DE102005040017A1 - Preparative method for a component, especially a motor vehicle internal covering part, such a part and a computer program for this uses laser radiation controlled by measuring a second frequency from a luminescent substance - Google Patents

Abstract

A preparative method for a component (100) comprises using laser radiation (118) of a frequency absorbed by the component and a substance that remits a second different frequency. The component is irradiated with the laser radiation (116), the remitted (luminescent) radiation from the substance measured and the laser beam controlled (120) according to this measurement. Independent claims are also included for the following: (A) A processing unit for the above; (B) A component absorbing the radiation; and (C) A computer program for controlling the above.

Description

The The invention relates to a method for processing a component with the help of laser radiation, in particular for the preweakening of a Automotive interior trim part, and a corresponding device, a component, in particular a motor vehicle interior trim part, and a computer program product.

From the prior art, the Vorschwächung of instrument panels with a laser beam for the production of airbag flap openings is known. In particular, the show DE 196 36 429 . DE 102 54 377 . EP 07 11627 . GB 2276354 and JP 2-99324 corresponding methods for laser attenuation.

to Regulation of for used the pre-weakening Laser radiation is generally the intensity of the remaining Remaining wall thickness transmitted laser radiation used. This assumes that the laser source and the sensor for sensing the intensity of the transmitted Proportion of the laser radiation with respect to the vorzuschwachter motor vehicle interior trim part opposite Pages are arranged. Furthermore, such prior art methods preceded by the material of the motor vehicle interior trim part vorzuschwachtenden sufficient transparency for the laser radiation used to the measurement of a transmitted portion to enable.

Of the Invention is in contrast The task is based on an improved method of processing a component, in particular for the preweakening of a motor vehicle interior trim part, to create, and a corresponding device, a component, in particular a motor vehicle interior trim part, and a computer program product for Regulation of the pre-weakening.

The The object underlying the invention is in each case with the features solved the independent claims. preferred embodiments of the invention are in the dependent claims specified.

Included in the invention the component to be machined, such as the motor vehicle interior trim part to be pre-screened, a substance that is responsible for the pre-weakening can absorb laser radiation to be used and at a different frequency re-emitted. For the regulation of the laser radiation during the execution of the processing, in particular the pre-weakening, is then not, as is customary in the art, the transmitted portion of Laser radiation, but the re-emitted by the substance radiation used.

This is particularly advantageous for a motor vehicle interior trim part, which has no or none sufficient transparency for the laser radiation, but probably for having the re-emitted radiation. For example, the motor vehicle interior trim part a lacquer coating for the laser radiation is substantially impermeable. However, the leaves Lacquer layer the reemit radiation due to the frequency shift through, allowing the regulation of laser power based on the measurement the re-emitted radiation can be performed.

One Another advantage is that depending on the distribution of the substance in the Automotive interior trim part, a greater freedom with regard to the arrangement of the measuring sensor. If, for example the substance as thin Layer is present in the motor vehicle interior trim part which runs approximately along the desired weakening depth, so only the occurrence of re-emitting radiation has to be measured without it depends on their exact intensity, so the measuring sensor in principle can be arbitrarily positioned.

According to one embodiment of the invention, the substance is a luminescent substance. Luminescence is a radiation that is generated during the transition from an excited state to an energetically lower state or a ground state. The luminescence can be excited by photons; in this case one speaks of photo luminescence. Depending on the time duration, a distinction is made between excitation and emission of the radiation between phosphorescence and fluorescence. In the case of fluorescence, the remission of the radiation takes place directly on the absorption, ie within, for example, 10 ^-8 seconds, whereas in the case of phosphorescence the remission takes place only after a longer period of time.

The substance is preferably a photoluminescent substance, in particular a fluorescent substance. According to one embodiment of the invention, the substance includes a sodium salt, a barium salt and / or another organic substance or a substance mixture which emits radiation of a different frequency than the laser source when excited by the laser radiation. As a laser, for example, a CO ₂ laser, a YAK laser or other laser is used.

According to one embodiment of the invention, the motor vehicle interior trim part has a substantially impermeable to the laser radiation Layer. This layer may be an outer paint layer of the motor vehicle interior trim part. This layer is largely impermeable to the laser radiation, so that no transmitted portion of the laser radiation can be measured. If the layer is sufficiently permeable to the re-emitted radiation, then the portion of the re-emitted radiation transmitted through the layer can be measured and used as the basis for the regulation of the laser radiation.

