In this instructable I'm going to go through the process of mixing different colors of resin for the Ember printer. I'll go over what you’ll need to have before you begin, and I'll detail the steps in metering out and blending the resin. We recently came out with a line of CMYKW resins for the Ember 3D printer, and you can go check them out at ember.autodesk.com
This is an easy process, and it should only take a few minutes if you're prepared and know the amounts of resin you're going to be using.
You can do this process by eye, but, similarly to paint, you probably won't be able to reproduce the color you make by just eyeing it. I'll show the method of mass measurement, but you can also use volume if you only have syringes or beakers lying around.
Step 1: Getting Everything Together
- Nitrile gloves.
- Safety glasses/safety shield
- Lab coat or similar PPE (personal protective equipment)
- Balance. The more accurate, the better, but at least to the nearest gram with a capacity for as much resin as you want to make. Assume a density of 1.1 grams/cc of material, and you’ll need at least 100 grams of resin for a full Ember tray.
Alternatively, you could use a beaker, syringe, or other method of measuring volume, but it probably will be hard to be as precise with very small amounts of material
- An opaque, resin compatible container. (We use Nalgene HPDE containers at Pier 9, but any chemically compatible container should work as long as it is opaque. Amber or translucent bottles will still let in too much light and may change the way your resin performs when printing)
- Disposable pipettes.
- Tongue depressor, spatula, or something to rough mix the material before automated mixing.
- An automatic mixer if possible. A clean, sealable container will also work, but may not be as thorough.
A note on automatic mixers:
First, you don't absolutely need to have an automatic mixer. A sealed container, that is clean, can work. You just add in the resins you want, and shake for 3-5 minutes after firmly closing the cap. It's not as thorough, but it will work.
Depending on the type of equipment you have, you may be able to accomplish the mixing of the material by many different means. Impeller, high shear, or magnetic stir bars are all acceptable methods of mixing the resin. However the materials are mixed, their complete blending should be verified visually before the resin mixture is used in the Ember. Multi-axis, or high shear mixers (e.g. Flaktek or Thinky), may not be able to mix for adequate amounts of time before they excessively heat the materials. Be sure to monitor the resin temperature if you are attempting to use this style of mixer.
Step 2: Measuring Out Your Resins
1. Place container on the balance and tare (zero) it.
2. Measure out your base resin. We measure out the resin with most mass first.
If you were going to tint a large amount of PR57-Y (Yellow) with a little bit of PR57-K (Key, or Black), then we recommend adding the PR57-Y resin to the balance first, taring, and then slowly adding the small amount of PR57-K to this until you get the correct amount.
Always be sure to slowly add the second or third resin slowly. Using a pipette will allow you to accurately control the amount of material you’re adding to the base resin, and it will also limit the chance of adding too much material. When you pour directly from a resin bottle, you run the risk of quickly adding too much material to the mixture.
4. After you have added the second (or third resin), take the bottle off of the balance and place it into your mixer. We use an impeller mixer, but your mixing setup may vary.
5. With a mixer: After mixing for 1 minute, remove the bottle from the mixer, replace the cap and verify that it is secure, and shake the bottle for approximately 5-10 seconds. This will make sure any material that is on the sides of the bottle or possible in a dead zone of mixing is incorporated into the resin mixture.
5. By hand: shake the closed, sealed container for 3-5 minutes. Open the container and ensure that the materials have fully blended. If you see any stripes, or banding, close the container back up and repeat.
6. Perform mixing until the shade is consistent and no lines or variations of color are perceptible.
7. Print with your new custom color!
Step 3: Tips
Whenever we are mixing and formulating materials at the Pier, we always calculate the mass of the formulation we’re going to make before we make it. You want to have an idea of the mass and the materials needed before you put on your PPE and start mixing. It’s not very much fun to realize that you need 30 grams of PR57-C when you only have 20 grams left. Laying all of the materials out and in easy reach makes the entire process much faster and easier.
These are a must. We have found that sitting in indirect sunlight, resin that is a in a clear vessel can cure completely in relatively little time. Frustration is inevitable if you ruin a batch of your hard-earned resin formulation with a little sunshine.
Mixing in PR57-W or PR57-K
When adding a shade to a resin (e.g. adding PR57-W to PR57-C), you want to make sure the formulation is at least roughly mixed before you decide to add more material. If the material is not mixed well it may look like not enough of material was added, but when the entire mixture is more thoroughly mixed it may actually provide the color desired. It’s very easy to add material to a mixture, but you can’t take it out once it’s in there.