How To: Print, Clean, and Post-Process SLA 3D Prints
Laser and resin 3D Printers have a very different workflow from the more common extruder and plastic 3D printers. Learn what it takes to use these high-resolution machines.
The Peopoly Moai has been a great machine to introduce more people to SLA 3D printing and the possibilities this 3D printing method brings with it. Whether it’s used for printing miniatures for tabletop games, high-resolution anatomical models, or for small but intricate engineer prototypes, there are just some things that SLA is much better suited for than FFF (Fused Filament Fabrication) 3D printing. There is a different workflow to the process, because rather than printing, removing support, and sanding to make a clean and finished model using FFF 3D printers, you need a couple different tools to make your SLA 3D prints come out that much better.
Tools and materials
- Nitrile/Neoprene gloves
- Jewelry ultrasonic cleaner
- Peopoly UV curing light
- Solar powered turntable
- Isopropyl alcohol
- Print removal tool
- Flush cutters
- Paper towels
- Plastic sheet
Step 1: Removing your print
Once your 3D print is finished, you’ll need to remove it from the build plate. Unlike FFF 3D printing, you have to be very gently removing every print. Whereas you can use a spatula and a good tap to remove PLA prints, you can’t do the same with your SLA prints. My recommended method is as follows:
- Lay out some paper towels or plastic sheet to catch any drips as you’re removing your part.
- Put on some nitrile or neoprene gloves to protect your hands
- Remove the build plate from the printer, being careful not to bump your print and break off any details.
- Use the supplied spatula to lift up either the brim or an edge of the print if there isn’t a brim.
- Use the print removal tool to glide under the 3D print, using the lifted edge as your opening to get underneath it.
- It should be really easy to slide this under your print. If it’s taking more force than expected, be careful not to slip and cut yourself or damage the print.
Step 2: Cleaning off supports
Some people like removing their supports after everything has cured, but I find it’s more destructive if you wait until then. In my experience, cured supports shatter and have taken off small divots of material where they attached to the print.
- Use the flush cutters to snip off the support material
- Make sure to be flush with the surface of the print, or as close as you can get.
- In some cases, the supports won’t take much effort at all to come off, but with some of the finer details with supports attached, you’ll want to be careful that the force of the snips closing doesn’t take the detail with it.
Step 3: Cleaning the 3D print
No matter how long your print is, there will be some amount of resin on the surface. If you let this harden, it will slightly distort the true shape of the model. In some cases it will harden as drips rather than a full coating and in others it will leave them sticky for a long time, allowing them to attract and stick to any dust and debris.
- Get an ultrasonic cleaner from the retailer of your choice.
- The biggest thing is making sure that its volume is big enough to fit the parts you will be printing.
- Cover your work surface with plastic sheeting or paper towels to collect any drips or spills
- Isopropyl alcohol will strip paints, stains, or varnishes, so be careful when handling on these surfaces.
- Fill it halfway with isopropyl alcohol
- Gently drop your 3D print into the alcohol.
- Make sure that there is either enough alcohol to completely cover your part, or intend to do a couple passes to cover all sides.
- Turn on the cleaner.
- I don’t usually heat the alcohol and have had great results without it.
- Normally I turn it on for 3 minutes and that’s enough to feel a significant difference between before and after putting the part in. It doesn’t need to soak for hours, but it couldn’t hurt letting it soak and clean for 10 minutes or so.
- Use the basket usually included with the cleaner to lift the part out of the alcohol.
- Gently dab the 3D print with paper towels to soak up as much of the isopropyl alcohol as you can.
Step 4: Post-processing the 3D print
Even though cleaning off any uncured resin is a great start, the step that really brings out the quality of your 3D print is the post-curing that’s necessary for SLA prints. A high wavelength UV light has the intensity to cure the entire part, it just takes longer for thicker, more solid parts. Peopoly makes their own UV lamp, but there’s a couple things you can do to make it work even better.
- Get a solar powered turntable
- You don’t need to be too particular about the size of it, but a battery powered one couldn’t hurt either. All you’re aiming to do is have the 3D print stand on it and rotate.
- Find a container to fit the turntable and any 3D prints you may need to cure.
- Most turntables, even the smallest you can find, are going to have bases bigger than the 3D prints you would be make using your SLA printer. That will usually be your point of measurement.
- The container itself doesn’t really matter, you just need something to bounce the light around. This can be as simple as a paint can, a cardboard box, or like in our case an unused cabinet
- If your container is not reflective, line the inside using aluminum tape.
- This will help bounce the light around in an attempt to get all sides of the 3D print completely cured.
- Mount the UV curing light to the container
- There are mounting holes in the bracket of the curing light, so you can use screws and make it permanent or use some adhesive to mount it. In either case, you want it mounted in a position where it can aim directly at the turntable.
- Place your part on the turntable and walk away.
- For small 3D prints, half an hour is enough time, for others overnight should do the trick. Basically leave it as long as you can afford to.
That’s everything! Once you’ve cured it with the UV light, you are free to use it as intended. So whether you printing parts for cosplay, prototypes, jewelry, or miniatures, this process is essential for creating stable, usable parts. If you have an SLA 3D printer and there’s something you find useful in your process that I don’t have listed here, feel free to leave a comment down below.
Happy printing and cleaning!