Molding a Multistep Process

Wednesday, September 10, 2014

Very rarely can an injection mold exist on its own without any surface improvements, especially when making small or detailed products through the injection process. Etching, polishing and high sheen are three finishes that can be created on a mold surface, affecting the end result of the creation.

To achieve an etching, polished or highly shiny finish, the mold must first be ground after the general machining process. The machine created mold will have extra edges and potentially surfaces that need to be shaped better. Grounding the mold helps prepare it for a finish.

Using different grades of polishing stones, the surface of the injection mold can be polished by hand. The stones, which range from 150 grit to 600 grit similar to sandpaper, should be used consequentially until the desired look is obtained. This will take time and effort on the part of workers that wish to get the mold from ground to finished.

Stopping there results in a polished finish. However, more polishing must be done to take the mold a step farther for a nicer, shiner finish. A 600 grit polishing stone creates tiny scratches that are close together, giving off a lustered appearance. The higher the grit used, the more shine the mold will have.

For an etched surface, acid will be used to burn different finishes into the mold. To create a product with a pebbled or wood finish, the design will be burnt into the mold. Etching is also used to imprint numbers, letters, words and more into places on products. This is most common for products that have hard to reach places that need to be labeled.

Each type of finished has a direct result on the end product from the mold. And although the work behind each type is extensive and intensive, the results speak for themselves. In fact, the finish is an integral part of the release product after product has been injected and molded.