HK1180645B - Method for fabricating a non-marking, matt ceramic - Google Patents

Description

Method for producing a non-marking matt ceramic

Technical Field

The present invention relates to a process for manufacturing matt (matt) ceramics, more particularly to a process for manufacturing markerless ceramics of this type.

Background

It is known to manufacture parts from matt ceramics to diversify their attractive appearance. However, it has been found that these components lose their primary requirement as a scratch protection due to the occasional allowance of markings.

Disclosure of Invention

The object of the present invention is to overcome all or part of the above drawbacks by proposing a process for manufacturing a matt ceramic part which maintains its advantageous attractive appearance and also maintains its scratch resistance requirements.

The invention therefore relates to a process for manufacturing a matt ceramic part, comprising the following steps:

a) manufacturing a ceramic component;

b) sandblasting portions of the ceramic part to matte the portions;

characterized in that the method comprises the following final steps:

c) the matte portion is ground (lapping) to level the surface of the matte portion.

It is thus clear that advantageously, according to the invention, an item in contact with the matt ceramic part will not be scratched, but will slide over the flattened area, thus preventing any cracks in the surface from being blocked and leaving a mark. Moreover, the ceramic advantageously retains the desired matte appearance.

According to further advantageous features of the invention:

between step a) and step b), the method comprises a step d): polishing the ceramic part in order to better control the roughness of the matt portions obtained in step b);

-step d) is obtained by vibro-deburring (trovalising);

-in step d), the roughness Ra obtained is less than 20 nm;

-step a) is obtained by sintering;

-step b) is carried out by corundum particle blasting;

-step c) is obtained by tumbling (tumbling);

-the milling obtained in step c) is preferably between 0.8 μm and 2 μm;

the invention also relates to a timepiece, characterized in that it comprises at least one matt ceramic part obtained according to any one of the variants of the method described above.

Drawings

Further characteristics and advantages will emerge clearly from the description that follows, given by way of non-limiting example with reference to the accompanying drawings, in which:

figure 1 is a schematic view of a timepiece;

figures 2 and 3 are schematic views of the surface states according to a first embodiment of the invention;

figures 4 and 5 are schematic views of the surface states according to a second embodiment of the invention;

fig. 6 is a flow chart of a method for manufacturing a matt ceramic part according to the invention.

Detailed Description

Fig. 1 shows a timepiece 11, which timepiece 11 may comprise at least one matt ceramic part obtained according to an embodiment of method 1 described below. The matt ceramic parts may thus form the external elements of timepiece 11, such as, in a non-limiting manner, case 13, bezel 15, control mechanism 17 and/or bracelet or wristband 19 including links 14.

All of these elements worn by the user may come into contact with everyday objects. After analysis it was found that the matt glazed porcelain part was still scratch resistant, but the roughness resulting from the desired matt appearance scratched any articles that come into contact with the matt porcelain part. Thus, since most articles encountered are made of softer materials, the ceramic scratches the material it encounters, which then fills the cracks in the surface of the matte ceramic part, creating the perception that the part was scratched.

To overcome this finding, a method 1 for manufacturing a matt ceramic part is elucidated below with reference to fig. 2 to 6. As shown in fig. 6, in a first embodiment, a method 1 comprises a first step 2 for manufacturing a ceramic component. This step can be achieved by various processes. Preferably, according to the invention, step 2 is obtained by sintering.

The method 1 continues with a second step 7, which second step 7 is used to sand blast parts of the ceramic part to make them matt. Step 7 is preferably obtained by locally blasting the desired matt part of the ceramic part with aluminium oxide particles. In fact, glass bead blasting has proven unsatisfactory. According to the invention, corundum particles are preferably used.

As can be seen in fig. 2, in a first embodiment the surface of the ceramic component is modified to form peaks 21 that are very aggressive towards articles formed from softer materials and cracks 23 having very unequal depths between 5 μm and 8 μm.

Finally, advantageously, according to the invention, the manufacturing method 1 of the invention comprises a final step 9 for grinding the matt portions, so as to level the surface of the matt portions and thus prevent the material of the article being scratched from filling the hollows in the surface of the matt ceramic part. Preferably, according to the invention, step 9 is carried out by tumbling, so as to obtain a grinding comprised between 3 μm and 7 μm.

