Here are some frequently asked questions we receive from users. If you’re having trouble, check to see if your solution is here.

My extruder is extruding too much plastic.
One extruder is extruding more plastic than the other.

Check the jumpers under your stepper drivers. All three jumpers should be installed for 1/16 microstepping. If you don’t have all three installed, your motors will extrude 2x, 4x, 8x or even 16x the expected rate. For double extruders, make sure both drivers are set to the same microstep level.

Check your e-steps setting.  If you’re using one of our milled extruder bolts in an Itty Bitty extruder, we recommend starting with an E-Steps value of 615 steps/mm.

Check your slicing software to be sure you have the nozzle sizes and filament diameters configured correctly. They don’t have to be the same, but the slicer needs to know what they are.

I can’t get the belt tight enough.
The belt is too short to fit over the pulley.

Make sure you’re putting the belt on the small, flanged pulley first. Then slip the belt over the larger pulley. The belts do not stretch, so putting them on the other way around doesn’t work.

Check to be sure you have the correct belt  The double extruders use 200mm belts and the single extruder uses a 188mm belt. They are not interchangeable.

Where do I plug the servo into my RAMPS board?

If you’re using a RAMPS 1.4 board, the servo should be connected to D11.

Where do I plug a print cooling fan into my RAMPS board if I’m using two extruders?

When using two extruders, the second heater is connected to D9, where the fan would otherwise be. If you want to use a print cooling fan, too, you’ll need a fan extender board. Either the RRD (RepRapDiscount) board or the Geetech one will work.

How do I plug in a fan extender and a servo at the same time?  They use the same pins.

If you shift the fan board up one or two pins, leaving D11 uncovered, you can use both. If you have the RRD fan extender (usually white) just shift it up one pin to leave D11 uncovered. Only one of the two channels on the fan extender will work, and it will be D4. If you have the Geetech fan extender (usually red) shift it two pins. Both channels will work, and they will be on D4 and D5. Connect the print fan to the one on D4.

Only one extruder motor turns.
My RAMPS board has only four drivers.

The RAMPS 1.4 board has spaces for five A4988 drivers to control steppers. One is typically used for both Z motors, one for X, one for Y and two for extruders. If your printer came with only one extruder, it may have been shipped with only four drivers. You will need a fifth driver to run the second extruder. You can get one from MakerFarm, Pololu or a number of other sellers. If you get a “Stepstick” driver, be sure to research the current settings.  They’re different from standard Pololu drivers.

My extruder doesn’t extrude material; the bolt just cuts a notch in the filament.

Make sure your hot end is at an appropriate temperature for your filament. All-metal hot ends like the Hexagon need to run a little hotter than PEEK or PTFE hot ends. 250C is a good starting point for ABS, and 225C for PLA.

Try printing a little slower. If it works properly at a slower print speed, you probably just need to raise the temperature a little.

Be sure you’re using the correct springs.  For hard filaments like ABS and PLA, we recommend our standard double extruder springs.  Our light springs are best for soft filaments like NinjaFlex.  They usually work with harder filaments, too, but you may need the standard springs if you have grinding problems.

If you’re using an all-metal hot end, make sure you have sufficient air flow to cool it. All-metal hot ends can jam if not properly cooled. The filament can swell if it is heated in the channel, causing a jam.

Your nozzle may be clogged. Disassemble the hot end and remove any remaining plastic. You will probably need to heat it up to unscrew the parts. You can often clear the nozzle with a guitar string. If you’re printing ABS, you can soak the hot end parts in acetone to dissolve or soften the hot end. You may need to soak it, pick out some of the plastic with tweezers and repeat until it’s clean.

While the hot end is disassembled, inspect all of the parts carefully to be sure there aren’t any burrs or bits of material on any of the edges or surfaces in the filament channel.

Check to be sure your filament is round and the correct size. 3mm filament should be between 2.85 and 2.95mm and it should be round; the diameter should be the same when measured from any angle.

Plastic is leaking out of my hot end at the joints.

All-metal hot ends, like the Hexagon, have to be tightened hot. The aluminum block expands more than the stainless steel heat break when it heats up, and this causes the parts to loosen. To prevent this, connect the heater and thermistor to the hot end and heat it up before installing in your printer. Heat to the maximum temperature you will use when printing and retighten the nozzle and the heat break.

My second extruder doesn’t do anything.
How do I print with the second nozzle?

To print using a dual extruder, you need several things:

  • A dual extruder mechanism with two hod ends.
  • Electronics that can drive two extruders
  • Printer firmware that can drive two extruders
  • A slicer configuration that generates multi-material GCODE
  • A multi-material object to print

You can find some tips on slicing for multi-material objects here:

 Slic3r Manual – Multiple Extruders

 Simplify3D – Printing With Multiple Extruders

A good place to start is with our double extruder calibration objects, here:

Double Extruder Calibration

What current limit should I set for my extruder motors?

If you’re using the motors that we sell, we recommend that you start at .75A and work from there.  For Pololu drivers, this corresponds to .3V at the trimpot wiper.  For StepStick drivers, this is 1.2V.

If your motors are skipping steps, increase the current.  If they are running too hot, lower the current.

If your motors are running too hot and still skipping steps, you may have a jam or a clogged nozzle.

How hot should my stepper motors get?

The stepper motors can stand much more heat than the plastic extruder parts.  Temperatures as high as 60C are acceptable, as long as the plastic parts don’t soften and droop.  If your motors are too hot, lower the drive current.

Where do I plug in the Z probe switch?

The Z probe replaces your Z endstop swtich. The only difference is that instead of registering the physical position of the carriage, it registers the absolute position of the bed surface relative to the extruder assembly. The firmware expects to see your Z probe on the Z endstop circuit. Unplug your old Z stop and plug your Z probe in instead.

What material should I use to print the plastic extruder parts?

We recommend ABS for the extruder. It has a higher melting point than PLA, less surface tack for better feeding and a little flexibility to handle stresses.

My auto bed level is doing something weird; what is it supposed to do?

This video shows the ABL sequence and the normal startup GCODE we use with the double extruder.

Do you have NEMA17 versions of your extruders?

Our extruders are all designed around NEMA14 motors. Check our Thingiverse listings for user-contributed remixes.