Air printing. It appears every time.

[mathdesign]

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I use 5th generation. Please look my photo.
It appears every printing time. I don' know why.


I think, it is not clogging. I was cleaning the nozzle.
And not about feeding. I tryed, directly supply filament.


when it is happen, i can heard unusal sound. tic-tic-tic.


Please help me.

[Bobby Lin]

Hi! I experienced the same problem before. I contacted Makerbot support and here was the solution they gave me.


1. Make sure you're using the latest firmware. pull the drive block off the extruder and make sure the drive gear is 4.9mm up the shaft. clean any filament off the drive gear. put the drive block back on. When you put it back on, press on it so you're pressing it towards the gear to make the tension tighter.


Let me know if this solution works for you or not.

[mathdesign]

Thanks you for reply.

" 1. Make sure you're using the latest firmware. pull the drive block off the extruder and make sure the drive gear is 4.9mm up the shaft. clean any filament off the drive gear. put the drive block back on. When you put it back on, press on it so you're pressing it towards the gear to make the tension tighter."

I use the latest firmware. and extruder assembled correctly.
But i can't fix it.
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[Alibert]

The tic-tic-tic you hear is probably the gear slipping over the filament.

There is a maximum amount of plastic you can extrude (expressed in cubic mm per second, of mm3/s). You can roughly calculat this as max_printing_speed_in_mm_per_sec * witdth_of_extrusion_in_mm * layer_height_in_mm.

For example, with a max 3000 mm/min extrusion (= 60 mm/s) at 0.25mm layer height and 0.44 mm width (0.4 mm nozzle) we get 60 * 0.25 * 0.44 = 6.6 m3/s which is within capabilities of a FF type extruder.

Depending on the type of polymer, the printing speed (expressed in mm3/s) and the temperature settings there is a maximum that you can extude. The extruder/gear combination has maximum torque it can put on the filament, and the polymer/temperature/nozzel_size will induce a viscosity/rheological backpressure.

When the back-pressure exceeds what the extruder can supply as torque (backpressure exceeds pushing power), then the filament will slip in the gears to the point that it may be grinding away.

To solve try any (combination) of the following:

1) reduce max printing speed and/or reduce layer height (reduces the max mm3/s extrusion as calculated above)
2) increase printing temperature (reduces viscosity)
3) use other type of polymer (has different temperature-viscosity profile).

Also, be aware that certain parts have an extra amount of plastic extrusion specified in the slicer, for example 150% width for infill. You need to include this in the max extrusion rate calculation. In the above example, this means that you may face 150% * 6.6 = 9.9 mm3/s. This is most likely over the limit the FF extruder can supply.

My advice is to always calculate the max extrusion rate in mm3/s to see where you are when evaluating a printed object.

See also this link: http://www.extrudable.me/2013/04/18/...ty-and-limits/

Cheers