Welcome to the SeeMeCNC Community

Hello Everybody,

Okay so I've had my RostockMaxV2 for a little while now and I love printing anything and everything. I knew from the get go that there were areas of this printer that could use improvements. I totally understand why the printer was designed the way it was, essentially to stay within a given price range. For majority of everything I've tried to print I've had a pretty good success rate.

What started this project was that blasted flex filament we all know as NinjaFlex. I've read that it's not good for bowden setups, but as I always do I ignored all the red flags and bought the material anyway. Lets not get into the fact that I took a pretty big printing job that required this filament and I've never printed with NinjaFlex before

After realizing how easily the extruder jams when trying to force this flexible filament thru it, I quickly realized I was in trouble. I did what anyone would do and go looking for answers. I did find a couple quick and dirty remedies. First being the one where you cut a piece of push to connect tubing and run it right up to the point of the extruder hoping the the filament will go thru it seamlessly with no trouble. This definitely made an improvement, but still jammed frequently. The second fix I found was to do the same thing, but with a piece of aluminum tubing. This was a big improvement over the push to connect tubing, but still jammed up.

I quickly realized that these solutions may only work with a bit of luck, but they are definitely not reliable solutions.

After a few days of thinking and thinking and thinking, I started to put together an idea to completely re-design the extruder that in theory should be jam free. After about a week I had down the prototype design pretty solid and it was time to make parts. Basically the reason EZstruder consistently jams with the flexible filament is because there is a lot of room around the hobbed gear that allows the filament to be sandwiched out in any direction possible. With my design there is only enough of a window cut out as ABSOLUTELY necessary so that the filament has no choice but to feed down the bowden tube. At least that's the idea. I won't know for sure until I finish a functional prototype.

I'm very early on in this project but attached below are some progress pictures and I will continue to update this thread as progress is made. I started off with the pivot arm that releases the tension on the filament so that you can easily load and remove the filament. I'm hoping within the next week I should have it all finished up.

This is cool, but have you checked out Nylocke's EZFlexstruder? I believe it is the same concept, but printed.

This is the first I've seen this design. Ultimately it's the same as adding a piece of tubing to extend the guide up to the hobbed roller. There is still room for the filament to get jammed towards the front of the extruder. With my design, the filament is totally surrounded except for where the hobbed roller and bearing need to make contact. I also feel an all metal design will be more rigid and perform better then a printed/injection molded design.

I do appreciate you sharing this with me.

Thanks, Scott

Sorry if this is too OT...

You guys have seen how the flexystruder from LulzBot works, right? Basically, the filament is completely enclosed in PTFE tubing except for where it's scalloped out for the drive gear. No idler bearing at all, the tension against the drive gear is a thumb screw pushing on the back of the PTFE tubing. It's a neat idea.

[img]https://ohai-kit.alephobjects.com/media ... x0_q85.jpg[/img]

[img]https://ohai-kit.alephobjects.com/media ... x0_q85.jpg[/img]

[img]https://ohai-kit.alephobjects.com/media ... x0_q85.jpg[/img]

That is cool! I had not seen it. Thanks for sharing.

Hi Jim, do you have a file for that one? It looks great.

I had thought about doing something similar to that but that doesn't provide a quick way to release the filament if necessary. Neat idea though

Tincho85 wrote:Hi Jim, do you have a file for that one? It looks great.

http://devel.lulzbot.com/TAZ/accessories/flexystruder/


All the credit goes to LulzBot, they're the ones who really trailblazed printing with flexible filament.

Isn't the Flexystruder for 3mm filament only?

mhackney wrote:Isn't the Flexystruder for 3mm filament only?

About the only thing I know about it is the mechanics of how it functions... I'm not familiar with the specs at all.

Yes. 3mm only. I have one.

