Troubleshooting Extrusion Problems

Extrusion problems are usually caused by errors in the extruder assembly or the hotend assembly.

Inspecting the Extruder Assembly

Never touch the hotend with unprotected skin while it is hot as it will result in burns!


1. Preheat the hotend to 200°C

2. While the hotend is hot, press the extruder plunger       arm inwards with one hand and feed the filament in       manually (fig.1).

  fig.1 - Manual Feeding of Filament

  fig.1 - Manual Feeding of Filament


3. If material starts extruding from the hotend
    smoothly, then the problem resides in the
    extruder assembly and may have just been fixed.

4. Release the plunger arm and try printing again.


5. If material still does not extrude automatically from       hotend then it may indicate that the extruder drive       gear is not securely fastened on the extruder motor       shaft or that the extruder drive gear is in the wrong       position. Ensure that the teethed groove of the             extruder drive gear is horizontally aligned with the         bearing above it, and that the filament fits in the           center of the groove. Securely screw in the headless     hex to fasten the extruder drive gear.


6. Ensure that the filament is free of missing chunks           caused by grinding of the extruder drive gear and         tightly clamped by the plunger arm when released.
    Ensure that the extruder drive gear is clean of any         filament shavings.

 

 




 

 
 fig.2 - Aligning The Extruder Drive Gear And Filament

 fig.2 - Aligning The Extruder Drive Gear And Filament

 

Inspecting the Hotend Assembly

                               fig.3 Do not over-tighten the components on the hotend assembly.

                               fig.3
Do not over-tighten the components on the hotend assembly.

Never touch the hotend with unprotected skin while it is hot as it will result in burns!
 

1. If the material does not extrude out of the hotend when the
   filament is pushed in by hand, then that may indicate a clogged    hotend.

2. First ensure that the heatsink is in contact with the flat part of
    the hotend and that the hot end cannot be further turned by       the ATOM Wrench (fig.3).

 

                                           fig.4                                fig.5

                     
                     fig.4                                fig.5

3. The problem should reside in one of the four following cases:

    Case 1 - Filament Stuck at Quick Tube Connector

    Case 2 - Overheated Teflon Tube

    Case 3 - Hotend Fan

    Case 4 - Unclean Hotend



Case 1 - Filament Stuck at Quick Tube Connector

The filament is stuck at the quick tube connector on the hotend assembly. Push down the plunger arm of the extruder assembly and pull out the filament. Make sure to trim the filament at an angle so it can be routed more smoothly.


Case 2 - Overheated Teflon Tube

The hotend temperature is set too high. If the temperature exceeds 250°C the Teflon tube in the hotend assembly may deform and constrict the flow of filament (fig.5). Set a lower hotend temperature.


Case 3 - Hotend Fan

The hotend fan is either not working or installed in the wrong direction, resulting in poor cooling and overheating. PLA that is heated and stationary in the hotend Teflon tube for a prolonged time will expand and plug it up (fig.4).


Case 4 - Unclean Hotend

Foreign particles on the nozzle or even inside the hotend prevent the material from extruding smoothly. Use a 0.3mm drill bit and carefully clear the hotend nozzle.
Insert the drill bit from the side with pointed tip of the hotend at an angle parallel to the hotend shaft.

 

Hotend Heating Problems

 
HotendAssemblyTerminals.png

Case 1 - Temperature Does Not Increase

Indicates a problem with the ceramic heating plate on the hotend assembly. To verify if the ceramic heating plate is damaged, use a multimeter (fig.1) and measure the resistance across its terminals (fig.2). A measurable resistance will indicate that it works normally. A resistance of -1 will mean that it is damaged. Check for bad connections on all points between the plate and the control board. Check if the ceramic heating plate in the hotend assembly is cracked.



Case 2 - Temperature Reading 0°C

Indicates a problem with the thermistor. To verify if it is damaged, use a multimeter (fig.1) to measure the resistance across its terminals (fig.2). The measured resistance should fall around 100K, whereas a resistance of -1 will mean it is damaged.


Case 3 - Temperature Reading Over 500°C

Indicates a failure with the thermistor. The thermistor must be replaced.
 

