How to Achieve a Professional Finish on Resin 3D Prints

Make your resin 3D prints look polished and professional by following these post-processing steps.

With resin 3D printing, you can produce intricate and detailed models in a relatively short amount of time. One of the most critical steps in this process is post-processing. This is essential to remove leftover bits of resin that have not cured during the 3D printing process, and it also helps achieve a smooth and glossy part.

Before we explore the process of finishing resin 3D prints, let's look at the essential tools required.

Some of the items required for post-processing include:

With the tools to hand, you can follow the steps below to post-process your resin 3D prints.

After 3D printing, put on gloves and safety goggles to protect your hands and eyes from the resin. Next, carefully remove the print from the bed with a spatula or scraping tool. You can also use a plastic razor blade or a dull kitchen knife. As you remove the print, move slowly and carefully to avoid scratching or damaging it. You can begin by scraping around the edges of the print, then gently lift it off the build-plate using your hand.

If there are leftover bits of resin on your design, you can start by wiping them off with a cloth. It's essential to use a gentle motion, as vigorous scrubbing can ruin the design, especially the delicate parts. Use a cotton swab instead if you don't have a soft cloth—I tried this, and it worked great, especially when the resin was still wet.

Use a pair of pliers or tweezers to cut away the 3D printing supports carefully. Be sure to take your time and be gentle as you do this, as the supports can be fragile. If the supports are difficult to remove, you may need to use the X-acto knife to cut them off. Once you remove the supports, you’ll want to use the scissors to trim away any excess material.

This will help ensure that your 3D print doesn't have bigger rougher surfaces.

If there is still excess resin stuck to it, you will need to soak the print in isopropyl. To do this, pour enough isopropyl alcohol into a container and submerge the print fully. The concentration of the alcohol should be at least 90% to ensure effective cleaning.

You can gently shake the container to loosen excess resin from the print. Leave it for a few minutes before removing it. Use gloves or tweezers to prevent the resin touching your skin. After removing it, wipe it with a cloth to remove excess isopropyl on the print.

Curing is where the print is exposed to UV light to cure the resin and harden it fully. You can use a curing machine like the Anycubic Wash & Cure or Elegoo Mercury Plus 2.0, sunlight, or a UV lamp. A curing machine is the most effective method, as it cures all the parts of your resin print uniformly.

To use the curing machine, start by placing your print inside the curing chamber and ensure that the print is in a position where the curing light can reach all surfaces of the object. Next, turn on the machine and set the timer and intensity settings according to the manufacturer's recommendations, and the curing process will begin.

You will need to wait a few minutes or hours (depending on your design) for the curing to complete before removing and inspecting it for any defects or issues. The good thing about curing machines is that most of them can wash your 3D prints. So you won't have to struggle to clean your print using isopropyl alcohol.

If you don't have a curing machine, you can simply expose it to sunlight. When doing this, ensure it is in a spot where it will receive direct sunlight throughout the day. If you’re working indoors, place the resin near a window where it will receive ample sunshine. Once the resin is in the perfect spot, it should take 15 minutes to an hour to cure.

You will need to use sandpaper to achieve a smooth surface on the print. You can start with a coarse grit, like 80-grit, to remove any large bumps or ridges. The surface will become softer and smoother as you move through increasingly finer grits, like 120-grit and 220-grit.

You can even follow this with fine sandpaper, like 400 grit, for a super smooth finish. Using the right sandpaper and sanding in the same direction is essential to avoid creating scratches or gouges.

After sanding, it's time to polish your print to achieve a shiny finish. To do this, you can take a polishing compound like Flitz multi-purpose polish and cleaner liquid, apply it with a soft cloth, and start polishing your design.

Once the polishing compound has dried, buff the print's surface with another soft cloth to make it shine. This is optional but highly recommended. After that, you can then paint your 3D print if you want to.

As with other 3D printing technologies like FDM, you need to apply various post-processing activities to your 3D print. Finishing is a crucial step that must be done on resin 3D prints to remove the resin that is not hardened and achieve professional-looking results.

With the steps described above, you should have a smooth, shiny, and hardened 3D print ready for use. As you post-process, remember that resin is dangerous to your skin and eyes, so you should ensure that you wear protective gear during the entire process.

Sammy has been covering 3D printing and 3D modeling topics since 2017. He has written for various websites, including All3DP (one of the most popular 3D printing magazines), 3Dsourced, and 3DWithUs. He owns six 3D printers, and when he is not writing, you will find him designing and 3D printing objects.He is currently pursuing a Masters Degree in Information Technology.