It is however for the implementation a method according to the invention By no means compelling that for the laser radiation impermeable layer for the re-emitted radiation permeable is. If the layer also for the re-emitted radiation is impermeable, so can by a Arrangement of the sensor, for example, on the back of the motor vehicle interior trim part Nevertheless, the re-emitted radiation can be measured on this basis to regulate the laser radiation.

To an embodiment of the invention are the particles of the substance in at least one layer of the motor vehicle interior trim part distributed. For example become particles of the substance the plastic granules, which for Production of the relevant layer of the motor vehicle interior trim part is used, added as an additive. This results in a In approximately homogeneous distribution of the particles in the relevant layer of the motor vehicle interior trim part.

To an embodiment According to the invention, the motor vehicle interior trim part has a skin, such as e.g. a foamy one Skin, a casting skin or a slush skin in which particles of the substance are dispersed.

To an embodiment the invention is the substance in the motor vehicle interior trim part as a thin one Layer available. For example, particles of the substance for this purpose sprayed on, imprinted or with the help of a carrier foil applied.

To an embodiment the invention, the measurement of the re-emitted radiation, that is, for example the luminescence, with the help of a sensor, only for the frequency the radiation re-emitted by the substance is sensitive. For this For example, the sensor may include a filter, such as e.g. have an interference filter, which passes this frequency, but not the laser frequency.

One Interference filter consists e.g. made of several thin layers of dielectric transparent material. These layers are in high vacuum, e.g. on a glass slide evaporated. At the interfaces between two layers, the reflection of the incident occurs Light. By overlay the reflected waves cause interference phenomena. With suitably selected layer thickness Radiation of certain wavelengths is caused by this interference extinguished, so not transmitted while Light of other frequencies, including the frequency of the substance re-emitted radiation, but not the laser frequency, happen can.

In In another aspect, the invention relates to a device for preweakening a motor vehicle interior trim part, which is a laser radiation a first frequency absorbing and at a second frequency having reemit substance. The device has a sensor for radiation the second frequency, so that the device also for the pre-attenuation of such Automotive interior trim components can be used, which is not or not sufficient for the laser radiation are transparent. Furthermore allows it is the use of the re-emitted radiation instead of the transmitted one Laser radiation as a basis for the Measurement or regulation, the sensor with respect to the motor vehicle interior trim part on the same side as the laser source.

In In another aspect, the invention relates to a computer program product with computer-executable Instructions for controlling the preweakening of a motor vehicle interior trim part. For example, the computer program is a processor of a Device according to the invention executed.

In a further aspect, the invention relates to a motor vehicle interior trim part with a luminescent substance, wherein the luminescence can be excited by a laser radiation used for the preweakening of the motor vehicle interior trim part, for example a CO ₂ laser, a YAK laser or another laser. The luminescence occurring in the implementation of the preweakening with the aid of the laser radiation is used as a controlled variable for carrying out the preweakening.

The The present invention can be applied to the machining of different components made of different materials, in particular of plastic, wood, textile materials, material mixtures or material stratifications, e.g. for laser drilling of blind holes or for cutting grooves. In particular, the present invention for the Machining of automotive interior trim parts be used, in particular by an airbag flap opening by pre-weakening realize.

In addition, preferred Ausfüh tion forms of the invention with reference to the drawings explained in more detail. Show it:

1 1 shows a schematic section through an embodiment of a motor vehicle interior trim part according to the invention and a schematic block diagram of an embodiment of a device according to the invention during the machining of the motor vehicle interior trim part,

2 the intensity profile of the luminescence measured with uniform distribution of particles of the substance in a layer of the motor vehicle interior trim part,

3 the intensity profile of the luminescence measured in the case of an inhomogeneous distribution of the substance in the motor vehicle interior trim part,

4 2 shows a block diagram of a further embodiment of a device according to the invention and a cross section of a further embodiment of a motor vehicle interior trim part according to the invention,

5 a flowchart of an embodiment of a method according to the invention.

The 1 shows a schematic cross section through a motor vehicle interior trim part 100 , In the motor vehicle interior trim part 100 it may be, for example, an instrument panel, a door lining, a pillar trim eg for the so-called A, B, C or D pillar of a motor vehicle, a headliner or another motor vehicle interior trim part.

