DE102016108162A1 - Method for the introduction of heat by means of a beam-based energy source, in particular a laser, induced chemical abrasion, in particular microtubing, and apparatus for carrying it out - Google Patents

Abstract

A process for the introduction of heat by means of a beam-based energy source, in particular a laser, induced chemical erosion, in particular microtubing, comprising: moving a Lichtleitrohres in a by an active medium for local dissolution laved or embedded therein workpiece, whereby through the Lichtleitrohr also effective medium for local dissolution of the material the workpiece is passed to the workpiece and wherein the jet of an energy source is directed onto the workpiece through the jacket of the light guide tube and / or the active medium in the light guide tube, and advancing the Lichtleitrohres, preferably the material dissolution front following, in the depth of the workpiece, and device to carry it out.

Description

The present invention relates to a method for the chemical introduction by means of a jet-based energy source, in particular a laser, induced chemical abrasion, in particular micro-drilling, and a device for carrying out the same.

The production of, for example, micro-bores with a high aspect ratio is possible only with a few technical methods. Such microbores are used, for example, in injection nozzles or as microfluidic channels. One of these methods is electrochemical micro-drilling, which, however, does not allow for variation of the bore cross-section during the drilling process.

In general, during chemical removal, the material reacts, in direct reaction with the active medium, into a compound which is liquid or at least easily removable. This often requires the delivery of a heat of reaction.

The basic principle of electrochemical machining (ECM) is that of an electrolytic cell in which a system of workpiece-electrolyte tooling forms the electrolytic cell in which, with the use of suitable electrolyte solutions, the anode goes into solution due to charge exchange processes , Between a workpiece (anode) and a tool (cathode) flows through a machining gap an electrolyte solution with the highest possible speed, wherein at the cathode hydrogen ions are discharged. The metal ions formed at the anode react with corresponding reactants, eg. Example, in basic electrolytes with OH ions of the electrolyte to form metal hydroxide compounds, which are carried along by the flowing electrolyte and transported away. Areas of application for electrochemical removal include aerospace technology (compressor and turbine blades (film cooling), turbine disks), drive technology, the food industry and medical technology.

The DE 199 60 790 A1 discloses an electrode for electrochemical drilling of workpieces, wherein the electrode has a hollow cylindrical shape and on the one hand serves as an electrical conductor for applying an electrical voltage and on the other hand can lead in its interior an electrolyte to the processing area in the workpiece.

From the DE 10 2004 054 587 B3 results in a method for electrochemical drilling of workpieces, is predrilled by means of laser drilling.

In the DE 10 2007 051 408 A1 For example, the caustic of a laser beam is used to create a bottleneck comet in a predrilled hole.

The US 2014 0210 116 A1 discloses a surgical instrument for laser treatment. The light is guided by a tubular optical waveguide from the light source to the processing location.

From the DE 11 2014 002 432 T5 results in an electrochemical process in which an electrolyte is passed through a flexible tubular electrode. The method can be used to produce curved holes.

The present invention is therefore based on the object of providing a method for the reproducible drilling of holes and grooves with a defined geometry having diameters in the range of about 50 μm to about 500 μm and an aspect ratio of about 1 to about 100.

According to a first aspect of the invention, this object is achieved by a method for chemical abrasion induced by heat input by means of a beam-based energy source, in particular a laser, in particular microtubing, comprising: moving a light guide tube into a workpiece surrounded by an active medium for local dissolution or embedded therein; wherein through the Lichtleitrohr also active medium for local dissolution of the material of the workpiece is passed to the workpiece and being directed through the jacket of the Lichtleitrohres and / or the active medium in the Lichtleitrohr the beam of an energy source on the workpiece, and advancing the Lichtleitrohres, preferably the Following material resolution front, in the depth of the workpiece.

The energy source can be used both in pulsed and in continuous operation.

The active medium may be, for example, an electrolyte. For example, the beam may be a light beam in the visible or non-visible range.

