Step by Step Guide on How to Post-process Your FDM 3D Prints!

3D printing is a very fascinating process. However, the aftermath of processing the printed models can leave you frustrated, if not mastered properly. 

Almost every 3D printed part needs some sort of post-processing for perfection. Since not every STL file will turn out exactly into the 3D model desired. These steps improve the overall looks and surface quality of the printed parts. 

Not just that, post-processing can also help better the 3D models’ strength and various other properties. Hence, if you haven’t yet found out the best practices to attain amazing-looking 3D printed parts, here are some tips to get you started. 

The post-processing of FDM printed parts happens in two different stages. Starting with the cleaning of the printed part, the components go through finishing methods to lock the overall finish.

For this you'll need:

• Low-grit sandpaper (150-400) and higher grit sandpaper (up to 2,000) for Sanding.
• Needle-nose pliers and Dental pick set for the standard support removal.
• Solvent-safe container, Solvent, and Ultrasonic Cleaner (optional) for the Dissolvable support removal.
• Tack clot, Toothbrush, Aerosol plastic primer, Topcoat paint, Buffing sticks, Masking tape (only if multiple colors are to be used), and Nitrile gloves & appropriate mask for painting and polishing.

Cleaning and preparing the parts for finishing is crucial to get rid of unnecessary support structures. In short, this method requires users to cut the extra materials from the 3D models. 

Although the process is pretty easy and the most basic one, it can get difficult at tight corners or difficult to reach places. Usually, there are two kinds of supports: Insoluble and soluble. The process of support removal will depend on the kind of material you used for printing these structures. 

If you are working with a single extruder, you will come across insoluble supports. These are created using the same material as the main model. Hence, to remove insoluble supports, users must snap the extra structures using their fingers or various cutting tools such as a pair of pliers.

Those with dual extruder printers can make use of soluble support to print the extra structures for realizing complex designs. Unlike insoluble supports that are tricky to remove at congested places, soluble supports are a breeze to take off. 

Simply soak the printed part in either water or another liquid to get rid of extra structures. Support with PVA dissolves in plain water while those made of HIPS go in D-limonene. Depending on which one you used for creating support, pick the liquid to submerge the printed model.

After removing supports, users must carry sanding to smoothen the surface as much as possible. Even parts with no support will benefit from sanding. Typically, models created using FDM printers exhibit slightly rough surfaces. 

Sanding also helps in getting rid of a few blobs that might appear on the part surface after printing. To carry sanding, all you have to do is, use the right grit sandpaper to remove these blemishes. 

Not to forget, wet your sandpaper and use a circular motion to smooth the surface.

The final steps of the post-processing methods are the finishing techniques. These allow users to realize smoother and shinier parts through sanding, polishing, and painting. Therefore, attaining parts with less or no visible layers, flaunting the smoothest possible surface. 

In short, you can hide the imperfections that are often a result of FDM printing.

Although a little time-consuming, painting can offer an amazing finish to your parts. However, before you pick up the spray paint or the brush, you must carry priming. This technique is used to prepare a suitable surface for painting. 

Coat the printed part with primer after sanding. This will act as a base layer. For better results, try two coats of primer, waiting after each coating to let the surface dry.

Once completely dry, use the color you wish to paint the parts with. For clearer and sharp intersections between two shades, use masking tape. 

In order to achieve the shinier and smoother surface possible, you can go with the polishing technique. To carry the polishing of 3D models, use plastic polishers along with a few tools you can easily find in hardware stores. 

To be precise, apart from the plastic polisher, you will require a microfiber cloth. Those seeking even better results, easily achievable, can also purchase a Dremel tool. 

Just remember, polishing goes after sanding. Hence, you must smoothen the surface with the finest sandpaper. Once sanding completes, do not forget to clean the parts by rinsing them to get rid of stuck particles on the surface. 

In case you have got a cloth, use it by rubbing along the models’ surface in a circular motion after applying the polisher. If you have got a Dremel buffer, the job will become simpler. All you have to make sure of is that the tool moves evenly when polishing the surface.