EP2189227B1 - Method and device for irradiating a body with electromagnetic radiation - Google Patents

Abstract

The device has UV radiation sources arranged in series in a preset direction of relative movement of a body, where two of the sources are pivoted at respective axes from the direction. The axes run perpendicular to the direction and perpendicular to radiation directions for UV radiation such that the sources are aligned. Regions (B11, B14) of an upper surface (O) of a body are irradiated with the UV radiation by the sources in a reference relative position to the body. Partial regions (TB11, TB14) extend from the regions by preset values at interval (l) defined for a measurement variable. An independent claim is also included for a method for irradiating a body with an electromagnetic radiation.

Description

The invention relates to a method for irradiating a body with electromagnetic radiation, wherein the body has a coating on its surface whose properties permanently change the electromagnetic radiation. The main application is the curing of paint on a motor vehicle body.

It is known in such cases to bring components of a motor vehicle as body to be irradiated in a closed space in which these components are irradiated from all sides. Such a UV exposure space discloses the DE 10 2007 012 897 A1 ,

In the present case, however, it is provided that the body is moved relative to sources of electrical radiation, ie either the body is moved or the source is moved or both. The relative movement should take place along a predetermined direction, typically in a straight line, wherein a distance variable can be defined along the predetermined direction. With a moving body, for example, it is easy to measure at which point in the room it is located and thus specify a distance.

All sources irradiate a respective area of the surface of the body with electromagnetic radiation.

A method in which the body passes sources of ultraviolet radiation is known in the art as operating in the art WO 2005/011878 A2 disclosed device known. The device serves to uniformly irradiate a motor vehicle body with ultraviolet radiation. To make this possible even with complicated shaped and very uneven objects such as vehicle bodies with good results regarding the curing of a paint, the spatial position of a source is motorized changeable. When operating is then provided that when passing the vehicle body, a tracking of the source takes place, so that all surface areas of the body are uniformly and completely cured.

It is very expensive if the source of ultraviolet radiation has to be constantly updated. In the device according to the WO 2005/011878 A2 An enormous effort is necessary because each individual source of ultraviolet radiation is controllable via a plurality of servomotors. A control unit must be constantly active and control the servomotors.

It is an object of the invention to allow a uniform irradiation of a body with electromagnetic radiation, in particular thus to allow a uniform irradiation of a painted body with UV radiation, so that the paint cures optimally without excessive effort must be operated.

UV-curing coating systems are of particular importance among the paints, or paints which can be radically cured by photochemical and thermal initiation. Ultraviolet radiation (UV radiation) or infrared radiation (IR radiation) are therefore suitable as suitable electromagnetic radiation for curing such coatings.

Different sources arranged one behind the other (typically offset in the direction perpendicular to the predetermined direction) irradiate such respective regions that at least a portion thereof extends over the same interval defined by two particular values for the distance.

In other words, there are two sources arranged one behind the other, which irradiate the same strip on the surface of the body, and precisely the boundary lines of the strip run perpendicular to the predetermined direction and each boundary line is assigned a value for the route size.

The invention is based on the recognition that two corrugations arranged one behind the other do not necessarily have to irradiate regions arranged one behind the other along the direction of movement of the body relative to the source. Rather, sources arranged one behind the other can simultaneously irradiate the same strip, wherein preferably the strip is completely irradiated. During the relative movement between the body and the sources, this strip then moves over the surface of the body, and the body is gradually irradiated uniformly. The complete irradiation of a strip by the source can be expressed in such a way that preferably all areas of the surface of the body irradiated by sources form a closed surface. As a rule, there will be an overlap between the areas irradiated by the sources. A first step in this regard is already given when the areas irradiated by two sources arranged one behind the other form a closed surface.

