Speed up init time?
Hi,
I recently received my Core One and while I am pretty happy with the printer, there is one thing that really annoys me. And that is that it takes several minutes (up to 5 minutes) until the print starts. I am not entirely sure what the printer is actually doing that takes so long, but it seems that it first heats the nozzle to 150°C, then does some checks, then heats the nozzle to 170°C, followed by the bed probing and then finally heats the nozzle to 230°C, before it starts printing.
I tried to speed up things by pre-heating the printer in the LCD menu, but that didn't help that much. Compared to my MK3S, it takes ages until the print starts. For longer prints I do not really care, but since I am doing a lot of prototyping, it is a bit frustrating to wait ~5 minutes for the init, just to do a 10 minute print.
Is the Core One's init routine really that slow compared to the MK3S? Are there any settings (either on the printer or in the slicer) that I can change to improve that?
Thanks a lot!
Bernhard
RE: Speed up init time?
Unfortunately, I can't edit my initial post anymore, so I'll put the additional information here. It looks like that the printer spends ~1:45min cooling down the chamber temperature to 20°C. I guess that is because the nominal chamber temperature setting in the slicer is set to 20°C?
RE: Speed up init time?
Unfortunately, I can't edit my initial post anymore, so I'll put the additional information here. It looks like that the printer spends ~1:45min cooling down the chamber temperature to 20°C. I guess that is because the nominal chamber temperature setting in the slicer is set to 20°C?
That should not be the case, in my understanding of the chamber temperature settings. There is a "minimal" chamber temperature, to which the printer will heat the chamber before it starts a print. And there is the "nominal" temperature, which the printer aims to reach and maintain during the print -- but it should start the print right away, even if the nominal temperature has not been reached.
I am not aware of a mechanism where the printer defers a print until the temperature falls below a maximum value. Do others see the same? Is this a bug?
The process of heating the nozzle in multiple steps, which you describe in your first post, should not extend the overall initialization time significantly. The total time should be the sum of the time to heat to 230°C, the time for bed probing, and for any other checks. Whether the probing and checks are done before or after the heating, or halfway while heating is paused, should not matter.
RE: Speed up init time?
Ouch. So I was not hallucinating...
I noticed the very same phenomenon when printing PLA. As we work in a pretty comfortable workspace the temperature might have been a tad too high to the CORE One's liking for PLA. If this is designed to work like that I find it pretty good, actually.
RE: Speed up init time?
You didn't mention the "absorbing heat" step which also adds a couple of minutes. The XL does this with its much larger "multi-plate" bed, I guess Prusa feels like their smaller machines can use this as well. I wonder if the MK4S will get this at some point. Anyway, if I'm near the printer I usually skip this as I'm using one of those BIQU Cryogrip sheets that I assume don't need to "heat soak" to 60 C if they are already perfectly "sticky" at 45 C and the material isn't prone to warping. So far so good on that (but again this is only if I'm babysitting the print start).
RE: Speed up init time?
Thanks a lot to everybody who replied - very much appreciated!
I did a couple of more tests and this time the chamber temperature was too low and the printer spent a few minutes in the "absorbing heat" step. To me it looks like the print only starts if the chamber temperature is at exact 20°C. If it is too hot, it waits until it is cooled down, if it is too cold, it waits until it is heated up.
Unfortunately, I can't edit my initial post anymore, so I'll put the additional information here. It looks like that the printer spends ~1:45min cooling down the chamber temperature to 20°C. I guess that is because the nominal chamber temperature setting in the slicer is set to 20°C?
That should not be the case, in my understanding of the chamber temperature settings. There is a "minimal" chamber temperature, to which the printer will heat the chamber before it starts a print. And there is the "nominal" temperature, which the printer aims to reach and maintain during the print -- but it should start the print right away, even if the nominal temperature has not been reached.
That was also my understanding, but at least for me, it seems to behave differently 🤔. Just double checked my Slicer settings and the min. chamber temperature is set to "0". What I also find a bit surprising is, that while the chamber gets heated up/cooled down, the nozzle temperature is lowered to 150°C again. Not sure what's the purpose of this is (safety feature?), but this means that after the chamber reached the required temperature, the printer again waits until the nozzle is at 170°C.
Does anyone know if I can (temporarily) disable the heating/cooling process and start the print immediately? To me this still sounds like a bug, but before investigating that behavior further, I would really like to test if I can somehow abort the heating/cooling process and if the print then starts immediately.
RE: Speed up init time?
You didn't mention the "absorbing heat" step which also adds a couple of minutes. The XL does this with its much larger "multi-plate" bed, I guess Prusa feels like their smaller machines can use this as well. I wonder if the MK4S will get this at some point. Anyway, if I'm near the printer I usually skip this as I'm using one of those BIQU Cryogrip sheets that I assume don't need to "heat soak" to 60 C if they are already perfectly "sticky" at 45 C and the material isn't prone to warping. So far so good on that (but again this is only if I'm babysitting the print start).
