Preheat acceleration - preheat bed and nozzle simultaneously

Marlin Firmware Service Feature Requests
1

When first loading a gcode project, the default preheat sequence is sequential… heat the bed until desired temperature, then heat the nozzle to desired temperature… This takes very long especially when printing with nylon or polycarbonate. Is it possible to preheat both bed and nozzle simultaneously to reduce time? This would be helpful during project debug. I understand I can set the bed and nozzle temperature manually, but the sequence remains the same.

Also, if we are using BLtouch with a 25 touch point cycle, why not allow this to begin during or near the end of the heating cycle to save another few minutes…

If this request has already been submitted and I didn’t see it, then please ignore.

Thx.

2

This is all controlled by the Start G-code in your slicer.

At this part, the printer just does what it is told. This could well include waiting for things to heat - but that’s what the slicer Start G-code has told it to do.

There’s some annotated Start G-code examples here that might help:
https://discourse.crc.id.au/t/improved-start-g-code-for-printers-cura-and-prusaslicer/55

3

Oh. Excellent. I did not realise that the slicer is controlling the steps prior to actual print. I’m new to g-code, but I will find the reference for this language and see if I can optimise the startup to do a few things simultaneously (ABL plus preheat)…hoping that the language support if… then, while…etc.