Bowden - Extruder-HotEnd issues

[UnLtdSoul]

Hey,
I got my Rostock Max last Jan/Feb and have used it a lot. I've gone through ~ 10+ 1 kg reels of ABS, and around 5 of PETG (most of which i bought from China ) - and a few reels of PLA.

But, from day one I've had constant issues with the heads/extruder. I tend to be an impatient person and so I put a 7mm nozzle on and print at .35 mm high layers (for what i'm doing, i don't mind the thicker layers) using ABS - with a good head - i run at 55mm speed. Actually the settings are at 30mm/sec and I run it at 182% (it worked and i never changed the base speed).

BUT, I have had many problems with the head. I've replaced the PTFE - or what ever letters they are, the inner teflon type tube a number of times. At least 5 times. And, I've had the PEEK go out of shape on me and cause jams. And, i've replaced the push on fit tube connectors on the extruder and head 'many times' finally found somewhat good ones on Ebay - but still need to replace every once in a while.

When everything is set up, it works - 'ok'.

LATEST PROB I am currently just printing with ABS I've been using Hatchbox off of Amazon with good luck, their White, Black, Red, Blue, even their Gold (which has shimmering specks of gold like particles in it), all work fine at 55mm /sec.

But, I'm trying their Translucent Red, I really like the color and translucent effect - and the first pieces I printed came out great, they were 200mmx50x20mm BUT, after those first 2 printed - the head/bowden set up keeps jamming.

Actually it' not the head jamming, as far as i can tell. I'm not exactly sure what's going on, but the plastic stops coming out and the extruder strips away at the filament. The thing is, I home it, and unscrew the push on fitting on top the head and manually feed the filament in, and it glides right through... So the head isn't jamming. Screw it back on and unscrew the push on fitting at the extruder end, and I can still feed the material through. Slap it back together and it prints a few more layers and 'jams' again. Several times I take out the translucent red abs and print with any other ABS and it prints fine. I've noticed the translucent is a bit more stiff, brittle, material. But, all the other ABS, even the shimmering gold one, all print fine (I had bought a gold, that looks exactly the same, from another supplier, and it jams the actual head after 10-20 layers of printing. I think the shimmering gold particles in that filament are larger in size -but the Hatchbox filament prints fine).

What frustrates me about the Rostock is the Bowden tube set up, due to weight issues you can't put the extruder directly on the head. But, when i take filament and feed it directly into the head by hand, it glides through almost effortlessly - it will come out as fast as it can melt. I put the tube on and feed by hand and you really have to push - I would say 2-3 times harder. Yet, i take the tube off and the filament glides through the tube 'ok', but, something about the tube + the head, and it takes so much more force to push the material through at the extruder side then directly on the head.

What i 'think' is happening : I think that there is a binding force at the push on connector on top the head. The tube doesn't always stick straight up from the head, but, as you print at times the tube goes off on an angle. So, I took the tube off and pushed filament through by hand and if i push the tube over to one side at the point of entering the push on connector, you can definitely feel the added friction.

As I said, the head doesn't appear to be jamming, but I'm suspecting that maybe the tube is flexing around and binding at the point of entering the push on connector. Any ideas on this? I really like the translucent red, i know there's translucent PLA, but, i need parts that won't turn soft if left in a hot car, PLA won't work. But, it seems the formula for the translucent ABS is just enough different that the bowden set up doesn't like it.

Too bad I can't just put the extruder right on top the head. I'm considering getting an all metal head, but, i don't think that would solve this current problem.

The next printer i get will be a Cartesian type that has the extruder mounted on the head, unless someone can convince me why i shouldn't.

Any one run into this sort of problem, any solutions? Thanks

The other ABS is prining fine, just printed 2 pieces that are nearly 8" in diameter, about 3" high, they are custom speaker mounts, they printed fine in black ABS, put back in the translucent red, i got 1 more of the 200mmx50 and on the second it jams again.

[Eaglezsoar]

You could try putting a couple of small washers under the spring on the EZstruder in an attempt to tighten the gear pulley against the filament.

[UnLtdSoul]

EagleSoar

Your advice helped out. I added just one thin washer and I could feel the difference in the tension (I have 2 extruders to test it against - , i 'was' going to try to add a dual head config, but, well, i never did. At some point i would like to print 2 colors, i'll save Q's on that for another time, though.

Putting the washer under the spring worked, but, i still feel that the bowden setup with the long tube isn't the best way to go.

Has anyone successfully tried putting an extruder directly on the head on the Rostock Max???? I know it has added weight, and maybe too much side torque?

Which brings me to another q - my reflector arms are getting worn and loose, i'm going to have to redo them at some point. I will ask here, but, may i should ask in another thread with appropriate title, what is the best, most solid and long term wearable reflector arms for this printer? Magnetic balls joints or ????

Thanks for the advice.

[Eaglezsoar]

EagleSoar

Your advice helped out. I added just one thin washer and I could feel the difference in the tension (I have 2 extruders to test it against - , i 'was' going to try to add a dual head config, but, well, i never did. At some point i would like to print 2 colors, i'll save Q's on that for another time, though.

Putting the washer under the spring worked, but, i still feel that the bowden setup with the long tube isn't the best way to go.

Has anyone successfully tried putting an extruder directly on the head on the Rostock Max???? I know it has added weight, and maybe too much side torque?

Which brings me to another q - my reflector arms are getting worn and loose, i'm going to have to redo them at some point. I will ask here, but, may i should ask in another thread with appropriate title, what is the best, most solid and long term wearable reflector arms for this printer? Magnetic balls joints or ????

Thanks for the advice.

You are welcome. Glad to help.
Putting the extruder directly to the the hotend results in too much weight as you have indicated but people have tried a "flying extruder" and if you would like to read about it
the link is here: http://forum.seemecnc.com/viewtopic.php ... 0&start=10

[Eaglezsoar]

I forgot your question about the effector arms.
Magnetic ball joints are good but have to be done perfectly, the arms have to be an identical length with no room for error.
I recommend the Trick Laser arms from tricklaser.com. They work great and are a very popular upgrade.
I would put them on first and then attempt the magnetic ball.