Monday, June 18, 2018

Aluminum Titan Extruder from China

The original Titan extruder from E3D works pretty reliably, but has a few issues.

It's made of flexible plastic, the V6 hot-end fits a little bit loosely inside the extruder body, and the way it mounts on the printer is not very user friendly.

The flexibility of the plastic cover is a problem.  It is easy to over-tighten the screw that passes through the drive gear, which bends the cover and causes misalignment of the bearing.  The bearings used are very small and can't withstand much side-loading.  Unfortunately, that screw is one of the screws that mounts the whole assembly on the motor, and you really want it to be tight.

The V6 hot-end, also a reliable performer, is not optimal when paired with the Titan.  One of the design problems with the V6 hot end is that it has no anti-rotation features.  When you put it into a Titan extruder, it can rotate easily, even from the small force produced by the heater cartridge wires. More on the shortcomings of the V6 hot-end, here.

You can either use E3D's plastic mount, or print your own - flexible- or you can mount the extruder to a metal plate, as I have done in UMMD.  If you opt for the more secure mounting to a metal plate, when you remove the cover from the extruder, there is only one screw holding the entire extruder on the printer.  Three of the cover screws go all the way through the extruder body to the motor, so if you just want to take off the cover so you can take out the hot-end to clear a jam or to change the nozzle, you have to trust the one screw to keep the extruder in place.  That remaining screw is located behind the hot-end, so if you want to remove the extruder from the printer, you have to disassemble it completely.

The good things about the Titan include high pushing force on the filament due to the gear reduction and small diameter drive gear.

I saw an aluminum version of the Titan in a forum post and ordered one from a Chinese supplier.  It has a couple flaws that are obvious from the start, but I thought maybe those can be fixed.

Here's the aluminum Titan assembled with a V6 hot-end.  The unit I ordered came with a metal mounting bracket that should make it possible to swap extruders without taking it apart.  One nice feature that the original doesn't have is the small lock screw that grips the hot-end to keep it from rotating.



Just like the original, there's one screw located behind the hot-end that holds the extruder body onto the motor.  Three of the cover screws pass through the extruder body and into the motor.



Cover off, hot-end in place, and filament inserted.  Notice the large gap between the bottom of the drive gear and the top of the tube that guides the filament into the hot-end.  That's very bad.


This is what can happen when there's a gap between the drive gear and the filament guide tube. This is a BullDog XL extruder on SoM, and the filament is PLA or ABS.


This is that BullDog XL extruder with the front cover off.  The arrow points to the gap that allowed that mess to occur.  All they had to do to prevent the problem was make the brass tube a bit longer.  Doh! 

One more problem- the filament doesn't ride on the center of the drive gear concavity.  That means that it may tend to wander back and forth on the gear teeth, especially with the wide gap between the feed tube and the drive gear.  The result may be inconsistent extrusion because the diameter of the drive gear changes with the filament's position on it.

Extend the Filament Guide Tube


I found a piece of 1/8" OD aluminum tubing at the makerspace and used a belt sander to put a couple 45 degree chamfers on the end of the tube, then cut the tube with a jeweler's saw to about 15 mm long and deburred the ends with some jeweler's files.  Next, I drilled out the feed tube hole with a #30 drill (0.1285") and the aluminum tube fit loosely inside it.  I mixed some epoxy, put a drop on the aluminum tube, and inserted it into the feed tube on the extruder body.  I pushed it up to the drive gear and inserted a piece of filament to help hold the tube in position while the epoxy set.

Side view of the extruder with the aluminum tube installed (inside red square) and filament inserted to hold tube in position while epoxy set.  The ID of the tube is about 2 mm.


Extruder with cover off showing aluminum tube in place.
Pinch roller removed. 


The addition of the tube has made it easier to load filament, and should help control the position of the filament on the drive gear teeth.

Tests


I was curious to see if the E3D parts were compatible with the Chinese parts.  In particular I wanted to see if the Chinese Titan mount would work with the E3D Titan extruder, and if the E3D drive gear would work, too.  I am pleased to report yes to both!

I swapped the E3D drive gear into the Chinese extruder and it fit perfectly.  The aluminum extruder uses the same bearings for the drive gear, and careful measurement of the two gears finds them essentially identical except that the original drive gear diameter (the steel part that grips the filament), measured at the deepest concavity of the teeth is 7.78 mm and the Chinese drive gear is 7.39 mm in diameter.  That difference means that the steps/mm settings for the two should be slightly different.  I also noticed that there are fewer teeth in the filament drive part and they are cut deeper in the original E3D part compared to the Chinese part.  The best thing is that the filament path in the aluminum Titan seems to have been designed around the original E3D part - the concavity in the filament gripper teeth lines up perfectly with the holes that guide the filament in the aluminum extruder.

Here's the Chinese drive gear in the extruder body.  You can clearly see that the filament will be off center in the gripper teeth.

Here's an E3D drive gear mounted in the aluminum Titan.  Notice that the teeth of the filament gripper line up perfectly with the filament guide tube.
I had to take the E3D Titan off UMMD before I could mount the aluminum Titan, so I checked to see if the original E3D Titan will fit on the Chinese mount.  I am pleased to report that it fits perfectly.

Here's the E3D Titan mounted on the aluminum mount that I got with the aluminum Titan.  A perfect fit!

The other side of the E3D Titan mounted on the Chinese aluminum mount.  

Print Testing


I mounted the aluminum Titan on UMMD, rezeroed the Z axis, and ran a test print.  No problems were encountered.  After calibration I found that 443 step/mm was a good number for the extruder with the Chinese filament drive gear.

Chinese aluminum Titan extruder mounted on UMMD with an XCR3D hot end.

Aluminum Titan mounted on UMMD.



UMMD Printing With Aluminum Titan Extruder from Mark Rehorst on Vimeo.

The real test of anything like this is how it holds up with use.  I'll be using it a lot in the coming months and will do more blog posts if I encounter any problems.

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Leave comments or a questions here and I'll try to post a response as soon as I can, if I can figure out how to get it working...