Finishing 3D printed parts with… crayons?

Helping additive manufacturing specialists develop more effective, more efficient post-processing stages is a huge priority for the team at RP Platform. We’re always looking for new ways of finishing 3D printed parts that will not only deliver exceptional results, but — equally importantly — how they could potentially be be deployed in a production capacity.

For example, one new post-processing technique that caught our eye recently was Formnext engineer Christian Reed’s new technique for using wax crayons to add a touch of colour to his plastic prototype. Christian’s technique involves smoothing the part with sandpaper to achieve a completely smooth surface, then using a heat gun to melt wax crayons, so the material drips into indented areas of the model. This is then allowed to dry, after which it can be cleaned and smoothed out. This way, an attractive coloured design can be added to a relatively simple plastic part, for relatively little additional effort.

While Christian’s solution was intended for a prototyping application (which we understand was successful, as his design has now been successfully funded on Kickstarter), we would be interested to see how it could be applied in other ways that could potentially be suitable for production applications. The most striking element of the process (beyond the nostalgic element of using wax crayons!) is the use of an indent in the model itself for the coloured design. While this will obviously need to be factored into the model during the design stage, it could in fact be a useful approach for models that require both a multi-coloured design and extremely precise dimensions, as the coloured areas can be added and then smoothed out to perfectly fit the surface dimensions.

It’s hard to see how this could be automated for large-scale production, but perhaps it could be a powerful solution for high-end, one-off parts (customised interior parts for sports cars, for example). In such scenarios, we would envisage more durable materials than wax being utilised — perhaps silicone, or even precious metals, such as gold and silver.

We look forward to seeing more creative finishing techniques like this, so if you have found a new way of creating a unique end result when finishing 3D printed parts, do feel free to share it with us!