What Do I Need for Resin Printing? More Than You Think!

Curtis Satterfield, Ph.D.

Curtis Satterfield, Ph.D.

Resin printing is great for producing parts with high levels of detail. Unlike FDM printing a resin part isn’t ready as soon as the printer finishes.

To get started with resin printing you will need; a resin printer, resin, a way to wash your prints, a way to cure your prints, extra printer consumables, and personal protective equipment.

There are several steps to a successful resin print including post processing. After the print comes out of the printer it must be washed, cured, and have the supports removed. I’ve detailed each step below with suggested items you can use to ensure successful printing. We will examine the steps for 3D resin printing in the next section. The rest of the article will cover each step of the process and the items you will need for each step.

Steps for Resin Printing

After a print finished on a resin printer it needs to go through a few steps before it’s ready for use.

  1. Print your 3D model on your resin printer
  2. Remove the Print from the build plate
  3. Wash the model in isopropyl alcohol to remove residual resin
  4. Cure the print with a UV source.
  5. Remove Supports
  6. Clean up any marks left on the print from the supports

The process is straight forward, but you will need extra equipment that didn’t come with your printer. This is the recommended process from most printer manufacturers. I like to remove the supports after the wash step and before curing. In my experience this makes the supports much easier to remove are less likely to leave scars on the print. For more information on how to get started with resin 3D printing check out my article here.

Printing Your Resin Model

Items needed for this step (Amazon links):

Recommended consumables to keep on hand:

We’ll start with the obvious items you will need. A 3D resin printer and some resin. There are several consumer grade resin printers available today starting around $250. The printers will usually come with the printer and all the components the printer will need to work. Some will come with a small tool kit that includes plastic scrapers and a few sets of nitrile gloves.

Elegoo Mars 3D Printer
Elegoo Mars Courtesy of Elegoo.com

What the printers don’t come with is everything else you need print. One of the big things they don’t come with are personal protective equipment. It’s important to understand that resin is toxic. You need to avoid breathing the fumes or getting it on your skinWear a respirator approved for use with organic compounds and wear nitrile gloves when working with the resin.

If you don’t plan to use your printer for a while, I recommend returning the unused resin from the vat to the resin bottle. You will need to use a paint strainer funnel to ensure no hardened bits of resin get back in the bottle. Your kit may have come with one or two funnels, but I recommend ordering more to have on hand. They are made of thin material and can easily be damaged.

You should also keep extra FEP film on hand. The FEP film will last a long time if well cared for but FEP is a consumable and will need to be replaced. I also recommend getting at least one spare resin vat. This will allow you to swap between two different resin types without the need to clean the vat each time.

The LCD panel in your resin printer is also a consumable. The LCD screen that is used for the actual printing part will eventually die and need to be replaced. If you’re not in a hurry you can wait until your screen dies and order a new one. If you want to be proactive you should order a spare to keep on hand, so you don’t lose any printing time.

If well cared for the build plate should last you a long time. It will eventually wear out and need to be replaced. If your prints stop sticking to the build plate, try sanding it with 400 grit sandpaper. If any of the screws or the connection between the plate and the Z-carriage become damaged, you will need to replace the build plate.

Washing Your Resin Print

Items needed for this step (Amazon links):

The first step after removing your resin print from the build plate is to wash the print. This can be achieved by dunking your print into a container of isopropyl alcohol. A popular method is to buy a plastic pickle jar with a sealable lid. Put your alcohol in the container, drop in the print, and shake for 30 seconds. Let the print soak in the alcohol for about 10 minutes.

There are also machines that can wash the print for you. Another popular option is to use an ultrasonic cleaner. Do not put isopropyl alcohol in an ultrasonic cleaner! Fill the ultrasonic cleaner with water then place your alcohol and print in a Ziplock bag. Seal up the bag and set the bag in the ultrasonic cleaner. Many people have found success using heated ultrasonic cleaners.

3D printer manufactures also make devices that will wash and cure your print as well. Anycubic sells the Wash and Cure station and Elegoo sells the Mercury Plus. Both machines will keep the cleaning solution moving over the print.

Anyubic wash and cure machine for resin 3D printing
Source: Anycubic.com

There are several alternatives to using isopropyl alcohol to clean your prints. I use Mean Green in an ultrasonic cleaner and it does a great job. I have also read about success with acetone, but you must be careful! Acetone will eat your print if you leave it for too long! No matter what method you use to wash your prints you will need to experiment with cleaning times to find what works best for each resin type you use.

Once the print comes out of the wash, I recommend scrubbing it with a toothbrush in warm water. Depending on your cleaning solution, you may not need to use a toothbrush. Again, you will need to experiment and find out what works best for you.

Curing Your Print

Items needed for this step (Amazon links):

The most cost-effective way to cure your print is to place it outside in direct sunlight. You can achieve better results by placing the print in a clear container filled with water. Place this container in the sun for 15-20 minutes. If the print still feels sticky or uncured leave it for another five minutes and check again.

But what happens if it’s raining or night-time when your print is ready to cure? You can use a UV light source to cure your prints. You can find an inexpensive UV curing light and turntable kit on Amazon for this purpose. I recommend building a box around the turntable lined with tin foil to help distribute the light.

On the more expensive side you can use a purpose build curing machine. The wash and cure machines we talked about in the previous section can cure your prints as well. If you have the budget, I highly recommend using a curing machine. It will make your post processing much easier.

Elegoo Mercury Plus
Elegoo Mercury Plus Courtesy of Elegoo.com

Removing Supports from Your Print

Items needed for this step (Amazon links):

Most manufacturers recommend removing the supports from your print after curing. I have tried both ways and I prefer removing the supports after washing but before curing. I remove the supports after rinsing them in warm water. The warm water helps soften the supports and they usually pop right off.

If you remove the supports after curing, you will need a pair of flush cutters to snip the plastic away. Snip as close as you can to the print to reduce the amount of sanding you will need to do.

Cleaning Up the Print

Items needed for this step (Amazon links):

The last step is to clean up any areas where the supports left marks on the print. This should be minimal if you removed the supports before curing. If not, you will need some sandpaper or sanding sticks. Using a fine grit sandpaper 400 or above, gently remove any points left from the supports. Let it dry and sand flush with the surface. Be sure to wear a respirator while sanding!

If you printed with a transparent resin your print will look scuffed and dusty at this point. You can use a clear coat to help bring back the transparency of the resin. The clear coat will fill in the gaps from the printing and sanding process providing a clean finish.

If you printed with an opaque resin and plan to paint your print, I recommend using an acrylic primer first. This will help any paint stick to the model and will cover up any areas you had to sand.

Personal Protective Equipment

You will go through gloves very quickly when working with your printer. To save money I recommend getting a thick pair of nitrile gloves like the ones I use (Amazon link). It can be a bit cumbersome at first because the gloves are not as thin. You can also use a simple pair of cleaning gloves. Now that I am used to the thicker gloves, I no longer need the disposable gloves.

Remember to store your respirator in a Ziplock bag when not in use to prolong the filter life. And if you opt for reusable nitrile gloves clean them off after each use to avoid resin build up.