Furthermore, this object is achieved by a device for the introduction of heat by means of a beam-based energy source, in particular a laser, induced chemical erosion, in particular microtubing, comprising: a Lichtleitrohr, a Wirkmediumzuführeinrichtung for Zufühhren an active medium to the Lichtleitrohr and passing it through the Lichtleitrohr, a beam-based energy source , a beam injection device for coupling a beam of the energy source in the jacket of the Lichtleitrohres and / or in the active medium in the Lichtleitrohr and directing the same on a workpiece and a traversing device for controlled by a control device method of the workpiece and the Lichtleitrohres relative to each other.

According to a particular embodiment of the method, when moving the light guide tube into the workpiece, the beam of the energy source is directed onto the workpiece only by the active medium in the light guide tube.

In particular, it may be provided that at least during a portion of advancing the Lichtleitrohres the beam of the energy source is directed only or through the mantle of the Lichtleitrohres on the workpiece.

Advantageously, the beam of the energy source is deflected out of the jacket of the light guide tube to the outside of the light guide tube into the workpiece.

According to another particular embodiment of the present invention, the workpiece and the Lichtleitrohr are electrically conductive and at least temporarily applied an electrical voltage between the Lichtleitrohr and the workpiece. For example, the Lichtleitrohr consist of a glass or polymer fiber or an electrically conductive metal or be prepared

Alternatively, the workpiece and the Lichtleitrohr are electrically conductive and at least during a portion of advancing an electrical voltage between the Lichtleitrohr and the workpiece is applied.

Again, it can be provided that the Lichtleitrohr is provided in the region of its end facing the workpiece with the exception of an annular gap with an electrically non-conductive layer.

Conveniently, the feed rate is varied. This makes it possible to achieve variable "drilling cross sections".

In addition or alternatively, the distance between the front end of the Lichtleitrohres and the workpiece is favorably varied. As a result, additional "drilling sections" can be achieved. A greater distance between the front end of the Lichtleitrohres and the workpiece surface within the "bore" leads, due to the Strahlkaustik at the end of the Lichtleitrohrs, to an illumination of the Bohrlungenlungen and thus to a material dissolution and enlargement of the cross section.

According to another particular embodiment of the present invention, advancement into the depth of the workpiece is followed by advancement parallel to the surface of the workpiece. A larger distance between the front end of the Lichtleitrohrs and the workpiece surface within the "bore" leads, due to the Strahlkaustik at the end of the Lichtleitrohres, to an illumination of the Bohrwandlung and thus to a material dissolution and enlargement of the cross section.

In particular, it may be provided that the steps of moving the Lichtleitrohres in the workpiece, the advancement of the Lichtleitrohres in the depth of the workpiece and the advancing parallel to the surface of the workpiece are repeated at least once in succession.

Conveniently, in the device, the Lichtleitrohr is electrically conductive.

According to a particular embodiment of the present invention, it has a voltage source for applying an electrical voltage between the workpiece and the light guide tube.

Advantageously, the Lichtleitrohr is provided in the region of one of its two ends with the exception of an annular gap with an electrically non-conductive layer.

Finally, in the region of one of its two ends, the light guide tube can have a deflection device for deflecting the beam of the energy source to the outside of the light guide tube. For example, the Lichtleitrohr of a translucent material such. As glass or polymer exist.

The invention is based on the surprising finding that holes and, for example, grooves with small dimensions can be produced by means of the method according to the invention and the device according to the invention. This is possible, at least in a particular embodiment, also in a relatively large depth in, in particular metallic, workpieces. For this purpose, a tubular electrode or a tubular optical waveguide is retracted into the workpiece. When a laser is used, the method may also be referred to as a laser chemical process.

In at least one particular embodiment of the present invention, an electrolyte flows through the tubular electrode or the tubular optical waveguide. Through the tubular electrode or the tubular optical waveguide is in a particular embodiment a Laser beam fed, which heats the workpiece, so that in conjunction with the active medium or electrolyte of the material is dissolved.

In addition, according to a particular embodiment of the present invention, the change in the distance of the front end of the Lichtleitrohres to the workpiece or material, the diameter of a bore during the process locally adapt, so that with the method, at least in a particular embodiment, undercuts can be made.

