Once your print is finished, you may want or even need to perform some post-processing to get a good-looking result. While you’ll likely understand the need to post-process areas where you’ve removed supports, you may want to smooth the whole print to get a professional-looking result. Unfortunately, the processes for smoothing prints can vary depending on which material you’re using. This article will cover tips for smoothing prints using PLA filaments.
Tips for Smoothing PLA Prints
Sanding is a common tip for post-processing 3D prints. It is often specifically targeted at artifacts caused by the removal of support structures. However, for PLA, it is often necessary to sand the entire print to achieve a smooth finish. When sanding, you should sand in a circular motion and start with coarse-grit sandpaper of around 200 grit. Over time you should progress to finer sandpapers like 4000 grit for the finishing touches if it’s available.
It’s best to avoid using power tools when sanding, as these can cause excessive vibrations, potentially damaging the print. Power tools are also much more likely to create excessive heat, a problem that can also affect manual sanding. Instead, it’s best to use wet/dry sandpaper as you can wet it to cool the print as you sand it. Wetting the sandpaper and rinsing the print also helps clean off particles and stop them from becoming airborne and inhaled.
Tip: Wet/dry sandpaper can generally be distinguished because the grit is black rather than tan or beige.
Once you’ve finished sanding, adding a polishing compound can help to fill in any layer lines and can then be smoothed back down to the plastic with further sanding. A less popular and much more risky approach is using a heat gun to carefully remelt the surface. The trick to this is to ensure that you keep the heat gun moving. If you let it stay on one area for too long, it can easily melt and irreparably damage the print.
A common method of smoothing a print made from ABS filament is to place it in a sealed container with an acetone mist. Unfortunately, this requires safety precautions, but it also doesn’t work with PLA as acetone doesn’t react in the same way with PLA. There are other possible chemicals that you could use. Still, all of them are even more dangerous to use due to their toxicity and are generally difficult to acquire. You can smooth some PLA filaments by placing them in a mist of isopropyl alcohol. However, this doesn’t work with all PLA filaments. It tends to leave the print with a sticky surface if it does work, so it’s best to give the print at least an hour to sit and dry in a dust-free environment before handling it.
Hopefully, these tips help you to smooth your PLA prints to get a professional-looking result. If you’ve got any other tips to help smooth PLA prints, please share them down below.