My printer had been working great until I had to reassemble the hot end and after repair my prints have drastically changed for the worse. some of my prints come out like the black one:
If you can’t tell, there is a strange pattern on the surface which is supposed to be solid, I don’t know how this actually happened but my best guess is that the plastic is just not sticking.
Also this blue print:
If you can’t really see what the top few layers of the infill is like, it is more stringy and not solid and part of the rest of it. This seems to be yet another problem I have come across.
As well as this (youtu.be/oOioSbiSsaA) and that is a print that is coming off the print bed due to the extruder rubbing up against it. I have leveled the bed fairly well and I highly doubt that that is the problem. My only other thought would be that it is a problem with the height of the extruder, but any less and the print comes out worse and any higher and it doesn’t stick. I would appreciate any help to any of these three problems.
Not sure whats happening, but a few things I would check. First, does filament still flow evenly? Just raise your extruder, heat it and manually extrude some filament, at least one full turn of the big gear. Does it flow nicely and evenly? You may have a clogged nozzle, or there may be an issue with the extruder gripping the filament.
Second semi random thought; is your temperature reading still accurate? Perhaps by working on it, you pulled out the thermistor and its not longer solidly connector to the heater?
As for the video; printing directly on the heatbed rarely works. I assume you are printing with PLA, if so, apply some blue painter tape on the bed so it sticks better. Thats not going to help with the other issues, but at least your print will stay in place if you do that and properly set the height.
I’m having the same problem with large object as andrew5427 is having. The top layer sort of crumbles and bursts open. I’ve already tried different settings (changed speed, with and without fan, fill density) but with large objects the problem stays.
[quote=“P4man”]Not sure whats happening, but a few things I would check. First, does filament still flow evenly? Just raise your extruder, heat it and manually extrude some filament, at least one full turn of the big gear. Does it flow nicely and evenly? You may have a clogged nozzle, or there may be an issue with the extruder gripping the filament.
Second semi random thought; is your temperature reading still accurate? Perhaps by working on it, you pulled out the thermistor and its not longer solidly connector to the heater?
As for the video; printing directly on the heatbed rarely works. I assume you are printing with PLA, if so, apply some blue painter tape on the bed so it sticks better. Thats not going to help with the other issues, but at least your print will stay in place if you do that and properly set the height.[/quote]
The filament does flow evenly. The black piece may have a problem just because the black filament I used was incredibly brittle. Also I am using PLA.
Since you took the hotend apart and reassembled did you recalibrate the Z axis?
I have found any time you work on the hotend you should check the Z axis calibration and check the thermistor for proper placement.
From all of the webbing it looks like it is running to hot this could have something to do with improper placement of the thermistor.
Once again just a guess.
The problem in the video has been fixed due to using painters tape, although the extruder does seem to tear up the tape. I have Kapton tape but haven’t used it, should I? Anyway the real problem is that the layers don’t stick to the previous one as shown in this picture:
the top which should be solid isn’t and is stringy, as well as the sides being more uneven, when i tried to remove this piece from the tape, the adhesion of the tape required me to use pliers, something i have done before without any problem. This time the piece was crushed and came off the bed in multiple pieces. I am going to assume that this does have a bit to do with the tape but since I haven’t had any kind of problem like this before I am going to say it is the printer.
As already suggested above, clearly your Z axis isnt calibrated correctly. Looks more like an etching machine than a 3D printer 
Also check your thermistor.
Hi andrew5427,
how far did you tighten the spring that puts pressure on the filament in the extruder? Some filaments need quite some force to get good grip on the hobbed bolt.
If the spring tension looks ok, please test the extrusion. Put a mark on the filament a few cm above the extruder (e.g. a piece of tape) and measure the distance. Heat the hotend and extrude some filament using the controls in Repetier Host. Specify the length to be extruded, e.g. 50 or 100 mm. Afterwards, remeasure the distance to your mark. Did your extruder pull in the correct length?
Cheers
kuraasu
mmm does look like a problem I suffered a few days ago. My issue was the solid surfaces over the infill hex pattern which looked like your first picture.
I messed around with the slicer setting all day, thinking that every other print type (wall, base solids) worked fine. In the end it was a clogged nozzle, I took it apart and cleaned it all out but I found now when this happens the best way is to try this:
Raise nozzle up about 50mm
head extruder to 190
extrude 5mm and when doing so use a wire brush and poke one of the little bristles up the nozzle and wiggle about.
Do this a few times.
Extrude 5mm more and see if the filament flow better out of the nozzle without curling up on the nozzle.
This works for me every time now.
PS! I have found that its easy to scratch the inside of the white tube just above the nozzle, caused by changing the filament a lot (I have many colours) and being too forceful. This then chips of a small part of the white tube which doesn’t melt and blocks things up and you have to strip down the hot end to clean out, if you remove the filament and use a torch against this tube and look down the top of the hot end you might see this. Be careful how you add new filament, straighten it up first and check you have cut it cleanly!
I increased the extruder temperature of the extruder by 14 degrees Celsius after seeing that it was only 176 degrees. I also increased the tension of the spring to be almost fully compressed. I get about 40 mm extruded after attempting to extrude 50 mm. I cleaned the tip and the PLA came out really smoothly for about 50 mm and then started coming out in a waving pattern before returning to its original act of bunching up on the side and then falling down in a big clump. As seen in this video: http://youtu.be/0f1EEtb-scs.
I think what you are seeing is the plastic that has been extruded is cooling and pushing the hot plastic back up to the nozzle.
I just decided to print something to see how it went. It went incredibly well after I re-adjusted the height so the gears on the extruder stopped jamming.Thank you to everyone who helped me with this problem. For my own and others’ future problems here is what I have found works well.
- Make sure the bed is level (check to make sure the extruder height is equal on each corner and not so much with a level)
- Clean out the tip of the extruder (Use a bristle from a wire brush (thanks Moorron))
- Check extruder spring tension (probably increase if it is fairly loose)
- Check the temperature of the extruder to make sure it is indeed correct
- Adjust the height by moving the Z axis and adjusting the screw depending on the height of the extruder
(move the Z axis while printing and get it to a point where the extruder is printing a good thickness then adjust the screw a bit up or
down depending on which direction it was moved more. Also you can try moving the Z-axis too low and then gradually increasing its
height (tighten Z screw) until the gears stop locking up.)
Hope this helps anyone who is has a similar problem.