• – Bohrungen mit einem Durchmesser von ≥ 50 μm und insbesondere von circa 50 μm bis circa 500 μm und/oder einem Aspektverhältnis im Bereich von circa 1 bis circa 100 und insbesondere von ≥ 10 bis circa 100
• – Schräge Bohrungen in einem Winkel von circa 10° bis circa 90° zur Werkstückoberfläche
• – Bohrungen mit variierendem Querschnitt bis zu einem Faktor von ca. 5 Bohrungen mit Hinterschneidungen, deren Querschnitt bis zum Zehnfachen des Bohrungsdurchmessers entspricht
• – Kavitäten (Langlöcher) mit Apektverhältnissen im Bereich von circa 1 bis circa 100 und bevorzugt von circa 10 bis circa 100.

At least in particular embodiments, the following geometries can be achieved:

• - Holes with a diameter of ≥ 50 microns and in particular from about 50 microns to about 500 microns and / or an aspect ratio in the range of about 1 to about 100 and in particular from ≥ 10 to about 100
• - Slanted holes at an angle of about 10 ° to about 90 ° to the workpiece surface
• - Holes with varying cross section up to a factor of approximately 5 holes with undercuts, the cross section of which corresponds to ten times the bore diameter
• - Cavities (slots) with Apektverhältnissen in the range of about 1 to about 100 and preferably from about 10 to about 100.

The method and the device are used, at least in special embodiments, for laser-induced microfill drilling in the purely chemical to thermochemical temperature regime.

Further features and advantages of the invention will become apparent from the appended claims and the following description in which several embodiments are explained in detail with reference to the schematic drawings. It shows / show:

1 to 3 Steps of a laser induced microtubing method according to a first particular embodiment of the present invention;

4 to 6 Steps of a laser induced microtubing method according to a second particular embodiment of the present invention;

7 to 9 Steps of a laser-induced microtubing method according to a third particular embodiment of the present invention;

10 to 12 Steps of a laser induced microtubing method according to a fourth specific embodiment of the present invention;

13 to 15 a method for introducing by laser heat induced electrochemical Abtragen to form a slot or a (deep) groove according to a particular embodiment of the present invention;

16 a perspective view and a sectional view of a Lichtleitrohr (with electrolyte) according to a first embodiment; and

17 a perspective view and a sectional view of a Lichtleitrohr (with electrolyte) according to a second embodiment.

To carry out the procedures described in the 1 to 3 and 13 to 15 [For the method according to the 13 to 15 (Production of a groove), other device variants can be used (especially those from the 7 to 9 )] becomes a device 100 used according to a first particular embodiment of the present invention, which is a Lichtleitrohr 6a (see also 16 ; therein the laser beam is simplified point and annular shown; but it does not have to be punctiform or annular), a Wirkmediumzuführeinrichtung 12 who have a Wirkmediumzufuhrschlauch 4 for supplying an active medium in the form of, for example, an electrolyte 5 in a Wirkmediumkammer 3 that with the rear end 6c the Lichtleitrohres 6a for supplying the electrolyte 5 to the light pipe 6a and passing it through the Lichtleitrohr 6a is in fluid communication comprises, a beam-based energy source in the form of a laser (not shown), a beam injection device for coupling a laser beam 13 in the coat 6e the Lichtleitrohres and / or in the electrolyte in the Lichtleitrohr and directing the same on a workpiece 9 wherein the beam injection device is a collimator 2 and an associated optical fiber 1 for guiding the laser beam 13 from the laser (not shown) to the collimator, and traversing means (not shown) to the workpiece controlled by a control means (not shown) 9 and the Lichtleitrohres 6a relative to each other, being from the laser via the optical fiber 1 and the collimator 2 supplied laser beam 13 through a protective glass 11 in the Wirkmediumkammer 3 it can be coupled in such a way that it passes through the active medium chamber 3 collinear in the rear end 6c the Lichtleitrohres either only through the jacket 6e or only through the central region of the Lichtleitrohres 6a or through both to the front end 6d the Lichtleitrohres is performed.

Also, the device comprises a pump (not shown) for supplying the active medium and a kind of chemical cell (not shown) or a catch basin (not shown).

