14 hours ago, gr5 said:I suspect you are talking about "stringing". Please post a photo as well.
Hi Gr5, yes I'm talking about stringing, not sure why I said webbing. I'll post a photo of my best attempt soon as I'm away at the moment.
I've run various retraction tests and printed other objects with 0 stringings, so i don't think the issue is with the material or the printer. I think its either the settings or this is simply something that cannot be done with an FDM printer
Thanks
Hi all sorry for my late response, been a crazy busy week travelling. Here are some images and the file.
I've tried normal surface, retraction everything I could to get better results bur still failing.
When the spokes print, each spoke receives just a dot of filament and then the printer moves to the next. You can see it here with my regular settings. The travel lines are dark blue because I'm not getting a retraction after each "dot" is put down.
This is with the "Retraction Minimum Travel" at 0.02 and the "Maximum Retraction Count" at 300. All those dark blue lines are now pale blue which indicates that there was a retraction.
Now your question "Is this impossible?" comes up. Your UM S5 or maybe a direct drive setup might be able to handle it. My Ender would scream bloody murder and then the hot end would clog, or the filament would get ground down to nothing by the drive gear.
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Thanks @GregValiant, I wasnt aware you could display travel lines and retraction in cura.
Is it possible to get the nozzle to travel into the centre between each spoke? If the stringing goes inwards or outwards then the old heat technique might be able to clean up an otherwise messy print?
Cura is going to plan an optimized path. The fastest most efficient path for that part is to travel spoke-to-spoke. Consequently, that's what you are going to get.
Maybe...if each of the spokes was a separate part...you could adjust the print order to give you a pattern that travels back and forth across the center.
Try setting the "Z seam Alignment" to User Specified, the "Z seam X" = 0, "Z seam Y" = 0, and "Z seam relative" checked. At least all the starts and stops will be on the inside.
Maybe...trying a print with the Z-hop height at 1.0 or even 2.0 would work?? That would force an "up-travel-down" move on every retraction.
A problem with that model is that the spokes are so thin that the pressure from the nozzle pushes the spoke down and you are getting very little "squish" and there is no room to "wipe".
In the end, that is not a good model for FDM. There is no continuity where the flow through the nozzle can really get going and that occurs on 75 to 100 consecutive layers. 80 retracts and primes per layer isn't good either. The nozzle pressure is bouncing up and down at a ridiculous rate.
Even sliced with a 0.20 nozzle and .16 minimum line width I have my doubts about this model. It looks good, reality is likely different.
Printing this at 5X size and putting it in the clothes dryer with your socks hoping it will shrink is unlikely to work.
Just sayin'.
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The retraction alone should be enough to eliminate the stringing. The problem is that with this part you will be doing probably about a kilometer of retractions. That's right. A kilometer. My printer can retract the same part of filament about 10 times safely. 20 times and there will likely be too much filament grinding. 30 times and almost guaranteed to fail.
Cura has a setting (well, 2 settings combined) to limit how many times the same piece of filament goes back and forth through the feeder. You can limit that to 10 times and you will get a few blue lines but much much fewer of them.
Any very whispy threads left over can be removed in 1/10 second by using a hot flame. I use a butane "torch" from amazon and I go over every inch but very fast. Test it on your finger first to make sure it's not painful. If you go too slow you will melt the plastic. If you do a second pass, let the part cool to room temp again first.
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The stringing is pretty solid, almost like it doesn't retract at all. The best result I've had was changing Jo settings except from normal mode to surface mode. The only problem is it misses out key areas like top and bottom layer. And without the ability to bypass the U5 start up process i can't even combine both modes to get a good result.
I've tried increasing the width of the spokes and reducing the amount of then, not ideal, but it did manage to print and feels very sturdy, however even at the finest setting the quality isn't good enough.
I'm confused. Did you try retractions yet? That seems to be the consensus. You don't have retractions. You need retractions. The settings are not that complicated. retraction minimum travel is the first one to mess with to get it to do more retractions. Using the display mode shown above you can verify it will work.
Maximum retraction count is the next one to play with after you've tried to make a print.
You can see all these settings at the same time if you type "retract" in the settings search box.
I'm really just repeating what Greg said above.
On 6/26/2023 at 8:51 PM, gr5 said:I'm confused. Did you try retractions yet? That seems to be the consensus. You don't have retractions. You need retractions. The settings are not that complicated. retraction minimum travel is the first one to mess with to get it to do more retractions. Using the display mode shown above you can verify it will work.
Maximum retraction count is the next one to play with after you've tried to make a print.