In the embodiment shown in the 1 is shown, the motor vehicle interior trim part 100 a carrier 102 made of a hard plastic, such as ABS (Acrylonitril Buthandiänstyren). On the carrier 102 there is a foam layer 104 eg made of PU (polyurethane). On the foam layer 104 there is a skin 106 , such as a slush skin or a casting skin, especially a skin made of PVC (polyvinyl chloride). The skin 106 is with a varnish layer 108 provided, which is visible here in the installation position of the motor vehicle interior trim part of the motor vehicle interior.

In one, several or all layers of the motor vehicle interior trim part 100 Particles of a photoluminescent substance can be distributed. Alternatively or additionally, the photoluminescent substance may be present in one or more of the layers of the motor vehicle interior trim part and / or between layers of the motor vehicle interior trim part in concentrated form, such as a thin layer.

For example, the motor vehicle interior trim part includes 100 a layer 110 between the foam layer 104 and the skin 106 containing the photoluminescent substance. Alternatively or additionally, the motor vehicle interior trim part 100 such a layer 112 between the skin and the varnish layer 108 exhibit.

The layer 110 and or 112 For example, the photoluminescent substance may be sprayed on or printed on. Furthermore, the layer 110 respectively. 112 also be applied with a carrier film.

To Vorschwachtung the motor vehicle interior trim part 100 becomes from the back of a groove or a blind hole 114 with the help of a laser beam 116 cut. The laser beam 116 is from a laser 118 , such as a CO ₂ laser or YAK laser delivered.

The pre-weakening should take place up to a weakening depth t = t ₁ , which in the 1 is shown by the dashed line. For this purpose, the device has a controller 120 for the laser 118 , The control 120 receives a sensor signal 122 from a sensor 124 , The sensor 124 serves to sense the luminescence in the motor vehicle interior trim part 100 distributed photoluminescent substance when passing through the laser beam 116 is stimulated. For this purpose, the sensor 124 a filter 126 have the luminescence, but not radiation of the laser frequency.

The sensor 124 can with reference to the motor vehicle interior trim part 100 on the same page as the laser 118 be arranged, wherein the sensor is aligned on the back of the motor vehicle interior trim part (position A), and / or on the laser 118 opposite side of the motor vehicle interior trim part 100 (Position B), as in the 1 shown.

The laser is used to perform the preweakening 118 positioned and turned on so that the laser beam 116 in the motor vehicle interior trim part 100 penetrates. Through the laser beam 116 becomes the photoluminescent substance in the skin 106 stimulated. The resulting luminescence is from the sensor 124 measured. The sensor 124 then generates the sensor signal 122 which is to the controller 120 is transmitted.

At the sensor signal 122 it may be an intensity signal indicating the intensity of sensed luminescence. The sensed intensity of the luminescence is controlled by the controller 120 compared with a threshold. As soon as the ints the luminescence intensity reaches the threshold value, the laser beam 116 switched off, so that the desired residual wall thickness below the blind hole 114 remains.

Alternatively, it is also possible that the sensor signal 122 is a binary signal which merely indicates whether luminescence from the sensor 124 was sensed or not. This is particularly advantageous if the photoluminescent substance no longer or less homogeneously distributed in one or more of the layers of the motor vehicle interior trim part 100 is present, but as a thin layer, for example in the form of the layer 110 and or 112 , Due to the concentration of the photoluminescent substance in one or more such thin layers, the luminescence accordingly has one or more distinct peaks for generating the binary sensor signal 122 can serve. For example, a sensor signal means 122 of logic "0" that no luminescence was sensed, whereas a sensor signal 122 of logic "1" means that luminescence was sensed.

Once the controller 120 a sensor signal 122 from logic "1", this switches, for example, the laser radiation 116 from. Alternatively, at the first "Umkip pen" of the sensor signal 122 from logic "0" to logic "1" the laser power is reduced until the sensor signal 122 a second time from logical "0" to logical "1" tips over. The latter is advantageous when the photoluminescent substance in the successive layers in the weakening direction 110 and 112 is present.

The paint layer 108 may be made of a material which is responsible for the laser radiation 116 is largely impermeable. If this material is permeable to luminescence, then the sensor can 124 on the laser 118 opposite side of the motor vehicle interior trim part 100 be arranged (position B), so that the sensor 124 through the paint layer 108 can measure transmitted luminescence. If the paint layer 108 is also largely impermeable to the luminescence, so the luminescence can still be measured when the sensor 124 with respect to the motor vehicle interior trim part 100 on the same page as the laser 118 is arranged (position A).

