# Specific 3D Printers, Scanners, & Hardware > QiDi 3D Printer Forum >  QIDI 1 surging fan

## JensC

1. Has anyone experienced the PLA cooling fan surging during operation.  Up until today mine would run at a constant speed during a print.  Now it surges up and down in speed while printing. It does not do it while waiting to print during preheat but once the job begins it starts this behavior.  So far it doesn't seem to affect the print quality but it is strange to listen to its whine wandering up and down the scale.

2. Is there a programmatic way to turn this aux cooling fan on and off without using the keypad?

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## Talon 3D

What program are you using? 
In Simplify 3D you can adjust fan speed. You might be able to in the MakerBot software that comes with it but I'm not sure. 
Also if it is a PSU issue that can happen when the extruder is heating and using more power and a failing PSU can't keep up. 
It could be the fan itself is dying also. 

Also one last thing.  Make sure the outlet you are using that nothing else is on the same breaker.  If an AC unit or something else that turns on and off can make weird changes where you notice it fluctuates.

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## JensC

The speed adjustable fans are the hotend cooling fans. The fan I'm referring to is the aux turbo fan on the left side of the dual extruder assembly.  It is enabled thru the keypad menu and only used for PLA filament.  It's speed changes almost seem to coincide with certain actions at certain speeds.  It might be Astroprint which I just recently connected.  I'll try printing from the card to see if there is a difference.

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## Talon 3D

I was referring to the Aux fan. The two on the front as you said is normal. 





> The speed adjustable fans are the hotend cooling fans. The fan I'm referring to is the aux turbo fan on the left side of the dual extruder assembly.  It is enabled thru the keypad menu and only used for PLA filament.  It's speed changes almost seem to coincide with certain actions at certain speeds.  It might be Astroprint which I just recently connected.  I'll try printing from the card to see if there is a difference.

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## JensC

You said there are hot end fan speed settings in Simplify3D.  This I know.  They do not, however, apply to the turbo fan.  It's either on or off. The hot end fans run fine making it unlikely to be a PS issue.

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## Alibert

Then it might be a power supply issue? 

Check the cables to the fan with a multimeter or such while jiggling them around. It may be a break somewhere in the leads that makes contact on and off as the carriage moves around.

You may also want to have a look and inspect the motherboard. Have a good look at the connectors and leads, and look out for any signs of scorching. Also check the specs of the power supply unit (the brick thing).

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## Talon 3D

I don't see where I specified hot end anyways but here is a screen shot where you can adjust the settings of the AUX fan.
As you see here I have it at two different speeds, one for the first layer and another for the rest. You can make it do more as you see with the settings.
Screenshot (128).jpg





> You said there are hot end fan speed settings in Simplify3D.  This I know.  They do not, however, apply to the turbo fan.  It's either on or off. The hot end fans run fine making it unlikely to be a PS issue.

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## DaveB

Unfortunately, the QiDi printer does not respond to the fan/blower/aux speed setting other than to be either on or off.   S3D does allow one to set the "fan speed" by layer, but my understanding is that there is no compatible "X3G" command to set the fan speed, so the QiDi just turns the fan on full, or off as a compromise.





> I don't see where I specified hot end anyways but here is a screen shot where you can adjust the settings of the AUX fan.
> As you see here I have it at two different speeds, one for the first layer and another for the rest. You can make it do more as you see with the settings.
> Screenshot (128).jpg

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## Talon 3D

Always works for me.  I send the gcode over via my OctoPi. 
I know though you are correct on x3g files via the SD card it does not work.  If you check the box in S3D (it may be on by default) it saves both the x3g and gcode. 





> Unfortunately, the QiDi printer does not respond to the fan/blower/aux speed setting other than to be either on or off.   S3D does allow one to set the "fan speed" by layer, but my understanding is that there is no compatible "X3G" command to set the fan speed, so the QiDi just turns the fan on full, or off as a compromise.

