<p>The extruder motor may be skipping steps because of insufficient current. Typically, the stepper driver will have a small potentiometer that lets you increase or decrease the current. Increasing the current will give the motor more torque/force, but also cause it (and the driver) to heat up more.</p>

CC BY-SA 3.0
2017-11-14T10:39:20.847Z
2017-11-14T10:39:20.847Z
Tom van der Zanden
<p>It sounds like your filament is not hot enough to be extruded, which will cause the stepper motor to 'skip' (and produce a knocking or clicking sound). 200°C sounds rather low for PETG, and I do not get good extrusion below 215°C. I normally print at 225°C, with the first layer at 235°C. I also print slower than I do for PLA -- 40mm/s and 30mm/s for the first layer.</p>

<p>Note that thermistors can be inaccurate, and may report temperatures several degrees lower or higher than are actually being achieved.</p>

CC BY-SA 3.0
2017-11-14T11:43:33.407Z
2017-11-14T12:02:37.293Z
2017-11-14T12:02:37.293Z
Mick
<p>I have a Prusa i3 printer with mk8 extruder. I am using PETG with (200-240/75-85) degrees recommended temp on it's box. but when I do printing i hear some knocking sound that means there is a problem in extrusion. last time I did increase my temp up to 270 degrees!! maybe this sound solved! but it damaged my extruder's screw's inner Teflon and I forced to change it! </p>

<p>Now I have a new nozzle and extruder's screw, but again I can hear this sound during the printing! I thought maybe it's because of very close distance between the nozzle and the bed, but when I increase the distance, the filament starts to warping!</p>

<p>My nozzle is new and it can't be for clogging. so I decreased the print speed from it's default 60mm(in Cura software) to 50, but didn't solve this sound. Also when I use pronterface and do extrusion manually, it works nice with 200 degrees! but I can hear the sound in 190 degrees. But when I do printing I hear the sound even in 200 degrees! Is this mean I must increase the temperature for printing? how much?</p>

<p>By knocking sound I mean the sound you can hear when you have a clogged nozzle and the extruder's stepper motor can't push the filament into it and rotates with knocking sound!</p>

<diy-3d-printer><print-material>
What is the meaning of extruder's knocking sound?
WDR
# What is the meaning of extruder's knocking sound?

(Asked by: username_0 on 2017-11-14)

I have a Prusa i3 printer with mk8 extruder. I am using PETG with (200-240/75-85) degrees recommended temp on it's box. but when I do printing i hear some knocking sound that means there is a problem in extrusion. last time I did increase my temp up to 270 degrees!! maybe this sound solved! but it damaged my extruder's screw's inner Teflon and I forced to change it!

Now I have a new nozzle and extruder's screw, but again I can hear this sound during the printing! I thought maybe it's because of very close distance between the nozzle and the bed, but when I increase the distance, the filament starts to warping!

My nozzle is new and it can't be for clogging. so I decreased the print speed from it's default 60mm(in Cura software) to 50, but didn't solve this sound. Also when I use pronterface and do extrusion manually, it works nice with 200 degrees! but I can hear the sound in 190 degrees. But when I do printing I hear the sound even in 200 degrees! Is this mean I must increase the temperature for printing? how much?

By knocking sound I mean the sound you can hear when you have a clogged nozzle and the extruder's stepper motor can't push the filament into it and rotates with knocking sound!

**Tags:** diy-3d-printer, print-material

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## 2 answers

### Answer by username_1 on 2017-11-14. Score: 3 | Accepted answer

The extruder motor may be skipping steps because of insufficient current. Typically, the stepper driver will have a small potentiometer that lets you increase or decrease the current. Increasing the current will give the motor more torque/force, but also cause it (and the driver) to heat up more.


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### Answer by username_2 on 2017-11-14. Score: 3

It sounds like your filament is not hot enough to be extruded, which will cause the stepper motor to 'skip' (and produce a knocking or clicking sound). 200°C sounds rather low for PETG, and I do not get good extrusion below 215°C. I normally print at 225°C, with the first layer at 235°C. I also print slower than I do for PLA -- 40mm/s and 30mm/s for the first layer.

Note that thermistors can be inaccurate, and may report temperatures several degrees lower or higher than are actually being achieved.


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