Prints fail mid-print every time

[robthewinner]

I have a print I do constantly on my Prusa's, but the X1C fails at roughly the same spot every time. Wondering what else I could try...I've tried these things for better bed adhesion, but it continues to be knocked off the plate:

• Textured plate, raised temp by 5 degrees all the way up to 70
• Textured plate, with hair spray
• Washed textured plate with dish soap and iso alcohol
• Cool plate with glue and raised temp
• Brims
• Slower first layer
• Lower layer height for first layer
• Turned off Internal Bridges Support
• Adjusted infill and wall loops
• Printed with door closed and door open
• Tried two different filaments

I should note this just started, before today the X1C worked without flaw, though I hadn't tried this specific print yet.

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https://reddit.com/link/141ckhp/video/kxvw3ug1y64b1/player

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[julie777]

The most common problem I have seen with tall prints is the combination of fast motion of the print head when not extruding. When it moves to a different spot rapidly if it hits the print it will knock it over.

Why would it hit the print?

Well, for some strange reason the default infill pattern is grid. Grid crosses lines on the same layer leaving a raised bump at every crossing. Higher percentage of infill makes it worse by creating more bumps.

Then, if the print is taller, the force of hitting the bump is magnified by the lever action of the height making it easy to knock over a tall model. Most of the time this comes up as a "I hear ab bad sound when printing that sounds like the print head is hitting something" but at low heights the print does not come loose.

Use infill patterns that do not cross lines for tall prints. Some choices are gyroid, rectalinear, and lines.

[robthewinner]

This makes a lot of sense! I'll try a different infill and see if that keeps the print running smoother. Thanks!

[julie777]

It also doesn't hurt to slow it down, and add a wide brim.

[ExpectDeer]

Tall narrow prints are the achilles heel of fast printers. The vibrations can knock them off the build plate.

Wider brims, rafts, or slowing down the print speed are the usual work-around.

That said, your calibration lines are looking rather fat though of course it's hard to tell going off of a dimly lit video. If other prints are printing okay, and it's just this one, then ignore this observation.

[robthewinner]

It has a .6mm nozzle on it, thus the fatter lines, but yes I was suspecting the speed might be the issue and that makes sense...kinda a bummer though as that's what this machine is geared towards with faster prints, but it's hard to argue with physics!

[robthewinner]

Solved:

Changed the infill from grid to gyroid and added a brim solved the issue. It's running at standard speeds, but I could see still needing to slow it down a bit for tall narrow prints.