One of the biggest shortcomings of resin 3D printing s the time-consuming post-processing of the finished prints. In this guide, we’ll look at how post-processing should be done and the necessary tools for the job.
Guide to Post-Processing Resin 3D Prints
After every successful printing process with a resin 3D printer, the printed products are first freed from liquid resin residues. Failure to do so can lead to loss of details and formation of contours.
The printing platform also needs to be cleaned since it is still covered with a film of resin even after it has been drained for several minutes. Finally, since the printed products are still soft after printing, they must also be post-cured.
All this should be done with the appropriate protective equipment.
Safety goggles are useful but not absolutely necessary. However, face masks and gloves are a must. The chemical properties of the liquid resin are dangerous. If you work without gloves, you risk skin irritations after a short time. In the worst-case scenario, this can lead to tissue death.
The face mouthguard protects against issues caused by toxic vapors.
Cleaning the Resin 3D Printer
Cleaning a resin 3D printer is time-consuming. Its important to work with an underlay to prevent soiling the table or worktop. Apart from face masks and gloves, you should have plenty of kitchen or toilet paper, and a rubbish bag.
After the printing process is complete, drain off the excess resin from the printing platform and the printed model. If you want to speed up the process, hold the plate at an angle. At Thingiverse, you can find adapters that allow the pressure plate to be hung diagonally above the resin tank.
Next, wear the gloves and remove the platform.
From experience, wipe off the remaining adhesions with kitchen or toilet paper. After that, carefully separate the objects from the platform using a spatula or blade. Objects that are still soft and slippery can be difficult to remove. Therefore, work carefully.
After removing the prints, put them in a container with isopropanol and swing the container back and forth until the superficial resin film has been washed off.
You can rinse and clean the printing plate together with the objects hanging on it. This is more convenient and less time-consuming. You will also time, use less paper towels and it will be easier to remove the finished print objects.
Ultimately, the size of the cleaning container is important.
For a good end result, wash out all excess resin from the corners and crevices. Don’t simply hang the platform and printed matter in the isopropanol bath. At least move the platform back and forth or stir the liquid. You can also use soft toothbrushes and brushes to clean deep grooves.
If you want to automate the process, get a magnetic stirrer. These come cheap (from about $30 on Amazon). Another option is large containers with locking options. If you don’t want to hold the platform in the bathroom by hand, you can make a holder yourself or download and print out a suitable solution from Thingiverse or other STL sites.
The movement of the liquid ensures an even cleaning. For very detailed objects, we recommend changing the orientation of the printing platform several times. This is the only way for the isopropanol stream to get into all bulges and depressions.
From experience, about five minutes in the magnetic stirrer are sufficient to get the platform and print object clean. However, ultrasonic cleaning devices also work,
After the first cleaning process, give the model a quick rinse in a second container. A lot of resin collects in the first container after only a few flushes. Therefore, to get everything perfectly clean, the wash cycle should be done again in a second, clean, isopropanol bath.
After a short drying phase, separate the printed products from the platform. Be careful here since the resin is still soft and prone to imprints. For this exercise, get a cutter knife blade and push it under a corner of the object at a flat angle. After this, slide a spatula between the blade and the print bed. This works very well without risking damaging the finished print objects.
Before you continue, let the objects dry sufficiently. Be patient or else white spots will appear on the areas that are still wet. If you are in a hurry, you can speed up the process with a fan or compressed air.
Since the now clean prints are still not completely hard, they have to be post-cured under a UV lamp with a light wavelength that matches the resin (usually 405 nm). Suitable lights, nail polish hardening chambers or light strips are available for about $20.
To achieve an all-round, uniform curing, the light should either come from all sides or the object must be repositioned several times. You can use a cheap solar turntable for this.
Post-curing takes about five to ten minutes.
Do not leave transparent resin under UV light for too long. Otherwise, it will yellow. Instead of having crystal clear prints, you will end up with smoky-looking ones.
The resin used should determine how long it should be placed under UV. If the surface is still sticky after more than ten minutes, then the print was not cleaned well.
All in One Solution
If the whole process is still too time-consuming, consider all-in-one solutions from Anycubic, Elegoo and other manufacturers. We are talking about Wash & Cure stations.
