DE102009013143B3 - Device for hardening coating of motor vehicle chassis by electron irradiation, has irradiation chamber with holding device for arranging chassis, where electron sources are arranged in irradiation chamber - Google Patents

Abstract

The device (10) has an irradiation chamber (12) with a holding device for arranging a chassis. The electron sources (18) are arranged in the irradiation chamber. The electron sources have beam deviation devices (20), by which the electrons emitted by the electron sources in an irradiation direction are deflected to a predetermined position of the surface of the chassis.

Description

The The invention relates to a device for curing a coating of a Motor vehicle body according to the preamble of claim 1.

The curing of coatings, in particular of polymeric coatings, by electron beam irradiation is well known in the art. For example, the DE 3 214 757 C1 a process for producing organic coatings from curable polymer systems, wherein the polymer systems applied to a substrate are cured by electron bombardment. This gives cured coatings with high Vickers hardness and high corrosion resistance. In the DE 29 22 367 A An arrangement for curing lacquer layers is disclosed. For this purpose, electron beams are fanned out into a beam bundle in a downstream deflection device and directed onto the object through an electron exit window. From the DE 1 808 719 B A method for curing enamel layers by electron beams is known, wherein the emanating from a beam source carrier beam is deflected by deflection fields and directed to the surface to be treated. DE 10 2004 023 539 A1 discloses a radiation curing apparatus in the form of a gantry. In order to completely irradiate the coated object, the radiator and the object must be guided past each other or one another. In the WO 99/52 650 A1 the arrangement of a robot-suitable irradiation device for curing paints is disclosed. In order to completely irradiate the coated object, the radiator is guided past the object by means of a robot arm. The DE 2 106 159 B describes a process for producing a resin-coated metal container on the inside by curing the coating with ionizing radiation. For this purpose, the ionizing radiation is generated or set free in the interior of the metal container.

Due to the relatively high investment costs for suitable electron sources, prior art documents generally aim to reduce the number of electron sources used. Such methods are particularly suitable for curing coatings on flat structures, such as carrier webs. Such an order irradiation system for electron beam curing coated films is for example from DE 10 2006 057 966 B4 known. However, such systems are not suitable for irradiating complex shaped three-dimensional bodies over their entire surface.

In order to solve the problem of the irradiation of three-dimensional moldings, discloses DE 10 2006 012 666 A1 a method which is based on irradiating such a molded part by means of three separate electron sources, each with a flat electron exit window. In order to achieve a uniform surface dose rate over the entire surface of the molding, the doctrine of DE 10 2006 012 666 A1 to control the electron energy density emitted over the area of at least one electron exit window such that the desired uniform irradiation is achieved. However, such a method is only suitable for the irradiation of relatively small moldings, since the size of the electron emission window associated with an electron source is necessarily limited. With increasing size of the exit window, finally, the total electron output of the electron source must be increased disproportionately in order to achieve sufficient electron energy densities.

Of the The present invention is therefore based on the object, a device of the type mentioned so to develop that a uniform electron irradiation a car body as a large and complex shaped three-dimensional body allows becomes.

These The object is achieved by a device having the features of the patent claim 1 and by devices having the features of claims 7 and 11 solved.

Such an apparatus for curing a coating of the three-dimensional body of a motor vehicle body by means of electron irradiation has an irradiation chamber with a holding device for arranging the body, and at least one electron source arranged within the irradiation chamber. According to the invention, it is provided that the at least one electron source has a beam deflection device, by means of which emitted from the electron source in a radiation direction electrons are deflected to predetermined locations of the surface of the body and the inner wall of the irradiation chamber is spherical and attached at least one electron source to the spherical inner wall In other words, the deflection device guides at least one electron beam over the entire area of the body to be irradiated for a predetermined irradiation time. Thus, it is not necessary to maintain a constant electron beam density over the entire surface of the body at a given time, rather the desired constant total dose for each surface element of the body is achieved by suitable guidance of the electron beam by means of the beam deflection device. As the adjustment of irradiation to the geometry of the body to be irradiated does not depend on the modulation of the electron energy density over the surface of the exit window, but the entire emitted from the electron source electron are deflected by the beam deflecting device to predetermined locations of the surface, the device can be scaled arbitrarily, so that the irradiation of arbitrarily large body, namely whole car bodies, is made possible.