Hi all
I did have a lot of problems with the extruder, bearing twisting against the filament, causing the filament to hit the edge of the hobbed gear, eating away at the filament plugging the gear to failure. This is my version. an all metal extruder. I to added a piece of tubing at top to guide the filament, and moved the filament slightly closer to the hobbed gear.
Jack
draw-tech

Nice machine work. Good info on flex filament experiences. Yeah, the Max V2 has the least costly parts possible. Right now, the buy-in on a good quality 3D printer is $1000. So, the V2 is built of parts that ask to be upgraded. The stock hot end needs to be upgraded with one that can reach 300 max for the flexible filaments.

Which flexible filament requires 300C?

g.

draw-tech wrote:

DSCN1444.JPG

DSCN1393.JPG

Hi all
I did have a lot of problems with the extruder, bearing twisting against the filament, causing the filament to hit the edge of the hobbed gear, eating away at the filament plugging the gear to failure. This is my version. an all metal extruder. I to added a piece of tubing at top to guide the filament, and moved the filament slightly closer to the hobbed gear.
Jack
draw-tech

To bad you cannot mass produce the all metal extruder and sell them, I have a feeling they would sell well.

Hey Jack,
Did you see any notable improvments with flexible filament using your extruder design?

Let's see how my extruder design performs. There's a definite possibility that I could start producing them.

Eaglezsoar wrote:

draw-tech wrote:

DSCN1444.JPG

DSCN1393.JPG

Hi all
I did have a lot of problems with the extruder, bearing twisting against the filament, causing the filament to hit the edge of the hobbed gear, eating away at the filament plugging the gear to failure. This is my version. an all metal extruder. I to added a piece of tubing at top to guide the filament, and moved the filament slightly closer to the hobbed gear.
Jack
draw-tech

To bad you cannot mass produce the all metal extruder and sell them, I have a feeling they would sell well.

all metal extruder is on my to-do list

Hi All
Haven't used any flex material yet, mostly print with ABS. This extruder is set for 1.75 mm filament, but could be made to accept 3.0 mm. As for the hot end, working on it, (close) If any of you guys want the drawings, dope me a PM, I'll work up a package of pdf files. By the way it works! While some of the components are not quite up to par for some of us Picky Nuts, I have to say that the guys at See ME did a great job on this printer. It gives us plenty to work with.
Jack draw-tech

BTP wrote:Hey Jack,
Did you see any notable improvments with flexible filament using your extruder design?

Let's see how my extruder design performs. There's a definite possibility that I could start producing them.

I managed to break away from my normal production parts and make a little progress on my extruder project. Just a couple of update pics.

A little more progress tonight. The back plate is 6 different ops (setups) and 16 tools. Seems like a lot for such a small part, but necessary nevertheless. All I need to make yet to test it is the pin that the quick release lever pivots on. Hopefully tomorrow.

Jack are you going to sell that all metal extruder?

Hey BTP
Looks great, looks like it may act as a good heat sink.
Hey Neptune
I am in process of pricing with my CNC shop, if I can produce them without loosing money I will.
BY the way it works great, start the filament through the PTEF tube on the top, make contact with the hobbed gear, and crank away. Jack

I got it to the point of where I can actually test it out. I think a couple tweaks will be necessary, but nothing major. The filament is truly encapsulated entirely. This should help greatly with jamming of flexible filaments.

Okay so a little update. I mounted the extruder to the printer for testing and everything fit great. However I highly under estimated how much pressure needs to be applied to the filament so that it doesn't slip and has enough grip to force it thru the hotend.

The next iteration will need two design updates. First being the spring seat will need to be moved up towards the stepper motor more to compress the spring resulting in more pressure on the idler bearing. The second change will be the cutout for the idler bearing. The idler bearing needs to be touching the hobbed drive gear, it currently does not touch.

I think with these two improvements it should work flawlessly. More to come soon.

Hi BTP

Funny you should mention spring tension. I have been using my extruder and working great,______ Until i tried to print some T-glase, it started to slip. It did not take much movement of the spring to increase the pressure on the idler bearing. So I added a .05 thick disk under the spring, and put an adjustment screw to accommodate any filament. The second change is the release arm, to expensive to make, so I made it CNC friendly and the pocketbook a little fuller. You can see the pad under the spring. Jack
Draw-Tech