Eliminate pauses between "one-at-a-time" objects

breathless19 · May 16, 2023

Cura 5.3.1

I have a bulk layout of identical very small objects that need to have a temperature gradient through each object (the gradient being identical in each object). I'm printing with TPU.

The first layer needs to be hot as possible, subsequent layers for most of the remainder of the print need to be 220, then there is a little stem at the top of the print that will not print properly at all unless the temperature is dramatically lower (around 200, and not much more).

To achieve this perfectly with a single piece, all I have to do is set my printing temperature to 220, and my "Small Layer Printing Temperature" to 200. This way, as soon as it approaches the little stem, it cools down quick enough to print that section at around 200. Perfect!

However, when I add more pieces to the mix and print "one-at-a-time", of course I get pausing between the objects - since it has to preheat to go back to 220 before it will start its print of the next object. This is of course unacceptable because the extruder just sits there drooling and ruins all subsequent pieces while its waiting to get to temperature.

So, I compromise on my initial temperature, and change that to 200. So, my ending temperature is 200, and my "printing temperature initial layer" is 200. It still pauses! But strangely enough, not all the time! Right after finishing the first object at 200, it seems to very temporarily ignore my starting temperature by several degrees sometimes and goes up past 210 right after finishing the last layer of the first print, which of course then has to come back down before it will start to print the next object. I've already calibrated my hot end.

It would be really nice if there was an option under "one-at-a-time" that allowed for "bypass pausing between objects". Short of that however, how can I make Cura not EVER pause between objects regardless of temperatures? This would solve my dilemma since I can technically compromise on the starting temperature of the first layer, but likely wouldn't really have to because by the time the extruder gets to the first layer of the next object, it will be at or relatively close to 220 because of how fast it heats up.

Thanks for your help!

GregValiant · May 16, 2023

Well, there is no such thing as a "Pause Between Objects". It could be an M109 which would wait for the temperature. At about 2°/sec it will be a 10 second wait for the temperature to raise 20°. M109 can inflict it's own additional 10 second wait (but it doesn't always do that as it is dependent on the printer-processor clock cycle).

BTW In the project I made up I'm not getting temperature changes after the first model and I think I should be.

Use the "File | Save Project" command and post the 3mf file here.

Post one of those gcode files that you don't like and I'll take a look at that as well. I've been working on post-processors for "One at a Time" projects but I haven't gotten to temperature changes yet.

In regards to the temperature over-shooting, that's on your printer. It's usually only 1 or 2 degrees and then it settles down at the set point. I would think nearly all of them do that to a lesser or greater extent. My printer is also calibrated and it over-shoots on temperature change. It's over-shoots worse on cooling than on heating. Part of it may be the response time of the thermocouple/thermistor.

Edited May 16, 2023 by GregValiant