These devices are a combination of washing cabin and UV chamber. The Anycubic Wash & Cure station also works with printing platforms from other manufacturers. For some models, for example the Elegoo Mars, you need to print an adapter. The printing platforms of the Nova3d Elfin and the in-house Anycubic Photon fit without any changes.
A Wash & Cure station looks similar to resin printers such as the Elegoo Mars. It is a small box with a display, control buttons and a high, transparent plastic hood. Under the cover is an outrigger for attaching the print platform. However, unlike with the SLA printer, this is not movable.
The device works well and is easy to operate.
An enclosed, lockable plastic container is used for cleaning. This holds up to 3.5 liters of cleaning fluid, such as isopropanol. There is a magnetic stirrer at the bottom of the container. The stirrer is driven by a motor installed in the station.
To post-process your resin print, take the print platform out of the printer and hang it upside down on the arm of the Wash & Cure station. If your container is not filled to the top, you can hang the platform lower using an adapter included in the scope of delivery.
Alternatively, the prints can also be placed in a screen basket and lowered into the washing tank.
Next, put on the lid on the station. This reduces the smell of the isopropanol considerably. You then have to select the wash function, time (2, 4 or 6 minutes) and start cleaning. After half the time, the magnetic stirrer will briefly stop and then change its direction of rotation. This makes for a nice thorough rinse. After the time has elapsed, the magnetic stirrer switches off automatically.
We recommend a short second pass or a manual rinse of the print in clean isopropanol.
Next, lay out the platform for it to dry together with the printed objects. When not in use, seal the container airtight and set it aside. The next step is to separate the object and printing platform. After complete drying, post-curing continues.
The first item we’ll use is the transparent plastic platform included in the scope of delivery. Insert it into a recess in the middle of the device and load it with the dry printed objects. Put the plastic hood back on, select the cure function and time span, and start the process.
The LEDs attached to the boom, which have a light wavelength of 365 nm and 405 nm, start to light up and the platform starts to rotate slowly. After the time has elapsed, remove the now clean and hardened prints.
Although gloves and face masks are necessary when working with the Wash&Cure station, the overall effort and amount of paper towels used is lower. The odor is also significantly lower than with manual cleaning.
Overall, a Wash & Cure station is a clean and visually appealing solution. Here are some Wash & Cure stations we recommend:
- Elegoo Mercury X
- Anycubic Wash & Cure
- Vevor Ultrasonic Cleaner
- Phrozen Cure V2
- Wanhao Boxman 1 Curing Station
- Anycubic Wash & Cure Plus
Although cleaning with isopropanol is common, there are also good arguments against it. The main concerns are its easy flammability and odor formation. For these reasons, you can opt to use special resin detergents should help here.
For example, Resinwash from Druckwege left a positive impression after the first attempts. However, the agent is not 100% odorless The main disadvantage of the solution is the relatively high price.
Some manufacturers also produce resin that can be washed off under water. The main advantages of this solution is the low price and constant availability of water. However, in addition to the special resin, you still need containers, magnetic stirrers or even a wash & cure station since the resin should never be washed off under the tap.
The dissolved resin is highly toxic and should never get into the water cycle. Therefore, if you work with water, you have to collect it and dispose of it or let it evaporate, just like is the case with isopropanol.
Although water-washable resin is also easily combustible and smelly, it is cheaper to clean it with bioethanol or spirits. However, in our Test Lab, we prefer to use the classic isopropanol.
With all methods of post-processing resin prints, there is a little trick to being able to use the cleaning liquid longer. Here it is: if some resin has collected in the wash tank, leave it for a few days so that the resin can settle to the bottom. Next, carefully pour the clean liquid into another container. Finally, discard the residue saturated with resin.
If the resin does not settle properly, expose it to UV light The resin will flocculates and can be filtered out with a paint filter. Make sure you wear gloves and face masks for this work.
If you prepare well, and have the right tools, you can get through the resin cleaning and drying process easily and with little mess.
While you don’t necessarily need a special washing station, we highly recommend getting on. We loved Anycubic’s Wash & Cure Station since it’s easy to use and has a neat design.
If you don’t want to buy a curing station, you should at least buy a magnetic stirrer. This will significantly reduce your workload.