Supramaker
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Posts posted by Supramaker
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13 hours ago, GregValiant said:
We know where the nozzle is, and where it's going to, so it could be post processed to produce this...
G1 X132.477 Y129.811 E1854.34812 >> Last extrusion before travel
G1 F2100 E1847.34812 >> Retract
;G1 F600 Z16.0>> Lose the Z-hopG1 F7200 X137.951 Y129.622 Z16.0 >> Add this line. The X Y are the mid-point of the original destination line.
G0 F7200 X143.424 Y129.432 Z15.0 >> Original destination but now the Z is the drop-to height.
;G1 F600 Z15>> Lose the Z-dropLooking thoroughly at your changes, this exactly what the linked diagonal z hop does (in the so called "traditional" version). Save your time and let the online service process your gcode files.
But to avoid stringing, the "alternate" version is better. Let us know how it goes for you if you happen to use that service.
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6 hours ago, Slashee_the_Cow said:
You can use it in almost any situation where you'd use PLA, the main differences are that stringing is unavoidable but it's less brittle than PLA and won't melt if you leave it in a car parked in the sun.
Yes but instead of PLA I am switching to PVB. You can easily smooth it with alcohol and it is getting cheaper (last role I bought was for 28 €).
One more hint regarding stringing: allegedly fine stringing can be avoided by using a bit of olive oil. Im my case, silicon oil has not helped (but not sure how stringing would be without, have not checked systematically).
So for decorative things I am going to use PVB. For other things most probably PCTG, but in the long run something else like PC (I need to upgrade the printer first, that's a project by itself)
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20 minutes ago, GregValiant said:
That is doable without too much work.
Well, I am impressed. For me that is not the general method. I would manually fiddle with the gcode file perhaps in an exceptional case.
20 minutes ago, GregValiant said:Trying to increment the Z-hop across 1/2 those lines and then incrementing it back down across the next 1/2 would be a PITA.
You defeated yourself 🙂
I will take a look at "AlterZhop" - later. It is about 03:00 hours in my time zone. Thanks for that.
I actually do not need this hassle. Just switching to Orcaslicer solves this problem. But Orcaslicer sucks at times, so I want to keep a prepared working environment in Cura.
I wonder why you mostly print PETG. I am enthusiastic about printing intricated things and PETG is not suitable for that. I am about to ditch that material. Have you tried PCTG? I have a role waiting for me...
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I can confirm that "Diagonal Z hop" works for my purpose, although it should not be used together with postprocessing scripts that manipulate retractions and the like. In special cases I would definitely go to https://teachingtechyt.github.io/diagonalZhop.html
I am reluctant to use an online service for everyday prints and would prefer a postprocessor script compatible with Cura. After some research I got the impression that there is a wide conciousness about this z-hop/stringing question and many people have developed solutions and so I hope to find one.
Your turn.
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I found this:
I will give it a try, although I would prefer a postprocessor script that runs automagically after slicing in Cura.
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While coping with PETG stringing, I printed dozens of parts and spent days trying to get rid of it.
I optimized certain settings like coasting (reduces pressure at the end of the loop), wiping (cleans excess material from the nozzle), retract priming (restores the missing material due to coasting, so avoiding underextrusion), increasing travel speed (to decrease the time for oozing), drying the role and printing inside-to-outside. Decreasing the temperature is not an option for me. It turns out, in my long Bowden setup retraction length and speed are not the game changing ways to tackle this question. Nonethe less, that all seems to work quite well.
But:
While stringing has been reduced, it is still there. Depending on the model, I am not always able to print really clean pieces.
I did not give up and decided to clear the question, whether PETG is a viable material as a PLA replacement for general use (to put it simple).
What I found:
After all my optimizations, if I print a challenging piece (just to test) there are two prominent stringing patterns that I could recognize:
Either there are no whisps at all; in this case, material gets accumulated at the spot where the travel movements cross the next border (typically when moving between towers). If the travel movement passes the same point in the border, the hanging tiny bit of molten filament gets caught there and accumulates. One gets stronger pieces of debris attached to the surface, which tend to stick to the nozzle and move around. The solution to this: Let the nozzle fly to the target above the current height - nothing else than a z hop movement.
