Bad Prints all of a sudden

#1

I’m not sure why all of a sudden I’m getting prints that have really thin layers. I thought it might be just not enough layers so increased top and bottom layers to 5 which helped a little bit but still not great. You can see in the picture how the top layer is almost missing in spots. (This print was with the default high quality setting) This isn’t just the top layer sometimes the infill is like that as well and is just missing. Any Idea’s?

20150921_205546 (2).jpg5312×1397 1.27 MB

Thanks!

#2

Looks thin and stringy, like not enough filament. Things I’d probably look at would be extrusion multiplier, correct setting for extruder mode (absolute vs relative), appropriate extruder feed, and making sure something isn’t clogged in the nozzle. Maybe try unloading and reloading filament. Also maybe make a sharpie Mark on the filament, and then manually extruder 100mm and ensure the mark actually moves 100mm.

#3

Most likely a clogging as already said by jpod.
A nozzle can also clog partially especially the original ZIM nozzles: the teflon tube slightly reduces the inner diameter which increases the force the stepper has to push the filament through the nozzle tip: you get those far too thin lines even if the feed multiplier is ok.

#4

Thanks guys I think your right about it being clogged. I did a test print last night with the other nozzle and it worked fine with the same settings so its something in my right extruder.

Any good way to unclog other than disassembling the whole head and taking a small drill bit to it?

#5

At the original ZIM nozzle I had to unscrew the bass nozzle with the Peek insert and also unscrew the flat nut so that the brown Peek tube comes loose. Then check if there is a Teflon inside the nozzle itself and remove it.

#6

Thanks! I will try that tomorrow after I get home and see if I can get it unclogged.

#7

How did you unscrew the flat nut out of the back to get the brown PEEK tube out?

#8

Described my myself here:

#9

If you can’t clean your nozzle like I described buy a pair of those:

http://zeeproforums.technobly.com/t/custom-hot-ends-for-the-zim/
http://www.3dprintermods.com/prestashop/index.php

#10

Maybe for a quick and dirty approach, I was able to unclog a complete or partially clogged nozzle by heating it up and using a 0.3mm drill or 0.3mm accupuncture needle with glove and safety goggles. Insert the drill or needle in the nozzle and wiggle and extrude until it seems completely free.
The gloves and goggles are important because the ~200° plastic ejects out and that hurts and is dangerous.

The complete disassembly is a lot of work and should be used as a last resort after trying all the other easier methods.

#11

I will try getting a pair of plyers and a 0.3mm drill bit.

Are these the same as the plyers you used King?

I have a set of the replacement heater blocks with nozzles so it will just be a matter of installing them if I can’t get my current nozzle clean.

Thanks for the help guys, I will post an update after I get the drill bits and plyers.

#12

Yes - but it was just a suggestion and it does not work well with it: but at least I could open this (bloody) thread.
Don’t break the brown plastic tube!

As already mentioned before: go for the M6 threaded hotend blocks so you can use Open-Soruce Parts and do not have the issue with those proprietary nozzles.

#13

Ok, after some more testing I figured out it was a combination of two things.

  1. The nozzle was partly clogged.
  2. My temperature for that plastic was to low.

I used a .35 mm drill and ran it through the nozzle and also bumped the temperature from 195 to 200 and now it is printing great :smile: I don’t know why different PLA brands have such different temperatures they like.

#14

Surprisingly it does not limit to different brands.
I have tried loads of different filaments and even within the same brand different colors have completely different temperatures.
So for example I have this silver with 220-225 and green with 200.
But who knows what is in the plastic and what pigments need what additives to work :wink:

#15

Ok, I just updated my printer to run off the computer instead of the zim board. I’m using Replicator and slic3r to control the printer. I get nice prints for the first little bit and then the print gets all rough. This doesn’t happen on small prints just prints with long straight edges. See picture. Anyone have any ideas on why?

20151009_055607 Small.jpg2943×1318 1010 KB

This is PLA running at 205 for one print and 210 for the other.
Layer height is 0.15 with a base layer of 0.2

#16

This could be so many things.
But just to throw in some problems I ran into:

  • if you are still using the top cover, remove it and the PTFE tubes from the hooks left and right, so that the bending is reduced; with my Zim the bending of the tubes is too much if the head is in the front area due to too much friction
  • or remove the tube altogether and try directly feeding from the top to see if its dust in the tube
  • check the upper motor working fully in different head positions; with my Zim my cable is damaged so that in the front right area the upper motor stops working and the lower is not strong enough to completely push it past the top motor
  • check temperature readings
  • checl lower and upper motor working properly and the filament is running free and does not need force
  • try higher temperature
  • try higher and lower extrusion multiplier
  • try slower or faster head moving speed, thus resulting in slower or faster extrusion
  • turn off cooling
  • check for partially clogged nozzle
  • try different filament, maybe this one just has problems
Extrude stepper motor stop mid print
#17

I will try some of these suggestions.
I only have a top extruder motor, I took the bottom one out when I removed the cubie board and also tweaked the voltage based on one of the tutorials I found in the forum. I will post an update tomorrow evening with results.

#18

If you tweaked the current limit, it could be the current limit kicking in on the extruder stepper I suppose. I tweaked both of my Zims the same way and have not seen any issues, but I do not have a long teflon tube any longer either (I feed from the back to the top, certainly lower friction than the original design). Try upping the extruder current a bit and see if that resolves the issue.

#19

Thanks Jpod, I will try upping the current limit on the board if it gives me problems today.

I printed a nice print last night by just turning off the cooling fan and it came out pretty good.