[Closed] Change temperature presets in preheat?  

Re: Change temperature presets in preheat?

It's hardwired in firmware.

Re: Change temperature presets in preheat?

You will have to compile your own firmware to change this. First, compile the firmware & ensure that you can flash it. Once you are past that phase, edit "Configuration_prusa.h"

Change these lines in the file to match your needs:

#define PLA_PREHEAT_HOTEND_TEMP 215
#define PLA_PREHEAT_HPB_TEMP 55

Then, recompile, flash & check again.

Re: Change temperature presets in preheat?

There is another option, to use a Raspberry Pi and OctoPi software.

Here, you can easily define presets for preheat managed by OctoPrint.

Re: Change temperature presets in preheat?

Thanks for your feedback, I'm using OctoPrint already, but I feel that I'm somehow too dependant on it (in terms of temperature profiles per filament at least). Currently I'm booting my Notebook to preheat via OctoPrint, which seems a bit odd. I'd love to be able to configure custom temperature profiles on the Prusa itself.

Of course recompiling the firmware is not the most user friendly option. Perhaps this is something for the improvements subforum? Only if I'm not the only one wishing for such a feature.

Re: Change temperature presets in preheat?

Hi Oliver,

I do not really understand the need for this feature, I mean in which situation do you need it ?

If you want to preheat before printing, it should be the job of the preambule of the gcode file generated by the slicer, which should preheat before printing to the right temperature, you can also tweak this part to increase a bit the bed temperature to give time to it to be fully heated everywhere.
And regarding the standard workflow for printing, you have to start the computer, slice the object, send it to OctoPrint or to the SDcard, then the laptop is allready

If you want to preheat for others usage, like unloading or loading filament, well, this can be done via the Support -> Temperature -> BEd temp (or nozzle temp) manually, which I recon is a bit less convenient than a predefined profile.

But maybe I did not understand something ?

Re: Change temperature presets in preheat?

I'd certainly like to change these temperatures without a recompile. Since I print almost exclusively with PLA on a cold bed I will be doing a recompile to change the preset for that. Otherwise, it seems that both the load and unload functions could be smarter about heating the head if it wasn't already hot. It might have to ask for the filament type first but that should be easy enough. There could also be a default filament type selection.

Re: Change temperature presets in preheat?

I wasn't aware this topic was already under discussion already...

My need to be able to define those temperatures is as follows:

I definitely do not like to preheat the nozzle to final temperature, as the filament then simply gets cooked without getting extruded. Wait some time in this condition and you'll have a clogged nozzle.
This is why I changed the start g-code to heat first the bed to temperature. Then the nozzle gets heated to 160°C. This is to have any remains in the nozzle soft, but not melted yet. Then calibration gets done. And only then the nozzle gets heated to first layer temperature.
Never had a partially or even fully clogged nozzle ever since...
Thus, it would be super-duper-dandy-handy for me, if I could change the presets to include a nozzle of 160.
That way, I could switch the printer on and have it preheat, while I prep and load the g-code to the sd-card.
If I want to preheat now, I first select the preheat-profile, then I need to enter the settings to amend the nozzle-temperature to 160. Every - beeping - time...

Maybe it's not something required from the developer's side as all the functionality is there. Awkward, tedious, time-consuming, but it's there.
But from a user's point-of-view, it would definitely make the unit more user-friendly.

Maybe at least one custom profile that can be edited by the user...?
That would be one more profile in the menu with the title "CUST" for custom.
And below the Cooldown there would be another line with title "EDIT CUSTOM" that opens a sub-menu which lets you edit the custom-profile.
That way, one could create a custom preheat-profile, which heats everything to the lowest of the possible settings. Once the printer starts, it only needs to heat the difference which is faster than heating from room-temperature. Especially the heat-bed when going commando with ABS...
Should not be too complicated from a programming point-of-view, but what about available memory in the chip?

I have to say - since this is usually a one-time-occurence when one does change those figures from the preheat-profiles, the way of editing the figures in the firmware, compile and flash it seems somewhat most efficient.
But we might need a little how-to: Which software for compiling, how to test, etc.

These are my five cents...

Re: Change temperature presets in preheat?

Would it help if you write a gcode file that does nothing but set the preheat temperatures you want. Save it to your sd card. Run it from the LCD interface. When you are ready to print use LCD panel stop print to cancel the running gcode and then select your print file.