What Is a Dual Extruder FDM Printer and Do I Need One?

Geeetech A10M Mix-Color Pruse I3 3d Printer

Most FDM filament printers come with one extruder. You add your filament, and you print one item at a time, with one material and one color. Dual extruders on the same machine offers you the ability to print in two different colors with the same material, or two different materials in the same model. Some items can really take advantage of this ability, but most, especially those that will be printed, may not.

You only need a dual extruder 3d FDM printer if you intend to take advantage of prints with multiple colors or that use two different materials, like hard plastic PLA and flexible plastic TPU filament. You can even print support materials in a different, water soluble material so that supports leave no marks on the model.

In home use, the dual extruder 3d FDM printer is a rare beast. But don’t shy away from getting one, despite the premium in price, if the use case is something that you’ll like to do. It’s more complicated than regular single extruder printers to use, but not that much more.

How Does Dual Extrusion Work?

Essentially, the printer has two spools of FDM filament, and two hot ends. The computer’s control software must know the offset for one extruder from the other. In other words, if extruder one is at one point, then the second extruder is to its right by half an inch. If you want extruder one to deposit material at point 1″ by 1″, then add material from extruder two to the same point, then the printer needs to know to move left by half an inch to get the second extruder to the same place.

If you’re buying a printer with the dual extruders already set up, it’s a simple case of loading an STL file that takes advantage of it. You’ll have to set the first material (that’s loaded into extruder 1) to whatever the best printing profile is (speed of print, nozzle temperature, amount of extrusion, etc.) Then, do the same to the second extruder is loaded with. That way, when the slicer comes across the second material in the layer, it will know to use the second material, and to extrude it with whatever profile you have set for it.

You can download dual material STL files from all sorts of places. Here’s an example of an interesting Easter Island Moai statue in two colors: https://www.thingiverse.com/thing:1560492. If you’re designing your own models, you’ll actually have to create two separate STL files that interlock, and then have the slicer, like Cura, do the combining. In Cura, you can set what each material is and what the print settings for that material are.

Dissolvable Supports With Dual Extrusion

Some models have very intricate details, or have unsupported details in areas where it’s very difficult to remove supports. With a dual extrusion model, you can set your slicer to create supports to be printed with the second extruder. So you’ll get only one color and material print at the end, but the supports will be in a separate material.

Check out SainSmart’s water soluble PVA support filament (https://amzn.to/3afVhpV). Once you’ve completed the print, immerse in water for a long period to dissolve the supports. It will leave your model without any marks where the supports held up the print. As long as the water can reach the support, it will dissolve. No need to get in there with your cutters to remove them.

Cool Uses For Dual Extrusion

Two colors, like the model from Thingiverse.Com above can be very effective in making a model stand out. It can make a good model outstanding, so consider it if you’re making display items.

Adding a second material, though, can be quite exciting, too. If you’re printing a phone case, you may want parts of the case to be hard, and in one color, with other parts being rubbery and another color. You can use PLA or ABS filament for the hard plastic portions. Use TPU filament for the rubbery bits. Choose two complimentary colors (like black PLA and red TPU filaments) to make interesting patterns that are nice to look at but also touch.

How To Get Your Slicer To Create Dual Extrusion Models

You will have to create two STL files, one that will print with one material, and one that will print with the second material. If you download a file from somewhere like Thingiverse.Com, it will also come with two STL files. 

In Cura, load the first model. Then, drag the second model into the scene to have it rendered, too. Select them both (select the first one, then holding the Shift button, select the second). Both should have the blue outline around them. Right-click to bring up the contextual menu, then select Merge. The models will be merged together. You can now position and then slice the model, ready for printing.

Remember to select each of the STL files and set the settings for that material. If you’re using the same material, but different colors, then no worries – you can use the same profile for each. If you’re using different materials, you’ll have to learn the different materials’ properties, and adjust these before you slice. That way, when the printer starts printing, it knows what to do with each material as it encounters it in the slice.

Dual Extrusion Printer or Dual Extrusion Upgrade Kit?

You can either find a printer already set up with dual extruders, or you can find a single extrusion printer that is compatible with a dual extruder upgrade kit. With an upgrade kit, you’ll not only have to install some hardware onto your printer, but you’ll have to modify the printer’s control software. This can be daunting for some, and so most who want dual extruders will go with a printer that already has them.

The price of dual extrusion upgrade kits can be similar to the price of the initial printer. Dual extrusion printers are also at a premium, but you can shop around and find a good buy on one in the marketplace. The Geeetech A10M is a good printer for a small premium over the price of a single extruder printer with similar characteristics.

The Downsides To Dual Extrusion

Dual extrusion is more expensive than single extrusion. You have to pay a premium for the extra hardware, whether it came with the printer or it was an upgrade kit. You’ve got double the material to purchase (two spools going at the same time) but you’re using less per model. If you had printed the model with a single extruder, you would cover the same volume, but in one material.

Printer hot ends (and the extruders themselves) are susceptible to breakdowns and needing maintenance. With two of them, you’re twice as likely to have issues. Thankfully, FDM filament printers are relatively simple machines, so fixing an issue is not that much of a problem, most of the time.

Related Questions

Are dual extruders worth it?

For home use, it’s not that useful or worth it. Some dual extruder printers are cheap enough, but most are a hefty premium in price over a regular single extruder printer. It will depend on your use cases as to whether two colors, or two materials in the same model is worth the extra expense.

What is the cheapest dual extruder 3d printer?

The Geeetech® A10M Mix-color Prusa i3 3D Printer is the cheapest dual extruder currently listed in the marketplace. With a Prusa i3 pedigree, it’s a solid printer to start, and adding dual extruders is a very good option. It retails for under $300.00USD.