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## JensC

> Always works for me.  I send the gcode over via my OctoPi. 
> I know though you are correct on x3g files via the SD card it does not work.  If you check the box in S3D (it may be on by default) it saves both the x3g and gcode.



Reality Check (back to the thread topic)

1.  Answer to my first original question:

 The aux cooling fan plug near the extruders was defective.  At rest it worked but when jerked around by the head in certain directions the fan power was intermittent.  Fixed.

2. Answer to my second original question:

The code to turn on the aux cooling fan is M106.  The code to turn it off is M106 S0.

*(END OF THREAD)*

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## Talon 3D

No need to be rude. 

Educate yourself. 

Glad you found the issue with the fan. 

For the fan issue in the file itself as I stated and posted a screen shot for you, Simply 3D allows you to control the fan speed layer by layer of you want. 
I setup OctoPrint on an RPi (hence the name OctoPi) and send my files to be printed directly to the printer through that instead of the SD card route. 
It does not like the x3g files and instead uses the gcode files.  S3D has the ability to save both the x3g and the gcode file at the same time. 
Fan on/off and speed settings work on the gcode file.  The x3g its either on or off. I've not looked into seeing if you can pack the speed control in the x3g file. 

Glad your up and running again. Enjoy. 





> Reality Check (back to the thread topic)
> 
> 1.  Answer to my first original question:
> 
>  The aux cooling fan plug near the extruders was defective.  At rest it worked but when jerked around by the head in certain directions the fan power was intermittent.  Fixed.
> 
> 2. Answer to my second original question:
> 
> The code to turn on the aux cooling fan is M106.  The code to turn it off is M106 S0.
> ...

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## JensC

> No need to be rude. 
> 
> Educate yourself. 
> 
> Glad you found the issue with the fan. 
> 
> For the fan issue in the file itself as I stated and posted a screen shot for you, Simply 3D allows you to control the fan speed layer by layer of you want. 
> I setup OctoPrint on an RPi (hence the name OctoPi) and send my files to be printed directly to the printer through that instead of the SD card route. 
> It does not like the x3g files and instead uses the gcode files.  S3D has the ability to save both the x3g and the gcode file at the same time. 
> ...


Fan speed was irrelevant to my original thread question.  Its inapplicable as the QIDI printer has no variable speed fans.

"Educate yourself"?!...  "No need to be rude"?...   Hey, Pot.... meet Kettle.

Jesus, Mary an' feckin' Joseph.   Honestly.....

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## Talon 3D

The fan that is the blower on the nozzles will vary in speed. S3D does allow that. it is not either on or off only as far as I have been able to see. I used PLA/PHA just last night to build the adjustable platform jack model and had the fan at 20% for the first 4 layers and at 100% for the rest. The fan did spin at a slower speed during the first four layers. Why?? I am not sure as it is not a 3 pin fan power connection that usually controls fans. I have not disassembled the unit to check the board but the control board may very well control the fan speed by adjusting the amount of power it sends to it. I will take it apart in the coming weeks and find out.


As far as being upset by your rude reply yes I was.





> Fan speed was irrelevant to my original thread question.  Its inapplicable as the QIDI printer has no variable speed fans.
> 
> "Educate yourself"?!...  "No need to be rude"?...   Hey, Pot.... meet Kettle.
> 
> Jesus, Mary an' feckin' Joseph.   Honestly.....

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## JensC

@bitcoin.com boy

The message you seemed to have taken as "rude" wasn't for you.  I was trying to end a thread that *I* started.  Quit busting my balls about the fan shit.  Since you appear to so desperately need the last word, it's yours.

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## printbus

Time for everybody to just back away from this one...

  - Moderator

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## Talon 3D

Just wanted to apologize. I read it wrong and thought you were busting on me too. 
Sorry for that.





> @bitcoin.com boy
> 
> The message you seemed to have taken as "rude" wasn't for you.  I was trying to end a thread that *I* started.  Quit busting my balls about the fan shit.  Since you appear to so desperately need the last word, it's yours.

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