Around a very precise Beam guidance and high energy density, it is particularly advantageous here To use electron sources, which has a substantially linear radiation characteristic to have. This also further improves the scalability of the device, because at a linear Radiation characteristic no significant electron energy density losses occur by beam expansion.

In Another embodiment of the invention are each spatial axis of the irradiation chamber associated with two electron sources, wherein the emission direction of the each first electron source an angle of approximately 180 ° with the Radiation includes the second electron source. With In other words, by such a device, the body is made can be irradiated in all spatial directions, so that the number of due the geometry of the body possible shadow zones as possible is kept low.

The Beam deflection device further preferably comprises at least a magnetic coil. The electromagnetic deflection of electron beams is well known and advantageously comes without moving Elements, which considerably increases the life of such a device. preferably, the beam deflection device is orthogonal at least two mutually aligned pairs of magnetic coils. This is one Deflection of the electron beam along two orthogonal axes possible, so that the electron beam is preferably in the range of a solid angle is deflected, which from the point of view of the electron source to be coated body Completely includes.

In Another embodiment of the invention is the at least one electron source a beam shaping device for focusing or expanding associated with the electron beam. Also such beam shaping devices can on an electromagnetic basis, d. H. designed without moving parts become. By the possibility the focusing or expansion of the electron beam, the on the surface of the body to be irradiated Electron energy density can be further regulated, so for example dependent on an angle of incidence of the electron beam to be irradiated surface the beam can be narrowed or widened accordingly, so that the per unit area incident electron currents over the the whole area stay constant.

The At least one electron source is furthermore preferably designed as a cathode ray tube. With such tubes can generated in the simplest way high electron densities and emitted directionally become. The at least one electron source is furthermore preferred arranged on an inner wall of the irradiation chamber. alternative it goes without saying also possible, additional Mounts, frames, portals or the like to provide, which pick up the electron sources of the device.

In An alternative embodiment of the invention comprises the device again an irradiation chamber with a holding device for Arrangement of the body to be irradiated, and at least one disposed within the irradiation chamber Electron source. According to the invention is here provided, a plurality of electron sources with cone-shaped radiation characteristic to use, with the respective Abstrahlkegel on the holding device or the body are directable. Due to the large number of conically radiating electron sources here is a uniform irradiation the entire surface of the body to be irradiated achieved without a Beam deflection is necessary. Also, this embodiment of the invention scales Excellent with the size of the one to be irradiated Object as the desired Radiation density each about the number of electron sources, their arrangement and the width the respective Abstrahlkegel adjustable and so on any size and arbitrary complex shaped objects is customizable.

In this case, the projections of the emission cone of the electron sources preferably overlap on the surface of the body. This allows the use of relatively inexpensive relatively low power electron sources. The desired electron density per unit area of the surface to be irradiated is thus achieved by the overlap of several comparatively weak electron sources. The electron sources are preferably arranged such that the body can be irradiated with a constant dose per area over substantially its entire surface. This allows the optimized curing of the coating of the body over the entire surface. Especially with electron irradiation, the dose introduced per area of particular importance, since too low a dose no sufficient curing occurs and make too high a dose negative effects noticeable, which leads to a decrease in hardness and For example, can lead to embrittlement of the irradiated surface.

The Electron sources are again preferred on an inner wall arranged the irradiation chamber. To adapt the device to enable differently shaped bodies to be irradiated, the electron sources are still preferably pivotable on the inner wall of the irradiation chamber arranged. The irradiation characteristic of the device can in the simplest way by moving the respective electron sources changed as desired become. Also for this embodiment According to the invention, it is particularly advantageous to use the electron source as cathode ray tubes form, as this form of electron sources a particular inexpensive and easily adaptable embodiment represents.

