3D Printing Troubleshooting

Yikes! What happened here? Use these photos and solutions borrowed from the folks at NinjaTek to diagnose issues and learn some new print settings.

3D Printing Troubleshooting
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1. Under Extrusion

Not enough material is being extruded. Lines and passes are clearly defined and are easily separated from one another or not uniform in shape.

Under Extrusion

Possible Causes:

  • Feed Tension – Flexible Filaments: Increase tension at feeders by rotating the screw to the right until the feed evens out.
  • Feed Tension – Rigid filaments: Loosen tension by rotating the screw to the left until the feed evens out.
  • Clogged nozzle: Set nozzle to max temp or 250°C (whichever is lower). Feed material untill you see a good even flow from the nozzle.

2. Over Extrusion

Too much material is being extruded. Each line or pass runs into the other lines causing the excess material to squish in to a new area. the nozzle may look gooey or become covered in extra material.

Possible Causes:

  • Nozzle temperature: It may be too hot. Try reducing the temperature in increments of 5°.
  • Incorrect filament diameter: Check your software settings to confirm you are set to use the same filament as shown on your spool label.
  • Flow percentage settings: Confirm your flow percentage settings are where you need them be.
  • Worn out nozzle: Brass nozzles do not hold up well to abrasive material. If you have used metal filled PLA or conductive materials, you may find your nozzle diameter has expanded and you may need to replace your nozzle.

3. Holes or Gaps in the Top Layer

Openings in the solid outer shell that allow you to see a previous layer.

Possible Causes:

  • Too little infill: Flexible filaments often require more infill than their more rigid counterparts. For NinjaFlex try to keep your minimum to 20% infill. For Cheetah try to keep your minimum infill to 10%. Keep in mind part complexity and where the infill actually lands can make a big difference.
  • Not enough solid top layers: Add additional top layers at end of print.
  • Feed Tension – Flexible Filaments: Increase tension at feeders by rotating the screw to the right until the feed evens out.
  • Feed Tension – Rigid filaments: Loosen tension by rotating the screw to the left until the feed evens out.
  • Clogged nozzle: Set nozzle to max temp or 250°C (whichever is lower). Feed material untill you see a good even flow from the nozzle.

4. Stringing or Oozing

Wisps or strings of extruded plastic that are not a part of the original design, They are commonly stuck on the outside surface of the finished part. Some remove easily while others need to be cut or scraped off. They can ruin a print by making it look less than perfect.

Possible Causes:

  • This is going to happen with flexible filaments but you can mitigate it by:
  • Travel speed: Increase your travel speed between points.
  • Print temperature: The cooler the temperature, the less oozing you will see.
  • Nozzle temperature: It may be too hot. Try reducing the temperature in increments of 5°.

5. Overheating

Each 3D printing material has its own optimal printing temperature and each printer is different. Printers and materials can range from a print temperature of 180°C to 250°C. Some materials handle a wide range of temperature while others only handle a 5° range. If a material is heated past its optimal print temperature, it gets too soft and can bubble, boil or burn, making it difficult to print.

Possible Causes:

  • Cooling fan: Add cooling or increase cooling fan speed to max speed after the 1st or 2nd layer.
  • Printing temperature: Cool your printing temperature down in increments of 5°.
  • Layer time: Add a layer timer of 20 – 30 seconds.
  • Print speed: If printing at recommended speed settings, decrease print speed in increments of 2 mm/sec.

6. Failure to Feed Filament or Stops Mid Print

The Print head keeps moving but no filament is flowing out of the nozzle.

Possible Causes:

  • Grinding Filament: Typically caused by too much tension at the feeder gear.
  • Flexible filaments: Increase tension at feeders by rotating screw to the right until the feed evens out.
  • Rigid filaments: Loosen tension by rotating screw the left until the feed evens out.
  • Clogged nozzle: Set nozzle to max temp or 250°C (whichever is lower). Feed material till you see a good even flow from the nozzle.
  • Filled or worn out hobbed gear: Clean bolt teeth or bite gear teeth. If worn out, replace gear.

7. Weak Infill

The infill appears thin, weak or uneven. It may skip or tear and have open holes with no infill present. The lines on the inside are typically not as thick as the outlines or shell surface.

