Be sure to read this post if you have time.. it will be helpful

Maker Steve’s 3D Printing Rules to successful 3D Prints

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This can assist with overextrusion but that is typically caused from running to hot or an uncalibrated extruder stepper.

This process generally works for all 3D printers.  This article contains pictures of Delta and Cartesian printers.

This is an example of underextrusion throughout a print.

This is an example of underextrusion in the middle of a print.

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This is underextrusion at the end of a print…

 

NOTE:  I print a lot of Basic Stringing Tests, it’s a reliable short print that shows the bed is level, layering is good and verifies there is no stringing.

My usual troubleshooting process for underextrusion is:

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Check for temperature variations.

Octoprint is a dead giveaway as you will see the temperature line get wavy.  Sometimes  you can see if from the control panel of the printer.

This is good..

This is OK..

This is BAD!

In the case above, consider hot end part cooler placement, rewrapping hotend with new kapton tape and insultation.

Replace the nozzle. – just do it, they are cheap

I collect em.. but I won’t use em.

Not kidding…

Print a Basic Stringing Test

Check the PTFE Tubing,  Capricorn is high quality PTFE but more expensive.  You may need to recut the ends with a PTFE Cutter.  PTFE should slide in and out with no friction.  If there is any, replace the tubing.  There should be no gunk on either end, just clean PTFE.  If it looks like the picture below.. replace it.

Print a Basic Stringing Test

Check the couplers on both ends.

The PTFE should be in till a solid stop and not pull out when locked.  Swap ’em if you doubt ’em.

Give em a tug…

Print a Basic Stringing Test

Check the hotend.

They have a small piece of PTFE tubing inside that needs to touch the nozzle cleanly, no goobers.  The PTFE going in the top needs to seat cleanly to the lip inside the hotend.

I made it a year on this hotend.. started getting bad prints..

then replaced it..  Back in Black!

Check out all the crusties..

See the black crunchies inside…

PTFE inside hotend was warped and clogged.

This hotend had a good life!

Print a Basic Stringing Test

Check the Extruder Assembly

When printing the drive gear needs to move at the same speed as the guide pulley.  I often mark the guide pulley with a sharpie to ensure they are moving the same speed, makes it easier to see if they are out of time; this is my timing mark.  See the blue mark.. I watch it go round.

Pay special attention to the extruder drive gear, ensure it is not biting to deep or not biting enough.  It should barely dent the filament and be consistent over the length of any filament that has passed into the PTFE.  If you see filament shavings on the extruder assembly, that is an indicator of a restriction.

All clear..

 

Sometimes you need to use a dental pick or awl to scratch the gunk out of each tooth.

Be sure the extruder pivot screw is tight enough, or loose enough to get a nice divot in the filament.

Inspect the allen screw on the extruder gear drive.. it needs to be tight.

But don’t over tighten, you’ll strip it.

You should also see one of the set screws line up with the flat spot on the drive shaft.

Also verify the teeth are sharp and not stripped.

Print a Basic Stringing Test

At this point the problem is solved… 60 percent of the time, every time.

The reason I print the the basic stringing test in between each change is because too many changes at once make it hard to identify the actual problem.

Summary

In my experience, underextrusion is related to a clogged nozzles or something obstructing the filament flow between the extruder motor and the nozzle.  PTFE can wear, or get clogged with stringy filament, or the hotend can get gummed up.
This was a brand new out of the box printer with barely a roll of filament through it.  I’ll be clipping zip ties from here forward.

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There is a ton of other useful stuff on Makersteve.com and more coming every week.

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Thanks for visiting,

Steve