So that a complete strip of the surface of the motor vehicle is irradiated, the sources should not all be arranged at the same height one behind the other. Rather, it is precisely preferred that sources arranged one behind the other in a predetermined direction in a direction which are simultaneously perpendicular to the predetermined direction and perpendicular to a (defined by a representative beam, preferably the central beam and thus, for example, a surface normal) emission direction is located in different positions, in other words, therefore, offset from one another. The offset may also look exactly like the holes in the strip that are not irradiated by sources of a first column being irradiated by the sources of a second column and vice versa.

The device according to the invention for irradiating bodies with electromagnetic radiation has a plurality of sources of electromagnetic radiation. The electromagnetic radiation includes those wavelength ranges which are suitable for curing UV lacquers. In the main application, the sources emit ultraviolet (UV) radiation. The device has means for generating a relative movement of a body to the sources in a predetermined direction along which a distance variable is definable.

The device should be designed so that the relative position between the source and the body is not entirely random, but should give a sequence of desired relative positions between sources and body to a predetermined body or to a kind of predetermined bodies. For example, a vehicle body on rails Passing fixed sources, the rails, along with the shape of the vehicle body, determine the distance at which a particular location of the surface to a particular source is at a particular traveling position of the body on the rail.

If the vehicle body is transported on a conveyor belt, there is a margin on how the bodywork can be placed on the conveyor belt. Even then, however, there is at least one sequence of target relative position between source and body, eg. B. when the body sits centrally on the conveyor belt. In all other positions of the body on the conveyor belt can also define additional consequences of Sollrelativstellungen, so define a whole host of such consequences in total.

At least two sources should now be arranged one behind the other in the predetermined direction.

According to the invention, these two sources are aligned or alignable that are radiated by the outgoing of you electromagnetic radiation at Given a Sollrelativstellung to a predetermined body or a body of predetermined type on the surface of this body respective areas, of which at least a partial area in each case the same, defined by two specific values for the distance size interval extends.

Thus, if it is determined to the device how a particular body is relative to the sources, then the inventive method can be carried out, namely in particular a strip on the surface of exactly this body completely irradiate.

In a preferred embodiment, at least one source is about an axis which is perpendicular to the predetermined direction of relative motion and perpendicular to a source-definable emission direction (eg, the direction of the center beam or a surface normal of an element of the body) for electromagnetic radiation , swiveling. Note that in the device according to the WO 2005/011878 A2 Sources of electromagnetic radiation are pivotable about an axis which is parallel to the predetermined direction of the relative movement. In the present case, the source should be able to change its emission direction relative to the movement path.

The desired effect of completely irradiating a strip on the surface of the body at the same time can not be achieved for all the bodies at the same orientation of the source. Therefore, the device is more flexibly adaptable to different shapes of bodies when the source is pivotable.

In this case, a certain automatism is preferably given: the pivotable source is preferably pivotable by means of an electric motor. For a plurality of predetermined types of bodies now different pivoting positions are defined. The relevant information is stored in a control unit which serves to drive the electric motors. Now, if the control unit information about the type of a body introduced into the device can be fed, the control unit can select the appropriate pivoting position for this body and control the electric motor accordingly. The information can be supplied, for example, via a simple input device by an operator, but it can also be used automatic detection mechanisms in the device. So there may be an image recognition, by which the type of the body is derived. It is easier if the body z. B. is provided as part of a production line with an identifier. The identifier may be a simple bar code on the body read by a bar code reader, radio tags may be used, etc.

In a preferred embodiment of the invention, sources of identical construction are used, and then the relative position of the sources relative to one another can already be recognized from the outside at the position of the housing. The invention then intentionally disregards parallel alignment of the sources. "Parallel" here means that the surface normals of certain surfaces on the same components are parallel to each other, exit openings for electromagnetic radiation in the same direction, etc. In the invention, the electromagnetic radiation is not just emitted in parallel, but the beams run towards each other in a plan view.

Also in the device according to the invention, the sources are preferably arranged offset to one another.