Indeed, when z hop is used, the nozzle lands to the target spot at a height where the oozed material won't touch the border. That works perfectly at the end of the travel move and there is no accumulation anymore. The problem is, that at the beginning of the travel move (when retraction takes place and the z hop is done), stringing occurs. It is minimal and very fine, but with repetitive travel paths one gets a beautiful curtain of dense whisps. I know that they can be burned, but that is not "clean", scars are still visible. Apparently, no reasonable retraction length will completely avoid stringing (at least in my case).
So I came up with the idea of the delayed z hop. What I mean: the actual lifting should not take place vertically at the beginning of the travel move.
Have you tried to rip the PETG filament oozing out from the nozzle with your fingers or twizzers? If you pull it downwards, it just streches endless and it is a mess as you get fine sticky filament everywhere. But if you rip it *sidewards*, the nozzle will be immediately clean at that moment. A normal z hop in Cura is like ripping the filament downwards - that does not work well and you get stringing. So what I want is a travel movement that begins sidewards after retraction (as usual), but also executes a z hop later, before crossing the next border. Well, a sloped z hop would probably be fine if the movement is not too steep. This way, no whisps are built at the beginning of the travel, and no material get caught at the next crossed border. A perfect solution.
Cura is not able to do that kind of thing (in contrary to Orcaslicer, which has a sloped z hop - for the time being, I can print PETG to my full satisfaction only with Orcaslicer).
But perhaps there is some postprocessing script that just converts a normal z hop into a delayed one (or to a sloped one) after retractions. I could not find anything.
I am a bit surprised since this retraction saga keeps annoying 3d printing hobbyists since ancient times. I can rule out that I discovered anything new in my analysis - so why has a solution to such a basic problem not yet been implemented? Just wondering.
Any idea or proposition will be welcomed.
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After many changes and experiments, I can confirm that higher retraction speeds are possible.
I cannot identify the exact step that solved the problem.
This issue can be regarded as closed.
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Thank you for guiding me to the retraction settings 🙂
There is no other place to do it...
2 hours ago, Slashee_the_Cow said:You also run the risk of the build plate (or print head, depending on what type of printer you have) slipping a step or two resulting in layer shift.
Yes I know this problem, it has happened to me. That is why I am working on an automatic calibration of stepper skipping, that is, finding the limits to avoid layer shifting. But in most cases, my belt was not tightened strong enough, so I got a belt tension gauge and since then no more layer shifting. I have also implemented a detection of stepper skips (using RRF) based on measurement of motor voltage/current.
At this very moment I am printing using RetractContinue, which is a bless, but is causing underextrusion after a number of retractions... still investigating.
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I included all speed settings to avoid questions. I thought the retraction speed is related to *filament* movement, not travel.
I do have the Autotowers plugin, that was how I noticed the limitation.
8 hours ago, Slashee_the_Cow said:Also retraction going up to 100mm/s sounds sort of overkill to me - I realise my Ender-3 V3 SE is hardly a high end printer but its direct drive extruder maxes out at 60mm/s and even then I never go over 45mm/s.
I was expecting that reaction. Yes, in general 80 mm/sec retraction is too high.
But I am not a general 🙂
My BMG geared extruder achieves 120 mm/s - but if repeating retractions in a row, I would risk slipping now and then.
I just found that in a specific case related to PETG and intricated models in a long Bowden setup the most effective way to avoid accumulation of oozed material in the travel path is to make the transition time between extrusions as short as possible. That means for travel movements: high jerk values (helps on short distances), high accelerations and high speed. The problem is, if you want a really clean printed part using PETG, and not to print it too slow, then fast travel movements are not enough in this case (direct drive might be different). The time spent while retracting also plays a role and it should be kept as short as possible - because even while retracting, material keeps flowing. Keeping a short time also implies *short* retraction lengths - the opposite as generally assumed. It is like paddling against the current in a river - you keep moving in the wrong direction, just a bit slower.
This is not just a theory. With this approach I am quite succesfull using PETG, but currently I have to use Orca for that because I have fast retractions then.
You should look at the nozzle after a print job using PETG is finished or just interrupting the job mid print - the filament flows and flows and flows by itself. How long would you have to retract to avoid that? Coping with this pressure is a challenge that demands non-conventional thinking. It makes no sense to retract longer if the the filament pressure overcompensates that movement at the same time.