The 2 shows the course of the sensor 124 measured intensity I of the luminescence as a function of the attenuation depth t, when the photoluminescent substance in at least one of the layers of the motor vehicle interior trim part 100 is present in the form of approximately homogeneously distributed particles.

At the desired weakening depth t ₁ , the luminescence has an intensity of I ₁ . This intensity I ₁ is also the switching threshold for switching off the laser radiation. The intensity course according to 2 obtained, for example, in an approximately homogeneous distribution of particles of the photoluminescent substance in the skin 106 ,

The 3 shows the intensity profile when the photoluminescent substance, for example as a thin layer 110 (see. 1 ) is present. In this case, the intensity of luminescence has a pronounced peak 128 for example, to "tip over" the binary sensor signal 122 (see. 1 ) from logical "0" to logical "1". After the shift 110 from the laser beam 116 has been pierced, the intensity of the luminescence goes back, so that the binary sensor signal 122 back from logical "1" back to logical "0". Because of this back-tilting of the binary sensor signal 122 the control switches from "1" to "0" 120 the laser 118 so that approximately the desired weakening depth t _{1 is} reached.

The 4 shows a further embodiment of a motor vehicle interior trim part according to the invention and a device for the preweakening of the motor vehicle interior trim part. Elements of 4 , the elements of 1 correspond are marked with corresponding reference numerals.

In the embodiment of the 4 is the sensor 424 with respect to the automotive interior trim part 400 on the same side as the laser head 418 arranged. The sensor 424 is in the direction of that of the laser beam 416 in the motor vehicle interior trim part 400 plasma generated during the preweakening 430 aligned. The laser head 418 and the sensor 424 are preferably on the same arm 432 a robot arranged.

The robot has a robot controller 434 that is a position signal 436 from the controller 420 receives. The position signal 436 specifies the target position of the robot arm 432 for alignment of the laser beam 416 on the motor vehicle interior trim part 400 , The robot controller 434 Can be used separately or as an integral part of the controller 420 be educated.

The control 420 has a processor 438 for executing program instructions 440 for the evaluation of the sensor signal 422 which is from the sensor 424 is delivered. Furthermore, the processor is used 438 for executing program instructions 442 for the control of the laser head 418 ,

The control 420 also has a memory 444 , in which at least one threshold for the Inten the luminescence is stored. Alternatively, different threshold values can be stored depending on the positon.

In the embodiment considered here includes the motor vehicle interior trim part 400 a photoluminescent substance, for example at least in the skin 406 ,

To Vorschwachtung the motor vehicle interior trim part 400 gives the control 420 a position signal 436 to the robot controller 434 out to the laser head 418 with the sensor 424 to position. After that, the laser beam 416 due to a corresponding control of the laser head 418 through the program instructions 442 switched on.

The from the sensor 424 meanwhile issued sensor signals 422 be from the program instructions 444 evaluated continuously. In the embodiment considered here, the sensor signal is 422 around an intensity signal. The from the sensor 424 Measured intensity of luminescence is determined by the program instructions 440 compared with the threshold stored in the memory. Upon reaching the threshold, the laser beam 416 due to a corresponding activation by the program instructions 442 shut off and the controller 420 gives a new position signal 436 down to the position of the laser head 418 for example, in the x direction to increment.

The 5 shows a corresponding flow chart. In the step 500 the laser or at least the laser head is aligned with the vorzuschwächende position of the motor vehicle interior trim part. Together with the laser or the laser head, the sensor for performing the intensity measurement can also be positioned.

In the step 502 the laser beam is switched on. After that, it will continue in the step 504 the luminescence measured. In the step 506 it is checked whether the intensity of the luminescence exceeds a threshold value. As long as this is not the case, luminescence measurements are repeated in the step 504 carried out.

As soon as the intensity of the luminescence exceeds the threshold value, the laser in the step 508 by one of, for example, the program instructions 442 (see. 4 ) and the position in the step 510 incremented. Thereafter, the flow control goes back to the step 502 ,

100

Automotive interior trim part

102

carrier

104

foam layer

106

skin

108

paint layer

110

layer

112

layer

114

blind

116

laser beam

118

laser

120

control

122

sensor signal

124

sensor

126

filter

128

peak

400

Automotive interior trim part

402

carrier

404

foam

406

skin 106

416

laser beam

418

laser head

420

control

422

sensor signal

424

sensor

426

filter

430

plasma

432

poor

434

robot control

436

position signal

438

processor

440

program instructions

442

program instructions

444

Storage

Claims (29)