In the 1 becomes the device 100 over the workpiece 9 , which is surrounded by an electrolyte (not shown), positioned. The electrolyte, which is the workpiece 9 surrounds, and the supplied electrolyte are preferably identical. Subsequently, via the Wirkmediumzuführeinrichtung 12 the electrolyte 5 in the Wirkmediumkammer 3 and subsequently into the light pipe 6a directed. For a laser-induced material resolution of the workpiece, the laser beam 13 optionally in the coat 6e the Lichtleitrohres 6a or coaxially coupled into the electrolyte jet and onto the workpiece 9 directed.

The heating of the surface of the workpiece 9 through the laser beam 13 (The laser beam provides the reaction in principle) triggers a chemical reaction and thus the material resolution (see 2 ).

By a feed in workpiece direction (feed direction V, see 3 ), following the material dissolution front, the device penetrates 100 into the workpiece 9 and creates a cavity (bore / cavity 8th ), which is larger in cross-section than the diameter D of the Lichtleitrohres 6a (please refer 3 ).

Although not expressly stated so far, the methods described herein may encompass more or fewer steps than described herein.

That in the 4 to 6 The method shown differs from that in the 1 to 3 shown method in that even holes with undercuts can be generated. For this purpose, a modified Lichtleitrohr 6a used. This indicates at its front end 6d in the coat 6e a deflection device 104 for deflecting a laser beam to the outside of the Lichtleitrohres 6a into the workpiece 9 on.

In the 4 becomes the device 100 over the workpiece 9 , which is surrounded by an electrolyte (not shown), positioned. Subsequently, via the Wirkmediumzuführeinrichtung 12 an electrolyte 5 in the Wirkmediumkammer 3 and then into the light pipe 6a directed. For a laser-induced material resolution, the laser beam 13 initially coupled coaxially into the electrolyte jet and onto the workpiece 9 directed. The heating of the surface of the workpiece 9 through the laser beam 13 triggers a chemical reaction and thus a material dissolution. By a feed in the workpiece direction (feed direction V), following the material resolution front, the device penetrates 100 into the workpiece 9 and creates a cavity (bore / cavity 8th ), which are larger in cross-section than the diameter D of the Lichtleitrohres 6a is.

Subsequently (see 5 ) becomes the laser beam 13 - instead of in the electrolyte jet - in the jacket 6e the Lichtleitrohres 6a coupled and over the deflection 104 directed to the sides. The heating of the bore wall triggers a chemical reaction and thus a material dissolution. It creates an undercut 106 ,

After that, the laser beam 13 again coaxially coupled into the electrolyte jet and drilling continues (see 6 ).

That in the 7 to 9 The method shown differs from that in the 1 to 3 shown method in that in addition an electrical voltage between the Lichtleitrohr 6a and the workpiece 9 is created. These are both the workpiece 9 as well as the light pipe 6a electrically conductive and has the device 100 a voltage source 108 on. This can be a elecktrochemisches Abtragen realize.

As is clear from the 7 results, the device becomes 100 over the workpiece 9 which is bypassed by an electrolyte (not shown). Subsequently, via the Wirkmediumzuführeinrichtung 12 an electrolyte 5 in the Wirkmediumkammer 3 and subsequently into the light pipe 6a directed. For a laser-induced material resolution, the laser beam 13 coaxially coupled into the electrolyte jet and onto the workpiece 9 directed.

The heating of the surface of the workpiece 9 through the laser beam 13 triggers a chemical reaction and thus a material dissolution. For electrically assisting material dissolution, an external voltage can additionally be generated by means of the voltage source 108 be created (see 8th ). By a feed in the workpiece direction (feed direction V), following the material resolution front, the device penetrates 100 into the workpiece 9 and creates a cavity (bore / cavity 8th ), which is larger in cross-section than the diameter D of the Lichtleitrohres 6a , which can also be referred to as an electrode in such a case.

This in 10 to 12 The method shown in principle represents a combination of in the 4 to 6 and 7 to 9 In principle, first of all, pre-drilling takes place and then producing the final borehole shape (shaping drilling).

The device 100 has a light pipe 6b on how it is in the 17 (the laser beam 13 is also simplified as punctiform) is shown. The light pipe 6b is with the exception of an annular gap 110 in the area of its front end 6d with an electrically non-conductive layer 15 or protective layer.

