Evaluation as we Enter February

This post is going to be a mix of great news and mixed news.

By now, I have had a chance to put the Cube3 to the test to the tune of probably a hundred objects,  Yes, I have had clogs with some of the newer filament.  But, overall the clog situation is not anything close to my first experiences with the Cube3 with the earlier PLA.

First, the mixed news.

Printing with ABS

I hear that people are successful with printing in ABS.  In fact,I have had little warping compared to earlier 3D printers I owned without a heated print table.  But, that assumes something will print at all.  And, I have had MORE clogging with ABS than with PLA.  The maddening thing is that what I call "EXTREME UNCLOGGING" tricks using a heat gun seem to work miracles... for a few minutes.  And, even the new PURGE function tantalizingly shows promise, only to have the cartridge fail early in the print.

So, at least for now I will stick with PLA until I hear better news from you.  All of my ABS was received because of the shortage of PLA.  So, it may be that the same issues affecting the early PLA also affected the ABS.  I don't know.  All I know is that at least for now I am having a LOT better luck with PLA.

Printing with PLA

As of now, I do not have a single PLA cartridge with the new filament that is permanently clogged.  Yes, I HAVE had clogs.  But, they have been easily cleared.  In fact, I have one design that I KNOW will cause a clog because of the way it is designed stresses the extruder.  But, each time I have brought a cartridge to a halt, the new purge function has been able to clear it up and get me back up and running.  I do now know if that is true of the initial version of the filament.  But, all the cartridges that I know have are running clean and free for now.

Printing with the Cartridge Open

I believe in being proactive when it comes to avoiding known issues with any technology.  This means that I now print only with the cartridge open so that if I hear the tell-tale clicking sound that signals a slipping extrusion gear, I can instantly push the filament past the trouble spot.  If you catch it fast enough there are little or no consequences.

But, I also make sure that the filament is stabilized before and after leaving the extrusion gear.

Filament Stabilizers for an Open Cartridge

This simulates having the cartridge top in place while allowing instant access.

Why this Pseudo-Top is Important.

With all the exprimenting that I've done, I've up close and personal with the Cube3 cartridge.  And, perhaps it is a better understanding of how it works that has made the different in the success I'm having now vs. what I faced when I first got the Cube3.

One of the most important parts of the cartridge assembly is the button like fixture that is held in place by the top at the point where the filament guide leaves the cartridge.  One of its functions is to keep the actual filament guide, a narrow tube, from being pulled out of the extusion housing.  If the filament is ubstructed, the pressure can actually pull the filament guide right out of the ferrule that holds it in place inside the extrusion housing.  Here is what I'm talking about.

Cube3 Cartridge - Extrusion Gear Housing

This is an extrusion housing, from the hub of the cartridge, that is opened.  Every part of the housing assembly is beautifully CNC machined to extremely tight tolerances.  In addition to the idler wheel bearing and gear, there is an small cavity designed to hold the filament guide in place using a pressed on metal ferrule.  What I am calling the 'cartridge exit clamp' is designed to take some pressure off the ferrule by holding back an outer spacer tubing.  The cartridge top provides the anchor for the spacer.

When we remove the top, the cartridge exit clamp is free floating and cannot take pressure off the filament guide and it can slip out of the ferrule.  That is why I use the 3D printed pseudo-top to hold the cartridge exit clamp in place.

I have begun to immediately remove the top and replace it with the 3D printed part each time I open a new cartridge.  If you wait until later it can be a bit more difficult to pull the cartridge exit clamp back into place due to the stresses placed on it during printing.

By the way, the object holding the extrusion housing is part of my 'Extreme Unclogging' system pioneered by Eric Albert.  :)

It consists of a 3D printed combo heat gun and tip holder along with a cartridge holder and the object you see, that allows me to heat the tip at a precise temperature while turning the extrusion gear with a T20 Torx driver.  I'm not sure how much I'll need it now that we have the PURGE feature in firmware.  But it has been very helpful up to now.

At any rate, things seem to be coming together nicely on the filament front as soon as they can catch up on the backlog.  I know that is frustrating; but, the good news is that the printer itself, with filament, software and firmware upgrades is doing a lot better in a very short period of time.

ACCURACY

The Cube3 is, hands down, the most accurate 3D printer I've ever used.  Moment of Inspiration lets me use one feature to cut away from a second object.  The little cover on the extrusion housing holder was created in this way.  Normally, I would not expect the printed parts to fit.  But, they DID!  Each part was so precisely printed that the fit, while tight, worked!