Hey gang, Tim here at Core Electronics, and today we're diving deep into dual-coloured prints, from CAD design all the way to 3D printing. This video is going to focus on dual extruding printing two of the same material that only differ in colour, and then improving the final printed result through material choices, hardware setup, CAD design, and I'm also going to demonstrate the slicing workflow.

Dual-extruding printing is the process of 3D printing with multiple filaments in a single print, which lets you print models like this rocket over here, or these dice that I have in my hands. What this means is your printer will have nozzles capable of depositing filament from two separate material spools one by one. Now, dual-extrusion capabilities are found on many, many 3D printers. That Ultimaker 3 3D printer behind me is a perfect example of one. Now, many 3D printers can also have dual-extrusion mounted or installed as an addition.

There are different ways to get multiple colours onto a single part. It can be done simply by stopping and changing out the filament spool with a new one with different colours, and then unpausing the print. This will limit you to colour changes in the Z-axis, but gives you an unlimited amount of options in that Z-axis. 3D printing filaments have a wide range of properties, and to successfully print multiple different materials, it is advantageous to do so with materials that have similar properties. Printing two completely different materials is normally not good engineering practice as bonding between them will often be weak and inevitably produce poor prints.

Now, for the best results, it is crucial to know the interactions between different materials when utilising dual-extrusion heads. Thus, I bring a table to the table. Now this shows the official compatible combinations and experimental combinations for a whole bunch of Ultimaker materials. Now this can be inferred on to represent similar filament materials. For Ultimaker machines, to get multiple colours on a single print without stopping and exchanging filaments midway is done by using that dual extruding and setting up the Cura settings to make one material to go one place and another material to go another.

Now, make sure you have the correct print core installed for your materials. Ultimaker machines with dual extrusion come with AA cores and BB cores. BB cores are used for support material, so will not produce a good result with PLA or other structural materials. Use the right print cores for the right materials and good results will follow. Thus, swap out all those BB cores for AA cores of the same diameter. Also, make sure your XY calibration is done. This is a calibration process which will occur on any dual extruder 3D printer and this is done to make sure that both nozzles know exactly where they are in relation to each other. Doing this will result in the sharpest, cleanest result. Also, while you're up and close and personal with those nozzles, give them a good clean and make sure they're extruding correctly. I will link two guides below which will get you up to speed on all of this.

Each colour needs its own unique CAD model as printing is done by overlaying these two models in the slicing software and then slicing it. This is what enables dual colored printing with dual extruders to work correctly. This means you either need to design each colour as a unique part or separate a full body into multiple parts. So keep this in mind when you're designing your components. On the screen now, you can see two models which represent the red part and the white part of the rocket from the Adventures of Tintin. Now to increase the crispness between the colour transitions, have a small relief or trench between colour sections on the surface when.Looking at the X or Y plane. In the Z plane, ensure that there's no gap between the colors and make sure that they don't overlap unless you want to start mixing the colors together which is possible but this guide will focus on making sharp transitions between colors and also have that trench.

Now this trench is less than a millimetre thick and is kind of imperceptible from a distance but it does make a huge difference. In a close-up of this rocket, you can see that tapered trench visible between the sections. It is subtle but it makes a huge difference in the final result and is very much worth the effort. So click that chamfer button in your CAD designer.

Now you have your finished parts, the next step is to set it up in your slicing program. Now the process to 3D print multiple colors is the same no matter what slicing software you use. However, this guide will go through the workflow in Ultimaker Cura. There is an Ultimaker Cura overview guide which is a great reference point if this is your first time in counting Cura and you want to hit the ground running which I will link down below.

I'm going to go through the workflow to make this middle section of the rocket print in Cura and make sure to overlay the center of the two models perfectly on top of each other. What position they are here is the position that the 3D printer is going to print it in. This can become tricky if rotating the model is required but take your time and the best results will occur. Make sure to zoom right in and double check the position of the 3D printer and make sure Next, make sure one model is being created with one filament and the other model is being created with the other filament. This is done by selecting the model and clicking on the corresponding filament symbol in the left toolbar. Cura also gives a visual colour indication on the surface of the model when particular colors or filament types are changed.

Next, importantly, is to use a purge tower and an ooze shield. Purge towers can be used to create a 3D printed 3D model. Purge towers or prime towers as they are known are an additional print created on the build plate made to the height of the component desired. Ooze shields are a one-layer wide wall that encases but does not touch the final model. Both methods are a technique 3D printers use to prime the printing nozzle for each layer. Without either a purge tower or an ooze shield, you will end up with stringy hair-like filament covering your desired component and emblemishes all across the surface.

Also, check out the guide Improving Your 3D Printed Models, which I will also link down below and this will enable you to create a great material print profile. So no matter what material you'll end up printing it out of, you will be able to get the best results out of your 3D printer. Now for Ultimaker materials, the default profiles for PLA and also ABS automatically work very well.

So once you've figured out your profile and you've locked in all your settings, make sure to print both nozzles using the exact same setup for both print materials. Now this will enable consistent results across the model with matching layer lines. Color differences between the same filament does change the material properties, but the effects is negligible. Also, minimize supports around surface areas. Support structures can mark and mar the final surface and this will affect the final result. You can see here on these dice different angles where it has printed well and hasn't printed so well. The sides that I used support with have a worse surface finish than the sides that I didn't use support with. This dice also demonstrates the advantages of dual colour surface on positive slopes and not on overhung sections. These had ooze shields and purge towers whenThey were printed. So that's it for today. The model of this rocket from Tintin is absolutely gorgeous and all credit goes to an excellent Frenchman Laurent Alcantara.

There is a really neat 3D printable sanding block designed by Laurent in his Thingiverse profile as well and I'm going to link this model and the other thing in the description below if you would like to have a go printing it yourself.

And with that, until next time, stay cozy.