In a further alternative embodiment The device is in turn an irradiation chamber with a holding device for the arrangement of the body to be irradiated, as well as at least one provided within the irradiation chamber arranged electron source. According to the invention is here the at least one electron source as a high voltage electrode trained and the body integrated into the circuit comprising the electron source, wherein the body to be coated one Counter electrode forms to the electron source. In other words be on the body radiated electrons in the form of a peak discharge at the high voltage electrode generated and by the integration of the body to be coated in the circuit is directly directed to this, so no devices are necessary for beam shaping and beam deflection. Neither need electromagnetic Ablenkspulen be provided still a mechanical pivoting allows the electron sources become. The device is therefore particularly resistant to wear. By the high electron densities to be achieved in the context of a peak discharge the described device is particularly well suited for irradiation very big and complex shaped objects.

For this Preferably, a plurality of electron sources is provided, which surrounding the holding device substantially spherical. This will be a particularly uniform irradiation of the body to be irradiated allows. Again, the electron sources are again on an inner wall of the Irradiation chamber arranged.

Also in a further alternative embodiment of the invention again an irradiation chamber with a holding device for arrangement of the body to be irradiated and at least one disposed within the irradiation chamber Electron source provided. The electron source is according to the invention as a shaped body formed an isotope, which emits beta radiation. These embodiment The invention thus dispenses with electrically driven electron sources like cathode ray tubes or discharge electrodes. This advantageously reduces energy consumption the device. Furthermore, by shape and volume of the molding as well by selecting the appropriate isotope, the electron beam density within the irradiation chamber to any shapes and sizes of the to be irradiated body be adapted so that this embodiment of the invention outstanding with the size of the irradiating body scaled.

preferred Way, the at least one electron source is formed substantially plate-shaped. To one as possible homogeneous irradiation of the entire internal volume of the irradiation chamber to achieve is in a most preferred embodiment an inner wall of the irradiation chamber with the substantially disc-shaped moldings lined. As the electron donation in the context of Betazerfalls essentially isotropic with respect The direction of space is taken from each point of the surface disc-shaped moldings essentially irradiated a hemispherical solid angle, so that the shadow zones on the body to be irradiated are minimized. The total dose, the body to be irradiated receives, can adjusted in the simplest way by the irradiation time become.

In a further alternative embodiment the invention, which in turn an irradiation chamber with a Holding device for arranging the body to be irradiated as well comprises at least one electron source, it is provided according to the invention, in that the electron source is movable relative to the body. By the relative movement between body and electron source can be advantageously ensured that every spot of the surface of the body to be irradiated, a uniform electron dose receives. Size and shape of the body do not represent any restrictions, since those for irradiation of the body necessary Trajectory of the electron source can be set arbitrarily. In a particularly preferred embodiment of this aspect of the Invention is the electron source on an arm of an industrial robot arranged.

In a further alternative embodiment of the invention, in turn, an irradiation chamber with a holding device for arranging the body and at least one electron source is provided. This embodiment is characterized in that, according to the invention, a plurality of electron sources are arranged on a portal and directed towards a portal passage opening are. The body or the holding device is in this case movable through the portal passage opening. The size of the portal and the number of electron sources can in turn be adapted arbitrarily to the size and shape of the body, so that there is also an excellent scaling with the size of the body to be irradiated.

The Embodiments presented below refer to all aforementioned alternative aspects of the invention and are free with all embodiments combined.

Around a danger to prevent workers in the vicinity of the device is It is particularly advantageous to provide a shield to prevent the Exiting the electron beams and / or Bremsstrahlung from the Provide irradiation chamber. Such a shield consists of a material which, depending on the energy of the in the irradiation device accelerated electrons as well as the chemical composition of the irradiated body or whose coating is variable. Especially here very dense materials with high neutron numbers, such as Lead. As a result, a particularly good shield against high energetic quanta involved in the interaction of in the irradiation device accelerated electrons are formed with solid matter. Alternative materials for the shield are, for example, water or Plexiglas, which are sufficient, if not with the occurrence of high energy Bremsstrahlung must be expected and only the electron radiation the irradiation device to be shielded.

A Another preferred embodiment of The invention comprises a pump device for evacuating the irradiation chamber. By performing Irradiation in a vacuum will cause the formation of ions or radicals greatly reduced within the irradiation chamber, leaving possible negative Effects due to the chemical reaction of said ions or radicals advantageously prevented by the coating of the body to be irradiated become.

Also through the addition or alternatively usable gassing of the irradiation chamber with an inert gas can such negative chemical reactions between the coating and ions or radicals are prevented. Preference is given here Gases with high ionization potentials and low chemical reactivity, such as Used argon or nitrogen.

