How do I separate bed preheat from hotend preheat?

Bambu Lab Software Bambu Studio
1

I have been 3D printing for less than a week with my new A1 printer. So far prints have been amazing quality and fairly straightforward! I’m genuinely impressed!

One thing I would like to do though is separate the bed preheat from the hotend preheat.

We don’t have great power here, and get occasional 1-5 second power blips. So I bought a smaller battery backup unit rated for 350w. Unfortunately during the preheat I’ve measured the A1 to draw up to 361w… This causes a horrible screeching alarm (cannot disable this particular alarm) to sound while above this power draw. It happens twice at the start of a print for about 8 seconds each time.

I’ve seen some discussion about G-code commands and that I might be able to solve it by preheating the bed first, then the hotend. But I’m not sure how to implement this, let alone for every print moving forward.

If someone could walk me through this it would be appreciated!

2

You will need to insert a M400 between the nozzle (M104) and bed (M140) heating.

Here is a great reference for Bambu Specific Gcode.

M400 - Finish the current command
M400 S[t] Wait for last command to complete + delay in seconds
M400 P[t] Wait for last command to complete + delay in milliseconds
M400 U1 Wait until user presses ‘Resume’

In the Printer Settings/Machine gcode/Machine start G-code you need to insert a “M400 S15”. This will allow the nozzle to finish heating plus add 15 seconds before the bed starts heating. You don’t need the blank lines, they were only added for clarity. You could also switch the M104 and M140 lines if you want the bed to heat first.

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3

You could also use the built-in M190 or M109 to auto-pause until the bed or nozzle temperature is reached.

4

Thanks for the responses! I’ll give them a go!