Filament stops extruding

Hi everyone,

I just received my printer last week and so far it has been a frustrating experience to say the least. The first night I printed 2 things just fine (5mm calibration cube and a vault boy statue). Since then I have not been able to get a single thing to print correctly.

I tried printing using ABS and the bed heated up to 100C and then all of a sudden just stopped and cooled back down. Since then I have not been able to get it to heat up for more than a few minutes and most times I can not even start jobs because the bed will not hit 100C before shutting down. For now I just switched back to PLA until I get that figured out.

My real problem has been that often the printer just stops extruding. The extruder keeps the temp it should but even if I open the feeder and manually push the filament down it will not go through. I have to remove the filament retrim it and refeed. This gets it going again but I have not been able to actually do any prints because when it stops extruding it ruins the job. When I am pressing down on the filament with the feeder open it feels like something is blocking it.

For awhile it was only printing garbage but I found that the bed wasn't perfectly level. I spent a good hour making sure it was absolutely perfect and that has helped a lot. I think once I can figure out why the filament keeps getting blocked I'll be able to start printing with PLA for now at least.

Thanks

 

I finally seem to have it printing steady. I have printed a few parts tonight and it hasn't stopped once yet. I am printing at 195 for the first layer and 190 for each layer after. The bolt that feeds the filament is perfectly clean. It had gotten caked up once but I cleaned it out. When I am trying to feed filament it often gets stuck going in even with the extruder open. When I push the filament down in it always feels like it is getting stuck on something. I usually have to keep wiggling it until it goes in all the way and then I close it up.

Now that I am up and printing I am having a new issue though and it may be related to why the filament was getting caught up. While I am doing prints I am noticing that filament is leaking down the yellow tape around the sides of the extruder. It forms a bubble on the flat surface of the extruder buttom until it gets big enough and drops down onto my print. It is leaving prints with black marks throughout. I just did a part with 276 layers and have 9 black spots on it. I am assuming this is not normal. Maybe my extruder has a leak? I'd like to take the tape off and look to see if I can see a leak but I am worried I wont be able to get it back on once its off.

 

Thanks for all of your help so far tesseract. I've done a ton of troubleshooting on the printer and have learned a ton in the process. The reason the extruder was getting clogged was because the entire hot end was assembled really crooked. The block was also not tightened all the way to the PTFE tube. I reassembled it and it has only jammed up once since.

The next issue I had was with my print bed. I couldn't get it level and found that one of the corners had its screw in upside down and was not connected to the rail at all and another corner had a cracked spacer from being over tightened. I printed out the auto bed levelers and spent a good amount of time getting that perfect. I am now able to click print and have it start off correctly every single time. My first layers always come out pretty good and the prints have been sticking well.

Now for the one that I just cant seem to figure out... My prints have been coming out wavy. The layers seem to expand out and shrink. I have tried adjusting the z axis more times than I can count. It seems to do it whether its too high or too low. I had played with slicer settings but even with going back to all of the recommended defaults it still does it. I am printing with pla and it does it whether I print at 190, 200, or 210.

I attached a picture of what is happening. The blue cubes are how it used to print and the white cubes are what I've been getting since fixing everything else. Once I can get this issue resolved I think I'll be able to start getting some prints done.

 

Yes. I have tried doing 300 200 and 100 micron layer heights. Increasing and decreasing print speed. I thought maybe the printer was wobbling on the table I had it on so I moved it to the floor. All belts are tight.

If I can find a resolution to the issue I'll post it up here.

 

I added one of each. I am currently printing a bigger part with flat sides so I can post that in the morning when its done. I know the cubes aren't the best example.

It doesn't seem to be shifting. Rather the layers are expanding and shrinking. I've gone through the layers one by one in repetier and they are normal in there.

Edit: I removed the pictures from last night and added in new ones. I printed a cube off to give a clear picture of whats going on. Since last night here is what else I have tried.

I was using a PC on Windows 8.1 running Repetier found through google. I tried running everything on a Windows 7 PC running the Repetier download on the Robo 3D site. I changed filament. It seems to look better in photos but it still feels the same in your hand. I guess it just shows better in white.

I also attached a photo of a print I made the first night I got the printer in. I honestly have no idea how that print even happened but it printed and the parts that didn't have supports came out really nice. It did not have the wavy effect either.

Edit #2: I think I got I figured it out! The rods that raise and lower the z axis are not perfectly centered in the bracket that holds them. When I switched to the Repetier that is hosted on the Robo3D site the printer started lifting up and dropping back down between each layer. When it does this I can see the rod moving on the bottom just about the same amount of wave that I am getting on prints. Another reason I think this may be correct is because whether I print at 100, 200, or 300 microns the waves are always at the same height intervals.

Tomorrow I am going work on disassembling and reassembling it.

 

Shaun, can you explain more on exactly what you did to correct the extruding error? I'm afraid to try my hand at taking apart the extruder head... I am having the same issue where it stops extruding during the print. I have made 10+ successful prints, and am having no issue with bed leveling, axis adjustment, etc. Thanks for you help.

 

I had the filament shaving problem and it's because the temperature is too low. Fortunately, I have a Flir thermal imaging camera. I checked the nozzle temperature and found it to be 20C below the setting. I set the first layer temp to 240 and others to 230, which is actually 220/210 and all my problems went away. I also slowed the print speed dramatically, will have to try speeding it up now.

Robo needs to invest in a thermal camera and calibrate their sensors. As an EE, I know part tolerances add up! -5% plus -5% = -10%!
Also, the heated bed is a lot hotter by its connector. Thermal imager shows a weird looking pattern. Could send imager photos?

 

Here is the Flir thermal imaging report. The extruder was set at 232 and the plate at 90.

 

Don't forget the 230 is a slightly internal temperature. Granted a 20 degree shift does seem a little high, but you won't measure 230 on the surface if you're measuring slightly internal of the block.