Surface finish – Why polish and etch are key

Surface Finish

Surface finish is one of those elements of product design that quite often doesn’t get a second thought, let alone a first thought.  In this post, we want to highlight the difference that surface finish can make in improving product quality.

So let’s just understand what surface finish is, and where it fits into the process.

Surface finish is about a couple of things:

1. Touchy feely interaction with a product – often applied to parts of a product that a user is contact with, to provide different sensations of touch.

2. Perceived quality – by breaking up the areas of a part with different surface finishes, you can create a sense that the part is a more refined design, with more care and forethought put into the product by the brand, without raising the unit price of that part.

3. Brand identity – polishes and surface etches can be employed as part of a brand guide, and used across a range of products. This is quite noticeable when used as a combination of “spattered” type surface roughness etch (or EDM finishes) and a geometric etch (or technical finish) such as repeated dots, crosses, triangles or another custom motif.

4. Hiding manufacturing defects – perhaps the origin of surface treatments, hiding sink marks, weld and flow lines, and other surface imperfections is a common use for polish and etch finishes.

Technically, surface finish can be created by either mould polishing, spark eroding (shaping a mould), or the treatment of a mould surface by “etching” a pattern into it.

So let’s take a look at an example of how this can be applied.

Polish and Etch

The image above shows part of a toolbox handle from a project we completed a while back. It is a two-piece construction – the main body, shown in black, which fastens to the toolbox, and the outer dress piece, in red, which clips into the handle body.  Both parts are made of ABS plastic.

The image on the left has no particular surface finish applied. The injection moulding tool has been finished in #1000 polish, which leaves a surface that is smooth to the touch, but has no interesting characteristic.

The image on the right shows the same part but after application of different etches and polishes.

The treatments applied are:

1. Highly polished branding text (shown here as TOOLBOX).

2. Coarse surface etch surrounding the text(Mold Tech 15605).

3. Highly polished shadow gap.

4. Geometric checker pattern etch (Mold Tech 14083).

5. Bump pattern, applied to the black handle part (Mold Tech 15080).

Polishing areas of a part and contrasting them with coarse etches is enough to create that extra level of detail.  The geometric etch used here is part of the brand guide, and would be replicated elsewhere on this and other products in the same range. We’ll talk more about geometric etches and branding in another post.

It’s quite clear to see that whilst the handle on the left looks good, once you see it with its final surface treatments (shown right), the original handle looks quite plain and unfinished.

Creating a great product is as much about the idea and function as it is about the “finishing” touches (pun intended). Don’t forget your polish and etch!

Lucas Lastman

An industrial designer with 15 years’ experience, working across a broad range of industries, from automotive, to consumer product, retail and packaging, to power tool and hardware. Lucas enjoys working directly with clients to facilitate the solution process and tackle challenges early on in the process.