Melted hot-end, filament getting chewed up

[cpunches]

Glad I spent the time to get the printer calibrated again, or I'd be really depressed now

I was starting to print something and started noticing that the filament coming out of the nozzle had deformations, like it was sausage links. I checked the bowden drive and found that there were a lot of "shavings" inside like the filament was getting chewed up by the roller. I figured that the "bites" in the filament were what was causing the sausage links. I decided to change filament just to see if it had anything to do with the plastic. I loaded some different filament and it seemed to be fine while i was loading it and manually extruded quite a bit that seemed to be ok.

Once I started running a job the same thing started happening with the new filament and I found a bunch of shavings. I've tried loosening the tension bolts all the way to where it doesn't feed at, but it still keeps chewing it up as soon as I get enough tension. I've taken the bottom piece out several times and put it back in thinking that perhaps the filament isn't in the groove. I finally noticed that the groove isn't directly below where the tube is and it makes a little bend as it enters the tube to the extruder. I assume it has to be that way as the tube entrance is between the two grooves. Anyone else ever see this? How did you fix it?

The second issue I ran into was when I started printing a job when the filament seemed to be feeding "ok". I was watching it print and wondering why it started looking like crap all of the sudden when I noticed that the nozzle had moved to the side. Looks like I melted the hot end? I was running the hot end at 240 (printing ABS). Any chance I can fix this without needing a new one? It's still to hot to touch, but I'm wondering if I should even waste my time.

Any help is appreciated as usual.

[elqisqeyano]

Glad I spent the time to get the printer calibrated again, or I'd be really depressed now

I was starting to print something and started noticing that the filament coming out of the nozzle had deformations, like it was sausage links. I checked the bowden drive and found that there were a lot of "shavings" inside like the filament was getting chewed up by the roller. I figured that the "bites" in the filament were what was causing the sausage links. I decided to change filament just to see if it had anything to do with the plastic. I loaded some different filament and it seemed to be fine while i was loading it and manually extruded quite a bit that seemed to be ok.

Once I started running a job the same thing started happening with the new filament and I found a bunch of shavings. I've tried loosening the tension bolts all the way to where it doesn't feed at, but it still keeps chewing it up as soon as I get enough tension. I've taken the bottom piece out several times and put it back in thinking that perhaps the filament isn't in the groove. I finally noticed that the groove isn't directly below where the tube is and it makes a little bend as it enters the tube to the extruder. I assume it has to be that way as the tube entrance is between the two grooves. Anyone else ever see this? How did you fix it?

IMG_1336.jpg

IMG_1337.jpg

The second issue I ran into was when I started printing a job when the filament seemed to be feeding "ok". I was watching it print and wondering why it started looking like crap all of the sudden when I noticed that the nozzle had moved to the side. Looks like I melted the hot end? I was running the hot end at 240 (printing ABS). Any chance I can fix this without needing a new one? It's still to hot to touch, but I'm wondering if I should even waste my time.

IMG_1334.JPG

IMG_1335.JPG

Any help is appreciated as usual.

Go to http://www.e3d-online.com/ourshop/prod_ ... Order.html get one of their hot ends, the DIY kit, it's pretty simple to install, can handle far beyond 400C. You might have to buy another hot end from Seemecnc to print the adapter for the E3D HOT END to install it. The stock hot end can die on you when printing ABS often, you won't get many ABS prints with stock hot end, unless you stay below 240C. Peek starts to loose int3egrity and fails. So just print your E3D adapter with the new Seemecnc hot end and install the E3d. You will be very happy you did. Also, you might want to check and make sure your thermistor input is not burned out. Hot end clogs could be a sign of bad thermistor input. Just my 2 cents.

[geneb]

I'd be highly suspicious of the values you're getting from the thermistor. It's my understanding that the PEEK section won't fail like that until you hit around 260C. I would invest in a multi-meter that's got a thermocouple probe with it. Use it to verify the temperature that the thermistor is reporting.

g.

[cpunches]

Yeah, I believe my temp readings have been off all along and probably the source of most of my print problems. I'm going to rebuild/replace the hot-end.

[Eaglezsoar]

You can buy the Peek plastic piece from SeemeCNC. It is threaded on both ends and sells for $9 if memory serves me right.
It is listed on their web site. For that price is certainly worth while to fix your hotend. I would also invest in the E3D hotend
as elqisqeyano suggests. That Peek plastic doesn't look as though it is threaded but it is. The link to the hotend parts on
Seemecnc is http://shop.seemecnc.com/Hot-Ends_c25.htm
And don't forget to get that meter that has the thermocouple so that you can verify the hotend temperatures. You can insert
the thermocouple directly into the hotend (remove the bowden) and make sure the thermocouple is all the way down to the nozzle or
kapton tape the thermocouple to the outside of the heat chamber bit internally is best. The laser type of heat detectors do not work
on reflective surfaces so don't try that route. The thermocouple meters can be had in the $20 range on Amazon.

[Polygonhell]

Unfortunately you can't trust thermistors, you either need something to verify the temperature, basically a thermocouple with a meter, or you need to start low and try feeding filament by hand until it feels right.
The issue with the second approach being until you know what it feels like it's not much use.
The usual issue with thermistors is they are not seated in the hot end well, the closer to the edge of the heater block (especially Aluminum blocks) the more incorrect they will be, if you are using a fan that disparity can be enormous. I lost my first hotend when the thermistor wasn't well secured and it creeped out of the hole during a print, the temperature read constant, but was steadily climbing until the hotend failed.

[cpunches]

Once I get the hot-end rebuilt, and verify the temp readings, is there a way to get the "real" temp to be reported by the firmware? Or is it just something to modify in my slicer settings as default?

Thanks for all the suggestions.

Anyone have any idea on the filament getting chewed up? I tried searching the forum for similar threads but didn't find any.

[mechneering]

Once I get the hot-end rebuilt, and verify the temp readings, is there a way to get the "real" temp to be reported by the firmware? Or is it just something to modify in my slicer settings as default?

Thanks for all the suggestions.

Anyone have any idea on the filament getting chewed up? I tried searching the forum for similar threads but didn't find any.

I think I know what your problem is with this. I noticed the same thing when I installed mine. There are tiny little guide bumps on the mounting bracket for the extruder. It is designed to be able to mount to one side or the other depending on if you are using 3mm or 1.75mm. I highly suspect that you have your extruder mounted on the wrong side of the little guide bumps. I would take a picture of mine and show you but i'm not near it just now. The tube entrance should not be between the two grooves. when properly installed it should be directly over the correct size groove.

Kyle

[cpunches]

I think I know what your problem is with this. I noticed the same thing when I installed mine. There are tiny little guide bumps on the mounting bracket for the extruder. It is designed to be able to mount to one side or the other depending on if you are using 3mm or 1.75mm. I highly suspect that you have your extruder mounted on the wrong side of the little guide bumps. I would take a picture of mine and show you but i'm not near it just now. The tube entrance should not be between the two grooves. when properly installed it should be directly over the correct size groove.

Kyle

Thank you!!

I've attached a couple of images in case anyone else runs into this. It was pretty easy to do I must have done it when I was doing some adjustments and had taken the bowden drive off.

The wrong way..

Fixed.

[geneb]

I love the graphic! How on earth did you do that?

g.

[cpunches]

Gene, it's a (free) application called Skitch. It's from the same people that created Evernote. I use it all the time to take screenshots and make annotations. I use it on my Macs and iPad. http://evernote.com/skitch/ There is a version for Windows and Android as well.

[geneb]

Very cool. Thanks cpunches!

g.

[cpunches]

Got my hot end rebuilt today I was concerned that the ptfe insulator was going to be screwed up since I didn't have the measurements that the tubing was cut to. Pretty happy I got that right, got some good use out of the calipers depth gauge. Got everything back together and made one of the better prints I've made yet. My thermocouple won't be here for a couple of days so I'm playing it pretty safe with the temps until I can verify the readings. I did notice during my rebuild that it appeared that one of the leads on the thermistor had broken, probably the root of my problem right there. I was a LOT more careful putting everything together this time, and wrapped everything up a little neater in kapton tape.

Also got my filament drive issues fixed too. So I think with a little tweaking I might actually be read to print something other than calibration prints. Thanks everyone for all the help!