WO2016097904A1

WO2016097904A1 - Method for manufacturing a household appliance component with a specific laser structuring as well as a household appliance component

Info

Publication number: WO2016097904A1
Application number: PCT/IB2015/059012
Authority: WO
Inventors: Jorge Alaman Aguilar; Carlos CONCHESO DORIA; Andres Escartin Barduzal; Francisco Javier Ester Sola; Carlos Gimeno Asin; Manuel Gimeno Asin; Oscar GIMENO LOPEZ; Martin Goldaracena Jaca; Clara Ángela JARAUTA CÓRDOBA
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2014-12-19
Filing date: 2015-11-20
Publication date: 2016-06-23

Abstract

The invention relates to a method for manufacturing a household appliance component, in which a metallic basic element is provided and the basic element is structured on a surface by a laser beam, wherein the laser beam acts in such a way upon the surface that by the structure generated in this connection the surface is changed in its colour and/or the structure is generated with craters on the surface, and after the generating of the structure an enamel layer is applied to the structure.

Description

Method for Manufacturing a Household Appliance Component with a Specific Laser Structuring as well as a Household

Appliance Component The invention relates to a method for manufacturing a household appliance component, in which a metallic basic element is provided and the basic element is structured by a laser beam. Moreover, the invention also relates to a correspondingly manufactured household appliance component. Metallic household appliance components are known in manifold designs. In this connection housing components are known as sheet metal components. In particular also aluminium components are known, which for instance are known as iron sole plate of an iron or as burner plates. It is also known that such metallic basic elements are then coated, in order to generate for instance an individual colouring of the household appliance component and/or impart a specific protective function, in particular against environmental influences, to this basic element. These coatings are used also for special functions such as hydrophilic or hydrophobic effects. It is also known to change the metallic surface to improve the coating adherence using well-known methods in the industry such as sandblasting.

It is the task of the present invention to provide a method as well as a household appliance component, in which a simplified manufacture of a coated embodiment of a household appliance component is achieved.

This task is solved by a method and a household appliance component according to the independent claims.

In an inventive method for manufacturing a household appliance component a metallic basic element is provided from which then the household appliance component is generated. This metallic basic element is structured by a laser beam. An essential idea of the invention is to be seen in that the laser beam is generated in such a way that by acting upon the surface it generates a structuring, which defines and changes the surface as to its colour as desired, or that an optically defined generated colour change occurs. With this specific structuring thus the optical colour perceptibility of this basic element with its metallic surface is changed. Additionally or instead, the structure is generated by the laser beam with specific structure elements, namely craters on the surface. After generating the structure an additional specific material layer, namely an enamel or a hydrophilic layer is applied to the structure and the structure is covered by this coating layer. By such a design a coated household appliance component is provided, which due to its metallic basic character and the structure of the surface of the metallic basic element provided for this purpose despite a coating then can be designed in a specific colour and moreover this specific coating, namely an enamel or ahydrophilic layer, can be applied also without optically disadvantageous appearance.

By the very craters thus a uniform overall appearance of the household appliance component is achieved, since in a metallic basic element, to which an enamel layer is applied, a hardening process takes place, in which in common methods undesired formation of bubbles and thus bulges on the surface of the basic element may occur, which then can be discerned through the applied coating. This is no longer the case in the case of the method according to the invention. Preferably, the structure as to colour change of the surface is generated as micro roughness. This is a very advantageous embodiment in this regard, which is easy to be generated by the effect of the laser beam and thus causes a very defined surface modification. In this connection by the laser beam a very high energy is radiated into a very small area so that a very high energy density occurs, and dependent on this specific effect then this micro roughness can be generated, which then leads to this desired colour change and then to the generated colour appearance of the surface. By this specifically generated laser beam thus the ablation of particles on the surface of the basic element is caused in a defined manner and thereby micro roughness is generated. This micro-roughness helps to improve the adherence of any coating to be applied afterwards. This is the same effect achieved by other pre- coating processes such as sandblasting, which can be substituted by the method of the present invention. Preferably, the laser beam is generated in such a way that due to the structuring the surface appears as mat white. This is a particularly advantageous embodiment, by which due to a direct structuring of the surface of the metallic basic element a colour appearance is achieved, which hitherto was not possible with regard to the mat white colour. In a particularly advantageous way this leads to it that then the enamel or another kind of coating layer such as a hydrophilic layer applied to this specific structuring can be colourless and in particular transparent. As thus a white enamel or another kind of coating such as a hydrophilic layer required for generating a white appearance is no longer needed, through this advantageous embodiment of the invention an improvement can be achieved also with regard to a more uniform colouring and a more uniform colour appearance. In particular if a coating with an enamel layer and additionally with a ceramic ink is generated or this enamel layer is employed as basis for this ceramic ink, by the thus facilitated use of an enamel layer undesired and thus bad colour impressions of the ceramic ink in the translucent matrix can be avoided.

