IDEX (Independent Dual Extruder) puts two independent toolheads on one gantry. IQEX (Independent Quad Extruder) puts four on a single X-axis. Both give each filament its own nozzle, so neither needs a color-clearing purge between heads. The difference is how many colors and materials you can print at once.
IQEX is the architecture behind Quadro, and the name comes straight from IDEX. Here's what IDEX does well, where two heads run out, and what four independent heads change.
What Is IDEX?
An IDEX printer has two toolheads that move independently along one X-axis, each with its own nozzle and filament. While one head prints, the other parks at the side of the bed, out of the way.
What IDEX Does Well
- Two materials in one print. A rigid part with a flexible one, or a model with a dedicated support material.
- Dissolvable supports. One head prints the part, the other prints supports that wash away.
- No purge between the two heads, because each filament has its own nozzle.
- Duplication and mirror printing on many IDEX machines, where both heads print the same part at once.
Where Two Heads Run Out
Two nozzles means two colors or materials at a time. Printing a third color means swapping the filament in one of the two heads, and that brings back the same unload, load and purge routine you were trying to avoid. We explain that routine in Purge Towers Explained.
What Is IQEX?
IQEX stands for Independent Quad Extruder. It follows the same idea as IDEX, with four toolheads instead of two, all on a single X-axis.
On Quadro, every toolhead has:
- its own stepper motor,
- its own belt and pulley, with four belts stacked on the X-axis,
- its own filament path,
- its own automatic belt tensioner.
None of the heads detach from the machine. When a head isn't printing, it parks in a QDock station at one end of the axis, with its nozzle sealed. Quadro has two stations, one at each end, and each holds up to three toolheads. For how the heads are coordinated, read how Quadro coordinates four independent toolheads.
IDEX vs IQEX at a Glance
| IDEX | IQEX | |
|---|---|---|
| Toolheads | 2 | 4 |
| Independent motor per head | Yes | Yes |
| Colors or materials in one print | 2 | 4 |
| Color-clearing purge between heads | No | No |
| Third color | Needs a filament swap and purge | Already loaded |
| Parking | Side of the bed | QDock stations at both ends |
| Head swapping | No | No |
What Four Heads Make Possible
- Four colors in one print with no color-clearing purge.
- Four materials in one print. For example, a rigid body, a flexible part, a dissolvable support and a structural material, each at its own temperature.
- Waste that doesn't climb with every color change, because each color stays in its own nozzle. See what that looks like in practice: How Much Filament Does Multicolor Printing Actually Waste?
The Trade-Offs
More heads on one axis means more to coordinate. Four nozzles need four sets of offsets, and the heads have to stay out of each other's way. That's a design problem we spent a lot of time on, and why Quadro calibrates its toolheads automatically and parks idle ones in sealed stations. If you rarely print more than two colors or materials, an IDEX printer may be all you need.
How to Choose
- Two materials, or a main material plus supports: IDEX is a good fit.
- Three or four colors or materials in one print: IQEX avoids the swapping and purging a third color forces on IDEX.
- Comparing every design: see our multi toolhead 3D printer buying guide, and for the other popular approach, AMS vs tool changer.
Key Takeaways
- IDEX has two independent toolheads. IQEX has four.
- Both give each filament its own nozzle, so neither needs a color-clearing purge between heads.
- A third color on IDEX means a filament swap and purge. On IQEX, four colors or materials are already loaded.
- More heads mean more coordination, which is why calibration and parking matter.
Want to see IQEX in action? See Quadro or visit the Kickstarter page.
3. FAQ
What does IDEX stand for? IDEX stands for Independent Dual Extruder. It is a printer design with two toolheads that move independently on one gantry.
What does IQEX stand for? IQEX stands for Independent Quad Extruder. It uses the IDEX idea with four independent toolheads on a single X-axis.
Is IQEX a tool changer? No. A tool changer docks and picks up heads on every change. In IQEX, every toolhead stays mounted on the machine, and idle heads park in stations at the ends of the axis.
Can an IDEX printer print four colors? Not at once. It has two nozzles, so a third or fourth color needs a filament swap in one of the heads, which brings back purging.
Why use four independent toolheads instead of two? Four heads let you load four colors or materials at once, so you can switch between them without swapping filament or purging the nozzle.
