Multi Material 3D Printing is a way of printing with different materials to create more complex parts and parts that have multi colours. Most of these machines only have the capabilities of printing two material but for the tutorial we used an Original Prusa i3 MK2s with the Multi material upgrade which can print up to four materials.
Multi material printing has some great advantages but it also has some disadvantage. these pros and cons need to be weighed up to find the balance to where you will make the most from the technology. Before we get into the pros and cons of Multi material printing lets us start with how to design for multi material 3D printing.
We decided to make the SOLIDWORKS 3D logo. To start we make a 50mm x 50mm x 50mm block. We then put an S on one face and a W on another face. For each letter we extruded them in a mid plane so half of it goes into the block.
We also unselected the merge entities options to make sure they are separate bodies. we then used the convert entities to create a sketch outline of each letter. We used this to extrude cut the block so the letters sit inside the block. We added a colour to each body to get an idea how it will look.
The last step was to save the files. We need to save each colour as its own STL. So we saved the block as one STL file and the two letters are in one STL file. We imported the files into the slicer, assigned an extruder to each body and hit print.
If you want a more in depth tutorial on designing this cube give the video attached to this blog a watch.
We built this easy model with two colours with out having to print them separately and assemble them. With really complex models this can be a great time saver. The robot head we designed is a good example of this. We had four different colours with very organic and complex shaped. Separately they would be very difficult to print but now they are much easier.
The problem with this now is the purge tower. this is the block used when you change from one colour to another, when you remove material a little bit stays in the nozzle. to get it out you push more material out till it is clean. the purge tower does this for you. This does mean this is a solid block of plastic that is as tall as your model that is pure waste. but no matter how large the model. the purge tower will always have the same footprint. it would just be as tall as the model. the image below of the head shows how much waste material there is with the support material and the purge tower.
the last advantage with multi material printing is printing with Water soluble support material. This is material that will be used as support material but its design to break away easily and dissolve if placed in warm water.
Soluble material can be very expensive. in some cases costing four times as much as your normal materials. This means you are spending a lot on wasted materiel. To combat this some companies have developed an option called interface support material. what this will do is it will print your support material with the same material as the main model until it gets 3mm before the over hang in printed. then it will switch to the Soluble material to use as little as possible while still being effective.
Soluble material is also printed closer to the model than normal supports. normal supports can be printed right on the surface as it will never break away. these two balls shows how 3D printing with soluble supports can achieve better results
Multi material printing has a good dose of advantages and disadvantages and these need to be weighed out and balance before deciding whether this is the technology you need. being able to print in multiple material can save a lot of time and allow you to create more complex items but this can take longer to print and use a but more material than intending for the purge tower. its a great piece of kit that is getting more popular and with it getting more popular and more people giving feedback the companies making these machines will develop better solutions to make it a more streamlined and waste free system.