How to post-process LCD, DLP and SLA 3D printed objects?

Cleaning and curring resin prints is a critical part of SLA post-processing. Learn how to wash and cure resin 3D prints in three easy steps.

Post-processing lets you take full advantage of our FunToDo and Dentifix-3D resins. Following the correct process will maximize the quality and mechanical performance of your prints, such as strength, durability and hardness.

After printing and removing the object from the build plate, it is necessary to clean the part. We advise rinsing it twice for three minutes in ethanol or IPA, preferably using ultrasonic cleaning or agitation. After cleaning, make sure to properly UV cure. The last step includes removing the supports with a model cutter. Finally, it is possible to improve the aesthetics or function of the part through optional post-processing steps such as sanding, polishing, priming and painting.

Unlike other resins on the market, FunToDo and Dentifix-3D photopolymer resins are developed to be as user-friendly as possible. Therefore, they have a manageable hazard classification and use fewer hazard statements. Please be aware of the hazard statements which are also displayed on the bottles.

TIP: For proper handling, you will need nitrile gloves, safety glasses, and a clear workspace with an open window or ventilation setup.

Step 1: rinse 3D printed models

Washing time: for our resins is a 3-minute wash cycle, repeated twice (ultrasonic power 50-80W). Between washes, a full drying should be done to avoid alcohol absorption.

When your part comes out of the printer, it is covered with uncured resin. You will have to rinse it off before proceeding further with post-processing.

Printed parts should be washed with alcohol (ethanol or IPA isopropyl). We highly recommend using 40-60% ethyl alcohol to rinse off the part printed with FunToDo or Dentifix-3D resin. The main reason is that our resin has a low viscosity and can be easily cleaned with diluted alcohol in a short flush cycle, which minimizes physical and chemical influences on the 3D printed part for the best results.

To thoroughly wash printed models, it is necessary to use an ultrasonic bath or a specialized washing station. Additionally, a synthetic brush can be used for washing models of complex shape.

There are other cleaning fluids you can use too, like Tripropylene Glycol Monomethyl Ether (TPM) and Dipropylene Glycol Monomethyl Ether (DPM).

Printed models absorb alcohol and can crack locally if exposed to cleaning solvents for more than 20 minutes. After this cleaning step, ensure the parts are dry before post-curing by placing them in a well-ventilated area for at least 30 minutes or using pressurized air for 2 minutes.

TIP: to optimize alcohol consumption, divide the washing operation into two parts. First, place the model in a container of dirty alcohol to wash out liquid resin, and then in an ultrasonic bath with clean alcohol to clean the surface.

TIP: even though it is much easier to remove supports after model rinsing, we recommend removing supports after the final UV curing in Step 3. This is especially important for models with a high degree of accuracy, such as engineering, dental, or jewellery models, so that the model has higher structural rigidity and retains its ideal geometric shape until all reactions are finished.

Step 2: heat 3D printed models (optional)

Heating time and temperature: 30 minutes under 70°C.

After washing, it is recommended to heat models in a dry heater. This is necessary in order to evaporate the alcohol from the surface layers of the model, as well as to remove any tension between the layers. This step is especially important for models used in dentistry that come into direct contact with patients.


Step 3: final UV curing of printed parts

Curing time: 20-30 minutes in UV station (80-100W). The preferred wavelength of the curing unit should be between 300 – 420 nanometres (nm).

After taking the model out of the oven after heating, you need to cure it in a UV station or under sunlight or a daylight lamp. This will allow the material to fully polymerize and achieve the stated strength. The final curing time may vary depending on the curing station used. For dentistry, it is necessary to use high-powered curing stations that are able to adequately cure the material; this will ensure biocompatibility and desired strength are achieved. Examples of such stations are Wanhao Boxman or Otoflash. Curing stations with heaters can be used, but it is necessary to preheat models before curing.

For your information: some of our resins, such as FunToDo Show White and Ash Grey, will have a greenish tint until the final UV curing. This shade is given by photoinitiators that have not completed their reaction. After proper UV curing under a wide spectrum of light, the color will be 100% pure.

For your information: another property that you will be able to observe on our transparent resins, such as FunToDo Nano Clear and Dentifix-3D Modelling Clear, is that after UV curing they take on a yellowish tint. This is an indicator that the photopolymerization reaction is still ongoing in the material, and the model will become perfectly transparent again after 10-12 hours.

TIP: If you plan to use the model for cold casting in silicone on a platinum catalyst, we recommend repeating steps 1 and 3 two to three times in order to completely wash away and solidify all resin residues. For proper UV curing, you should use a combined 365nm and 405nm light source or daylight to prevent platinum-cure silicone cure inhibition in resin printed molds that can react with remaining photoinitiators. You can also use any type of separating layer, such as hairspray.

Step 4: remove supports

Remove the tree-like support structures attached to your model. If you are not concerned about small details, the quickest way to go is to break off the supports by hand. However, if your model has fine features, it is best to be more cautious.

For more intricate parts, use flush cutters or scalpel to carefully snip off the supports as close to the model as possible without marring the surface. With both methods, small nubs will be left on your print; however, this is inevitable but easily remedied with a little sandpaper and some patience.

All that remains is to wish you good luck with the post-processes of your 3D prints. If there are any questions, please contact: