What is causing this filament jam.

Hi,

Suddenly the filaments starts to jam up before it gets down to the hot end. See pictures. I started notecing this when the printer had run for some time, and no filament was coming out.

I've tried to play with the extruder speed, and the:

#define DEFAULT_MAX_FEEDRATE

but nothing I do seems to work.

Does anybody have a clue?

The heater in the extruder is a 50w cartridge.




The first layer is printed perfect, then all of a sudden, nothing is happening. I'm suspecting the filamnet ot dry out and grow "old" - it's a few month old now. Or I've changed some sliceing options I'm not aware about. I'm slicing with Slic3r.

- nerdegutta

Edited 1 time(s). Last edit at 12/30/2014 04:51AM by nerdegutta.

You need to set your software so that it cannot extrude below a certain temperature. I just print with ABS and I have the cut off set at 190 deg C. It can be anything of course, depending on the plastic. This prevents it trying to force filament through a cold nozzle.
Also adjust the pressure on the extruder hobbed bolt so it just "bites" and does not start to cut into the filament.

Thanks, but I've done all that.

Printing with ABS, having extruder temp at 230. It happens when it is printing the infill. I have the infill at 25% homeycomb. The first few layers are OK, but then something is happening. I'm trying to adjust the infill speed, but the cmoputer doesn't seem to reconize it. Yes, I do save, and occasionally restart the program...

BTW: I used to use a Win XP with Pronterface. Now I'm trying out Pronterface on Ubuntu. But I don't see that it should matter.

- nerdegutta

I just printed this test, and it looks fine.



But here there's noi infill...

- nerdegutta

I noticed that the date on the camera is not quite up to date - Nevermind that.

The test looks good, but if there is no infill then it must be the slicer I think.
I am on XP/ repetier firmware/ repetier host/ slic3r.
I would slice it then save the slicer gcode to SD card and run it from that to see if it solves the problem.

Edited 1 time(s). Last edit at 12/30/2014 03:36PM by dave3d.

I don't have an SD card reader...

What setting determins the infill speed?

This is my Slic3r speed settings.

- nerdegutta

Edited 1 time(s). Last edit at 12/30/2014 03:53PM by nerdegutta.

Your infill is at 30mm/sec.
Actually everything is at about 30mm/sec. Is there any reason you are printing so slow? I run about 40 at my lowest up to about 100mm/sec for fast/rough items.

I'm trying to get this to work - the infill speed. When that's up and running, I'll tweak the other values up.

- nerdegutta

You did not mention what hotend is being used. My experience has been that unexplained jamming as a job runs is usually caused by the melt zone in the hotend transitioning up into the heat sink area. On all metal hotends, you really need a fan on the heat sink. The Chinese E3D clones forget this feature. Every time that I've ever had a fan failure with a real E3D, the result has been a filament jam and wasted part.....

Ok,then I need to install a fan...What if I reduce the heat from 230 to 210 or something? I need to try that.

- nerdegutta

I wonder what I cat do with these...



The first layer prints OK, but from the second.... It jammin'...

I've tweaked all numbers I can think of. From Slic3r to firmware....

- nerdegutta

I think that you have too cold hot end. I run 232C or 235C for white ABS. Perhaps you have to go even higher. I have never used a fan with my Catnozzle. See my signature video down... to see it and some explanation (text under). I dont know how your hotend handles the heat but I can go 245 and even higher, and no melting extruder body, without a fan. . I have Pronterface and I use always manual temperature.

Edited 1 time(s). Last edit at 12/31/2014 06:03AM by Plasteroid.

---

Prusa i3, Ramps 1.4. Catnozzle 0.4mm
SketchUp - Enveloping Globoid Worm Gear - Part One - 3D Printed: [youtu.be]
DesignSpark Mechanical & more precise screw thread: [youtu.be]
Nicer Screw Thread In SketchUp ( Bolts,Nuts): [youtu.be]
How To Model A Heart Shape In SketchUp: [youtu.be]
How To Draw 3D Printable Snap Fit Ball Joint In SketchUp: [youtu.be]

I had a similar problem with my printer. It took me a few months to figure out what was wrong. I tried every possible thing starting from bed levelling... Z height... printing speed... temperature... different material... etc and I eventually found the actual reason.
The metal hotend heats spreads the heat up to the cold zone and as a result the entire extruder is filled with melted plastic. the weight of this melted plastic is too high for the cold filament to push down through the nozzle, however the motor is strong and keeps turning... now this is what causes the filament to grind. once the filament grinds, the fine dust from this grinding can easily find its way into the nozzle and will clog the nozzle too at a later stage.

solution:
attach a small fan to the extruder (make sure it is connected to the main power and NOT to the fan socket, so that the fan is switched ON as soon as the printer is switched ON). E3D-Online have small fans designed for this.
Cleaning the extruder and nozzle needs to be done with acetone. DO NOT buy polish remover / acetone from the supermarket. if you have no other choice, make sure the bottle does not contain LANOLIN. this makes the problem even worse. the best place to get good acetone is a shop which sells professional hair saloon equipment (ask ur local hair salon, they should be able to tell u). when you get acetone, soak the hotend, extruder bolt (the long bolt which is grinding against the filament) and nozzle (basically all metal parts) in acetone. drown it all in acetone i mean
leave it for a few hours and the plastic inside would have melted or soften enough for u to pull it out with ease.

I'm prining at 350 - 240.

I read somwhere that if I had the extruder too close to the hot-bed, it could cause Retrograde Extrusion.
https://www.matterhackers.com/articles/how-to-clear-and-prevent-jams

I've adjusted the hight a little bit. 0.012". (I don't have that tool in mm) I used a feeler tool. Earlier I used 0.008".

Current print's at layer 46 of 81, so I might be on to something.

Thanks for the link. What kind of hotend do you have? Never seen one of those before.

- nerdegutta.

If you see the latest picture, you'll see that the cold zone is not filled with melted filament. I need to adjust the height better,I hope that helps in the long run.

- nerdegutta

I think that It is a spanish invention. I bought it from here, I dont know if there are other places where to buy.
[www.kitprinter3d.com]

After some hours (many) I got a jam, but It is easy to unclog. Heat, open springs, reverse from Pronterface and pull slightly with hand, cut a new end to a filament, clean the hobbed bolt, push the the filament in again etc. 5 minutes procedure...

I have my bed adjusted just with a paper sheet. I don't always lose the piece because of the jam. I just measure and cut & slice and print the rest of the pice.

---

Prusa i3, Ramps 1.4. Catnozzle 0.4mm
SketchUp - Enveloping Globoid Worm Gear - Part One - 3D Printed: [youtu.be]
DesignSpark Mechanical & more precise screw thread: [youtu.be]
Nicer Screw Thread In SketchUp ( Bolts,Nuts): [youtu.be]
How To Model A Heart Shape In SketchUp: [youtu.be]
How To Draw 3D Printable Snap Fit Ball Joint In SketchUp: [youtu.be]

Is it possible that I've set the temperature too high?
- nerdegutta

Got some "usable" prints. I've added a fan, and adjusted it to blow on the part above the heater element. To do that I had to reconfigure the extruder part a bit. I have the extruder mounted on 4mm plywood. Before the configuration, I had the extruder, metalplate and motormout screwed togeter in one piece, and put on the plywood. Now I have the plywood between the metaplate and the motormount. My theory is that it was getting too hot, so the ABS acted like boiled spagetti in the area where the hobbed bolt is.



Extrudertemp is 230, bed temp is 80, all in Celcius.





The large herringbone gear took abut 3 and a half hour. It's printed on a raft. That's the longes run my homemade 3d printer has run. I sliced the models with Cura, which is growing to be my favourite slicing program. Printed with Pronterface.

Don't mind the dates on the pictures, camera is not so often used, so I don't bother adjusting the date. :-)


- nerdegutta

Your parts look a little bit melted. Have you checked, calibrated your thermistor? Perhaps that hot end type has some problems and the heat travels up ?

---

Prusa i3, Ramps 1.4. Catnozzle 0.4mm
SketchUp - Enveloping Globoid Worm Gear - Part One - 3D Printed: [youtu.be]
DesignSpark Mechanical & more precise screw thread: [youtu.be]
Nicer Screw Thread In SketchUp ( Bolts,Nuts): [youtu.be]
How To Model A Heart Shape In SketchUp: [youtu.be]
How To Draw 3D Printable Snap Fit Ball Joint In SketchUp: [youtu.be]

After these prints, I had several misprints. After changing the heat element to a 50W, and the powersupply to a 300W (from 230W), the printer has run for about 4, 5 hrs. I changed the heat element after Pronterface reported "echo: heater error". Again things seems ok.

How do I calibrate the thermistor?

- nerdegutta

Here is some talk about the "calibration": [forums.reprap.org] I think that the things you can do are: check that your thermistor gives correct readings, check firmaware, check if it is well connected to the heat element. I have my bed, hot end and a thermometer showing 21C quite exactly at the room temperature. I haven't boiled / checked then my thermistor (100C, perhaps difficult). If there is a big difference with the real temp and the thermistor reading, it can make problems.

I don't have IR thermometer, but it would be nice to check hot end and compare with what the thermistor is showing.

---

Prusa i3, Ramps 1.4. Catnozzle 0.4mm
SketchUp - Enveloping Globoid Worm Gear - Part One - 3D Printed: [youtu.be]
DesignSpark Mechanical & more precise screw thread: [youtu.be]
Nicer Screw Thread In SketchUp ( Bolts,Nuts): [youtu.be]
How To Model A Heart Shape In SketchUp: [youtu.be]
How To Draw 3D Printable Snap Fit Ball Joint In SketchUp: [youtu.be]