Does RRF have "look ahead"? Or will it?

3DPMicro · 13 Mar 2021, 20:22

Perhaps not the right term but I did a search and didnt find specifically what I was looking for. An example of what I mean would be to preheat and purge the parked standby extruder while the other is printing

HebigT · 14 Mar 2021, 03:39

@3DPMicro Hey, I don't think so, but that would be a nice feature for tool-changers/Dual extruders.

Here's a post-processor someone made for the E3D TC that adds that functionality:

https://github.com/mkudzia84/toolchanger-pspp

jens55 · 14 Mar 2021, 03:41

The specific function you mentioned is in fact incorporated. Not the purging part but yes, the currently unused extruder heats up based on a configuration option and also cools down based on another configuration option.

3DPMicro · 14 Mar 2021, 04:58

@HebigT said in Does RRF have "look ahead"? Or will it?:

@3DPMicro Hey, I don't think so, but that would be a nice feature for tool-changers/Dual extruders.

Here's a post-processor someone made for the E3D TC that adds that functionality:

https://github.com/mkudzia84/toolchanger-pspp

I am building something kinda like an IDEX. Definitely look in to that to see if or how it can be modified. No prime towers though

@jens55 said in Does RRF have "look ahead"? Or will it?:

The specific function you mentioned is in fact incorporated. Not the purging part but yes, the currently unused extruder heats up based on a configuration option and also cools down based on another configuration option.

I must have missed that.

Thanks guys

o_lampe · 14 Mar 2021, 07:51

@jens55
Do you talk about standby temperature? I'm sure @3DPMicro knows about that. Question is, when does it change between working and standby.
With the known PID tuning parameters it should be possible to estimate the re-heating time and compare that with the remaining printduration before the toolchange is due.
I'm not sure if it's practical to do that during print, but while uploading to DWC or SBC would be an option. "Just" have to add a pre-processing app that fits the heating commands into the gcode

jens55 · 14 Mar 2021, 08:04

I sit corrected .... the feature I am talking about is in Cura and not in Duet. Furthermore, it is in an add-on to Cura.
Specifically it is an add-on for printer settings (and I installed it years ago so don't ask me how to do it). It has settings for 'heat up speed' and 'cool down speed' in degrees C per second. Given that information, for dual (or multi) extruder machines, the slicer can determine at what time to call for heat-up of the currently unused tool so that it is at or close to operating temperature when the new tool is called for. Also, it allows the current extruder to start cooling down to standby temperature before it is finished.
I am pretty sure that the calculations involve temperature minimum settings in the slicer as to what temperature is hot enough to start printing or so that it doesn't cool down below minimum temperature before stopping to print with the tool.
The setting up of this was kinda hit and miss when I tried it but it definitely reduced wait times during tool changes.

Sorry to not clarify this before.

Edit .... I am assuming that extruder temperatures and standby temperatures of all extruders have been set. The slicer will call for the standby nozzle to heat up before the nozzle is actually used. The 'when' is based on your heat-up speed and the setting of what the minimum temperature should be before starting to print.
The same thing happens on cool-down of the currently in-use tool. The cool-down happens before the current nozzle has stopped printing. Cool down is not that important because it happens quickly but heating up the new nozzle in advance can be a big time saver.