Dual Extrusion: Change Temperature upon tool change

Hi Chaps,

I recently finished my new printer with dual extrusion capability. It is now well calibrated and works good so far. There is only one drawback: If I use two different coloured materials, the inactive extruder keeps its original temperature and little bits of material drop out the extruder even though I do a major retract upon extruder change.

Now my Idea is to change the temperature of the extruder as long as it is inactive.
I read that it is possible in slic3r to have variables (but I am not too much into programming... so help would be apprechiated!!!).

--> my idea is to do the following upon tool change:

On beginning of the Print I preheat both extruders to target temperature. As soon as the extruder is changed, the previous extruder should be cooled down by 25°C (or so) from its original temperature (I would like to go from the initial target temperature and not work with absolute temperatures, since depending on the material I work with different temperatures). The next extruder (which shall be used to print the next g-code) is heatet up by 25°C from idle temperature (where it was set before...) and as soon as it is ready to print, it should go on.

I try some code... but as mentioned I am a greenhorn on coding... perhaps someone can help...?!

[[previous_extruder==0]]
M104 Sinitial-25°C T0
M104 Sback to initial T1
M109 Swait to reach initial T1
[[/previous_extruder==0]] 
[[previous_extruder==1]] 
M104 Sinitial-25°C T1
M104 Sback to initial T0
M109 Swait to reach initial T0
[[/previous_extruder==1]]

Depending on the active extruder I would - with other words - like to cool down the inactive extruder by a certain amount and reheat the next extruder and wait for it to be on temperature before continuing printing...

Any ideas how this can be handeled?

Thank you guys!
Best Regards

Sebastian

Edited 1 time(s). Last edit at 02/07/2014 07:48AM by Elk.

Supposedly, slicer allows you to specify something like:

M104 S[temperature_[next_extruder]]

in your tool change g code, but I've never been able to get it to work - at least not in linux. When I use that statement, I end up with exactly that statement in my output - no substitution is done. On the other hand, I CAN use something like [temperature_1] and it substitutes correctly, but however that doesn't solve the original problem.

I have yet to be able to do anything with my dual extrusion printer because I do not feel that the software is quite ready yet. Cura provides some support, such as a wipe pillar, but it has some issues as well. RIght now the only way I can print dual color is to modify the file manually.

hey all

after quite a bit of testing I came to the solution to print at the lowest possible temperature, where extrusion is still fine to prevent ooze.
this seems to work quite good.
I also tried the built-in lowering of temperature... but the breaks are still too long and some of the materials did not like it to bee cooled and re-warmed (they stuck in the extruder after some cycles...).

regards
sebastian