In inventive design According to the invention, the inner wall of the irradiation chamber is substantially spherical executed. By attaching the electron sources to such spherical Inner wall becomes a particularly homogeneous irradiation of the to be irradiated body realized.

in the Below is the invention and its embodiments with reference to the drawings be explained in more detail. Hereby show:

1 A schematic view of an embodiment of a device according to the invention with electron sources with beam deflection device,

2 a schematic detail view of the beam path of one of the electron sources of the embodiment of 1 .

3 a schematic view of an alternative embodiment of a device according to the invention with a plurality of electron sources with conical radiation characteristic,

4 a schematic detailed view of several electron sources of the embodiment of 3 with the respective beam path,

5 3 is a schematic view of an alternative embodiment of a device according to the invention with electron sources designed as high-voltage electrodes,

6 a schematic detail view of the beam path in the embodiment of 5 .

7 1 is a schematic view of an alternative embodiment of a device according to the invention with beta-emitting isotopes as electron sources,

8th FIG. 2 a schematic view of a further alternative embodiment of a device according to the invention with a robotically moved electron source, FIG.

9 a schematic view of a portal for a further alternative embodiment of a device according to the invention.

One in total with 10 designated device for curing a coating of a motor vehicle body according to 1 includes an irradiation chamber 12 in which the motor vehicle body 14 is received in a holding device, not shown. On the inner walls 16 the irradiation chamber 12 are electron sources 18 arranged. At the electron sources 18 these can be, for example, cathode ray tubes.

In the exemplary embodiment shown, the electron sources 18 arranged so that each spatial direction is a pair of electron sources 18 is assigned, the emission direction is different by 180 °, so that the motor vehicle body 14 can be irradiated from all spatial directions. Every electron source 18 is a magnetic coil 20 associated, which generates a variable electromagnetic field. In 2 are schematically the magnetic 22 and electric field lines 24 indicated. Due to the influence of the electromagnetic field of the coil 20 and a plate-shaped capacitor electrode arranged in the region of the electron emitter 26 can be from the electron source 18 radiated electrons are deflected at a solid angle, which is a cone-shaped area 28 Are defined. This makes it possible, by controlling the electron beams of the individual electron sources 18 all areas of the car body 14 to irradiate evenly with electrons so that each area receives the same dose per area. This allows the coating of the body 14 be cured optimally without causing radiation damage. To workers around the device 10 To protect this additionally has an enclosure and shielding 30 on, which prevents the escape of electron radiation and from the interaction of electrons and matter resulting Bremsstrahlung. This may be a shield made of lead, water, Plexiglas or the like.

3 shows an alternative embodiment of a device 40 , Again, there is an irradiation chamber 42 provided in which a holding device, not shown, a motor vehicle body 44 can record. About the inner walls 46 the irradiation chamber 42 is a plurality of electron sources 48 essentially spherical around the motor vehicle body 44 distributed around. For the sake of clarity, not all electron sources are 48 designated. Unlike the in 1 As shown, the electron sources 48 no device for deflecting or shaping the emitted electron beam here. How out 4 It has every electron source visible 48 a substantially conical radiation characteristic, wherein the Abstrahlkegel 50 overlap in the area of the motor vehicle body. As a result, weaker electron sources 48 be used, which by overlapping on the car body 44 nevertheless achieve the desired dose per area. By the spherical arrangement of a plurality of electron sources 48 around the car body 44 will give a uniform and shadowless irradiation of the entire surface of the bodywork 44 guaranteed. The electron sources 48 are in turn by a shield 52 shielded to the outside, so that no electron or Bremsstrahlung can escape, which workers in the vicinity of the device 40 could endanger. The electron sources 48 are again preferably designed as cathode ray tubes. To the radiation characteristic of the device 40 better at different objects to be irradiated 44 to be able to adapt, it may additionally be provided that the electron sources 48 swiveling on the inner wall 46 the irradiation chamber 42 are arranged.

