Cura 13.11.2 ignores Minimal Layer Time

[peetersm 124]

I have a print that ends in a small diameter peak and need to slow down the print or the whole thing is a melty blob. I have tried using 2 and 5 minimal layer time, but I do not see the print slowing at all, it just keeps going at the normal speed.

My expectation would be that it would slow down to the point of only printing 1-layer/Minimal layer time. So if the setting is 2 secs the z-axis should only advance every 2 seconds.

Has anyone else see this, or is there another setting I need to check?

 

[cor-kiekens 0]

There is also a setting "min speed". Regardless of how slow your printer wants to move to stay above the desired min layer time, it won't move slower than this min speed. But lowering this"min speed" even more than standard setting I'd not really recommended. This will transfer so much heat from the slow moving head into your print that you will get blobs etc. try printing 2 or more objects at once... Be sure to set your gantry height at 0. (found in printer settings)

[peetersm 124]

thanks for the input, I did not notice the min speed.

So my min speed is set to 10mm/sec, ganrty=0. I am not sure it's slowing to 10mm/sec but I will watch is closely to see if this is the limit I am reaching. (normal print speed 70mm/sec)

Multiple objects might be the way I need to go.

 

[coen 11]

What would really help for these sharp tips to print correctly is if the printhead would retract and move away a little, so that no longer the hot-end is touching (and heating) the model, and the print time will actually result in cool-down time. Preferrably the head is moved a little away from the model with the fan on, to let the fan cool the model during the ' minimal layer time' .

Can I add this feature request somewhere?

 

[illuminarti 18]

Coen, it's already there. Expert -> Open Expert Settings -> Cool Head Lift

 

[cor-kiekens 0]

Iluminarti, whats your personal experience with this function...sounds to me like this"cool head lift" could also cause a lot of oozing and pressure loss in the hotend...

[illuminarti 18]

I haven't used it much... but I did use it for the owl print I did:

There was a bit of oozing during the pauses, which resulted in some junk getting dragged back onto the outside of the ear tips, but it was easy to clean up. I think you'd only want to use it with relatively slow volume/second prints, but I do think it has potential.

 

[cor-kiekens 0]

Thanks...

[coen 11]

Coen, it's already there. Expert -> Open Expert Settings -> Cool Head Lift

 

Ha, never noticed that one! Great, I will give it a try.

 

[gr5 2,167]

I don't like cool head lift - it tends to make vertical strings. I wish there was a sideways head pause. The best looking result solution is to print a tower (or print two items) next to your print.

I set my minimum speed to 0. Never had a problem with it. I think it was more for the old ultimaker V1 print head which was updated over a year ago.

 

[peetersm 124]

thanks all. for sure this is not a bug.

it is me trying to understand the settings and getting them right for this print. I will start a new thread describing my diffculty with printing this model under the "Questions & Answers (Help Each Other)" forum. thanks again for the great input, and pointing me in the right direction.

 

[illuminarti 18]

Post pictures. That's the best way to get useful advice.

 

[yellowshark 153]

Personally I use all, or a combination of (all depends on the size and geometry)

• print two off the pieces concurrently (same as using a tower but can be more productive)
  
• set minimum layer time to 10 secs (I know George likes to go lower but it suits me).
  
• minimum speed to 10mm/s
  
• also I have been using z-lift in recent months which has been effective. Yes you can suffer from oozing but with a little practice you can wipe that away just before the head moves back to print the next layer
  
• fans 100%