A huge range of textures can be applied such as stone, leather-grained or regular dimpled patterns
Textures on rotational mouldings
By far the most common way of applying a surface texture to a rotomoulded plastic component used to be shot peening. Small pieces of cast steel shot strike the surface of the mould until it is completely covered with dents; the result on the plastic product is a series of tiny regular pimples, giving a uniform textured appearance overall.
Shot peening can be varied in depth but it does not provide much variety. This limits the range of applications for rotomoulded components, so tecni-form now frequently use photo-etching on aluminium moulds, a texturing process often seen in injection moulding. The sharp detail and uniformity give a very high quality appearance, and there are over 10,000 patterns to choose from.
Photo-Etching for rotationally moulded plastics
The photo-etching process is, in brief:
- Prepare the surface of the aluminium tool
- Apply an etch-resistant pattern to the tool
- Immerse the tool in a chemical etchant
- Remove the by-products from the tool surface
- Apply a proprietary protective coating to the tool surface
- Clean, degrease and coat the tool ready for moulding.
The process can be applied to all aluminium tools – either cast or machined from the solid.
Advantages of photo-etching rotationally moulded components
Although the photo-etching process is more expensive and time-consuming than shot peening, the process has some significant advantages:
- A huge range of textures can be applied such as stone, leather-grained or regular dimpled patterns
- Several different textures can be applied to a single tool
- The quality of the surface finish is higher than can be achieved by other processes
- A deeper texture can be achieved than all other processes with the exceptions of engraving and casting-in
- Textures can be applied to modified, repaired or old tools.
If you would like more information on using photo-etching on rotationally moulded plastic components, please see their Design Library.