After removing the support structure, there will be small nubs on the part where the supports came in contact with the print. These are referred to as "contact points". In order to get a smooth finish, the print surface will need sanding. Additionally, the surface or the entire part can be polished afterwards. Below are guidelines for a few options, but adjustments can be made to better suit the needs for different applications.
Option 1 | Standard Finishing Procedure
Sand with 200 grit sandpaper first, then with 400 grit. Use oil or water with 400 grit to avoid clogging the paper. Mineral or baby oil is useful to help clean dust and remove the sanding marks without polishing. A clear-coat spray can be used instead of oil to avoid polishing the 400 grit marks.
Option 2 | Getting a Clear or Class A Finish
The following steps can be used as initial guidance for improving the finish or clarity of most parts, the exact steps and method will be determined by the geometry and application requirements:
Mark both sides of the printed object with a black ink or an available guide coating material.
Using 240 grit sandpaper, evenly sand the surface in an opposing 45-degree angle pattern until the surface has been fully sanded and the guide coat has been removed.
Remove sanding dust and any other debris from the surface of the part before proceeding to the next step.
Repeat steps 1 through 3 stepping up the numerical grit size: 400, 600, 800 and finishing at a buffing compound until the surface is smooth and has achieved the desired level of clarity.
Optional step: After using the above sanding method through grit size 800, thoroughly clean the surface of the part removing all dust and debris. Using multiple light coats of a high quality automotive clear coat, coat the surface of the printed part. Once the clear coating has fully cured, buff the surface as needed to achieve the desired level of clarity.
Dental materials require a level of finishing that leaves the printed parts ready for a number of biocompatible uses. Specialized post-processing steps such as sterilization via the use of a steam autoclave (among others) are needed to make printed parts fully biocompatible.
Keystone has provided detailed instructions for use with their dental materials, which can be found on their website linked below: