I have trouble printing particular models with scaffold for example this wheel of a T34 RC tank there are hidden cavities underneat the wheel that need scaffold, then its solid XT fo 15 layers and then scaffold is needed again. The main problem I have is the fact that scaffold clogs up when its sitting idle for too long in the extruder, this is mentioned in the data in the site so fair enough. I have now come up with the solution to turn off the extruder when its not needed for a while (by checking the layers manually and adding setpoints with 0°C at certain layers) I then add folowing line to the tool change script to turn it on again when the extruder is needed (after purging but before priming) {IF NEWTOOL=1}M109 S215 T1 My question is this: is there a certain temperature where scaffold can sit idle for much longer without having to turn off the extruder completly, for example 150 °C ? @Greg Holloway or @Sanjay you guys have any suggestions ? I do realize this may affect print time allot but if i can only lower it, it would speed things up again
Marlin does not support this syntax, the command is executed though... M109 is executed for the selected extruder, you cannot say T1 in that command, it just won't do that if T0 was selected previously... So what you have to do is for example to heat up again: Code: {IF NEWTOOL=1}T1 {IF NEWTOOL=1}M109 S190 or Code: {IF OLDTOOL=1}T1 {IF OLDTOOL=1}M104 S0 to cool down... Gotta correct myself. It is not really documented. You find nothing in the Gcode docs or in the Marlin help but you are right this should work... I had a look in the code base and though the documentation in the code does say nothing about if that syntax is valid, it is unfortunately...
If all else fails, how about placing a second object / process alongside that's just solid scaffold so a little is extruded every layer?
find where the last layer of scaffold is and then insert an M104 T0 S0 to turn off the hotend. It's a bit of a hack but it's what I do. Do not leave scaffold at temperature for long (15 minutes) as it degrades and will block the nozzle!
Ok so whats the safe temperature than i can keep the filament on while its idle and before the degrading starts
Yeah I do the same but I just use the temp control in S3D. I slice and find the layer where no support is printed and add a control point to that extruders temp. But the question was how to do in mid print if there are areas you need no supports for a lot of layers and then again support is needed and if you have to cool down completely or maybe one to 150 or 100 degrees to have the heat up faster? I would not do this in tool change because then it happens every tool change. I didn't have such a part yet. But thinking of it and the restrictions of S3D I would probably edit manually the file and cools down.
These are my temp settings for turning off the extruder when needed The extruder will be switched on again by M109 command in tool change script as I posted above
Ahh cool yeah didn't think about that way... Creative... So you just set the temp with M109 in the tool change, the cool down you set only on one specific layer... Cool, have to write that in my docs
ran into a small problem S3D ignored the temp setting on layer 50 because it was the same as layer 17, so I changed its temperature to 2 so S3D wouldn't ignore it, double checked in the gcode doing a new print right now, i'll know the results in an hour
