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How to smooth 3D printed parts (PLA only)

One of the most common questions asked regarding 3d printing is, “Can you smooth out the parts after they are 3D printed?”

Of course, the answer is “yes”, but the details are what matter here. To answer the question properly let’s discuss a few key terms first. (Note: these terms are broken down to the simplest form so that people not familiar with the industry can understand.)

Filament – The term used to identify the material used in FFF 3D printing.

FFF- Fused Filament Fabrication – The process of using filament that is extruded from a print head (extruder) and laid down upon itself in layers form an object.

PLA  – Polylactic Acid – A plastic used in 3d printing process. This is the type we will focus on in this article.

Why smooth out the parts?

In FFF 3d printing, parts can sometimes appear coarse, have blemishes, or have other slight issues depending on settings or other factors. If you are just prototyping a part and expect changes or you don’t need a clean looking object, then finishing a 3D printed part may be unnecessary. If you are someone who is trying to make a mold from a 3d printed object, putting objects out to display, or creating finished products for clients, then this article is for you. Personally, I do not spend a lot of time finishing parts. The reason is that as a 3D printer manufacturer I want people to see the finished objects as what they are.  But from time to time I will spend the extra time for clients or if a museum asks for objects to display.

The process to smooth out the parts

Depending on your project’s need, first decide on what the end product should look like . Will the object look better shiny or dull? Will the object be somewhat hidden among other parts or be stand alone? Will the object only have one part or side of it visible? These questions make a difference in how much work and time it takes for the process from start to finish. For this particular project I provided both finished and unfinished parts. The bottom and back of the objects are not going to be seen so I didn’t spend a lot of time on those areas.

Step 1: Print out the objects.

These objects in particular took about 6 hours each and were printed with Hatchbox PLA. They were created in AutoCAD and were fabricated on our large format 3D printer.

  • Step 2: We sanded the rough lines that you see on some of the objects. The dots that you see are from overheated material. They can be sanded as well.

  • Step 3: We cleaned up the sanded object with just soap and water then fully dried.

  • Step 4: The finish. We used a two part coating XTC-3DThis is a two part epoxy that you mix. Directions are on the box. Take extreme caution as this stuff is highly toxic. Use proper ventilation and safety gear. 

  • Step 5: Let dry.

  • Step 6: Install.