Gigabot X Extrusion Issues

There are many reasons why GBX won’t extrude as expected. This troubleshooting guide is organized into the following sections:

• Extruder Diagram
• Issues Extruding Through Simplify3D
• The Extruder Motor Does Not Attempt to Spin At All
• Extruder Motor Skipping
• The Extruder Motor Spins, but Nothing Extrudes
• Inconsistent Extrusion
• Consistent Under or Overextrusion

Extruder Diagram

Below is a cross sectional diagram of the GBX extruder assembly to be used as a reference during troubleshooting.

Legend:

1. Extruder motor
2. Motor coupler
3. Feed throat
4. Extruder body inlet hole
5. Top heat zone
6. Middle and bottom heat zones
7. Nozzle and nozzle receiver

Issues Extruding Through Simplify3D

Possible causes of extrusion issues with Simplify3D include:

• The computer is not connected to the printer
• The active toolhead is not set to Tool 0
• The extruder jog speed is set too high

To troubleshoot:

1. Check that the printer is connected to the computer via USB.
2. Ensure that Simplify 3D establishes a connection to the printer. In the Machine Control Panel, it should have a “Disconnect” button with a green icon if it is correctly connected.
3. Ensure that Active Toolhead is set to Tool 0. 
   • If it is set to Tool 1, the motor won’t turn. 
   • If it is set to Tool 2, it will turn in the wrong direction
4. Ensure that the extruder jog speed is set to a reasonable value. 
   • If it is too low, the motor may not visibly turn. 
   • If it is too high, the motor will make a high-pitched droning noise.

The Extruder Motor Does Not Attempt to Spin At All

Possible causes of an unresponsive extruder motor include:

• Extruder temperatures are below the cold extrusion temperature
• The motor wire is disconnected

To troubleshoot:

1. Check that the extruder is heated to above the cold extrusion temperature (120C is the default). To extrude at lower temperatures, use the gcode M302 to set a lower cold extrusion temperature limit (Marlin documentation for M302: Cold Extrude).
2. Check that the extruder motor is connected to the motor cable. Turn off the printer before attempting to unplug or plug any wires.

Extruder Motor Skipping

The motor skips when it attempts to turn, but does not have the torque required to turn the extrusion screw, resulting in skipped steps and a clicking noise. Possible causes of motor skipping include:

• Heat zones are not at operating temperatures
• Operating temperatures are too cold
• Extrusion rate is too high
• The nozzle is clogged

To troubleshoot:

1. Check that all the heat zones are at operating temperatures by looking at the Viki info screen. If any of the 3 heat zones are too cold, it can make the motor skip (Extruder Diagram Sections 5 and 6).
2. Assess if the operating temperatures are too cold. This is likely if the extrudate has a high viscosity. To solve this, increase the heat zone temperatures (Extruder Diagram Sections 5 and 6).
3. The extrusion rate may be too fast for the motor to handle (Extruder Diagram Section 1).
   • If extruding from Simplify 3D, lower the extrusion speed.
   • If printing, reduce the speed on the Viki, or re-slice the gcode at a lower speed.
4. Assess if the nozzle is clogged (Extruder Diagram Section 7). This is likely if contaminants were present in the extrudate, the printing material is a filled material, there was previously an inconsistent extrusion rate, and/or the extruder abruptly stopped extruding.
   • Troubleshoot by removing the nozzle (instructions: Replacing the Gigabot X Nozzle). If the material extrudes as expected with the nozzle removed, the nozzle may be clogged.
   • Alternatively, poke a thin wire through the bottom of the nozzle while it's heated. This may dislodge any large chunks of contaminant.
   • For more information on mitigating contaminants, refer to Contaminated Materials.

The Extruder Motor Spins, but Nothing Extrudes

Possible causes of lack of extrusion despite a working extruder motor include:

• The printer ran out of printing material
• The extruder screw is spinning in the wrong direction (retraction)
• Motor coupler halves are decoupled
• Motor coupler is not adequately clamped onto the motor shaft or the extrusion screw
• Printing material is stuck in the feed system
• Material bridging

To troubleshoot:

1. Check if more material needs to be loaded into the feed system, or if materials are stuck in the feed tube or feed throat (Extruder Diagram Section 3). For information on optimal material properties for printing with Gigabot X, refer to Choosing Gigabot X Print Materials.
2. Check that the extruder motor coupler is rotating to the right (Extruder Diagram Section 2).
   • If it is rotating to the left, make sure that you are sending an extrusion command to the printer, and not a retraction command.
   • If it is rotating to the left in response to an extrusion command, make sure that Tool 0 is selected, either in your gcode command or in your slicer interface.
3. Check that both halves of the extruder motor coupler are coupled correctly (Extruder Diagram Section 2). 
   • If the two halves of the motor coupler are decoupled, send a retraction command to the extruder motor to rotate the motor axle backwards until the top and bottom halves of the motor coupler are correctly aligned. With the extruder heated, slip a flathead screwdriver under the bottom coupler half and push it up until it re-engages with the top coupler half. 
     • Note: if the motor coupler insert is damaged, it will need to be replaced.
     • Note: The screw and the bottom half of the coupler may fall if material is not feeding into the extruder during printing. To prevent this in the future, make sure that the feed system is loaded with material before performing any extrusion commands.
4. Check that the motor coupler is fastened securely to both the motor axle at the top and the compression screw below, and both are rotating when the printer is attempting to extrude (Extruder Diagram Section 2). 
   • If the coupler is not adequately clamped onto either the motor shaft or the compression screw, use the Simplify3D Machine Control Panel or the Viki to rotate the motor coupler such that the set screw is exposed. Use a 3mm Allen wrench to torque down the set screw. Remove the feed throat if needed to improve access to the motor coupler.
5. Material may be stuck in the feed system, and is not flowing properly into the extruder.
   • Inspect the hopper and feed tube for any signs of material blockage.
   • If there is no visible signs of material blockage, there may be a blockage in the feed throat (Extruder Diagram Sections 3 and 4). Place a bucket beneath the extruder and remove the 4 x M5 screws that connect the feed throat to the extruder body. Pull the feed throat away from the extruder body and allow the material in the feed system to drain into the bucket. Inspect the inside of the feed throat (Extruder Diagram Section 3) and the inlet hole to the extruder body (Extruder Diagram Section 4) for any blockages.
6. The material may be bridging at the top of the extruder (Extruder Diagram Section 5). This is when particles partially melt too high in the extruder and stick together.
   • Reduce the temperature of the top heat zone. Extrude for at least five minutes to push any bridged particles farther down the extruder.

Inconsistent Extrusion

Inconsistent extrusion may be caused by a variety of reasons, and sometimes it is caused by multiple reasons occurring simultaneously. Possible causes of inconsistent extrusion include:

• Printing material flows inconsistently through the feed system
• Improperly calibrated Z gap
• Clogged or partially clogged nozzle
• Material bridging
• Extruder temperatures are too low

To troubleshoot inconsistent extrusion:

1. Visually inspect if materials are getting stuck in the feed tube or feed throat, preventing them from flowing consistently into the extruder (Extruder Diagram Section 3). For information on optimal material properties for printing with Gigabot X, refer to Choosing Gigabot X Print Materials.
2. Check if the bottom layer has gaps or ridges between the lines, but subsequent layers look different. If yes, the issue may not be the extrusion rate. Instead, the Z distance between the bed and the nozzle may need calibration. Refer to Setting the Z Axis Home Position to calibrate the Z gap.
3. Assess if the nozzle is clogged or partially clogged (Extruder Diagram Section 7). This is likely if contaminants were present in the extrudate, the printing material is a filled material, there was previously an inconsistent extrusion rate, and/or the extruder abruptly stopped extruding.
   • Troubleshoot by removing the nozzle (instructions: Replacing the Gigabot X Nozzle). If the material extrudes as expected with the nozzle removed, the nozzle may be clogged.
   • Alternatively, poke a thin wire through the bottom of the nozzle while it's heated. This may dislodge any large chunks of contaminant.
   • For more information on mitigating contaminants, refer to Contaminated Materials.
4. Prevent bridging by lowering the temperature of the top heat zone (Extruder Diagram Section 5). Bridging occurs when particles melt too high up in the extruder and stick together, causing underextrusion. After reducing the temperature, extrude for at least five minutes to push any bridged particles further down the extruder.
5. Check that the bottom and middle heat zones are at a high enough temperatures (Extruder Diagram Section 6). Materials may extrude fine at certain temperatures if the extruder is left heated for an extended period of time, but the material may have extrusion issues at the same temperatures during printing as the material flows through the extruder and the system reaches steady state. To mitigate this, increase the temperatures of the bottom and middle heat zones.

Consistent Under or Overextrusion

If the extruder is consistently under or over-extruding, the extruder motor may need to be recalibrated for that material. For instructions on how to calibrate the extruder motor, refer to Calibrating the Gigabot X Extruder Motor Extrusion Rate.

Questions or concerns? Reach out to our support team at support@re:3D.org or open a support ticket.