3D printing in resin? Don’t!
If you’re thinking about getting into 3D printing in resin you need to know the hard truths. It requires huge amounts of resiliency and determination. The process itself sounds easy enough, but here’s the step by step details.
Find or design a file. There are heaps of files available to download for free or a small charge. Websites like thingiverse and cults3D are full of them. The website stlfinder.com will search all the sites and present you with the options. Once you have downloaded the file you can then print it. Not yet though, you have to slice it.
Slicing involves adding “supports” to the model so it will print properly. Just learning how to add supports is a steep learning curve by itself. Expect failures while you are learning. Most slicers offer an “auto support” function that I’ve never really trusted. It’s worth learning to do it yourself. One properly supported the software will “slice” it into the layers that the printer will print one at a time. At this stage you also need to ensure you’ve got the correct resin settings in the software, the most important being the exposure time of the layers. Too short and the model won’t be able to stay together under printing pressures. Too long and it will blow out all the detail. A single model can be thousands of layers. Once sliced you can send the new file to the printer.
Standard resin is really nasty stuff. It’s very smelly, and is a skin and lung irritant, so be prepared to be wearing a respirator, safety glasses, gloves, apron, etc. You also need to clean up with isopropyl alcohol. Vast quantities of it. After getting a nasty skin rash every time I went near wet resin (even with the PPE) I changed to a water washable resin which is much nicer. The waste water or alcohol can’t be disposed of into drains though - another big issue. I sieve mine through 120 micron sieves and evaporate the water - difficult in winter.
The printer will then begin the print one layer at a time. Each layer could be 4 or 5 seconds so expect it to take hours. The printer will form the model in the vat of liquid resin and you wont be able to see it until it finally gets above the edge of the vat. It may fail and you cant even tell for a few hours. If you do get a failure you need to remove all print remnants, clean your printer, and sieve your resin. You may need to replace the clear plastic film on the bottom of the resin vat too. This needs changing from time to time anyway.
Once the printer is finished you have to scrape the model off the build plate. It will be firmly stuck there and it can be difficult to get it off without damaging the model. At this point it is dripping with uncured resin and needs to be washed . This uncured resin will cure quickly if exposed to natural light, so keep away from windows until it’s all washed off. The water washable resin I use is easy as I can wash it off in a bucket of water. I then blow dry it using the compressor and then dunk it in a bath of meths (cheaper than alcohol) to remove all the remaining water. Another quick blow dry and I have a clean dry model.
At this stage the model is still supported with all the supports you we added in step 2. These supports need to be carefully clipped off the model - another chance to damage it if you’re not careful and a time consuming process on most models.
Now you can properly cure the model. If you haven’t shelled out on a UV cure station it will take hours in the sun. Buy a cure station.
Your newly printed model is now ready to paint.
In short it is a long, messy, and expensive process. The printers themselves have a limited life too. The screen is considered a consumable item and will fail. Elegoo only offer a 3 month warranty on their screens. I am using Anycubic printers now as they offer 6 months on their screens. I’ve been resin printing now for less than 2 years and I’ve purchased 5 resin printers. The resin I use is $80 a kilogram (liter). You will need replacement FEP/ACF films, screen protectors, bulk meths, huge quantities of disposable towels or tissues, etc. Now, having said all of that, it is HUGELY rewarding to print out something cool, especially if you designed the file. There is a great deal of satisfaction mixed in the disappointment. And when I visit someone else’s layout and see my models on it - well, for me it makes it all worth it. Just.