I advice to open one's mind to information diverging from the "main stream", based on own experienced facts. I have gathered dozens of printed parts ("facts") and spent days (actually weeks) while playing with settings to avoid stringing. This is very specific to PETG in a long bowden system. Want more hassle? Use TPU. Or anything compressible.
But we are digressing. Still, no progress in my question: why is my retraction speed limited??
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I tried to use a retraction tower for a new filament material using retraction speed as height modifier, and while doing so, I noticed that the maximum retraction speed at the top of the tower (80 mm/sec) never gets reached (I estimate it gets at 40 mm/sec max).
I checked my settings and could not find where this limit is set.
To verify, I did the same using Orcaslicer - there I went up to 100 mm/sec (just to test the limits). This means that the limit is not due to any firmware setting.
I need your help trying to identify where this limit is set in Cura 5.7. These are my pertinent settings:
I don't see where the limitation of filament speed comes from. The settings are similar in Orca.
Is there a json file or something with "buried" settings that I need to edit manually?
I can't remember if I ever had this limitation before (my retraction/prime speed settings are usually lower).
Thanks for your help, if any.
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Thanks, that is easy to verify, as I can put Gcode commands directly in the console section of the Paneldue display while sitting just in front of the 3d printer.
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Yeah, exactly that is what I am working on. I am trying to find out how to independently control one fan output in my Duet2 WiFi (I've got several) and setup a macro for that, should be viable.
I meant the postprocessor for annealing purposes; not a bad idea, by the way. Depending on isolation of the cover and of the underside of the heatbed, a quite high temperature can be achieved (I would need something like a tart cover or a bottomless cardboard box to cover the build plate since my printer is not fully enclosed). I left a bluetooth sensor inside while drying the filament role and can easily control the temperature in real time. Last time I got rid of about 15 g of water.
I recently read somewhere that annealed PLA has allegedly the highest stiffness of all kinds of common filament materials.
A quite troublesome thing remains though: The unpredictable degree of shrinkage, which makes the piece useless as technical part. But anyway.
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Thanks, now I am certain how to deal with those values.
I already have the Material Settings plug-in installed, and just because I wish to consolidate the settings a bit I wanted to know how this works. Then I will have to probably put all types of flows in the Material profile itself and only change what is needed case by case. For example, I found that for hinges, it helps to lower the flow 1-2% to allow for clearance (I know that there are better ways like Horizontal Expansion, ordering or outer walls, and exclusive mode).
It is a pity. I hoped to be able to separate strictly material dependent things from all other cases.
May be I will come back to you for a postprocessing script to anneal the parts in place. Actually, I am not annealing but I printed a support part for filament roles featuring a small fan, all covered, on the heated print plate, in order to dry filaments - not far from annealing (just a higher temperature is needed then).
Thanks a lot.
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I have a simple question that is intriguing me for a while now and I need to solve it at last, because it is so basic for a good print.
Assuming following situation:
I define a new custom material and set a flow for this new material to 98% (for example). This is the optimal setting relative to what I have already determined via e-steps calibration.
Then in the materials section of the quality profile, I set the flow to 100%.
Now what is going to be the effective flow of my prints with this custom material selected? Will it be 98% or 100%? Will those settings substitute each other or are they supposed to be multiplied?
To be more clear:
If I set flow 95% in the quality profile, will be the resulting flow 0.98 x 0.95=0.931 (or 93.1%)? Or will it be just 95%?
I already know that the quality profile settings override the material settings if changed. In this case, I see no symbol at the left side of the corresponding field that would allow me the reset the changed value in the quality profile to the "default" value of 98 from the material settings, suggesting that both values work together (by multiplying).
Although the quality profile settings override the material settings, in this case of the flow value it would make sense that the quality profile setting would be just a modifier to consider flow settings specific to the particular print part than to the material.
And by the way, what other settings of the quality profile behave in a manner that they do not replace but modify the materials settings, if any? Thinking about "Scaling factor Shrinkage Compensation" - it depends also on which part I anneal or not after the print, and since there is no special setting for shrinkage of annealed parts...
Sorry to ask that simple question but I could not find an explicite answer.
(using Cura 5.5).
