Looking at buying a dual or multiple extruder 3D printer? Perfect! Now you can print twice as fast, right? Well, not exactly.
The benefits of having two (or more) extruders are perhaps not as obvious as you may think. The easiest trap to fall into is thinking your printer will print faster because of multiple extruders. They will in fact speed up the overall printing process, but not because they print faster – because they print continuously.
Having multiple extruders allows you to have multiple filaments ‘piped in' and ready to be used whenever the object being printed requires them, and this is where the saved time comes from.
Having different filaments ‘ready to go' means you no longer have to pause a print, empty out the extruder of the previous filament, feed in the next filament, and resume the print every time you need a different material. The printer will simply call on which filament it needs, when it needs it.
Dual extruder limitations.
Thinking multiple extruders will print faster because of the additional material is like thinking a color laser printer will print faster than a black and white printer because is has more ink cartridges. The limitations of multiple extruders come as a result of the different extruders currently sharing the same print head. Since each extruder is locked to one another and unable to move independently, more material could only be printed if the object required a symmetrical object to be printed the exact distance apart from the original, as the two extruders are positioned. This is the key limitation of multi-extruders and one that's often misunderstood. Until the extruders can move independently, the benefits of duel extruders come only from having multiple materials readily available.
Popular uses of dual extruder 3D printers.
Currently, the most common use for multiple extruders is to separate the material used for printing your object from filament used to print any required support material. This enables you to use a separate lower grade filament for your supports (which will ultimately be discarded) and save your best stuff for the final object. In some cases, a special degradable or soluble filament can be used for easier removal once your print is complete. Again, this can speed up the overall printing process and reduce the inconvenient and time consuming chore of removing the support material.
Multi-colored 3D prints!
Here's where dual extruders get fun. Having multiple filaments ready to go means your printer can quickly switch to different colors, adding even the smallest amount before switching again. This enables prints with far more complexity in the color variation to be completed without needing to stop a print and physically change the filament every time you need a different color.
What multiple extruder FDM printing cannot currently do is blend the two (or more) colors together. At best, different filaments can be layered on top of one another to create a gradient effect between the two colors. How good the blending effect will be depends on how thin you can print. Lower resolution prints (thicker layers) will quickly appear as stripes when the two colors don't mix together, but simply stack on one another. Here is more information on printer resolution.
Do you need more than one extruder on your 3D printer?
Whether or not you choose to buy a multiple extruder printer really depends on the complexity of what you intend to print. If what you're printing is really simple, a single extruder may be just enough for your needs. Likewise, if you require highly detailed color prints and still plan to paint or finish your object in some other way to add color after it's printed, you still might benefit from the use of separate support material. For those types of prints, we would recommend a dual extruder 3D printer. And for those of you wanting to have multi-colored prints without the need for photo real gradients and color variation, multiple extruders will be a perfect ‘out of the box' solution for you.
Now that you know what an extruder is, make sure to check out our detailed guide to the choosing the best 3D printer extruder.