Having some issues with stringing and blobs the exterior of prints. I already upped the retraction setting to 3.5mm and I’m running pla at 200C. Does anyone have experience with this problem?
Its interesting that the back sides are smooth, and I’ve been able to print a hollow test cube with pretty decent success.
The strings are from the nozzle from one place it has to print at to another place it has to print at. It will now show on a side of the print that does not face another part. Those little hairs and blobs are baby strings.
The extruder motor may not be fast enough to retract before a significant amount of ooze forms on the nozzle. For further comment, the real retract experts will need to know what hot end, cold end, bowden or not, and retract speed. Depending on your hardware, there may not be any settings that eliminate the problem.
They may also want to know what you have above the nozzle. Often enough for PLA, there is a slitted cylinder thing with a fan on it or metal fins with a fan on it. Along with that comes fan settings.
Have you tried printing at a lower temperature? I was having this sort of problem a while ago and solved it by cooling my extruder down to 170.
As a general rule, the filament should be cold for as long as possible before reaching the nozzle. If you are printing at 200 without a fan on the extruder, your filament will melt higher in the chamber and it will just kill extrusion control.
@Evan_Gillespie I may try and back off the extruder temps a bit tonight. One of the downsides of not knowing the specific melt temp of your material.
@NathanielStenzel I’m running a .35" j-head right now. The green object in the second photo is a fan duct that blows air across the middle of the j-head to prevent heat migration in the barrel.
After playing with the temps I believe my next best option is to look at further retraction and print speeds?
@Brett_Giesler Sadly, I can’t say too much on the topic of PLA. Maybe after I play with it some. I have never used PLA though. I have only used ABS.
@Brett_Giesler You can easily figure out the melting temperature by following these instructions:
Note that filament should be extruding in a uniform ‘tube’ strait down out of the nozzle.
@NathanielStenzel Ahh my wife was less than enthused with the odor of ABS… 
@Brett_Giesler I don’t know. Maybe I will switch away from both some day and use paste instead. I would love to make a paste extruder with the heated bed actually cooking the paste to harden it. lol Maybe I could even make my own paste out of alum or concrete or wood pulp or whatever. I think I would love that. I wonder if the paste extruder users have problems similar to yours.
Is the extruder direct drive or Bowden based? If you’re using a wades extruder I could help.
It’s a Greg’s (wade based?) Extruder. Prints great with no gaps… haha. I lowered the temp to 190, but still suffered the same problem. Will experiment with more temps later tonight.
It seems the problem is isolated to an oozing when moving between open spaces. I’ll post my detailed retraction settings tonight.
With the wades extruder typically the head of the hobbed bolt is loose in the large extruder gear so putting something in the gap helps to make it for better. Also you will know if you bolt is loose if when retracting your printer makes a clicking noise.
Bolt is secure… I also just realized I’m running RC2 version of slicer. Downloaded 1.1.0. WIll give that a shot after this next print is done in hour and a half.
I also realized I can split the combined prints into separate objects and print them one at a time. But, it feels like cheating when I should find the real rootcause.
Still having issue. Ran out of filament. Need to hassle filament central to send me more
Running out of filament sucks.
Does anyone have an approximation of how many meters of filament is in a 1kg 1.75mm sized ABS filament?
You might want to make your own topic Nathaniel if you want it to get seen.
good point.
