How to Wash and Clean 3D Resin Prints

comparison of unclean and clean print
(Left: before clean; Right: after clean)

Resin printers can make a 3d print with a smooth surface and incredible details. Indeed, resin 3d printing can do well in tolerance, resolution and accuracy, compared to FDM 3d printing. However, as to post-processing works, resin 3d printing would be much more complicated than FDM, which will mess up everything when done inappropriately.

Washing and cleaning resin prints is one of the most important steps in the post-processing of 3D resin prints. The purpose is to improve the quality and the mechanical property of your prints, by way of removing any sticky uncured resin that may remain on the surface of the print. In this article, we'll discuss how to clean 3D resin prints, the comparison of different washing methods, and how to quickly recycle used solvents like IPA.

How to Wash a Resin 3D Print

Resin prints are made of liquid resin by using UV light to cure. However, some residual uncured resin will remain that needs to be cleaned, or they can be sticky and reduce the accuracy of the print surface. The most common way to wash 3d prints is using isopropyl alcohol (IPA) as a solvent to remove the sticky resin and make the surface clean and smooth. Three cleaning methods will be introduced in the following.

1. Soak and rinse in a container

Soak and rinse in a container

Using a container to wash is a budget way, which is immersing the print in a bath filled with isopropyl solution for 5-10 minutes. The concentration of alcohol used for washing should be more than 95%, or the print will turn white after washing and curing. You also need to prepare a soft brush to deal with the prints with small corners behind the supports in order to make a full cleaning. Finally, it is recommended that prepare 2 baths for rinsing twice with fresh IPA to confirm no liquid resin remaining on the part.

This washing method by hand shows it is a complicated process, compared to the method of using automatic machines mentioned below.

The Pros and Cons of DIY washing bath

PROS: CONS:
  • Low cost
  • Widely available
  • Manual cleaning takes time and attention
  • Dangerous since IPA is in the open air during cleaning
  • 2. Ultrasonic cleaner

    principle operation ultrasonic cleaner
    (Image source: Tangible Day)

    An ultrasonic cleaner works by creating high-frequency sound waves that cause microscopic bubbles to remove the uncured resin. This technology seems to bring the makers convenience and high efficiency, but it is relatively expensive and noisy due to the high-frequency vibrations.

    Additionally, it's considered to be dangerous when washing resin prints in an ultrasonic bath with flammable liquids like IPA, because the high-frequency vibrations can create sparks and trigger fire.

    The Pros and Cons of ultrasonic cleaner

    PROS: CONS:
  • Cleans efficiently
  • Works conveniently and automatically
  • High cost
  • Creates noise
  • Exists fire hazard
  • 3. Washing stations machine

    Washing stations machine

    Many manufacturers have provided washing stations for their 3d resin printers, for example, Anycubic Wash & Cure 3 Plus Machine features a combination of washing and curing functions. Its wash mode works by a turbine that drives to a large and strong vortex allowing the solution to clean every corner of the part.

    What's more, it offers two enclosed washing methods. One way is to put the parts into a stainless steel basket, the other way is to hang the build plate on the basket to avoid direct contact between the part and the surroundings, which can protect the print surface during washing. When comes to safety, it can detect whether the machine lid is covered up and prevent a mess.

    Washing method

    Whereas it needs more IPA than manual cleaning, when cleaning small prints like miniatures. Since the machine needs a certain amount of fluid to get the turbo run, sometimes a glass of IPA is all it takes to clean a miniature.

    A washing station machine is the most appropriate choice as its advantages outweigh the disadvantages. In general, it is not as dangerous and expensive as an ultrasonic machine, but also it can reduce work in post-processing and free your hands. So why not just let the cleaning work be handed over to the washing station machine by pressing a button?

    The Pros and Cons of washing stations machine

    PROS: CONS:
  • Cleans efficiently
  • Works conveniently and automatically
  • Enclosed washing for safety
  • Offers two washing methods
  • More affordable than an ultrasonic cleaner
  • Consumes more solvent than washing by hand
  • Cost more money than washing by hand
  • How Long to Wash a Resin 3D Print

    Poor time management for washing can easily damage the prints. For example, if the print doesn't get a full clean, it will cause a sticky surface. Conversely, soaking too long, the printed parts will absorb too much liquid and swell, resulting in cracks and brittleness. 5-10 minutes should be enough to clean away uncured resin from a regular-sized print. But large prints usually require 10-20 minutes and it's best to pay attention to the observation.

    For the washing station machine, cleaning times may vary with machines from different manufacturers, and use it according to the instructions provided by the manufacturer. The following is the reference for cleaning time, which is suitable for Anycubic Wash & Cure Machines:

    Model Size Wash Solvent Recommended Washing Time
    Small
    (≤64×40×80mm)
    IPA ≤2min
    water* 10min
    Middle
    (64×40×80-96×60×122mm)
    IPA 2min
    water* 10-12min
    Large
    (96×60×122-192×120×245mm)
    IPA 2-4min
    water* 10-12min

    *Notice: Only models printed with water-washable resin can be washed by water.

    When finishing up the washing step, move to support removal, and then dry the resin print in order to get a full cure. With respect to the guideline on the post-processing of curing 3d resin, like the methods of curing 3D resin prints, you will see that in the article: How Long to Cure 3D Resin Prints?

    How to Clean and Recycle IPA

    recycle the solution

    After used for cleaning about 30 resin prints, the IPA might become muddy and cloudy, here are 4 steps to quickly recycle the solution.

    Step 1: Allow the residue to stay still for over 10 hours, so it could be precipitated and settled.

    Step 2: Pour the top layer of IPA into another container and then dispose of it. (Notice: Expose the residue under sunlight or UV light until it is completely evaporated and cured. And the cured resin can be treated as general solid plastic waste.)

    Step 3: Rinse the washing bucket several times with water. If the sediment at the bucket bottom is sticky, remove the bucket rotor and brush them separately.

    Step 4: Pour the filtered IPA into the washing bucket and covered it with a lid for later use. (Notice: The filtered solution may still contain dissolved resin, but still can be used to wash prints.)