction machine table 10 appropriate. In the space between and above the rollers 20 . 20 comes the workpiece W at rest via line contact on the rollers 20 . 20 to lie. In the direction of the longitudinal axis of the workpiece W to the rollers 20 . 20 There is no relative movement. In the circumferential direction of the workpiece W, it depends on the friction conditions, pressure forces, moments of inertia of the rollers 20 . 20 and acceleration of the workpiece W to unroll (no slip in the contact line) or sliding (slip in the contact line). The rollers 20 . 20 can either have a distance from each other or be interlocked by sections different diameters or recesses.

• 1. Nur das zylinderförmige Werkstück W wird angetrieben und rollt dabei aufgrund ausreichender Reibungskräfte in der Kontaktlinie in Umfangsrichtung auf den Walzen 20, 20 ab (reine Rollreibung). Damit das zylinderförmige oder rohrförmige Werkstück W die Rotation auf die nicht angetriebenen Walzen übertragen kann und nicht auf den Walzen 20, 20 hochrollt, kann es zusätzlich notwendig sein, es mittels eines kleinen Wälzkörpers, wie beispielsweise einer Rolle bzw. Andrückrolle bzw. Andrückwalze 25 oder einer Kugel auf der den Walzen 20, 20 gegenüberliegenden Seite an diese anzudrücken.
• 2. In einer anderen Ausführung für Fälle, in denen die Abrollbewegung nicht durch das Werkstück auf die Walzen 20, 20, übertragen werden kann, werden die Walzen 20, 20 zusätzlich über ein (nicht gezeigtes) Getriebe oder einen Direktantrieb so angetrieben, dass in den Kontaktlinien kein Schlupf entsteht (reine Rollreibung bzw. Abrollbedingung erfüllt).

Regarding the relative movement and forces between workpiece W and rollers 20 . 20 the following versions are to be distinguished:

• 1. Only the cylindrical workpiece W is driven and rolls due to sufficient frictional forces in the contact line in the circumferential direction on the rollers 20 . 20 off (pure rolling friction). So that the cylindrical or tubular workpiece W can transmit the rotation to the non-driven rollers and not on the rollers 20 . 20 Rolls up, it may be additionally necessary, it by means of a small rolling element, such as a roller or pressure roller or pressure roller 25 or a ball on the rollers 20 . 20 on the opposite side to press this.
• 2. In another embodiment for cases where the rolling motion does not pass through the workpiece onto the rollers 20 . 20 , can be transferred to the rollers 20 . 20 additionally driven via a (not shown) gear or a direct drive so that no slip occurs in the contact lines (pure rolling friction or Abrollbedingung met).

• 1. zylindrische Walzen mit einem Abstand zueinander.
• 2. Ineinander verschränkte Walzen: a) entweder Walzen, die abschnittsweise und alternierend unterschiedliche Außendurchmesser aufweisen und so ineinander verschränkt werden können oder sind. Diese würden eine volle oder mehrmalige Rotation des Werkstücks W erlauben, weisen aber ein erhebliches Trägheits- oder Inertialmoment auf. b) oder hohle Walzen, die auf einem Teil ihres Umfanges Aussparungen besitzen, die ebenfalls das Ineinanderverschränken der beiden Walzen ermöglichen. Da ein gewisser Teil des Umfangs zur Erhaltung der Stabilität der Walze durchgehend erhalten sein muss und sich die Walzen überdies gegenläufig bewegen, erlauben diese Aussparungen nur eine teilweise Rotation der Walzen. Wenn aber der Walzendurchmesser ausreichend groß gegenüber dem Werkstückdurchmesser ist, ermöglicht diese teilweise Rotation der Walzen eine vollständige oder sogar mehrmalige Rotation des Werkstücks, wobei zur vollständigen Bearbeitung der Zylinderoberfläche eine Rotation ausreichend ist. Die Synchronität der Walzen muss gewährleistet werden, um ein Blockieren der Walzen zu vermeiden. Dies kann beispielsweise durch ein Getriebe oder einen Direktantrieb gewährleistet werden, wie bereits beschrieben ist.

Regarding the execution of the distance of the rollers 20 . 20 (parallel or interlocked rollers) the following versions are possible:

• 1. cylindrical rollers with a distance from each other.
• 2. Intermeshed rolls: a) either rolls which in sections and alternately have different outer diameters and thus can be interlaced or are. These would allow a full or multiple rotation of the workpiece W, but have a significant inertial or Inertialmoment. b) or hollow rollers which have recesses on a part of their circumference, which also allow the interlocking of the two rollers. Since some of the circumference must be maintained throughout to maintain the stability of the roll and, moreover, the rolls move in opposite directions, these recesses permit only partial rotation of the rolls. However, if the roll diameter is sufficiently large relative to the workpiece diameter, this partial rotation of the rolls enables complete or even multiple rotation of the work piece, with sufficient rotation for complete machining of the cylinder surface. The synchronicity of the rollers must be ensured in order to avoid blocking of the rollers. This can be ensured for example by a transmission or a direct drive, as already described.

Possible modifications:

• - Replace the rollers by individual roles, which are z B mounted on a common axis, but are movable relative to each other;
• Arrangement of the rollers over the workpiece with pressure from below, which although a better accuracy of accuracy in the laser beam direction, but only for relatively stiff workpieces W is practicable.

LIST OF REFERENCE NUMBERS

10

machine table

20

roller pair

25

Andrückwälzkörper

30

chuck

L

laser beam

M

electric motor

W

workpiece

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

• US 2004/0004063 A1 [0007]
• JP 2003001490 A [0008]

Claims (10)

Device for machining cylindrical or tubular workpieces (W) by means of a laser (L) comprising: a rotary drive (M) with chuck ( 30 ) for clamping and rotating the workpiece (W); a pair of rollers ( 20 . 20 ) for rotatably supporting the workpiece (W); a laser device for working the workpiece (W) during rotation thereof. Apparatus according to claim 1, further comprising a pressure roller (10). 25 ) substantially opposite the pair of rollers ( 20 . 20 ) is arranged to move the workpiece (W) with a defined force against the pair of rollers ( 20 . 20 ). Device according to one of the preceding claims, wherein the pair of rollers ( 20 . 20 ) and / or the Andrückwälzkörper ( 25 ) is driven. Device according to one of the preceding claims, wherein the workpiece (W) by means of the Andrückwälzkörpers ( 25 ) with a contact force of about 0.1 N to about 50 N, preferably a contact pressure of about 1 N to about 20 N, against the pair of rollers ( 20 . 20 ) is pressed. Device according to one of the preceding claims, wherein the rollers ( 20 . 20 ) of the pair of rollers ( 20 . 20 ) are interlaced. Device according to one of the preceding claims, wherein the chuck ( 30 ) and the pair of rollers ( 20 . 20 ) on a machine table which can be moved relative to the laser device ( 10 ) are arranged and / or the laser beam of the Device according to one of the preceding claims, wherein the Andrückwälzkörper ( 25 ) has at least one roller, roller or ball or the like. Device according to one of the preceding claims, wherein the pair of rollers ( 20 . 20 ) via a with the rotary drive of the chuck ( 30 ) coupled gear are driven. Device according to one of the preceding claims 1 to 7, wherein the pair of rollers ( 20 . 20 ) and the rotary drive of the chuck ( 30 ) are directly driven by electric motors which are electronically coupled together. Device according to one of the preceding claims, wherein the Andrückwälzkörper ( 25 ) is pressed against the workpiece (W) via a spring or a solid-state joint or a pneumatic cylinder.

Images