Please help diagnose my printing problem - stringy areas

[cbgrey]

Hi All-

I'm having a particular problem with my printer that I just can't seem to figure out. Could really use some help. As you can see in the attached pictures I'm getting some very weird yet consistent stringy, unaligned layers. Specifically look at the frog's throat and the gopher's eye. It seems that no matter what I change it has no appreciable affect. What's most frustrating is that 90% of the prints look quite good but there are small areas that are terrible. The area is pretty consistent from print to print of the same object.

What else can I try or look at?

FlashForge Creator (dual) - purchased 12/2013
Installed Sailfish firmware awhile ago (not sure what version)
Using mostly MakerBot Desktop but sometimes use ReplicatorG. Similar results.
Makerbot PLA - variety of temps from 190-230.
Layers from .20 to .30
Speeds down to 60/90 and up to 90/120 - no difference.
Thinking the second head was interfering or that the weight of the dual heads was too much mass to move around, I removed the left extruder and raised the nozzle well above the build plate. No real difference.

Any thoughts, tips or guidance would be very appreciated.

Thanks
Chris

[soofle616]

It's a lack of support and/or lack of cooling causing those areas to sag. Either add an active cooling fan and duct and/or use more supports.

[mdharrington]

Lack of supports....(for the underside stuff)

simplify3d has some bridging settings, not sure the equivalent in the other slicers, but for me slowing the print down and reducing the extrusion multiplier helps in these situations. But supports are probably neccessary.

but the topside stuff is a little rough as well....not sure on that. Could be over/under extrusion....have you measured your filament diameter?

[Gene Crady]

I'd also say, you are printing way too fast for such a small object.. Try 30/45. As you slow down you'll have to drop the temp also. Fine Quality comes from slow speeds (20/40),,, just as much as layer height.

[curious aardvark]

yep too fast, and no cooling.

Just add some active cooling and that stuff gets fixed - like magic :-)

use this bracket with the linked cooling duct: http://www.thingiverse.com/thing:350649

Bear in mind that the smaller the model the less time the layers get to cool.
So you either need to print 2 or more things at the same time, slow the print down (actually the least effective) or add active cooling - the most effective.

I presume your machine uses the same mightyboard motherboard. I which case you need a 24volt 40mm fan.

Bear in mind that the software's so called 'idiot settings' are for idiots :-) Ignore the low,medium and high settings. They're totally non-ideal.

I print most things at between 40-75 mm/s

But until I added active cooling I never managed to print the underside of a curve or sphere with any kind of accuracy.

[Ghosty]

since i began my 3d printing journey some 4 or 5 months ago, i have had all sorts of issues, one of witch was that damn treefrog i coll never get the sod to print right (i tried every combination of settings under the sun, moon etc) i then took CA's advice ok so i modified it a little, im now running a 12v led tent strip light from ring (£34.99, maplins) came with a switch, ac power and car power adaptors but the best thing about this is it has a fly lead to connect more led strips, however i purchased a 12v dc fan (£6.99, maplins) and am now using this to cool objects, and i can comfirm it makes a hugh difference, i now have that treefrog on my desk, still not 100% but id say its about 99.8% perfect (probably dont help im using cheap black pla).

i would hawever say that that bracket will come out a mess unless you use somthing like this http://www.thingiverse.com/thing:327387 it still wont be perfect, but you can use the failed one to print a better one, this is what i did and it really does mak a difference, try printing low poly pikachu http://www.thingiverse.com/thing:376601 without cooling or supports, and you have no hope, ear messes up as does his tail. add cooling and no supports required i have printed several of these now for work collegues and all are 100% perfect.

as for my latest im trying to print the thorn hand cannon from destiny http://www.myminifactory.com/object/4494 .

[jdg56]

ooooh! That last bracket link, http://www.thingiverse.com/thing:327387, looks brilliant! I see there are some concerns about whether the fan screws are long enough in the creator pro, but that looks like a pretty nice way to have a removable duct without all that messy wiring. Thanks for posting the link!

Cheers,

John

[Ghosty]

np, it doesnt actually provide that much extra airflow as it is relying on the backflow from the existing fans, but it is a way to get a better duct printed, there are numerous solutions out there just look on thiniverse for "flashforge cooling" you will see there are some that dont require much wiring, mine as it happens is quite a neat install i even designed the brackets that hold the led strip using tinkercad theres still a little fetteling to do but for now they do as i want.

[jdg56]

Oh well. I have one of the robust fan ducts already; I was looking for something I didn't have to remember to plug in (I'm not messing with internal power), and that was easy to remove. I like that the referenced duct can be attached to just one side, for better visibility of the printing process. My quest continues....