Extruder Seizing

[CalifDan]

I had problems with my Makerfarm similar to yours the first few months I had it. I solved the pull tension issue of the spool by setting it up with bearings. It spins with almost no effort at all. However, that did not resolve the problem completely. I was using the hex hot end and actually went through two of them over about four months. I then bought an E3D v6. I drive it with a Bull Dog Lite and my problems have all but disappeared. Now, if there is a jamb it is usually associated with printing a very small part or portion of a part where the retraction happens to frequently. On those rare occasions, I just turn off retraction.

[TopJimmyCooks]

A greg's wade has enough ass to pull the filament in even if you use the makerfarm spool holder and it's a little sticky. Mine would only stop feeding when the filament was completely crossed up or pinchedand dead stopped from coming off the roll, and then in that case it would pull the x carriage off the nuts. I use 3mm. I now mount my spool on a bearing setup, but i put pretty decent pressure/tension on the roll so it can't freewheel, preventing the filament from getting loose and tangled or pinched.
The backpressure of the nozzle is a bigger factor. if the motor/extruder can't hold the filament down in the nozzle it is under backpressure and will relieve itself by slipping or skipping

Raise your temps. Hotter = easier to push out generally. at least, experiment with it.

tighten your idler. as long as you can run a piece of filament in and out easily by turning the wheel by hand (cold, filament not down all the way into the nozzle, motors off) it's not too tight imo. there should be teeth marks on the filament.

Make sure the teeth of your hobbed bolt are clean and not full of shredded plastic. dental pick can help there. Make sure when you look down the extruder the passages, hotend opening and notch in the hobbed bolt all line up.

Make sure you're slicing for the right nozzle diameter that you have.

make sure your idler bearing spins freely and doesn't have a flat spot somewhere - they are tight sometimes and the makerfarm idler print needs to be clearanced a bit. if the bearing is questionable rotate it to the bolt and bring a bearing from the bolt to the idler.

try different filament and see if one is problematic- maybe oversized or out of round.

[Drone]

I ran into a problem similar to this, where the print would start fine and then after 10 to 20 minutes it would be air printing. The filament was grooved by the hobbed bolt and would no longer feed. The amount of retraction made no difference, and the hot end temp made no difference. After multiple tear downs and re-assemblies I found the problem was the cooling fan (which I also have turned to blow out rather than towards the fin area). The fan was working, but it had slowed considerably and was not providing enough cooling. The heat was traveling up the filament and making the filament to soft at the hobbed bolt. Replaced the fan and everything prints perfectly again. Hard to diagnose, but easy to fix.

The cheap fans that come with the MakerFarm just don't seem to last well. If anyone knows of a quality maglev fan to use as a replacement I would appreciate a link, but until I find a better one I know if the filament is being gouged by the hobbed bolt, it's time to change the fan. It would be great if a future firmware revision could add support for a 3 wire fan and could show fan rpm on the LCD. That would be a big help in determining when the fan is slowing down because it's not really obvious just from looking at it while it's running.

[BLKKROW]

Thank you for all of your comments and suggestions!

I have been emailing Colin and it has come down to a few things, it appears my large gear is being pulled into the extruder body and causing it to seize. With this and the filament spool having a large moment of inertia it is causing the filament to get chewed at the hobbled bolt.

So I am going to spend some more time fixing these issues and can hopefully get some printing time in. I will also change the fan per your suggestion, I never thought of that and will give it a go.

[BLKKROW]

I am still trying to work through the issue.

Right now, I am looking into calibrating the extruder, where do you modify the EStops? Is it directly with the firmware on the Rumba board?

[printbus]

...where do you modify the EStops? Is it directly with the firmware on the Rumba board?

Do you mean E steps? The extruder steps per mm is the fourth value in the Marlin DEFAULT_AXIS_STEPS_PER_UNIT array of constants in the configuration.h source file.

...it appears my large gear is being pulled into the extruder body and causing it to seize.

Actually, if you think about it this can't be the reason for your troubles. Yes, the large gear seizing could cause the extrusion to stop, but it couldn't cause a notch in the filament. The gear seizing against the extruder body would simply bind up the motor, causing it to stop rotating or skip steps. For the filament to get notched, the large gear and hobbed bolt are likely rotating just fine.

Many of the possibilities for extrusion stopping have already been mentioned, but FWIW this post has my composite list based on what people have reported - http://3dprintboard.com/showthread.p...ll=1#post58220

[BLKKROW]

Do you mean E steps? The extruder steps per mm is the fourth value in the Marlin DEFAULT_AXIS_STEPS_PER_UNIT array of constants in the configuration.h source file.



Actually, if you think about it this can't be the reason for your troubles. Yes, the large gear seizing could cause the extrusion to stop, but it couldn't cause a notch in the filament. The gear seizing against the extruder body would simply bind up the motor, causing it to stop rotating or skip steps. For the filament to get notched, the large gear and hobbed bolt are likely rotating just fine.

Many of the possibilities for extrusion stopping have already been mentioned, but FWIW this post has my composite list based on what people have reported - http://3dprintboard.com/showthread.p...ll=1#post58220

Thank you for your reply Printbus! I did mean ESteps I was just typing to fast on my break at work

Also, thank you for the link! A lot of the suggestions in your post I have been trying to narrow down on my printer. My main concern was the fact that I was printing just fine, then it started seizing.

So I am going to keep working with things tonight as the wife is out of the house.

Looking through the Configuration.H file, this is what I found. Is this correct and if so what value should I change?

[printbus]

...Looking through the Configuration.H file, this is what I found. Is this correct and if so what value should I change?

As said before, the extruder is the fourth term in the array. So, 841 steps per millimeter is the current Esteps setting in your Marlin baseline.

[BLKKROW]

As said before, the extruder is the fourth term in the array. So, 841 steps per millimeter is the current Esteps setting in your Marlin baseline.

I apologize I did not catch that, thank you! I have been talking to Colin as I am having issues modifying the firmware. No matter what I do it will not upload new firmware.