5 shows a further alternative embodiment of a device 60 in which again in an irradiation chamber 62 a car body 64 is held by a holding device, not shown. On the inner walls 66 the irradiation chamber 62 are in turn multiple electron sources 68 arranged, for the sake of clarity not all are designated. The electron sources 68 are designed here as high voltage electrodes, the car body 64 is integrated into the circuit and acts as a counter electrode. Naturally, the car body 64 In this case, be isolated from the rest of the chamber to prevent short circuits and leakage currents.

The electrodes of the electron sources 68 are preferably designed tapered so that electrons can be released in the form of a peak or corona discharge. Due to the field gradient between the electrodes 68 and the car body 64 the electrons will look like 6 without the need for additional beam deflection or beam shaping means on curved paths 70 to the car body 64 directed. This results in a uniform irradiation of the entire body without the need for additional measures 64 , Again, there is a shield 72 provided at which the electron sources 68 are attached and which is the leakage of electron or Bremsstrahlung from the device 60 prevented. To ensure the most uniform possible irradiation, the electron sources 68 again spherical around the car body 64 arranged.

In another, in 7 illustrated alternative embodiment of a device 80 is completely dispensed with active electron sources. The irradiation chamber 82 in which the car bodywork 84 is received, rather has arranged on the inner walls shaped body 88 from an isotope, which emits beta radiation during its radioactive decay. In the example shown are the moldings 88 discretely over the inner wall 68 distributed. To a particularly homogeneous irradiation of the inner volume of the irradiation chamber 82 However, it is also possible to achieve the moldings 88 form plate-shaped and the entire inner wall 86 with the moldings 88 to dress up. This is the irradiation of the car body 84 as homogeneously as possible designed and shadow zones largely reduced. The area dose on the car body 84 acts, now only the residence time of the car body 84 in the irradiation chamber 82 certainly.

In the in 8th illustrated alternative embodiment of a device 90 becomes the car body 92 via only one electron source 94 irradiated, which from the arm 96 an industrial robot 98 to be led. By the movement of the electron source 94 along the surface of the motor vehicle body 92 Every area of the surface can be reached and evenly irradiated.

Alternatively, as in 9 shown in a further embodiment of a device 100 the motor vehicle body not shown here through a portal 102 be guided, at which several electron sources 104 are provided, which in each case on a portal passage opening 106 are directed.

In all embodiments shown, the respective device 10 . 40 . 60 . 80 . 90 . 100 still not shown ancillaries included. For example, the interiors of the respective irradiation chambers 12 . 42 . 62 . 82 be evacuated or filled with an inert gas so as to prevent the formation of ions or radicals, which could undergo chemical reactions with the coating, which in turn would lower the coating quality. Also, the illustrated in each case substantially cubic shape of the respective irradiation chambers 12 . 42 . 62 . 82 can be varied. In particular, it is advantageous to the irradiation chambers 12 . 42 . 62 . 82 to give a spherical shape to allow the most isotropic possible irradiation of the body to be hardened.

According to the invention Device used to paint on a motor vehicle body or to harden bodywork components. In particular, free-radically curing lacquer compositions are used as lacquers in question. Which includes preferably light- or UV-curing lacquers.

10 40, 60, 80, 90, 100

contraption for curing one Coating of a motor vehicle body

12 42, 62, 82, 92

irradiation chamber

14 44, 64, 84, 94

Motor vehicle body

16 46, 66, 86

inner walls

18 48, 68, 104

electron sources

20

solenoid

22

magnetic field lines

24

electrical field lines

26

capacitor electrode

28

conical area

30 52, 72

shielding

50

emission cone

70

curved tracks

88

moldings

96

poor

98

industrial robots

102

portal

106

Portal through opening

Claims (19)

