Fan stops when I start print

This is the order of events

Start Fan
Start print i.e. SD -> SD Print
Fan stops
Temperature rises to 200
Need to manually start FAN again. Fan On Button does not always work first time. So need to bring down temp to 80 and clean out nozzle and start again.

Also i've had prints that fail halfway through i.e. the fan just cuts out for no apparent reason. Check the fan connections they look sound.

Any ideas what might be going on?

Edited 1 time(s). Last edit at 05/19/2014 05:19PM by Harvey.

The file i'm trying to print is the test print from the Docs. i.e frame-vertex-2off.stl

Converted this to G-code using slic3r.

Looking at the converted file I see I have fan commands M106 & M107 being issued. i.e.

M107 //near beginning
.
M106 S216,S229,S231,,S246,S255 //various M106 commands in middle of file
.
M107 //near the end

Why do I have a M107 at the beginning? Makes no sense as fan needs to be on before head is heated to 200c.


M106: Fan On
Support FiveD Teacup Sprinter Marlin Repetier
yes yes yes
Example: M106 S127
Turn on the cooling fan at half speed.
Mandatory parameter 'S' declares the PWM value (0-255). M106 S0 turns the fan off. In some implementations the pwm is specified by a real fraction: M106 S0.7.
M106 in Teacup Firmware
Additionally to the above, Teacup Firmware uses M106 to control general devices. It supports the additional P parameter, which is an zero-based index into the list of heaters/devices in config.h.
Example: M106 P2 S255
Turn on device #3 at full speed/wattage.
Note: When turning on a temperature sensor equipped heater with M106 and M104 at the same time, temperature control will override the value given in M106 quickly.
M107: Fan Off
Deprecated. Use M106 S0 instead.

Edited 3 time(s). Last edit at 05/19/2014 05:22PM by Harvey.

Quote
Harvey
Why do I have a M107 at the beginning?

Because your slicer inserts it there. Either it can be configured out or it's time to report a bug there.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

You should have a look at the Filament settings on the Cooling tab. If you want to have the fan always on you just have to tick the first option and that's all. By default the option is disabled and, if only auto-cooling is set, you get M106/7 here and there in the file set by the cooling strategy embedded in Slic3r and depending on the sliced model.

The hot end fan should be on ALL THE TIME, to keep the top of the hot end cool. The 'fan' output is for an additional cooling fan. Do not connect the hot end fan to this.
See: [reprappro.com]
"The fan wires do not connect to the connector marked “FAN”. That is for a different optional fan for cooling prints as they are being built from materials that require that."

Ian
RepRapPro tech support