First Print Issues

[Billy D]

Hello Everyone,

First time forum post and after receiving my M2 I was very excited to get printing.

The first print didn't come out perfect, I had a lot of strings. I used the PLA that came with the printer, printed a spiral vase http://www.thingiverse.com/thing:550604 , using the Single outline corkscrew printing mode (vase mode), Layer 1 Temp 225° Layer 2 215°, Fan Speed Layer 1 0 and Layer 2 70.
A weird thing I noticed was that for layer 2 and on my fan to cool the extruded PLA was not turning on so I manually set it to 100%. I never paid attention to the extruder temp.

I did a little research on G Code and found that M106 is for setting fan speed. I can see in my code where for layer one the code is "M106 S0" and for Layer 2 the code is
M106 S255
G4 P500
M106 S178

So I did a little trial in the Machine Control Panel (S3D) under the communication tab I sent M106 S255 and the fan comes on and then I sent M106 S178 and the fan shuts off.

Why am I getting a stringy print? (I think its cause the extruder was accidentally set to 225°)
Why does my cooling fan not come on like its supposed to for layers 2 on?

Thanks,
Billy

[jimc]

billy on the newer 24v machines the fans are for the most part on or off. there is not much variable speed there. M106 is the fan command the S is the voltage. that goes from 0 to 255 so S255 would be full on.

[jsc]

Fans vary on how well they adjust their speed through PWM. Most adjustable fans use a third wire to send a control signal. Two wire fans adjust the speed by PWMing the incoming power, but fans aren't simple electric motors these days and many don't take kindly to getting their power chopped like that.

If you want finer fan speed control, you have two options. One is to switch your fan to one that can handle power PWM better. The other is to modify your firmware to change the fan PWM frequency lower, which is better handled by many fans. There is a configuration option to do just that.

[Billy D]

Thanks jimc and jsc.


I am just going to be happy with the fan on or off.