As can be seen in fig. 3, in a first embodiment the surface of the ceramic component is modified such that the peaks 21 become planar and form substantially planar regions 21 ' between the cracks 23 ', the depth of said cracks 23 ' being reduced or eliminated.

It is therefore clear that advantageously, according to the first embodiment of the invention, the items in contact with the matt ceramic parts are no longer scratched, but slide on the substantially flat areas 21', and the ceramic still retains its matt appearance.

As shown in fig. 6, in a second embodiment, a method 1 comprises a first step 2 for manufacturing a ceramic component as in the first embodiment.

In a second embodiment, the method 1 continues with a second step 5, which second step 5 is used for polishing the ceramic component in order to improve the control of the roughness of the matt portions obtained in step 7. Preferably, according to the invention, step 5 is carried out by vibro-deburring, so as to obtain an Ra roughness of less than 20 nm.

The method 1 continues with a third step 7, which third step 7 is essentially identical to step 7 of the first embodiment. Thus, as can be seen in fig. 4, in the second embodiment, the smooth surface condition of the ceramic component is changed to form spikes 25 aggressive to articles formed of softer materials and cracks 27 having a depth that is very uniform and between 1.5 μm and 3 μm.

Finally, advantageously, according to the invention, the manufacturing method 1 according to the invention comprises a final step 9, this final step 9 being substantially identical to the final step 9 of the first embodiment. Preferably, according to the second embodiment of the invention, a grinding between 0.8 μm and 2 μm can be obtained in step 9.

As can be seen in fig. 5, in the second embodiment, the surface state of the ceramic component is changed so that the peaks 25 become planar and form substantially planar regions 25 ' between the cracks 27 ', which cracks 27 ' are more uniform and have a reduced or absent depth than in the first embodiment.

It is therefore clear that advantageously, according to the second embodiment of the invention, the items in contact with the matt ceramic parts are no longer scratched, but slide on the substantially flat areas 25', and the ceramic still retains its matt appearance, which has a greater resulting uniformity than the first embodiment.

Of course, the invention is not limited to the illustrated examples, but comprises various modifications and alterations as would be appreciated by a person skilled in the art. In particular, the application of the invention is not limited to the field of timepieces. Thus, by way of example, jewelry may be envisaged.

Likewise, the exemplary embodiments of steps 2 to 9 of method 1 are not limited to the technique used. In particular, other grinding and polishing techniques are contemplated.

Claims (10)

1. Process (1) for manufacturing a matt ceramic part, which process (1) comprises the following steps:

a) manufacturing (2) a ceramic part;

b) blasting (7) portions of the ceramic part to matt the portions, altering the surface state of the portions of the ceramic part to form peaks and cracks;

characterized in that the method (1) further comprises the steps of:

c) the matt portions are ground (9) so as to level the surface of the matt portions, thereby flattening the peaks to form flat areas between the cracks and maintain the matt appearance.

2. The process (1) according to claim 1, wherein the grinding obtained in step c) is between 3 μ ι η and 7 μ ι η.

3. Process (1) for manufacturing a matt ceramic part, which process (1) comprises the following steps:

a) manufacturing (2) a ceramic part;

d) polishing (5) the ceramic component;

b) blasting (7) portions of the ceramic part to matt the portions, altering the surface state of the portions of the ceramic part to form peaks and cracks;

characterized in that the method (1) further comprises the steps of:

c) the matt portions are ground (9) so as to level the surface of the matt portions, thereby flattening the peaks to form flat areas between the cracks and maintain the matt appearance.

4. The process (1) according to claim 3, wherein the grinding obtained in step c) is between 0.8 μm and 2 μm.

5. Method (1) according to claim 3, characterized in that step d) is obtained by vibro-deburring.

6. Method (1) according to claim 5, characterized in that, in step d), the roughness Ra obtained is less than 20 nm.

7. The method (1) according to claim 1 or 3, wherein step a) is obtained by sintering.

8. A method (1) according to claim 1 or 3, wherein step b) is obtained by sandblasting corundum particles.

9. The process (1) according to claim 1 or 3, wherein step c) is obtained by tumbling.

10. Timepiece (11), characterized in that the timepiece (11) comprises a matt ceramic part obtained according to claim 1 or 3.