According to 10 becomes the device 100 over the workpiece 9 , which is surrounded by an electrolyte (not shown), positioned. About the Wirkmediumzuführeinrichtung 12 becomes an electrolyte 5 in the Wirkmediumkammer 3 and then into the Lichtleitrohr 6b directed. For laser-induced material resolution of the laser beam 13 coaxially coupled into the electrolyte jet and onto the workpiece 9 directed. The heating of the surface of the workpiece 9 by means of the laser beam 13 triggers a chemical reaction and thus a material dissolution. Following a feed in the workpiece direction (feed direction V) of the material resolution front, the device penetrates 100 into the workpiece 9 and creates a cavity (bore / cavity 8th ), which is larger in cross-section than the diameter D of the Lichtleitrohres 6b ,

Subsequently (see 11 ) becomes the laser beam 13 switched off and the voltage source 108 switched on. This induces at the annular gap 110 the Lichtleitrohres 6b an electric field. This leads to a dissolution of material at the bore wall. It creates an undercut 106 ,

After that (see 12 ) becomes the voltage source 108 switched off again and the laser beam 13 again coaxially coupled into the electrolyte jet and the drilling process continued.

By means of in the 13 to 15 shown method can be, for example, a slot or a deep groove 112 in a workpiece 9 form by removal. As before, for example, in the 1 and 2 shown, the device becomes 100 above the workpiece 9 , which is surrounded by an electrolyte (not shown), positioned (see 13 ). Subsequently, via the Wirkmediumzuführeinrichtung 12 an electrolyte 5 in the Wirkmediumkammer 3 and subsequently into the light pipe 6a directed. The laser-induced material resolution is a laser beam 13 on the workpiece 9 directed. The heating of the surface of the workpiece 9 through the laser beam 13 triggers a chemical reaction and thus a material dissolution. Following a feed in the workpiece direction (feed direction V) of the material resolution front, the device penetrates 100 into the workpiece 9 and generates a shallow cavity, which is larger in cross-section than the diameter D of the Lichtleitrohres 6a ,

Subsequently (see 14 ), a feed of the device takes place 100 transverse to the bore direction along the surface of the workpiece 9 , It is introduced a flat elongated cavity in the material.

By repeating the in the 13 and 14 shown method steps penetrates the device 100 further into the workpiece 9 and it creates the deep groove 112 (please refer 15 ).

The diameter D of the Lichtleitrohres 6a respectively. 6b Depending on the application, it can be between approx. 40 μm and approx. 550 μm. The maximum length of the Lichtleitrohres may be depending on their diameter D at about 55 mm.

Exemplary parameters in the purely chemical resolution range may look as follows:
Laser power: about 0.1 watts to 5 watts
Pulse duration: approx. 100 μs to cw (continuous wave)
Electrolytes: acid, basic and neutral aqueous solutions
Flow rates: approx. 0.1 m / s to approx. 20 m / s.

Exemplary parameters in the thermochemical resolution range may be as follows:
Laser power: about 1 watt to about 200 watts
Pulse duration: approx. 5 ps - cw (continuous wave)
Electrolytes: acid, basic and neutral aqueous solutions
Flow rates: approx. 0.1 m / s to approx. 20 m / s.

Optionally, for example, an annular, circular, for example Gauss or top hat, or an interconnected intensity distribution on the workpiece can be realized.

The features of the invention disclosed in the present description, in the drawings and in the claims may be essential both individually and in any desired combinations for the realization of the invention in its various embodiments.

LIST OF REFERENCE NUMBERS

1

optical fiber

2

collimator

3

active medium

4

Active medium supply hose

5

electrolyte

6a

light pipe

6b

light pipe

6c

rear end

6d

front end

6e

coat

8th

Bore / cavity

9

workpiece

10

Wirkmedium- / beam exit

11

protective glass

12

Active medium supply device

13

laser beam

14

Active medium flow direction

15

layer

16

E-field / beam emitter

100

contraption

104

deflecting

106

undercut

108

voltage source

110

annular gap

112

groove

D

Diameter of the light pipe

V

feed direction

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

• DE 19960790 A1 [0005]
• DE 102004054587 B3 [0006]
• DE 102007051408 A1 [0007]
• US 20140210116 A1 [0008]
• DE 112014002432 T5 [0009]

