Stringy print  

Re: Stringy print

Some stringiness is a fact of life with 3D printing, and some filaments are worse than others.

That said, there are a few things you can do to combat the stringiness.

1) Lower the temperature. The stringy ness is in part because the filament is too flow-y when not being pushed through the extruder. This is typically because it is a bit too hot. People have made calibration towers (see Thingiverse) that does lots of different temps and lets you see the stringyness at each temp, but in reality, you can just drop your temp about 5 deg and see what you get. Repeat. (Temperature also affects overhangs, bridging, and stringing - there are tourture tests available on Thingiverse for all.)

Quick ooze test example: https://www.thingiverse.com/thing:22263

2) The retraction settings. This is the setting by which the printer "pulls back" on the filament when it moves or lifts. If you set it too high, it can clog your extruder. Too low, and you get excess stringing. People on the forum recommend keeping it less than 1mm or less than 0.8mm depending on who you ask. Some users push it higher with no issues. Others have issues if they push it higher. Try it out.

Re: Stringy print

For reference, this is a 'hairy unicorn' and the STL looks like this:

Re: Stringy print

Some stringiness is a fact of life with 3D printing, and some filaments are worse than others.

That said, there are a few things you can do to combat the stringiness.

1) Lower the temperature. The stringy ness is in part because the filament is too flow-y when not being pushed through the extruder. This is typically because it is a bit too hot. People have made calibration towers (see Thingiverse) that does lots of different temps and lets you see the stringyness at each temp, but in reality, you can just drop your temp about 5 deg and see what you get. Repeat. (Temperature also affects overhangs, bridging, and stringing - there are tourture tests available on Thingiverse for all.)

Quick ooze test example: https://www.thingiverse.com/thing:22263

2) The retraction settings. This is the setting by which the printer "pulls back" on the filament when it moves or lifts. If you set it too high, it can clog your extruder. Too low, and you get excess stringing. People on the forum recommend keeping it less than 1mm or less than 0.8mm depending on who you ask. Some users push it higher with no issues. Others have issues if they push it higher. Try it out.

Thank you, that's good information, and I'll try out the 'torture' tests and testing different temperatures. For retraction setting, to be clear, are you talking about Length, Lift Z, or something else? Here's my retraction settings box, and I want to make sure I'm tinkering with the correct setting.

Re: Stringy print

There really should not be a stringing problem with this model

Printed a few months ago with the MMU. Just get the settings right and they print fine.

Failures are MMU load/unload issues

Peter

Re: Stringy print

Thank you, that's good information, and I'll try out the 'torture' tests and testing different temperatures. For retraction setting, to be clear, are you talking about Length, Lift Z, or something else? Here's my retraction settings box, and I want to make sure I'm tinkering with the correct setting.

The Z-Lift is the little "Hop" the printer does when moving around. This prevents the head from hitting the print.

Retraction Length is amount of filament "sucked back up" when it should not be printing.
The Retraction speed is how quickly it does that.

Some people have reported that the speed can affect the stringiness. I have length = 0.5, speed = 10 and am pleased with that. Your machine/filament may be different.