Preferably, then in such an embodiment this colourless or transparent enamel can be the basic coating or the matrix for the then additionally used and introduced or applied ceramic ink material.

Advantageously, the laser beam in such embodiment is generated in such a way that additionally to generating the structuring for the colour change the laser beam also cleans, in particular degreases, the surface at the same time. This is advantageous to the effect that, since such a cleaning, in particular degreasing, for the very applying of enamel layers and ceramic ink material for instance integrated therein, and the structuring can advantageously be effected in one step.

In a particularly advantageous way then thus quasi by a single method step, namely the specific generating of a laser beam and its acting upon the surface of the metallic basic element a degreasing as well as a generating of a micro roughness of this surface is formed to improve the adherence of the coating to be applied during the next process step and at the same time then also a colour change towards mat white appearance of this structured surface is achieved. This micro roughness can be designed individually, in that the parameters of the laser beam are adjusted individually. Thereby mechanical and chemical adhesions can be optimized. Preferably, it is envisaged that the velocity, with which the laser beam is moved across the surface for generating the micro roughness, amounts to greater than or equal to 1 ,500 mm/s. Preferably, the frequency amounts to a relatively low value and is smaller than 60 kHz, preferably essentially 50 kHz. In a further advantageous embodiment it is envisaged that the laser beam acts in such a way upon the basic element that in the basic element bubbles formed and enclosed close to the surface burst open or explode and thereby the craters in the structuring are generated. This is a particularly advantageous embodiment precisely if the metallic basic element is an injection moulded or die-cast aluminium part.

This is because for the application of an enamel layer upon such a specifically manufactured aluminium part for hardening a certain heating is required. In common processes this leads to it that beads extending from the surface of the household appliance component upwards are generated and visible. This impairs not only the optical appearance of this household appliance component, but can also lead to functional impairment of the household appliance, which comprises this household appliance component. Precisely if for instance in an iron the iron sole plate is designed correspondingly, such undesired bulges may cause an undesired unevenness of the iron sole plate.

Through this very specific laser effect upon the surface with the generating such burst open or exploded bubbles that then become craters particularly during heating and thus during the hardening process of the household appliance component the occurrence of undesired strong bulges can be avoided, because in this regard close to the surface no such correspondingly high bubbles can be formed anymore, as the air can escape from the craters.

Preferably, the craters are generated with a diameter of between 20 μηι and 50 μηι. In particular these very specific diameter dimensions are particularly advantageous, in order to avoid an impeding the hardening of the applied enamel layer and to avoid impairing the final appearance of this enamel layer with regard to undesired strong bulges.

By this agency of the laser beam and the generation of the crater thus quasi also a perforation of this zone of the metallic basic element that is close to the surface and equipped with bubbles is achieved.

In an advantageous way after generation of the craters and prior to the application of the enamel layer the basic element is heated and thereby correspondingly hardened. The above-named advantages are thereby promoted.

In an advantageous way this heating of the basic element prior to the application of the enamel layer, however, already takes place with generated craters for a period of time of between 5 mins and 10 mins and/or with a temperature value of between 520 °C and 570 °C, in particular of between 545 C and 555 C.

In an advantageous way the basic element upon application of the enamel layer is heated for hardening the enamel layer, in particular for a period of time of between 5 mins and 10 mins and in particular with a temperature value of between 520 °C and 570 °C, in particular of between 545 °C and 555 °C.

These tempering steps are preferably performed in such a way that the desired final temperature, for instance essentially 550 °C, is reached after about 1 min to 3 mins after starting this tempering operation.

Here, too, the enamel layer can be applied as colourless or transparent enamel layer and then preferably ceramic ink can be inserted or applied.

However, in this embodiment it may also be envisaged that the enamel material itself already has the desired colour, for instance white enamel is applied.

Preferably a coating applied to the structured surface besides the enamel layer also comprises ceramic ink. The ceramic ink can be inserted into the enamel material. Preferably, prior to the application of the enamel layer after the heating a cooling process is performed, by which the basic element is cooled down again in particular to, particularly not below, room temperature. When a hydrophilic layer is applied instead of enamel, it is applied after the surface has been prepared by the laser beam. Once applied, the coating has also to be heated for its hardening or curing, wherein the temperatures are much lower than those required for enamel. The curing temperatures for coatings normally range from 190°C to 300°C, in particular from 200 °C to 250 °C.

In an advantageous way as household appliance component an, in particular die-cast, iron sole plate or an, in particular die-cast, burner plate is manufactured. Preferably, thus these specific household appliance components are mounted in an iron or a burner, in particular of a cooker for preparing food. In the following, embodiments of the invention are explained in more detail.

In a first embodiment as household appliance component for instance an iron sole or a burner plate are manufactured. For this purpose, to start with, a metallic basic element is provided, wherein the metallic basic element is an, in particular die-cast, aluminium part. From this specific metallic basic element then the household appliance component is manufactured by structuring the basic element by a laser beam. Thereby the laser beam is generated and directed at a surface of the basic element to act upon it in such a way that thereby the generated structuring the surface is changed in its colour.