Claims (16)

Method for inducing chemical abrasion induced by heat input by means of a beam-based energy source, in particular a laser, in particular microtubing, comprising: moving a light-conducting tube ( 6a ; 6b ) in a workpiece surrounded by an active medium for local dissolution or embedded therein ( 9 ), wherein through the light guide and active medium for local dissolution of the material of the workpiece is passed through to the workpiece and wherein through the jacket ( 6e ) of the Lichtleitrohres and / or the active medium in the Lichtleitrohr the beam of an energy source is directed to the workpiece, and - advancing the Lichtleitrohres ( 6a ; 6b ), preferably following the material dissolution front, into the depth of the workpiece ( 9 ). Method according to claim 1, wherein during movement of the light guide tube ( 6a ; 6b ) in the workpiece, the beam of the energy source only by the active medium in the Lichtleitrohr on the workpiece ( 9 ). Method according to claim 2, wherein at least during a part of advancing the light guide tube ( 6a ; 6b ) the beam of the energy source only or through the mantle ( 6e ) of the Lichtleitrohres on the workpiece ( 9 ). Method according to claim 3, wherein the beam of the energy source is removed from the jacket ( 6e ) of the Lichtleitrohres ( 6a ; 6b ) to the outside of the Lichtleitrohres in the workpiece ( 9 ) is deflected. Method according to one of claims 2 to 4, wherein the workpiece ( 9 ) and the light pipe ( 6a ; 6b ) are electrically conductive and at least temporarily an electrical voltage between the Lichtleitrohr and the workpiece is applied. Method according to claim 1 or 2, wherein the workpiece ( 9 ) and the light pipe ( 6a ; 6b ) are electrically conductive and at least during a portion of advancing an electrical voltage between the Lichtleitrohr and the workpiece is applied. Method according to claim 5 or 6, wherein the light guide tube ( 6b ) in the area of its to the workpiece ( 9 ) end ( 6d ) with the exception of an annular gap ( 110 ) with an electrically non-conductive layer ( 15 ) is provided. Method according to one of the preceding claims, wherein the feed rate is varied. Method according to one of the preceding claims, wherein the distance between the front end of the Lichtleitrohres ( 6a ; 6b ) and the workpiece ( 9 ) is varied. Method according to claim 1, wherein advancing into the depth of the workpiece ( 9 ) follows a feed parallel to the surface of the workpiece. Method according to claim 10, wherein the steps of moving the light pipe ( 6a ; 6b ) in the workpiece ( 9 ), the advancement of the Lichtleitrohres in the depth of the workpiece and the advancement parallel to the surface of the workpiece at least once in succession be repeated. Contraption ( 100 ) for chemical abrasion induced by heat input by means of a beam-based energy source, in particular a laser, in particular microtubing, comprising: a light-conducting tube ( 6a ; 6b ), - a Wirkmediumzuführeinrichtung for supplying an active medium to Lichtleitrohr ( 6a ; 6b ) and passing it through the light guide tube, - a beam-based energy source, - a beam injection device for coupling a beam of the energy source into the jacket ( 6e ) of the Lichtleitrohres and / or in the active medium in the Lichtleitrohr and straightening the same on a workpiece ( 9 ) and - a traversing device for controlled by a control device method of the workpiece and the Lichtleitrohres relative to each other. Contraption ( 100 ) according to claim 12, wherein the light guide tube ( 6a ; 6b ) is electrically conductive. Contraption ( 100 ) according to claim 12, wherein it has a voltage source ( 108 ) for applying an electrical voltage between the workpiece ( 9 ) and the light pipe ( 6a ; 6b ) having. Contraption ( 100 ) according to one of claims 12 to 14, wherein the light guide tube ( 6b ) in the range of one ( 6d ) of its two ends ( 6c . 6d ) with the exception of an annular gap ( 110 ) with an electrically non-conductive layer ( 15 ) is provided. Device according to one of claims 12 to 14, wherein the Lichtleitrohr ( 6a ) in the range of one ( 6d ) of its two ends ( 6c . 6d ) a deflection device ( 104 ) for deflecting the beam of the energy source to the outside of the Lichtleitrohres.

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