Fig. 1

schematisch eine Seitenansicht von bei einer Vorrichtung gemäß dem Stand der Technik verwendeten Ultraviolettquellen zeigt,

Fig. 2

eine Draufsicht auf die Quellen aus Fig. 1 und einen an den Quellen vorbeigeführten Körper,

Fig. 3

die Verteilung von Bereichen auf einer Oberfläche des Körpers aus Fig. 2, auf die die Quellen aus Fig. 1 strahlen,

Fig. 4

die zeitliche Variation der Intensität der Bestrahlung von zwei unterschiedlichen Punkten auf der Oberfläche des Körpers aus Fig. 2, wie sie sich durch die Verteilung der Bereiche gemäß Fig. 3 ergibt,

Fig. 5

schematisch eine Seitenansicht von bei einer erfindungsgemäßen Vorrichtung verwendeten Ultraviolettquellen zeigt,

Fig. 6

eine Draufsicht auf die Quellen aus Fig. 5 und einen an den Quellen vorbeigeführten Körper,

Fig. 7

die Verteilung von Bereichen auf einer Oberfläche des Körpers aus Fig. 6, auf die die Quellen aus Fig. 5 strahlen,

Fig. 8

die zeitliche Variation der Intensität der Bestrahlung von zwei unterschiedlichen Punkten auf der Oberfläche des Körpers aus Fig. 6, wie sie sich durch die Verteilung der Bereiche gemäß Fig. 7 ergibt,

Hereinafter, a preferred embodiment of the invention will be described with reference to the drawing, in which:

Fig. 1

schematically shows a side view of ultraviolet sources used in a device according to the prior art,

Fig. 2

a plan view of the sources Fig. 1 and a body passed by the springs,

Fig. 3

the distribution of areas on a surface of the body Fig. 2 to which the sources point Fig. 1 radiate,

Fig. 4

the temporal variation of the intensity of the irradiation from two different points on the surface of the body Fig. 2 as reflected by the distribution of the areas according to Fig. 3 reveals

Fig. 5

schematically shows a side view of ultraviolet sources used in a device according to the invention,

Fig. 6

a plan view of the sources Fig. 5 and a body passed by the springs,

Fig. 7

the distribution of areas on a surface of the body Fig. 6 to which the sources point Fig. 5 radiate,

Fig. 8

the temporal variation of the intensity of the irradiation from two different points on the surface of the body Fig. 6 as reflected by the distribution of the areas according to Fig. 7 reveals

The invention relates to the arrangement of ultraviolet sources in an apparatus for irradiating a body with ultraviolet radiation. Typically, the body is a painted automotive body, and the exposure to ultraviolet light serves to cure the paint. For the paint to cure optimally, the ultraviolet radiation must be irradiated for a predetermined time at a predetermined intensity. A disadvantage of the quality of the paint is when the intensity fluctuates during the predetermined time or even in the meantime the irradiation is permanently interrupted and resumed.

The irradiation of the motor vehicle body now takes place by means of ultraviolet radiation sources, which are spaced from the surface and irradiate certain areas of the motor vehicle. It should be ensured that, when the motor vehicle moves past the radiation sources, all points on the surface of the motor vehicle, ie all the paint spots, are irradiated in such a way that the paint cures optimally.

The prior art has now used an arrangement as shown schematically in FIG Fig. 1 is shown. In the schematic representation, it has been assumed that a side wall of a motor vehicle body K is irradiated, which we assume to be even for a present simplified consideration. For irradiating the wall, two rows of ultraviolet radiation sources are provided, namely a first row of the radiation sources Q1, Q2 and Q3 and a second row of the radiation sources Q4 and Q5. The motor vehicle body K is transported past the sources according to the arrow P in a manner known per se. As a result, any point on the surface of the motor vehicle body K will eventually pass by one of the sources Q1 to Q5.