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On 11/24/2023 at 6:13 PM, Cuq said:
To be honest, I expect to be one hundred percent right, depending of your futur years of experience in 3D printing 😁
You will have to wait asymptotically long. Or blow yourself very, very large.
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23 hours ago, Cuq said:
And 110% for the flow it's not normal even if it's standard for you.
I took your advice seriously and went through the process again.
It turned out that all my flow calibrations were made with small, filigree parts. They do need a higher flow than ascertained by the esteps measurement. But the larger the prints, the closer the flow should be to the "official" 100% rate. So I was biased. I have never printed a piece weighting several hundreds grams yet and if I did, 110% would be too much.
In short, you were a couple percent right, depending on the weight 🙂
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3 hours ago, Cuq said:
I am honestly quite surprised that you have not already switch to this solution, considering that it is so basic and could potentially solved all your issues.
However I am quite new to 3d printing. My self-made printer is about 4 weeks old (building it took 2-3 months, mainly due to 3d printing parts needed), and is still work-in-progress. I want to gather experience without Klipper or other magic first. But yeah, Klipper is one of my many ideas in the project.
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47 minutes ago, Cuq said:
And 110% for the flow it's not normal even if it's standard for you.
As I said: going down to 90% (which is huge if 110% is the correct value) does not diminish the amount of excess material, on the contrary: The blobs can be seen even more noticeable, as the surrounding is scarcer.
We already know: The results of a e-steps calibration are not mandatory to set flow rate. Of course, the number of steps per mm must be set correctly in the config, but there are other factors like diameter of the nozzle and/or of the filament, or whatever else. I noticed that using the 100% defined by the calibration, I was getting holes in models made of just one wall. Then I did a "real life" flow calibration, using approriate models in a set with varying flow rate. The result was 110% and that has proven to be fine until now.
It dawned on me that there is no fix for this issue, which happens to hit me severely with this particular piece. I can still do mitigation or tricks, like using just one top/bottom layer with gradient infill combined with coasting and ironing (for the topmost layer), but I hate when the nozzle strips the blobs on the solidified surface, causing vibrations and mechanical stress, not to speak about knocking the print off the bed.
Another kind of "solution" would be to define per-modell settings blocks containing the top/bottom layers only with their own parameters, like snailspace speed. Unfortunately, coasting is not available for per-model settings.
The best solution would be to anticipate the flow decrease based on the number or frequency of turns ahead.
I am honestly quite surprised that this issue has not been addressed by Cura developers, considering that it is so basic and could potentially affect every print.
Seems like most Cura experts are on holidays.
I will take a look to Klipper asap.
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3 minutes ago, Lommm said:
n fact, the model contains a huge number of errors
I cannot follow, with the best of intentions.
In Cura, using the Mesh Tools, I get a message "The model is watertight" when doing a check.
I don't know how to recognize further errors in the model, give my a hint. I would willingly learn to correct them.
That looks to me like tiny details in the mesh, which would be ignored by Cura (in my understanding).
Do you see any link between those errors and the issue I am adressing?
Because no matter what model I use, the depicted behaviour is almost unavoidable: When building a bottom or top layer with a pattern of lines, very often the nozzle will move doing turns in a limited area, without having adapted the extrusion rate to this effectively slower speed, resulting in overextrusion. That happens in the inside of the print, but cannot always be ignored.
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Alright, please find the project file attached, including the corresponding picture. In the picture, the blobs are deformed by the nozzle passing through them.
Be aware that in my case, 110% flow is usually the correct rate (e-steps calibration has been done, but using it as 100% would yield underextrusion in many cases).
It took some time as I wanted to be sure that my statements still stand and I spent hours doing experiments. No matter how you look at it: In the spots where the bottom layer pattern is "squeezed" and in the connection points of the hexagons (there is a small area there in the middle that wants to be filled by itself, slowing down the nozzle) there is excess flow.
But I admit: TPU balls won't suffer from this defects 🙂
And I still don't know how to cope with that.
Perhaps I will try other slicers? Rather not, they will have their own quirks, which I will have to learn the hard way again.
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3 hours ago, Cuq said:
Such pattern depends of a new parameter introduce in Cura 5.5 call small top/bottom surface. Try to change this parameter. But on my pointvof view you have also an issue with your flow. Try to reduce to 96 - 98 %
I also tried larger values of that parameter without success. The point is, this is not a small bottom. It is a small area in the bottom.
