WO1999028535A1 - Etching methods - Google Patents

Abstract

There is disclosed a method for etching a predetermined pattern onto a substrate comprising the steps of: cutting a cut-out pattern from a sheet of etch resistant material; masking the substrate by adhering the cut-out pattern onto the substrate; and etching the masked substrate thereby to produce the predetermined pattern.

Description

ETCHING METHODS

This invention relates to methods for etching a substrate, with particular, but by no means exclusive, reference to the etching of moulds, especially moulds for components of automobiles and the plastics industry in general.

There are numerous moulded components of automobiles which are desirably moulded with some form of pattern theron, which pattern might comprise lettering, graphics, geometric patterns, grain effects or texturing. Examples of such components include handles and dashboards. The pattern is produced by appropriate etching of the mould parts. One commonly used method of etching involves the use of photolithographic techniques to produce a photomask. However, the technique is laborious and cannot easily be applied to non-planar surfaces. Furthermore, flaws in the pattern are often apparent, caused by imperfections which allow the etchant to seep in.

The present invention overcomes the above problems and provides a method for etching which is flexible, convenient, accurate and easily applicable to non- planar surfaces such as curved surfaces.

According to the invention there is provided a method for etching a predetermined pattern onto a substrate comprising the steps of:

cutting a cut-out pattern from a sheet of etch resistant material;

masking the substrate by adhering the cut-out pattern onto the substrate; and

etching the masked substrate thereby to produce the predetermined pattern. The pattern can comprise, for example, lettering, graining, texturing or graphical representations.

The substrate may comprise a mould part, which part may be for moulding a component of an automobile.

Alternatively, the substrate may comprise a tool. Information relating to the tool maker may be etched onto the tool.

The substrate may be fabricated from steel.

The cutting may be controlled by a computer, and the cut-out pattern may be produced on a CAD design system.

The etch resistant material may be a plastic, which may be a vinyl plastic.

The cut-out pattern may be adhered to the substrate by a low tack film.

The invention also comprises a substrate etched by the above described method.

Methods in accordance with the invention will now be described with reference to the accompanying drawings, in which:-

Figure 1 is a cross-sectional view of a cut-out pattern adhered to a substrate; and

Figure 2 is a face on view of a cut-out pattern for use on a highly curved substrate. The cutting of the cut-out pattern is preferably and conveniently performed using a commerically available cutter plotter device (an example being a Mimaki CG-61 cutter plotter) which operates under computer control. The entire package can be part of a CAD design system, offering enormous design flexibility. Further, essentially flawless patterns of great intricacy can be routinely produced. The sheet of etch resistant material can be any suitable material, such as a vinyl plastic. The vinyl is cut to the required cut-out pattern while on a wax release paper backing and can be separated therefrom by the application of another release, or simply by peeling off from the backing a matrix out of which "islands" have been cut, leaving "positive" and "negative" patterns corresonding to the desired pattern to be produced on the substrate.

The substrate is marked by adhering the cut-off pattern to the substrate in a suitable manner. Figure 1 shows a cut-off pattern 10 adhered to a substrate 12 by a low tack film 14. Such is suitable for use with steel substrates (usually primed before the application of the low tack film). Other substrates are also within the scope of the invention. Correct alignment of the cut-off pattern with the substrate is easily accomplished and, in any case, adjustment of the positioning is readily performed.

The masked substrate is then etched, thereby providing the predeterminded pattern. Any suitable etchant may be used, such as a ferric chloride solution in the case of a steel substrate.

The method is flexible, convenient and accurate, producing high quality patterns and preventing etchant from seeping underneath the masking cut-off pattern. Furthermore, it is advantageous that the method can be applied to non-planar surfaces due to the flexible nature of the sheet and, if used, the low tack film. For a substrate which has curvature in two directions it is possible to produce a distorted pattern, such as the pattern 20 shown in Figure 2, which can be based on biaxially orientable film and streched appropriately to fit the substrate to compensate for the curvatures and yield a regular, well oriented pattern.

An important example of a substrate is a mould part, which is frequently highly curved. The invention is well suited to the production of mould parts for use in moulding a variety of components for the plastics industry in general, and for automobiles, many components of which, such as handles and dashboards, commonly have features such as raised texturing or knurling. Mould parts suitable for other purposes, for example in the production of a wide range of domestic goods, are also within the scope of the invention.

Another example of a substrate is a tool. The tool can be a purpose built tool, made by a specialist tool-maker, in which instance the tool-maker's name and/or other details can be etched onto the tool.

Claims

1. A method for etching a predetermined pattern onto a substrate comprising the steps of:

cutting a cut-out pattern from a sheet of etch resistant material;

masking the substrate by adhering the cut-out pattern on to the substrate; and

etching the masked substrate thereby to produce the predetermined pattern.

2. A method according to claim 1 in which the substrate comprises a mould part.

3. A method according to claim 1 in which the substrate comprises a mould part for moulding a component of an automobile.

4. A method according to claim 1 in which the substrate comprises a tool.

5. A method according to claim 4 in which information relating to the tool maker is etched onto the tool.

6. A method according to any of the previous claims in which the substrate is fabricated from steel.

7. A method according to any of the previous claims in which the cutting is controlled by a computer.

8. A method according to claim 7 in which the cut-out pattern is produced on a CAD design system.

9. A method according to any of the previous claims in which the etch resistant material is a plastic.

10. A method according to claim 9 in which the etch resistant material is a vinyl plastic.

11. A method according to any of the previous claims in which the cut-out pattern is adhered to the substrate by a low tack film.

12. A substrate etched by a method according to any of claims 1 to 11.