Contraption ( 10 ) for curing a coating of a motor vehicle body by means of electron irradiation, with an irradiation chamber ( 12 ) with a holding device for arranging the body ( 14 ), as well as within the irradiation chamber ( 12 ) arranged electron sources ( 18 ), the electron sources ( 18 ) a beam deflection device ( 20 . 26 ), by means of which of the electron sources ( 18 ) emitted in a radiation direction electrons to predetermined locations of the surface of the body ( 14 ) are deflected, characterized in that the inner wall of the irradiation chamber is designed spherical and at least one electron source is fixed to the spherical inner wall. Contraption ( 10 ) according to claim 1, characterized in that each spatial axis of the irradiation chamber contains two electron sources ( 18 ), wherein the emission direction of the first electron source ( 18 ) an angle of approximately 180 ° with the emission direction of the second electron source ( 18 ). Contraption ( 10 ) according to claim 1 or 2, characterized in that the beam deflection device ( 20 . 26 ) comprises at least one magnetic coil. Contraption ( 10 ) according to one of claims 1 to 3, characterized in that the beam deflection device ( 20 . 26 ) comprises at least two orthogonally aligned pairs of magnetic coils. Contraption ( 10 ) according to one of claims 1 to 4, characterized in that at least one electron source ( 18 ) is associated with a beam shaping device for focusing or expanding the electron beam. Contraption ( 10 ) according to one of claims 1 to 5, characterized in that the at least one electron source ( 18 ) is designed as a cathode ray tube. Contraption ( 40 ) for curing a coating of a motor vehicle body by means of electron irradiation, with an irradiation chamber ( 42 ) with a holding device for arranging the body, as well as within the irradiation chamber arranged electron sources ( 48 ), wherein a plurality of electron sources ( 48 ) is provided with a conical radiation characteristic, wherein the respective Abstrahlkegel ( 50 ) on the holding device or the body ( 44 ) can be directed, characterized in that the inner wall of the irradiation chamber is spherical and the electron sources ( 48 ) on the spherical inner wall ( 46 ), so that a plurality of electron sources ( 48 ) spherically around the motor vehicle body ( 44 ) are distributed around. Contraption ( 40 ) according to claim 7, characterized in that the projections of the Abstrahlkegel ( 50 ) of the electron sources ( 48 ) on the surface of the body ( 44 ) overlap. Contraption ( 40 ) according to claim 7 or 8, characterized in that the electron sources ( 48 ) pivotable on the inner wall ( 46 ) are arranged. Contraption ( 40 ) according to one of claims 7 to 9, characterized in that the electron sources ( 48 ) is designed as a cathode ray tube. Contraption ( 60 ) for curing a coating of a motor vehicle body by means of electron irradiation, with an irradiation chamber ( 62 ) with a holding device for arranging the body ( 64 ), as well as within the irradiation chamber ( 62 ) arranged electron sources ( 18 ), the electron sources ( 18 ) are formed as high-voltage electrodes, and the body ( 64 ) is connectable to a circuit comprising the electron source, that it forms a counter electrode. characterized in that a plurality of electron sources ( 68 ) is provided, which surrounds the holding device spherical and the electron sources ( 68 ) on an inner wall ( 66 ) of the irradiation chamber ( 62 ) are arranged. Contraption ( 80 ) according to one of claims 1 to 11, characterized in that at least one electron source ( 88 ) is formed as a shaped body of an isotope which emits β-radiation. Contraption ( 80 ) according to claim 12, characterized in that the at least one electron source ( 88 ) is substantially plate-shaped. Contraption ( 80 ) according to claim 13, characterized in that an inner wall ( 86 ) of the irradiation chamber ( 88 ) is lined with the substantially plate-shaped moldings. Contraption ( 10 . 60 . 60 . 80 ) according to one of claims 1 to 14, characterized in that the irradiation chamber ( 12 . 42 . 62 . 82 ) a shield ( 30 . 52 . 72 ) for preventing the escape of electron beams and / or Bremsstrahlung from the irradiation chamber ( 12 . 42 . 62 . 82 ) having. Contraption ( 10 . 60 . 60 . 80 ) according to one of claims 1 to 15, characterized in that a pumping device for evacuating the irradiation chamber ( 12 . 42 . 62 . 82 ) is provided. Contraption ( 10 . 60 . 60 . 80 ) according to one of claims 1 to 16, characterized in that a gassing device for gassing the irradiation chamber ( 12 . 42 . 62 . 82 ) is provided with an inert gas. Contraption ( 10 . 60 . 60 . 80 ) according to one of claims 1 to 17, characterized in that the inner wall ( 16 . 46 . 66 . 86 ) of the irradiation chamber ( 12 . 42 . 62 . 82 ) is substantially spherical. Use of a device according to one of claims 1 to 18 to harden a paint, in particular a UV varnish, on a motor vehicle body or body parts.