Possible Causes:

  • Clogged nozzle: Set nozzle to max temp or 250°C (whichever is lower). Feed material till you see a good even flow from the nozzle.
  • Spool issue: There may be a feed issue or filament may be knotted or wrapped around the arm.
  • Print speed: Lower the print speed.

8. Gaps Between Infill and Outline

When gaps appear in the corners created between the outer shell and the infill’s diagonal lines.

Possible Causes:

  • Not enough overlap: Increase overlap in increments of 2% (0.02).
  • Print speed: Slow the print speed of the infill.

9. Curling/ Peeling Off Print Bed

The print begins to peel up from the print surface at corners or thin sections curl up during printing.

Possible Causes:

  • Poor adhesion: not typically an issue with flexible filaments, but it can cause issues with more riged material. Try blue painters tape or a standard glue stick.
  • Add a brim or raft at start of print.
  • Use a heated bed: Suggested temp specs 80°C- 110°C.

10. Surface Imperfections

These are drips or scars caused by the nozzle passing over already finished section of the print.

Possible Causes:

  • Drips – Over extruding plastic:
  • Nozzle temperature: It may be too hot, try reducing the temperature in increments of 5°.
  • Incorrect filament diameter: Check your software settings.
  • Travel speed: Increase travel speed in increments of 5mm/sec.
  • Scarring – Z-hop: Adjust to be, at minimum, equal to your layer height.

11. Side Layer Surface Issues

When one section of a print looks poor or textured, but other surfaces of the finished print are clean and well formed.

Possible Causes:

  • Material flow rate: Increase the flow percentage or increase the extrusion multiplier by 5% at a time. If your software permits, you can also decrease the filament diameter by 3% to 5%, or decrease the nozzle diameter by roughly 10%.
  • Restart distance: Increase or add restart distance after retraction.

12. Clumping On Top Surface

Wads or lumps of spare/ oozed filament deposited on or outer surfaces of a print.

Possible Causes:

  • Printing temperature: Increase your printing temperature in increments of 5°. This allows the material to flow better and stretch across openings in the infill, preventing it from breaking and clumping on infill walls.
  • Top and bottom surface speed: Decrease your top and bottom surface speed, this allows the nozzle to perform a more precise application of the filament during each pass.
  • To little Infill: If you have infill that is to sparse the filament can sag or clump between supports, creating blobs that then stick to the nozzle and become clumps on outer surfaces. Flexible filaments often require more infill than their more rigid counterparts. NinjaFlex try to keep your minimum to 20% infill. For Cheetah try to keep your minimum infill to 10%. Keep in mind part complexity and where the infill actually lands can make a big difference.
  • Number of surface layers: If your surface layers are less than 3 or the shape of the surface layers is challenging consider adding additional layers to even out top surface.

13. Overly Matte Or Textured Surface Finish

The print results in having a textured surface. NinjaFlex specifically should have a smooth, glossy finish. This error is typically seen on the sides, but can be on a top surface occasionally.

Possible Causes:

  • Too much Retraction: Try turning retraction off, then add small amounts of retraction back in until you find a good balance between retraction and material feed. If your software allows for it, you can try adding a restart distance.
  • Partly clogged nozzle: The nozzle might have a partial clog or a piece of previous rigid filament obstructing the nozzle. This is common if switching from ABS or other high temperature rigid materials.
  • Too much heat: Too much heat can make the material bubble or break down, giving the outer surface a textured look.
  • Not enough heat: This can make the flow from the nozzle irregular and uneven, leading to a textured more lumpy surface.

14. Outer Shell Not Sticking To Inner Shell

When the print’s outer shell separates from the inner layers with no appearance of adhesion.

Possible Causes:

  • Outer shell speed: Decrease the outer shell speed to the same as or close to your bottom layer speed.
  • Material flow rate: Increase the flow percentage or increase the extrusion multiplier by 5% at a time. If your software permits, you can also decrease the filament diameter by 3% to 5%, or decrease the nozzle diameter by roughly 10%.
  • Partly clogged nozzle: The nozzle might have a partial clog or a piece of previous rigid filament obstructing the nozzle. This is common if switching from ABS or other high temperature rigid materials.