Don't be surprised to know that the first thing I did was to decrease the flow to 90%. It looks inded as a case of overextrusion. Result: light signs of underextrussion appeared, accompanied by the same blobs. So it got worse.
The material flowing at this spots in excess is not accounted for anywhere. It just flows "without permission". Of course a lower flow means a slightly lower pressure, and the blobs would be smaller, in theory. Practically? No.
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4 hours ago, Slashee_the_Cow said:
It would really help if you could provide the Cura project file (.3mf, in Cura go to File > Save Project). Without it, it's hard to test things and figure out what works.
You can reproduce this behaviour with ANY model actually. I have been seen that happening from the first piece I ever printed, but I did not try to troubleshoot it. It was not necessary, as usually the layers are buried later on if the effect is not so pronunciated. So I used to ignore that, things are not perfect in the 3d printing world.
It just happens that with this model due to its shape there are many such spots, while at the same time several bottom layers are defined, using the notoriously leaking PETG.
But I will provide a project file, why not.
5 hours ago, Slashee_the_Cow said:It's also worth noting that many printers' motherboards only load a few lines of gcode at a time, so if there's a lot of tiny moves close together at a high speed, it might not be able to keep up (which would make it pause momentarily and leave a glob).
No pause, just slower. I observed cautiously many times while printing. Do not expect a Duet 2 WiFi to have that weakness (the idea would be digressive).
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Today I tried to print a kind of grid, several mm thick.
While printing the bottom layers, lines are layed to fill areas that are often small and have narrow corners (between the holes).
So lines are printed one after the other, but as the nozzle approaches the narrow corners, the pattern dictates that the lines get shorter and start cornering around more often. At some point, the nozzle seems to "dance" slowly on a small area. Then I can literally see the plastic flowing in excess, a drop appears. Then the nozzle is moved away going through the huge blob, and drags rests of it around. An ugly picture. Stringing is the smallest concern.
This is due to the fact that the nozzle effectively moves slower and slower as it executes turns in short order, but appareently Cura does not take this into consideration and does not compensate the flow. The flow simulation confirms: no variation. The same applies for speed display.
This is not a pure cosmetical issue. With several such layers, the excess material accumulates. The nozzle hits the blobs violently when traveling and even knocks the piece off the bed.
Incidentally, I used 5 bottom layers and 5 top layers, exacerbating this effect (not knowing what would happen).
This problem can be mitigated by a very slow printing speed, so that the flow in the problematic spots is not very different from printing at regular speeds then. But I am not happy printing at 10 mm/sec, when I can do it 10x faster at least.
While experimenting, I tried coasting with high values (0.3) and I could indeed eliminate some such spots but only when they happened to be at the end of the line, otherwise they were clearly recognizable. However this is not a general solution. I also tried different line patterns, and even a flow equalization ration of up to 400% - no effect.
What is the proper way to tackle this problem? (Not just mitigating it)
PS:
Would Klipper be aware of cornering lines? (I don't use it).
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I am determined to write a post-processing script aiming to give an overview of what is happening layerwise (not changing anything).
After what I experience with troubles due to unexpected quirks of Cura, I got tired of looking at the Gcode and numbers to figure out what is happening.
I actually have begun trying to process the Gcode, using awk (since it is actually just text).
At some point, I will do it in Python as a post-processing script.
And nobody asks what actually was spoiling my prints... My post must be very boring. Had I have that analysis tool, I would have recognized the problem at once. That's why I will write one.
Sloped or delayed Z hop?
in UltiMaker Cura
Posted
As it turns, the diagonal Z hop did improve my PETG printing, but not enough.
The left piece is the "improved" version (using diagonal Z hop on the Cura generated gcode). Well, the original print using Cura... I just won't show it, it is just a failure even after applying all known tricks.
The right piece is the result using an alternative slicer which provides the capability to wipe after retraction and does Z hop in different ways.
The improvement after applying the diagonal Z hop postprocessing is rather modest, because it only provides a flat starting lift (better than Cura's vertical one).
Of course this model exacerbates the issue with stringing, but that is the point.
My last cent.