Method for processing a component ( 100 ; 400 ) with the help of laser radiation ( 116 ; 416 ) of a first frequency, wherein the component has a substance absorbing the laser radiation and re-emitting at a second frequency, wherein the first and second frequencies are different, comprising the following steps: - loading the component with the laser radiation, - measuring the radiation re-emitted by the substance , - Regulation of the laser radiation as a function of the measurement. The method of claim 1, wherein the Substance is a luminescent substance. The method of claim 1 or 2, wherein the substance a sodium salt, a barium salt and / or an organic substance includes. The method of claim 1, 2 or 3, wherein the laser radiation is generated by a CO ₂ laser or a YAK laser. Method according to one of the preceding claims, wherein the motor vehicle interior trim part one for the laser radiation has substantially impermeable layer. Method according to claim 5, wherein the layer is a lacquer layer ( 108 ). Method according to one of the preceding claims, wherein particles of the substance in at least one layer ( 102 . 104 . 106 . 108 . 110 ; 402 . 404 . 406 ) of the construction are partly distributed. Method according to one of the preceding claims, wherein the measurement as an intensity measurement is formed and the admission of the motor vehicle interior trim part terminated with the laser radiation at a certain position of the component when the measured intensity reaches a threshold. Method according to one of the preceding claims, wherein the substance between two layers (( 104 . 106 ; 106 . 108 ; 402 . 404 ; 404 . 406 ) of the component is present. Method according to one of the preceding claims, wherein the regulation of the laser radiation is such that the admission the component is terminated with the laser radiation as soon as the radiation is measured. Method according to one of the preceding claims, wherein the measurement by means of a sensor ( 124 ; 424 ), which with respect to the component on the same side (A) as a laser ( 118 ; 418 ) is arranged to generate the laser radiation. Method according to one of the preceding claims, wherein the measurement by means of a sensor ( 124 ; 424 ), which is designed to measure radiation of only the second frequency. The method of claim 12, wherein the sensor comprises an interference filter ( 126 ), which transmits only the radiation of the second frequency. Method according to one of the preceding claims, wherein it is the component to a motor vehicle interior trim part is. The method of claim 14, wherein the motor vehicle interior trim part suggested by the processing becomes. The method of claim 15, wherein the preweakening a Airbag flap openings is created. Device for processing a component ( 100 ; 400 ) having a laser radiation of a first frequency absorbing and re-emitting at a second frequency substance, wherein the first and second frequencies are different, comprising: - a radiation source ( 118 ; 418 ) for the laser radiation ( 116 ; 416 ) of the first frequency, - a sensor ( 124 ; 424 ) for the re-emitted radiation of the second frequency, - control means ( 120 ; 420 ) for the laser radiation as a function of a sensor signal supplied by the sensor. Apparatus according to claim 17, wherein the sensor comprises Reference to the component on the same side (A) as the radiation source is arranged. Apparatus according to claim 17 or 18, wherein the Control means for controlling the laser radiation in dependence the intensity the radiation of the second frequency are formed. Component with a laser radiation of a first frequency absorbing substance re-emitting at a second frequency, wherein the first and second frequencies are different. A component according to claim 20, wherein the Substance is a luminescent substance. Component according to claim 20 or 21, wherein the substance a sodium salt, a barium salt and / or an organic substance includes. A component according to claim 20, 21 or 22, wherein the Substance in at least one layer of the motor vehicle interior trim part is distributed. Component according to one of the preceding claims 20 to 23, wherein the substance applied between two layers of the motor vehicle interior trim part is. Component according to one of the preceding claims 20 to 24, wherein the substance is sprayed on. Component according to one of the preceding claims 20 to 24, wherein the substance is printed. Component according to one of the preceding claims 20 to 24, wherein the substance is applied by means of a carrier film. Component according to one of the preceding claims 20 to 27, which is a motor vehicle interior trim part, which for a prelude to form an airbag flap opening is trained. Computer program product with computer-executable instructions for controlling the machining of a component ( 100 ; 400 ) with the help of laser radiation ( 116 ; 416 ) of a first frequency, wherein the component has a luminescent substance, and the executable instructions are designed to carry out the following steps: switching on the laser radiation, evaluating a luminescence signal 122 ; 422 ), which is measured during the exposure of the component with the laser radiation, - generating a switching signal for switching off the laser radiation, when the intensity of the luminescence exceeds a threshold value.