 

The Filament Is Stuck In The Hotend


Sometimes the filament can be stuck in the hotend, which is most likely caused by over-retraction with the [Suck] and [De-String] functions.

When heated PLA filament is over-retracted, it may start to expand in the gap between the quick tube connector and the hotend shaft. If it cools down and hardens, it will prevent any kind of movement.
 

Never touch the hotend with unprotected skin while it is hot as it will result in burns!
Let the hotend cool down completely before proceeding to fix it.

 

 


Follow these steps to clear the hotend of obstruction:

1.     Let the hotend and the entire effector assembly cool down and then shut down the printer.
2.    Detach the Teflon tube from the hotend assembly’s quick tube connector.
3.    Cut the exposed filament.
4.    Unscrew the quick tube connector and remove the hotend assembly from the effector cover.
5.    The part where the expanded or stuck filament should now be apparent. Clear the hotend of the obstructing            material. Note that there is a segment of Teflon tube inside the hotend shaft. Do not damage nor try to remove        that tube.
6.    Re-install the hotend assembly on the effector cover and screw in the quick tube connector
7.    Reattach the Teflon tube to the quick tube connector on the hotend.

 

Smoke And Odor Coming from Hotend

Overheated Hotend

When the hotend emits smoke with an odor it typically means it has exceeded it maximum temperature. Often the status screen on the LCD display may show, for example, 180°C whereas the heating plate actually continues to heat up to 230°C.
 

   fig.4 - Thermistor Is Centered              fig.5 - Thermistor Is Out of Place


   fig.4 - Thermistor Is Centered              fig.5 - Thermistor Is Out of Place


Although it is unlikely that this problem will occur on the improved ATOM 2 hotend
assembly, the cause of this problem is likely because the thermistor is out of place
(fig.5). Carefully reposition the thermistor back to the center of the chamber in the
hotend. To ensure that this problem does not occur in the future, do not tug on the hotend wires, and make sure there is some slack on the lines leading from the hotend to the control board

.

Never touch the hotend with unprotected skin while it is hot as it will result in burns! Let the hotend cool down completely before proceeding to fix it.
 

 

Hotend Temperature Fluctuates Around Target Temperature

fig.1 - Pronterface Returning Measured PID Values

fig.1 - Pronterface Returning Measured PID Values

 


Fluctuations up to ±10°C around the target temperature during preheat and printing is normal. Upon initial heat up, ATOM 2 firmware has a proportional-integral-derivative (PID) control algorithm that takes over temperature controls when the temperature reaches within 10°C of the target temperature to help it stabilize. The PID controller also helps maintain the temperature during printing.



If there are frequent fluctuations that are larger than ±10°C or if the hotend takes more than 2 minutes to stabilize at the target temperature, first ensure that the upper and lower hotend windshields are properly installed and that the side and rear fans are properly installed.


The PID values can be recalibrated through the following process:

1.  Connect your ATOM 2 to your computer through USB (DC power still needed)
2.  Start Pronterface (software) and connect to the printer
3.  Use the command [M303 C8 S200] (C=Cycles and S=Target temperature) in the console and wait for it to run         and return with measured values of [kp] [ki] [kd] on the console. The more cycles (C), the more accurate the             calibration may be.
4. On your printer control panel, navigate to [Control | Temperature] and adjust the [PID-P] [PID-I] [PID-D] values to       match the measured values from Pronterface
5. Navigate to and use the [Control | Store Memory] function to save your new PID settings.


If you followed steps 1-5, the printer will already have the new PID settings.
However if you prefer, the PID settings can be saved in the firmware defaults instead of storing it on the EEPROM with the following steps:

fig.2 - Replacing Firmware PID Values With Arduino

fig.2 - Replacing Firmware PID Values With Arduino


1. Open the Configuration.h file of Marlin with the Arduino software.

2. Search for the line [DEFAULT_Kp]

3. Replace the [DEFAULT_Kp] [DEFAULT_Ki] [DEFAULT_Kd] values with the values returned by the M303 function.

4. Save the Configuration.h file and upload to ATOM 2’s control board.