Absorbing heat is intended for the steel frame and other metal components. Because steel slightly expands when it absorbs heat. That's the reason why Core One has all structural components from the steel. There are some other printer brands which mixed steel, aluminium, carbon, and other materials with different thermal properties for structural parts. And it affects precision, especially when they don't absorb heat before printing but during it.
I'm sometimes skip absorbing heat for PLA and PETG, because I have printer in heated room. But I can imagine it would be good for printing in cold environment. I definitely never skip it for ASA and other materials printed with chamber at high temperatures.
RE: Speed up init time?
Thanks for the info- I thought absorbing heat was just to "heat soak" the bed. I would think that the printer sucking air through it trying to keep the chamber temps down for a PLA print would keep a considerable amount of heat from being absorbed in the parts that aren't being actively heated (e.g. the bed and build plate, etc.).
You didn't mention the "absorbing heat" step which also adds a couple of minutes. The XL does this with its much larger "multi-plate" bed, I guess Prusa feels like their smaller machines can use this as well. I wonder if the MK4S will get this at some point. Anyway, if I'm near the printer I usually skip this as I'm using one of those BIQU Cryogrip sheets that I assume don't need to "heat soak" to 60 C if they are already perfectly "sticky" at 45 C and the material isn't prone to warping. So far so good on that (but again this is only if I'm babysitting the print start).
Absorbing heat is intended for the steel frame and other metal components. Because steel slightly expands when it absorbs heat. That's the reason why Core One has all structural components from the steel. There are some other printer brands which mixed steel, aluminium, carbon, and other materials with different thermal properties for structural parts. And it affects precision, especially when they don't absorb heat before printing but during it.
I'm sometimes skip absorbing heat for PLA and PETG, because I have printer in heated room. But I can imagine it would be good for printing in cold environment. I definitely never skip it for ASA and other materials printed with chamber at high temperatures.
RE: Speed up init time?
I too find it frustratingly slow when printing small 10 minute prototypes - it took me 45 minutes this morning to print two 10 minute prints with a filament change.
I'm finding that the calibration is also adding unnecessary time to the procedures, like changing the filament.
I noticed that I can change the temperature of the chamber to 40ºc - this stops the fans from trying to cool it to 20 all the time - my room temperature is higher than 20 so the fans would never have cooled it.
RE: Speed up init time?
But how do you turn off the "absorbing heat"? 6.1 in the CORE ONE Handbook tells us that it speeds things up, but not how to do it, and this bear of little brain has not yet found the switch.
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RE: Speed up init time?
But how do you turn off the "absorbing heat"? 6.1 in the CORE ONE Handbook tells us that it speeds things up, but not how to do it, and this bear of little brain has not yet found the switch.
I don't think you can disable it in advance. But you can skip it when it happens, if you are in front of the printer. (Or have remote access via Prusa Connect, I assume.)
RE: Speed up init time?
But how do you turn off the "absorbing heat"? 6.1 in the CORE ONE Handbook tells us that it speeds things up, but not how to do it, and this bear of little brain has not yet found the switch.
I don't think you can disable it in advance. But you can skip it when it happens, if you are in front of the printer. (Or have remote access via Prusa Connect, I assume.)
You can. You just edit the custom gcode in your slicer.
G29 G ; absorb heat
RE: Speed up init time?
I now see that while absorbing heat there is an option on the screen to SKIP.
But why doesn't the Handbook say so? I've been overlooking it for six weeks.
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RE: Speed up init time?
I noticed that I can change the temperature of the chamber to 40ºc - this stops the fans from trying to cool it to 20 all the time - my room temperature is higher than 20 so the fans would never have cooled it.
I don't think this is a good idea if you are printing PLA. When starting out with the Core One, I turned off the noisy chamber fans, but with a bit longer prints that resulted in a clogged hotend several times caused by heat creep. That's why most printer manufacturers tell you to keep the enclosure open when printing PLA. Prusa has solved this by having the top vents and chamber fans instead. So either keep the fans on or open the enclosure door. I haven't had a clog since I started doing that.
RE: Speed up init time?
This has to be fixed, at least so the absorbing time can be skipped via prusa connect. Atm for small parts i think my mk3 would be faster in total, since i could just slap in the se and go, if i knew i didnt have to preheat the enclosure.
RE: Speed up init time?
You can. You just edit the custom gcode in your slicer.
G29 G ; absorb heat
And if you're going to do this, then you might as well comment out the idle temperature setting step as well, since there's no need for the nozzle to cool down and then immediately reheat.
; M104 T{initial_tool} S{if is_nil(idle_temperature[initial_tool])}100{else}{idle_temperature[initial_tool]}{endif}
I've made both of these changes and saved them as a new version of the preset, and called it "Prusa CORE One HF0.4 nozzle - 'hot start'", and I use this if I know that my printer is already hot, for instance.