The reason why one does not simply arrange a plurality of sources close together in a row is that the sources Q1 to Q5 can not radiate beyond their full dimensions, but typically have a small exit window for radiation. Thus, the sources Q1, Q2 and Q3 irradiate the surface O of the body K in regions B1, B2 and B3 which do not form a closed surface but are spaced apart from each other. The sources Q4 and Q5 are now offset from the sources Q1 to Q3 of the same construction and radiate to areas B4 and B5. During movement of the motor vehicle body K corresponding to the arrow P, all points on the surface O pass through the radiation pattern according to FIG Fig. 3 from right to left. This means that z. B. a point on the surface, which is exactly in the movement of the body K between the areas B1 and B2, at a subsequent time exactly in the area B4 and is also still irradiated.

The use of two rows of ultraviolet radiation sources thus results in that each point on the surface of the body K is eventually irradiated.

Fig. 4 However, it can be seen that this irradiation is uneven: A point on the surface O, which moves on the trajectory PA, first passes through the beam from the source Q2, that is between a time t ₁ and a Time t ₂ in the area B2 and later from a time t ₃ to a time t ₄ in the area B4. At a point moving on the trajectory PA, therefore, an irradiation with a fluctuating intensity according to the in Fig. 4 shown curve 10.

For a point moving on the trajectory PB, it is said to be in the range B5 at times between a time t ₅ and a time t ₆ and irradiated by the ultraviolet radiation source Q5.

Thus, the results in Fig. 4 shown and designated 12 curve.

Curves 10 and 12 indicate how the intensity with which certain points are irradiated varies over time.

It has now been found that in the arrangement according to Fig. 1 and basically identically constructed arrangements, the differences in the nature of the irradiation with ultraviolet radiation from place to place on the surface of the motor vehicle body K are such that the curing of the paint does not take place optimally. This means that the varnish has locally cured differently differently and therefore has varying properties from place to place. This is undesirable.

Identification of the arrangement Fig. 1 is it that, as in Fig. 2 to recognize, the respective central rays Z1 and Z4 of the beams emanating from the sources Q1 and Q4, parallel to each other. The central rays are in this case equated with the surface normals of the body K facing front surfaces of the sources Q1 and Q4, z. B. the exit window.

In accordance with the invention, this configuration is deviated from: sources Q11, Q12 and Q13 from a first series of ultraviolet radiation sources are inclined to sources Q14, Q15 from a second series of ultraviolet radiation sources. In the present case, both groups of sources are inclined to the surface normal N of the vehicle body K. Both the central beam Z11 from the source Q11 and the central beam Z14 from the source Q14 are not perpendicular to the surface of the body K.

Compared to Fig. 3 the situation arises that the groups of areas B1, B2 and B3 on the one hand and of areas B4 and B5 on the other hand have moved towards each other. The source Q11 thus irradiates a region B11, which coincides with a region B14 The area B14 overlaps with the area B12 irradiated by the source Q12, the area B12 overlaps with an area B15 which the source Q15 irradiates, and the area B15 overlaps with an area B13 which the area Source Q13 irradiated.

By overlapping all areas B11, B14, B12, B15 and B13, the effect is now achieved that a total of a closed area is irradiated. It is possible to define a strip with boundary lines S1 and S2, which is completely irradiated from top to bottom. The boundary lines S1 and S2 can be assigned values I ₁ and I ₂ for the length along a path that runs along the direction of movement according to the arrow P.

If now the motor vehicle body K passes according to the arrow P at the sources Q11, Q12, Q13, Q14 and Q15, then a continuous strip of the surface of the body is irradiated, and this strip migrates on the surface of the body K. As a result, the body K homogeneously irradiated at each point in the area of the strip. Therefore, a point moving along the trajectory PA 'receives a radiation intensity according to the curve 14, and a point moving along the trajectory PB' receives a radiation intensity according to the curve 16. The radiation intensities according to the curve 14 and The curve 16 hardly differ from each other.

