The Basics of 3D Print Finishing
Author: 
Duncan Ryan

In the world of 3D printing, the printing process itself gets a great deal of attention. What most people don't give quite as much thought to is the finishing process that takes place afterward. Finishing a print can drastically improve its surface quality, appearance and function. Following, you'll learn about some of the most common finishing techniques you can use to improve your 3D printed objects.

Sanding

Sanding is probably the most common and easiest method for getting an improved finish on a 3D print. If done correctly, sanding can take a print with rough or uneven edges down to a perfect, smooth finish in very little time. For best results, you should sand your prints with several grits, beginning with a 100-grit sandpaper and moving gradually up toward finer and finer grits until you get the desired finish. Remember, not every object needs to be sanded to the same degree. An ABS part meant for functional use likely will not require the same precision finish as a decorative object.

Chemical Washes

Another common approach to finishing 3D prints is to use a chemical wash to even out the surface of the print. For resin prints created on stereolithography machines, isopropyl alcohol is often used to remove the uncured layer on the outside of a print, producing a smoother finish. Acetone can be used to similar effect on ABS prints, as the solvent will actually dissolve the outermost layer of the print and smooth out the surface. Whenever you're using a chemical wash to finish a 3D print, be sure to read and follow all safety precautions and to provide for appropriate ventilation.

Support Removal

If you're printing more complex objects with arches or overhangs in their geometries, you'll likely have to go through the step of removing excess support material before you can use or display your print. You can remove supports by stripping them away with a knife or pliers, or by breaking them off with your fingers if the material is brittle enough. Always use caution when removing supports, since it's easy to damage the print itself if you try to remove them too quickly or use too much force. Applying a bit of heat to the supports with a handheld torch or lighter can make the job easier by rendering the plastic softer and more pliable. After you remove the supports, you'll want to sand the print, as there will always be some leftover material once the support structures are removed.

Joining

If you're 3D printing a large object, you may have to slice your design, print it in pieces and then join those pieces together once the printing process is complete. There are several ways to do this, and the appropriate method will vary by the size of the object you're printing and the strength the joint needs to have. At its simplest, joining can be accomplished with a layer of superglue applied to flat surfaces. If you need something more robust, you might consider building interlocking joints into your design that can then be fitted together in combination with an adhesive for a stronger connection.

Painting

A final common finishing step in the 3D printing process is painting. This is especially common with prints meant for decorative use, as paint can be used to give objects more vibrant and varied colors than the one-color filament from which they're printed. 3D printing is all about creativity, and painting gives designers a final chance to imprint their own vision onto a printed object.

Whatever finishing steps may be needed for the particular print you're working with, it's always important to start with the highest possible print quality. Starting with a great print reduces the need for surface finishing and will make damage less likely when you're removing supports. For this reason, it's crucial to use a high-quality 3D printer like the Dremel DigiLab 3D45. Because it can print at up to a 50-micron resolution, the 3D45 creates prints that are suitable for both hobbyist and commercial applications, If you start with a great print from the 3D45, you'll find that the finishing process is less labor intensive and produces a better final result.