Method for laser processing glass with a chamfered edge

Abstract

A laser machining process is described for laser machining glass or glass-like materials. This process machines articles or features in articles with chamfered edges in one manufacturing operation. Chamfered edges are desirable in glass and glass-like materials because they resist fracturing or chipping and eliminate sharp edges. Producing articles or features in articles in one manufacturing operation is desirable because it can save time and expense by eliminating the need to transfer the article to a separate machine for chamfering after laser machining. Alternatively, it can permit use of less expensive equipment because the same laser used for machining can be used to form the chamfer instead of having a separate process perform the chamfering. Producing chamfers with laser machining results in high quality chamfers without the need for a separate polishing or finishing step.

Description

FIELD OF THE DISCLOSURE[0001]The field of the technical subject matter relates to laser machining glass or glass-like articles. In particular it relates to laser machining an article with a chamfer on an edge that adjoins the top or bottom surface of the article or on a feature laser machined into the article. In more particular it relates to laser machining glass or glass-like article with a chamfer in a single manufacturing operationBACKGROUND OF THE INVENTION[0002]Laser machining chamfered features in glass or glass-like articles such as sapphire, ceramic or glass ceramics is desirable because adding a chamfer to an edge makes the edge safer, in the sense that it is less likely to cause cuts or scratches when handled, makes it less likely to chip or crack and in general, makes the edge stronger. While chamfered edges are desirable, no methods exist for creating an article with a chamfered edge in one manufacturing operation. Prior art methods of producing chamfered edges involve ...

AI Technical Summary

Benefits of technology

[0008]The instant invention is a method for forming chamfered features in glass or glass-like materials in one manufacturing operation. By one manufacturing operation we mean the article being processed is fixtured on a laser processing machine, the desired feature is laser machined into the article and one or more of the resultant feature edges are chamfered using the same laser processing equipment that formed the feature prior to the article being removed from the machine. While adding the chamfer in this fashion necessarily adds a step to the manufacturing operation, the additional time required is minimized because the chamfer is added while the article is still fixtured on the laser processing machine, thereby eliminating the need to remove the article from the machine, fixture the part on a different machine and then produce the chamfer. Producing a feature and chamfer in one operation eliminates the need to refixture the article and eliminate the need for an additional machine to perform the operation, thereby reducing the time and expense required to produce an article with chamfered edges. In the instant invention, the laser parameters can be varied to produce chamfers of different sizes and shapes without changing the equipment or fixturing. In addition, by varying the laser parameters appropriately, a desired level of surface smoothness and finish can be achieved without additional manufacturing operations or equipment.

[0013]FIG. 9 shows a further embodiment of the instant invention. FIG. 9 is a side view showing laser beams 120, 122, and 124 impinging on bulk material 128. In this embodiment, the mechanism (not shown) moving the laser beam along a path with respect to the material does not change its path, rather the angle at which the laser beam is directed to the material is altered. The laser beam is pivoted about point 126 as it travels around a path on the bulk material 128, but only in a plane perpendicular to the path. This allows more control over the shape and size of the chamfer, but at the cost of slightly more complex mechanism. FIG. 10 shows a chamfer 130 machined into bulk material 128 using this method. FIG. 11 shows an article 129 separated from bulk material 128 by machining cuts 132 which extend from the bottom of the chamfer to the bottom of the material 128 by machining the material with a laser beam 121 which is perpendicular to the surface.

[0014]FIG. 12a shows another embodiment of the instant invention. This embodiment works with materials that are transparent to the wavelengths of light used to machine the material. As shown in FIG. 12a, the laser beam (not shown) is moved along a path 140 on the bulk material 146. The arrows indicate that the angle the laser beam has with respect to the material is always perpendicular to the path. FIG. 12b shows the laser beam 142 at an angle α with respect to the material. FIGS. 7a-d show a chamfer 100, 102, and 104 laser machined into the material by focusing the laser more and more deeply with each pass along the path, thereby ablating material and machining the chamfer. The chamfer could be machined into either the top surface 143 or the bottom surface 144 (FIG. 7e) or both the top surface 143 and the bottom surface 144 (FIG. 7f). The advantage of this approach is that in the case of transparent materials, the angle of the laser with respect to the workpiece would not have to be altered while machining, making the apparatus required to implement this method simpler and less expensive to build. Also, less material is remove with this approach, thereby speeding the process.

Problems solved by technology

While chamfered edges are desirable, no methods exist for creating an article with a chamfered edge in one manufacturing operation.

Such resultant stress and microcracks may either be sufficient to cause the glass to fracture and separate along the designed trajectories or may require a follow-up breaking step to separate the glass.

This technology, however, does require an initial mechanical notch to function as a pre-crack.

None of these methods address forming a chamfer on the resulting edges.

This prior art illustrates the difficulty in creating chamfers on features internal to the article, such as holes or other openings machined into the article.

Chamfering these edges often requires specialized equipment and fixturing in addition to requiring additional manufacturing steps.