How to control ozzing and stringing

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jccdesign
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How to control ozzing and stringing

Post by jccdesign » Thu Jul 10, 2014 6:25 pm

Hi what are the best settings for controlling the stringing ?

Dale Reed
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Re: How to control ozzing and stringing

Post by Dale Reed » Thu Jul 10, 2014 8:56 pm

Depends on which slicer you are using.....

S3D: Look for things like Coast and Retraction, and other items on that same tab of the "advanced" process settings. Coast is basically a way of stopping the filament extruder motor BEFORE the end of a move, so that built-up pressure in the hot end can be relieved --- this helps deal with filament that "keeps flowing" for a bit after the extruder stops. Retraction is a way to prevent hot filament from "drooling" out while the printer is doing a "rapid" -- a fast X/Y move with no extrusion to go to a disjoint portion of the print (like between columns on the Make Magazine torture test object). The filament is "backed out" just a little bit before the rapid, and returned to position after the rapid. Another setting (can't recall the name right now, I'm at work!) biases/tweaks how far the filament is "returned" after the retract and move. Some of us use a small NEGATIVE number here so the filament is put almost, but not quite, all the way back into the tip of the hot end (because some drools down there even with the retract).

If you're over-extruding a bit (filament diameter entered higher than actual filament, or extrusion multiplier too high), you may see or hear the nozzle "clonking" into parts of the print while it does a rapid. This is more of a problem if you have bed adhesion issues, because as the part curls up, the layers are higher in vertical space than what the printer put down and the nozzle runs into them. In this case, you might get benefit from "Z-lift" --- the Z is increased by a small amount (the bed drops, equivalent to the nozzle being lifted) before a rapid happens, then is returned to position when extrusion resumes.

For Slic3r, you'll have to check with others here on the forum. But many of the parameters have similar names between the two. (Those are the two most common slicers in use here...)

For either slicer, if you post a ZIP of your settings (for S3D, it's a .FFF file export of your "process"), we can open it up and look at the settings. If you post some pictures of what you're getting for whiskers, blobs, etc., and we have the settings, we can recommend some changes based on collective experience.

So, "More info, please!!!" ;) And welcome to the fun!
Dale

jsc
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Re: How to control ozzing and stringing

Post by jsc » Thu Jul 10, 2014 10:57 pm

If you have retraction set from 1 to 1.5mm and a fairly fast acceleration, you shouldn't see much stringing at all. If you do, I highly recommend taking the fans off, dismounting the extruder, and ensuring that the extruder gear that pushes the filament has no play in it. It is very common for that to become loose, which can cause stringing. Tighten the set screw, and use loctite to keep it that way.

If your filament gets too much moisture, it can also cause some ooziness, but that takes some time.

jccdesign
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Re: How to control ozzing and stringing

Post by jccdesign » Fri Jul 11, 2014 1:56 am

ok , i was just trying to print a coral cuff from thingverse attached are my settings
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jccdesign
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Re: How to control ozzing and stringing

Post by jccdesign » Fri Jul 11, 2014 2:10 am

how can i calculate what speed to use compared to the extrusion?

jccdesign
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Re: How to control ozzing and stringing

Post by jccdesign » Fri Jul 11, 2014 2:41 am

This is the problem im getting
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jimc
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Re: How to control ozzing and stringing

Post by jimc » Fri Jul 11, 2014 3:38 am

strings like that are controlled by the retraction setting. as jin said 1 - 1.5mm usually is enough.

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