Post-processing


Washing your models

After carefully removing your model from the platform once printed, you will need to wash off excess resin. This is a normal process in SLA printing. After dipping in and out of the resin vat many times during printing, it maintains a thin layer of uncured resin which needs to be washed off before further curing and solidifying the object.

We recommend using Isopropyl alcohol (IPA) to achieve this, regardless of resin brand or type. A small glass jar or drinking glass can be used to fill with IPA and then bath the model in. We love to repurpose household items such as peanut butter jars that have been washed and cleaned out. You can then use an implement like our included model scraper (with the wooden handle) to agitate the IPA around the model. Or if you still have a lid to the jar, you can close the lid and gentle shake it – though be careful to not damage your model as it will still be slightly delicate before post-curing!

An advanced solution is the use of ultrasonic cleaners to perform the rinsing function. You can place the glass jar in an ultrasonic cleaner’s tank filled with water, in the basket usually provided and allowing the ultrasonic cleaner to run for 5 minutes or so. The ultrasonic function loosens the excess resin making the process much more efficient and repeatable.

Once washed, remove from the IPA and allow the IPA to dry completely before moving onto post-curing.

Remember to dispose of the IPA as though you are disposing of uncured resin. This cannot go down your bathroom or kitchen sink! Please see our section on Cleaning and safety.

Post-curing

All SLA printers cure resin just enough to form the model, but they still require post-curing in order to harden the outside surface. This post-curing process hardens the model and allows the model to be safe to touch and removes the sticky or tacky feel as they harden.

The resin can be post-cured at any wavelength between 225nm and 420nm but we recommend staying as close to 405nm as possible, which is the same wavelength that the Lotus EZ uses, along with many other LCD SLA 3D Printers. This wavelength especially important for our clear resin. Wavelengths outside of 405nm can a yellowing effect in the finished model.

Length of time spent post-curing is dependent upon the strength of the light source, the thickness of the walls of your model and its overall size. A good indicator of sufficient post-curing is that it loses the tacky feel (remember to still wear gloves throughout this process!).

If you have strong enough sunlight in your location, it is also an option to simply allow the model to sit in the sun. The length of time required to cure by direct sunlight will of course be determined by the strength of the sunlight and again, the thickness of the walls on your model. For example, winter sunlight will take a significantly longer period than in summer months.

 

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