Smooth Finishing of 3D Printed Objects (TfCD)

by irischung

9.1K1336

Intro: Smooth Finishing of 3D Printed Objects (TfCD)

The use of 3D printing for quick prototyping or producing small batches is popular nowadays. For the master course Advanced Concept Design (subcourse TFCD) at the Technical University of Delft, a learning tool is created for medical students to draw on 3D printed body parts, to improve their spatial knowledge. There are more applications in- and outside the medical world, where writing and drawing on organic surfaces can be beneficial for communication. Teachers and students shall draw with non permanent (dry erase) markers, so they can reuse the learning tool. The ink will evaporate rapidly, leaving dry ink on the surface which makes it easy to wipe off. Therefore it is necessarily to have a smooth surface, so the ink of the marker won’t sink into the material/print layers.

STEP 1: Collect All Items Needed

You will need:

  • Kitchen paper
  • Aluminum foil
  • Plastic container and lid

Use PP or any other plastic that won't dissolve with acetone. Also consider the size of the container, the 3D printed object should fit in easily.

  • Aceton 50 ml
  • 3D printed object (ABS)

When using another plastic than ABS, check the plastic chemical resistance chart. Not all plastics react with acetone. NOTE: Some alternatives can be dangerous.

  • Protection
  • Last but not least: a well ventilated environment or outdoors

STEP 2: Prepare Container

  1. Cover the green lid with the aluminum foil, so the object won't stick on the surface of the lid.
  2. Place the kitchen paper in the container on each side. The kitchen papers shall absorb the acetone liquid. The 3D object should only be in contact with the acetone vapor. You could leave a gap to see what is happening inside.
  3. Carefully place the 3D printed object in the center on the lid.

STEP 3: Add Acetone and Start Vaporizing

1. Add a small amount of acetone in a cup. 50 ml is enough, but there is no strict guideline. Avoid touching the skin and inhalation, this can cause irritation.

2. Empty the cup in the container and wet the kitchen towels. Try to be quick since the liquid is already evaporating.

STEP 4: Wait for One Hour

1. Make sure the container is airtight by placing an heavy object on top.

2. Be patient and wait for one hour at least.

STEP 5: See Result and Redo Step 4 When Needed

1. Take the container off the lid and see if the 3D printed object has the desired result. It should be smooth and shiny. If not, redo the process by adding more acetone and wait for another hour or two.

2. Wait a few minutes extra to be sure the product is hard. It is now possible to draw with whiteboard markers!

6 Comments

AlexFW 8 years ago

Is there an alternative chemical for PLA prints?

trevoratkinson 8 years ago

try dichloromethane I find this dissolves both PLA and ABS

irischung 8 years ago

Yes there is. I have used ABS as an example since it is not difficult to buy some acetone. This technique is based on chemical reactions, and apparently PLA reacts with Ethyl Acetate. I used the 'cold' vapor method which doesn't involve boiling the substance. When that doesn't work you could try to boil the Ethyl Acetate,... but do some research first since it is dangerous to work with these chemicals!

NikolajR3 8 years ago

I guess this technique only works with ABS prints, or...?

irischung 8 years ago

Other combinations might work as well such as PLA and Ethyl Acetate. Look for the temperature when the substance is evaporating (Acetone evaporates at room temperature, which is good so I don't have to use the 'dangerous' boiling technique.). I do not have any experience with other combinations other than ABS and acetone, so please do some research first before trying it out. Other than vapor, you can also brush it on the 3D printed object or a bath, but printed details could disappear.