The reason for this is that both the area B11 has a partial area TB11 (in Fig. 7 hatched), as well as the area B14 has a partial area TB14 (hatched in the other direction), which extends over the interval I ₁ to I ₂ . On the other hand, the areas lying outside the subareas TB11 and TB14 are negligible, and an overlapping area Ü is also negligible. This is the case in particular when the subregions TB11 and TB14 comprise at least 50% of the respective regions B11 and B14, preferably at least 70% and particularly preferably at least 90% of these regions. The central rays of the beams emanating from the sources Q11, Q12, Q13 and Q14 as well as Q15 present here on the surface O at points which form exactly a straight line. This corresponds to the situation according to Fig. 6 in which (only) in plan view, the central rays Z11 and Z14 intersect exactly on the motor vehicle body K.

Thus, the device is also suitable for other motor vehicle bodies, the sources Q11, Q12, Q13, Q14 and Q15 are preferably designed pivotable, at least according to the arrow V1 to a perpendicular to the central rays Z11 and Z14 on the one hand and perpendicular to the direction of movement of the motor vehicle body according to the arrow P on the other hand pivot axis A11 and A14. Changes in the exchange of the vehicle body K by another body, the distance from the surface to the sources, the sources are simply pivoted according to the arrow V1 about the respective axes A11, A14 until again the situation according to Fig. 7 prevails. The pivoting according to the arrow V1 can be done by means of an electric motor, which is assigned to the respective source Q11, Q12, Q13, Q14 and Q15. A control unit can then according to their information about the vehicle body K, the sources Q11 to Q15 then pivot accordingly.

In addition to the possibility that the sources are brought into a pivoting position for the duration of the irradiation of a body, there is also the possibility of pivoting the sources while driving past the vehicle body K, so that in each case on the surface in Fig. 7 the situation prevails. This is useful if, due to the shape of the body K, the distance between the surface of the same to the sources when driving past the body changes greatly.

Optionally, an additional pivoting possibility according to the arrow V2 around an axis parallel to the direction of movement according to the arrow P extending axis in at least some of the sources Q11, Q12, Q13, Q14, Q15 is advantageous.

The presently said for the irradiation of a body K from the side applies accordingly for an irradiation from above or from below. On the other hand, the sources Q11, Q12 and Q13 on the one hand and the sources Q14 and Q15 on the other hand could also be arranged on a curved arc so that on a curved surface O of a body K a situation according to FIG Fig. 7 will be produced.

Claims (2)

1. Device for irradiating bodies (K) with electromagnetic radiation, comprising a plurality of sources (Q11, Q12, Q13, Q14, Q15) for electromagnetic radiation and means for generating a relative movement of a body (K) with respect to the sources in a predetermined direction (P) along which a track variable (I) can be defined, wherein there exists at least one sequence of desired relative positions between the sources (Q11, Q12, Q13, Q14, Q15) and an individual predetermined body or a group of bodies of a predetermined type, wherein at least two sources (Q11, Q14) are arranged one behind the other in the predetermined direction, of which at least one source (Q11, Q14) is pivotable about an axis (A11, A14) which is both perpendicular to the predetermined direction (P) of the relative movement and perpendicular to an emission direction (Z11, Z14) for electromagnetic radiation which can be defined to a source, so that an alignment of the two sources (Q11, Q14) arranged one behind the other in the predetermined direction can be obtained in which alignment, if electromagnetic radiation is emitted by the sources and one of the desired relative positions with respect to a body is present, regions (B11, B14) are irradiated by the individual sources (Q11, Q14) on the surface (O) of the respective body, of which regions (B11, B14) at least one sub-region (TB11, TB14) extends across the same interval defined by two specific values (L1, L2) for the track variable (I).
2. Device according to claim 1,
   characterised in that
   the pivotable source is pivotable by means of an electric motor, in that different pivoting positions are defined for a plurality of predetermined types of bodies, and in that relevant information is stored in a control unit, wherein the control unit can be supplied with information on the type of body fed into the device and wherein the control unit is used to select the at least one electric motor as a function of this information.

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