By the effect of the laser beam this surface is very individually processed in this connection. A multi-functionality is achieved in that by this laser beam with specific laser beam parameters the surface is degreased and moreover a micro roughness of the surface designed. By this design then a defined and desired colour change of the surface is effected and in particular an optical surface appearance generated, which comprises a mat white colouring. In particular, then after this specific structuring a heating of this metallic basic element now processed in such a way is performed.

However, this heating may additionally or instead also not be performed until the enamel layer has been applied to the respective structured surface.

In this connection then also a preferably transparent enamel layer is applied to this structured surface. Preferably then a tempering method, in which then the basic element and the enamel layer are heated, in particular essentially to 550 °C is performed and this is effected for a period of time of between 5 mins and 10 mins.

It may also optionally be envisaged that ceramic ink is imported into a coating on the surface that comprises an enamel layer. In a further embodiment preferably equally a iron sole plate or a burner plate is manufactured as household appliance component. Again, a metallic basic element is provided, which here, though, is provided in particular as die-cast aluminium component.

A surface of this basic element is structured by a laser beam, wherein the laser beam with regard to its parameter values is generated in such a way that the structuring with craters is designed on the surface. By the laser beam pores or bubbles occurring close to the surface in the basic element can be broken open in this connection so that they are no longer closed towards the surface. These bubbles which occur in particular in a hardening process of the basic element therefore can no longer lead to undesired strong elevations or bulges in a further hardening process that is performed after application of the enamel layer, since warming gas is not entrapped anymore, but can escape from the craters, which therefore cannot expand in an undesired way, either.

Preferably, then after the generation of this structuring with the craters an enamel layer is applied to this structured surface of the metallic basic element and in the following then a further hardening process is effected by heating this basic element together with the enamel layer. In particular it is envisaged that a coating with an enamel layer and ceramic ink is applied to the structured surface.

Preferably the aluminium part in the embodiments is die-cast, and an aluminium alloy is employed that is in particular AISi8Cu3 or AISi1 1Cu2. The named embodiments can be combined in individual method steps and/or with regard to the design of the basic element and/or the applied enamel.

Other possible coatings are hydrophilic silane coatings applied on the iron steam chamber of an aluminium die-cast soleplate, ceramic coatings or sol-gel coatings used for soleplates of ironing products.

Claims

1. A method for manufacturing a household appliance component, in which a metallic basic element is provided and the basic element is structured on a surface by a laser beam, characterized in that the laser beam acts in such a way upon the surface that by the thereby generated structure the surface is changed as to its colour and/or the structure with craters on the surface is generated, and after generating the structure a a coating layer is applied to the structure.

2. The method according to claim 1 , characterized in that the structure for changing the colour of the surface is generated as micro roughness.

3. The method according to claim 1 or 2, characterized in that the laser beam is generated in such a way that by the structure the surface appears as matt white.

4. The method according to claim 2 or 3, characterized in that the laser beam is generated in such a way that additionally to the generating the structure of the surface is also cleaned, in particular degreased.

5. The method according to claim 1 , characterized in that the laser beam acts in such a way upon the basic element that in the basic element bubbles formed and encapsulated close to the surface burst open and thereby the craters of the structure are generated.

6. The method according to claims 1 or 5, characterized in that the craters with a diameter of between 20 μηι and 50 μηι are generated.

7. The method according to claim 1 or one of claims 5 or 6, characterized in that after generating the craters and prior to applying the coating layer the basic element is heated.

8. The method according to claim 7, characterized in that the heating is performed for a period of time of between 5 mins and 10 mins and/or with a temperature value of between 520°C and 570°C , in particular between 545°C and 555°C.

9. The method according to any one of the preceding claims, characterized in that the coating layer is an enamel layer and in that the basic element after applying the enamel layer is heated for hardening the enamel layer, in particular to a temperature value of between 520°C and 570°C , in particular of between 545°C and 555°C.

10. The method according to claim 1 or 2, characterized in that the coating layer is a hydrophilic layer and in that.after applying the coating layer, the basic element is heated for hardening the coating layer, in particular to a temperature value ranging from 190°C to 300°C , in particular from between 200°C to 250°C.

11. The method according to any one of the preceding claims, characterized in that a transparent coating layer is applied on the structuring.

12. The method according to any one of the preceding claims, characterized in that on the surface a covering comprising the coating layer and ceramic ink is applied.

13. The method according to any one of the preceding claims, characterized in that the basic element is generated and provided as injection moulded aluminium component.

14. The method according to any one of the preceding claims, characterized in that as household appliance component a, in particular injection moulded, iron soleplate or a, in particular injection moulded, burner plate.

15. A household appliance component, which is manufactured by a method according to claims 1 to 14.