Error report: Cura software 4.10.0

[GregValiant 1,317]

"It’s not a software problem either apparently. It’s just physics."

 

Just to be clear - you've changed your opinion and it is not a Cura problem?

 

I am attaching a version of your original file that I post-processed to alter all Z-Hops from a height of 0.6 to 0.  It is not a re-slice, but rather your file with no Z-Hops.  If you are right and it's "just physics" then the problem will still occur.

 

This is the relevant area of the gcode as read into AutoCad.  It showed that there are no missing layers.

NoHop.gcode

[Torgeir 248]

Hi @ZachariahS,

First, -what you observed -and corrected by turning off "combing" (before slicing) is possible..

I'm just focusing, -what is going on here.

Lets look what kind of improvement Cura does when using "combing" vs., turning it off.

 

The wording below, is just in the first part of the "official description" of the combing mode under "Travel Setting" in Cura.:

 

Combing will reduce the chance of defects on outer surfaces of the print by recalculating all nozzle travel moves to stay within the perimeter of the print. This results in greater travel distances, but with a reduced need for material retraction.

If combing is disabled, the material will retract and the print head will move in a straight line to the next point.

 

Here you'll find the full description:

https://support.ultimaker.com/hc/en-us/articles/360012611299-Travel-settings

 

Here is a picture of your two object to be compared between the "two" settings.

 

 

The picture above shows "two sessions" of Cura 4.10.0 running simultaneous in Windows 10.

In the left side, combing is off and in the right combing is on.

Using the calculated time in the gcode files, give:  3h & 53 min (no comb) -and 3h & 42 (with comb).

(The printing pattern inside the object is all the same in both situations.)

 

So, travel, retraction and time are the "only" difference in between those two sliced object.

 

So the question is; how can this "little" difference destroy my print?

 

Let's do some more analysis using Cura, this time for the speed;

 

 

The speed selected here is;

Printing Speed         : 70 mm/s

Infill Speed               : 90 mm/s (brown)

Wall Speed               : 35 mm/s (blue)

Outer Wall Speed   : 35 mm/s (blue)

Inner Wall Speed    : 60 mm/s (green)

Top/Bottom Speed : 60 mm/s (green)

 

The temperature settings are: Bed 55 deg.Celsius and Extruder 200 deg. Celsius.

 

I've had a good look at your pictures and been reading the observations you recorded:

 

 

L is low temp and h is high temp.  (Meaning not very Low and not very high -but kind of outside norm printing temperature.)

I can see that you are strugeling with both over and under temperature..?

Your nozzle temperature must fluctuate some, right? Or maybe no?

 

Next picture:

 

 

Using combing, make the printer "demand" for "more and less" filament at a little higher rate, but lack of heat energy bring down the temperature at the nozzle and when there is less demand the heat climb..

This is a classic example of lack of heat transfer!

 

If your nozzle temperature do not fluctuate much or actually is stable, -the above is the problem.

 

I'll think this is the main problem you've being fighting for too long.

 

------------------------------

 

When printing without using Combing, the "constant" demand of feed is reduced and the temperature become more "normal" stable for this object printing with this speed..

 

Also, keep in mind, combing is not meant to be used on all kind of object.

 

-------------------------------

 

But your original problem(s) are still there.

 

(I'll guess you have an aluminum heat block with brass nozzle, -do you have a picture of it?)

 

Well, this is just my theory about your problem

 

Good luck and happy printing.

Torgeir

 

 

 

Edited July 18, 2021 by Torgeir
Text err.

[gr5 2,192]

On 7/18/2021 at 3:36 PM, Torgeir said:

Using combing, make the printer "demand" for "more and less" filament at a little higher rate, but lack of heat energy bring down the temperature at the nozzle and when there is less demand the heat climb..

This is a classic example of lack of heat transfer!

@Torgeir I don't understand what you are saying.  To review, things are better when combing is turned off (more retractions happening, more hops happening).

 

Are you saying that because the print job is slightly slower (with combing off) that the printer has more time to keep the nozzle hot?  That seems unlikely - the difference in print speed is pretty small (11 minutes out of almost 4 hours).

 

 

[Torgeir 248]

Hi @gr5 and @ZachariahS,

 

Yes, exactly, all this extra retractions pull back the filament and this make the temperature just a little higher.

When you study the lines in there, there is a "tiny" balance between hot and cold.

In order to "make" this situation better one use to increase the temperature, but this makes it harder to control

and hold a steady temperature.

 

If you print with less speed and flow the printing will be good, but as soon you try to increase the speed for bigger project this issue will occur.

 

In the picture with combing off.

When we look at the objects wall's, it looks quite "normal" -cause there is a good balance between the speed selected and the amount of energy this heat block can deliver. The top floor inside is also kind of good, but have sign of low temperature.

Moreover, if you look at the top of the object we still can see the sign of "too low temp" as the lines is not adhered together as  thy normally should be, but here we see no sign of over temperature as we saw with combing.

 

 

The connection between the heater and the heat block is good and so is the thermistors connection to the block.

So temperature at the block is good and under control by the main "PCB".

 

However, the thermal connection between the block and the nozzle are not!

 

So, if your nozzle has a little play -all the way (during installing into the heat block) until you tight it up, -your nozzle lost about half of its theoretical heat transfer capacity.This because only one half of the coils are effective and the other half have "air pockets".

If this happen, -the temperature will start decreasing at a given speed.

 

I've asked some questions about the printers nozzle temperature during printing, that's important for what to do.

 

As we never heard anything about the temperature, -the above might be the problem causing this issue.

 

Just for the record.

I've tried to reduce the speed using "combing" on, to the same printing time as -without "combing", time h 3:53.

Reduced printing speed from (70 to 50) mm/s and infill speed from (90 to 50) mm/s gave time h 3:53.

Changing the speeds like this, Cura may change other as well, -if -do not adjust!

But what effect this has on the print quality, sure I do not know..

Nothing else was changed.

 

Hope this clear up the issue.

 

To go on further, if necessary, we'll need some feedback here.

 

Thanks

Torgeir

 

Edited July 20, 2021 by Torgeir
Text error.

[Torgeir 248]

Hi @gr5 and @ZachariahS,

 

I just made a little drawing of Cut Section of nozzle with heath block and coupler.

This to illustrate the problem with a short nozzle with limited heat transfer due to "tread play", or printing to fast in general, both with increased temperature in order to solve the problem.

As long as we're printing a round object this "can" work, however if we print an object with speed changes etc. "over temperature" will ruin your print at places.

 

Here is the drawing, somewhat exaggerated to clarify the problem.

 

 

Here is such a setup, bought in Asia 2018. (Having the above issues).

 

 

If you have such a nozzle, it is important to screw the nozzle all the way to the flange stop against the heat block.

You may also use heat sink compound to increase/improve the heath transfer to the nozzle.

 

Thanks

Torgeir