MarkForged Visual Troubleshooting Guide

Note: Legacy documentation is no longer being updated. For up to date instructions, see our Troubleshooting support articles.


The MarkOne 3D Printer is capable of producing high quality functional parts. In order to reliably produce quality parts you may have to 'tune' your machine for optimal performance. There is a bit of a learning curve associated with this. This guide aims to be a visual glossary of part quality issues that you may encounter and their recommended solutions.

Look through the part quality images, identify the pictures / issues that best describe your issues.

If you find any inaccuracies or if something is unclear, please let us know.


Nylon Under-Extrusion
The printer is not extruding enough plastic leaving gaps in the print.
There are 'strings' of plastic coming off the side of your part.
Part Warping
The edges of the part are peeling up off of the bed or are warping.
Part Burning
The plastic is brown or black (instead of clear/off white) or has black specs encased in it.
Part Curling
The top of the part is deformed or curls upwards.
The printer has encountered a dislocation error.
Fiber Tracking
Fiber is failing to print where it's supposed to or fiber is sticking outside of your print.

Nylon Under-extrusion

Under-extrusion is when less plastic comes out of the nozzle than is commanded. This will manifest in your parts in several ways:

Under-Extruded First Layer
Under-Extruded Features
Under-Extruded Purge Tower
Under-Extruded Top Surface

This is what your part should look like if it is extruding properly:

Properly Extruded Purge Tower
Properly Extruded Top Surface

To Test for Under-extrusion:

Run a Calibration Extrude Test

Run the Load Nylon routine - a few seconds after the nylon filament enters the printhead, a the extruder should start making a clicking sound. If not your extruder may be underperforming. Contact MarkForged Support. 

Verify that the nylon spool is not tangled in the drybox. You can do this by unloading nylon and then detaching the nylon inlet tube from the extruder and manually pulling on the nylon to see if it is stuck in the drybox. If you open your drybox you risk ruining your nylon. Please be incredibly careful to minimize the time the nylon is exposed. 

Common Causes:

  • Plastic Extruder mis-calibrated
  • Plastic PTFE Insert clogged or melted
  • Nylon wrapped around spool axel in drybox
  • Wet Nylon

Common Solutions

  • Re-calibrate the extruder
  • Remove all the nylon for the machine, cut a new end and re-route it through the machine
  • Try new, dry nylon



Stringing is the deposition of FFF material outside of or between parts in a build. It occurs when plastic is expelled or leaks from the nozzle unintentionally, plastic sits in a heated nozzle for an extended period of time, or when part of a new layer fails to completely adhere to the layer before. Stringing can look like wispy, spiderweb-like strings between features or parts on a build or strings climbing off the outside of a part.


Common Causes:

  • Wet Nylon


To Reduce stringing:

  • Replace nylon filament
  • Check nylon Bowden tube for kinks and make sure that filament slides back and forth easily
  • Ensure that the temperature of the heater block matches the temperature displayed on the printer
  • Avoid leaving the nozzle heated longer than necessary
  • Make sure to keep nylon drybox closed at all times. See this support article for more details


Part Warping

Part warping is when the bottom of the part starts to peel up and away from the print bed. Warping happens when the plastic cools and then contracts. As the print cools down and shrinks internal stresses in the plastic form and pull the plastic in towards itself. Eventually the internal forces become so great that the part begins to pull away from the print bed.


It is also very important to make sure your bed is leveled as perfectly as you can. If the Nylon is not properly deposited and squished onto the print bed it will not adhere well which will lower the amount of force the internal stresses need to exert on the part before warping it. See bed leveling for more details.

Common Causes:

  • Little surface area in contact with the bed
  • Very large parts that have high density plastic infill 
  • High density plastic infill in small features that are in contact with the bed
  • Poor Print Bed Leveling


To Combat Part Warping:

  • Print with the Brim turned on
  • Re-orient the part to increase the surface area in contact with the bed (if possible)
  • Glue the print bed prior to printing
  • Reduce Plastic Infill Density
  • Re-level the Print Bed


Part Burning

Part burning is when your part has black or brown spots on or in it. For the most part burning is strictly aesthetic and will not affect the strength of your part.


Part Burning is usually caused by burnt nylon falling or rubbing off of the nozzles into the part while it is being printed: 

Clean Nozzles
Clean Nozzles
Dirty Nozzles

Common Causes:

  • Dirty Nozzles
  • Dirty Printhead
  • Part is Curling


To Reduce Burning:

  • Clean Nozzles
  • Use Brim Feature To Increase Bed Adhesion


Part Curling

Part Curling is when the edges of your part curl or warp up above the printing plane. This happens because as the nylon is being printed different sections are cooling at different rates which causes internal stresses (very similar to warping). This often occurs on the edges of parts which are at an angle.



Common Causes:

  • Poorly supported overhangs
  • High Density Infill


To Reduce Part Curling:

  • Turn on Supports
  • Re-orient part to reduce extreme angles
  • Reduce the infill density



Dislocations occur when the printhead collides with either the part or the printer causing the stepper motors to skip. This occasionally happens when a print is going poorly. If the print curls or warps such that the printhead or nozzles collide with it then it will likely lead to a dislocation.

Dislocations are unrecoverable. The Mark One is capable of detecting dislocations and will stop itself from wasting material or potentially damaging itself by aborting a dislocated print.


Common Causes:

  • Warping
  • Curling


Common Solutions:

  • Run the calibration routine and re-level the bed
  • Use the Brim feature 


Interlayer Adhesion

To get a successful print it is crucial that each layer adheres well to the previous layer. While this is a problem that all FFF printers face, the Mark One has managed to significantly decrease its impact by using engineering-grade nylon and partially remelting previous layers to ensure strong bonding. If a part fails prematurely along layer lines, there is likely something causing decreased interlayer adhesion.

Common Causes:

  • Nozzle is too cold
  • Under-extrusion
  • Part geometry


To Increase Interlayer Adhesion:

  • Ensure that on Eiger the printer displays a nozzle temperature of 265oC while printing
  • See “Under-extrusion”
  • Avoid creating parts that include thin walls directly on top of large, flat bases. Instead chamfer or fillet walls to ensure a stronger bond.


Fiber Tracking/Fiber Nozzle Level

The CFF filament that the Mark One prints with is very different than the Nylon FFF filament. The CFF filament is one long continuous strand. Because it is all one continuous strand the dynamics that affect how it prints are quite different than with the nylon. Fiber tracking refers to how well the fiber tracks (or adheres) on the desired printing path. If the fiber pulls away from its path then the part will end up with an excess of fiber - which will result in fiber tails that may stick out of the part.

Additionally, the fiber needs to fully adhere to the plastic in order to form a structural bond. If the fiber nozzle is not properly leveled then the fiber will most likely not form this bond correctly.

The deposited width of the fiber should be from 0.8mm to 1.0mm. 

Bad Tracking
Bad Tracking
Good Tracking

If the fiber nozzle is too close then it will cause fiber jams, damage to the part, dislodge the part from the print bed or cause a dislocation.

If the fiber nozzle is too far away then it will cause fiber jams (from not adhering), poor fiber adhesion to part (structural) and fiber tails.

Several things can affect how well the fiber prints.

  • Pictures of too high (thin fiber)
  • Too close jamming
  • Tight corners
  • Small "back and forths" for iso