Enable Cooling and an out of Control Heated Bed

Hi all,

Using Marlin with slic3r on a prusa.... Switched to PLA recently

If I print without a fan attached and cooling not enabled the heated bed does 85C for the first layer and 60C for subsequent layers just fine (as I have it set in slic3r)

When I attach a fan (to D9 on my ramps) and enable cooling in Slic3r the first layer on the heated bed stays at 85C.When subsequent layers start though the heated bed start to spike in temperature and increase up and up. At this point I can't manually set the temperature in proterface or disable the bed in pronter while the print is running.

Anyone have any ideas what slic3r setting or marlin issue I might be having?

Thanks!

Edited 2 time(s). Last edit at 01/12/2013 03:21AM by bobby_rep.

Start with a fresh copy of the Marlin firmware.

Get everything hooked up. D8 Hot End, D9 Fan, D10 Heat Bed.

Open your host software and send the G-Codes to turn on each of these.

If the results are predictable. Look more closely at your slic3r configuration.

Or try PID autotune. Personally I did it twice each for my bed and hotend. Once with fans on and once with fans off, I then took the median of the two values, and have very very stable temps. 1°C variance.

But the bed heats so slowly, it's curious why it would spike so high, especially with a fan on it.

Definitely autotune your hotend...

M303 with the hotend cold.

Also, check the wiring on your bed thermistor.

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Thanks all. I'll try some of those steps and give it a go. Just further information what I did as a test was:

1. Disabled and removed the fan from D9. Ran a print. Hot end and bed temperatures were correct for the first later and subsequent layers

2. Re attached the fan and put it on D9. Ran a print. Hot end and bed temps were correct for the first layer. SUBSEQUENT layers though the hot end was fine but the bed started to rise uncontrollably (from pronterface I couldn't do anything to disable it or change it) until the print finished.

So it's definitely and interaction with the fan attached. Had a friend (who is well versed in the reprap world) look at my slic3r code and said it was fine. He thinks I might have some arcing going on in the 5A terminal with the fan plugged in.

I'll try some of the suggestions you guys had. First off fresh copies of all the software sounds like a good approach after I double check the wiring (again )

Any other suggestions or comments are appreciated.

Thanks!

Edited 3 time(s). Last edit at 01/13/2013 11:10PM by bobby_rep.