i need a good extruder

I have tired with extruders. I was using Greg's extruder but the problems are that i loose too much printable space because of that big gear on one side and there is backslash because of gears.
So , i decide to go on direct extrude.
I am using A4988 driver with Wantai 42BYGHW811 and my extruder is Prusa Mendel Delta Rostock extruder , i am using only abs at 230 celcius and teachup . Torque of driver is full but motor as you can see has not enough power to extrude. Noozle is 0.5 and filament is 2.75mm.
I cannot understand why it works to everyone but not for me, i have tighten springs , i have loosen spring , i have change springs, i have use 2 different mk8 gears, i have use 3 differnet A4988 but nothing. It wokrs good for 20mm filament but after it jams.
I have to say when maximun speed is 30mm/s it works good enough, but it is really slow speed , i want to print like before with Greg's extruder at maximum speed 60mm/s.


What would be the solutions:

1.Use a geared nema 17 motor with planetaqry gearbox but as i can see there is a backslash <1 degree. IS THAT BIG BACKSLASH OR NOT ???

2.Using a bowden extruder and print a base for motor and use belt for geard ratio 1:3, but get in drouble if no good relustls again

3. Buy this Geeetech upgrade MK8 extruder J-head but I AM NOT SURE at all is is going to work properlly because direct extruder is not working for me.

4.And last an all in one ready but enough expensive soluytion GT8S extruder All Metal J-head .Does anybody know something about this?


https://www.youtube.com/watch?v=sZPwq-8OXpw&feature=youtu.be



I suppose many reprapers will have the same problems as me, so giving a good solution woulf be good for many of us.
If you have to suggest something else it would great full

[www.alfadex.com]

EDIT: I just now noticed the youtube video you posted! Sorry! Still, try turning the temperature up.

The first thing I recommend trying is increasing the temperature on your nozzle. Even if you've always had success with 230 degrees, maybe this spool of plastic likes it hotter. I've found ABS that worked best when I set my nozzle as high as 275.


Now, if that doesn't help, I've got a couple questions about what you said above.

First question: When you say that your filament is "2.75mm" is that a typo to say 1.75mm, or is that closer to 3mm?

I use 1.75mm with a non-geared setup, and there are no issues at all with my motor having enough torque to push the filament.
I think if you're using 3mm filament (no experience there, though), the increased pressure might require a better mechanical advantage, though, and you'd want something with either internal or external gearing.

Second question: What are the symptoms you're seeing? Depending on what you're seeing, a number of things can be happening.
1.) motor skipping steps
This could be due to a weak motor, as may be the case if you're trying to push 3mm filament without a geared step-down.
Or, it could be due to having the current setting for your motor too low, or too high. If it's too high, the motor will overheat and skip just as much as if it's set too low. Adjust the trim pot on your A4988 to find the "sweet spot" for your motor.

2.) filament getting stripped by the hobbed gear
No amount of motor changing or gear ratio will help this. Here are some things that might cause it:
-your hobbed gear teeth have gotten filled with bits of plastic from a previous jam
-your springs are too loose, causing the gear to slip instead of pushing through
-you have something jamming the nozzle, through either not enough heat or something plugging it up.



To speak to the other things you mentioned:
1. Backlash really isn't an issue with extruders, it can be corrected in your retraction settings. A planetary gearbox is a reasonable approach to increase torque from your motor. It's the same thing the Greg's extruder does, just internally.

2. Bowden will help by taking weight off your print head to make it more maneuverable, but really doesn't address whatever you're seeing here. Bowden also has inherent backlash, but you just tune the retraction settings to stop it from being an issue.

3. That is basically replacing the entire melty portion of your printer. If you truly have any problems with either your extruder or your hotend, this will replace it, guaranteed. But I'm not sure you need it. Try increasing your nozzle temperature first. And I have no comment on what the quality of that specific part might or might not be.

4. I use an E3D Mk6 all-metal hotend and have loved it. It's important to have a fan on the fins of the heatsink though, or the plastic will melt up into the chamber. My gut feeling on what you have there is that the fan is in the wrong place.


I hope some of that is helpful!

Edited 1 time(s). Last edit at 03/05/2015 05:07PM by maso.

Hi friend, temperature is at 231 degree. I raise it up 240 with a little beter result. I would like to go it further but i am afraid the plastic that is screwed the bolt of the hot end is going to melt.Those two fans are not at full speed, i adjust those with pwm and are very low speed, are used so that heat don't go up to the x-cariage. Even if i turn fans so that face the hot end, temperature will pass through the plastic of the delta extruder and is going to melt, i don't know the temp that it can stand.
My filament is close to 3mm, of course it need more power to extrude and i am sure it need geared motor. I found this motor but anybody has use this geared motor and i don't know if it really works, maybe there will be backslash problem but as you tell i may use retraction.

I have a question for you,in case i buy e3d like yours, but this bowden one, i have in my mind to make a bowden system but in case i regret it ,can i use this bowden e3d taking of that blue screw that hold the PTFE tube and use it as direct extruder with the geared motor above? I have conclude e3d j-head bowden or not is the best at this time

I don't know what you have your fans doing or how vital they are, but I would say it's worth trying to use a faster speed blowing directly onto your hot end heat sink and see what you get. If an increase from 231 to 240 helped it could be worthwhile trying to go higher.

As for your extruder melting, here are the setups for my two printers:


Both of them are held by ABS, and both have fans. I've had the temperature up to 280 on both and not had issues, as the heat doesn't conduct that high up the hotend.

As you can see in the picture, my E3D is bowden. I can't tell you how the one you've linked is built internally, but on the real E3D one the PTFE tube extends all the way down the heatsink to eliminate seams. That said, I'm sure that even mine could be converted by simply cutting the PTFE tube off at the end. So yeah, I think you could probably use that one for either bowden or direct.

The motor you found looks like it would work beautifully. The backlash really isn't something to be concerned about--getting retractions settings figured out is part of setting up most printers anyway.

EDIT: Thinking about going from bowden to direct-drive, I think you might wind up needing to trade the pneumatic nut at the top out for a hollow-lock set screw like these to hold everything together. But you wouldn't really know if you needed it or not until you got the nozzle and took it apart.

Edited 1 time(s). Last edit at 03/06/2015 11:36AM by maso.

Yes i will wait for hot end . I don't want gears at all. I may do something with idler ,maybe all together on x-cariage or bowden,i apreciate your help, i will come back

Edited 1 time(s). Last edit at 03/06/2015 04:48PM by alfadex.

Hi friend , i finally made my own belt E3D extruder. I bought bowden E3D in case does not work direct extruder , but it works perfect! look here

[www.thingiverse.com]

Looks excellent!
And it's great to see thorough documentation. So many designs out there (mine included, I'm afraid) are lacking in the "how to put it together" department. This is easy to see and understand.

So no worries about backlash with the belt, and I'm assuming you've improved the clearance issues you were having with the Greg's. I'll keep your design in mind in case I find myself with a similar printer setup.

Also, are those threadless lead screws on your Z-axis? It was hard to tell in the video on Thingiverse, but it kinda looked like it.

Yes, thank you, no backslash at all, i think i will not bother any more with extruders.I raise temperature until 270 for test purpose for 1 hour and no problem anywhere .
No Z axis is no lead screws , it is threaded rod M8. This video is 0.2 layer heigh