You can see all these settings at the same time if you type "retract" in the settings search box.
I'm really just repeating what Greg said above.
I'm confused too, I'm definitely using retraction, from what I've observed it seems as though the retraction just don't kick in, or isn't effective because the spokes are too close together 🤔.
I've printed over 20 samples with various retraction settings. Even minimum travel set at 0 all the way up to 0.7.
I've even tried going a 5mm z hop, super slow speeds, and using a 0.25 nozzle which actually is worse.
Here is a section sample using different spoke diameters from 0.6 in the middle 0.8 on the right and 1mm on the left.
You can see that 0.6 actually performs the best which doesn't make sense to me.
The black os 0.4mm nozzle and the white is a 0.25 nozzle.
I just pulled this off the printer.
Quality
1mm layer height
0.15 line width
Wall
Minimum wall line width 0.2
Travel
0.1 - retraction minimal travel
300 -max retraction count
Tick - retraction before outer wall
2mm - z hop height
Post Heat treatment
Not sure this qualifies as possible
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Hi @djorn,
This was an interesting test.
Hmm, this was the impossible one. The problem is the tiny "beams" that's kind of glued to the nozzle and bent when nozzle try to get red of this tiny thing.. But I'll think this was a god one.
Is this a kind of filter or?
If this is a must to be printed, maybe the fluid printer (SLA) is a what you'll need.
Thanks
Torgeir
I agree with Torgeir, that's pretty darn good even with the warpage/deformation. I didn't get close to that quality and I tried a couple of times. I was going to switch to the 0.2 nozzle and do a test but my printer isn't good with the .2 and all those retractions tipped the scale and scared me away.
I'm guessing you have more than a few minutes into that thing now.🥇
@Torgeir
Yes this is a filter! The bent area you see was my fault trying to get rid of the stringing.
After this print I realised the material was blocked and ground down so I think I'll call this a fail as breaking your machine for a 5g part doesn't make sense to me haha.
I think sls or sla will work, but wanted to push the limits before I push in the card details
Thanks guys, I'm so close it's driving me mad.
The worst part is the 0.2 should perform better but running the same settings with a 0.4 I get better results. It doesn't make any sense.
I even rotated it 90 degrees so it stands tall with a 0.4 standard settings and got 0 stringing, but poor sagging.
I've resulted in 3d printing a mould and casting it in resin as I'm running out of time and patience.
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Now that is a serious workaround.
On 6/29/2023 at 9:26 AM, djorn said:
I'm confused too, I'm definitely using retraction, from what I've observed it seems as though the retraction just don't kick in, or isn't effective because the spokes are too close together 🤔.
I've printed over 20 samples with various retraction settings. Even minimum travel set at 0 all the way up to 0.7.
I've even tried going a 5mm z hop, super slow speeds, and using a 0.25 nozzle which actually is worse.
This is indeed a good observation, -also the specs from Ultimaker state this fact as an UM S5 and S3 have:
------------------------------------------------------------------
Layer resolution
0.25 mm nozzle: 150 - 60 micron
0.4 mm nozzle: 200 - 20 micron
0.8 mm nozzle: 600 - 20 micron
And XYZ accuracy 6.9, 6.9, 2.5 micron
------------------------------------------------------------------
I've digged a little into this and think that the flatness around the nozzle opening is just a little to big cause filament hang a little on this flat part. But think this is done to make the nozzle last longer, -but relative resolution is better.
Just my 5 p.
Thanks
Torgeir
Thanks all.
I've now removed 95% of the stringing but do get serious blobs when there are.
the 0.25 nozzle is definitely worse for stringing.
Printing it tall gets better results, but the sagging is hurting my eyes, even when set very slow and lower layer heights and cooler temperatures its too much to hide.
I also tried speeding it up by 150%, which actually produced very good results. Not sure whats going on here.
p.s mould didn't work, the resin was too thin and broke on release
Alright, we know this isn't an easy model to print as a single piece so how about as an assembly?
If you printed the lower ring, and the upper ring, and if each ring had slots to receive the spokes, and if you printed 76 or so spokes, then you could super-glue the mess together, you would have 1 assembly.
If you lost the taper on the spokes and made them a constant .4mm wide they would probably come out pretty good because you could print them flat on the build surface.
If you need 30,000 then that probably won't work (unless you can hire elves). If you only need one or two then it might be a viable option.
Edited by GregValiant@GregValiant, not a bad shout and was something I considered.
i thought about printing the larger diameter circle woth the spokes going outward as one piece. Print the smaller diameter as one piece, then simply fold the spokes over, down and inward towards the smaller diameter then heat it into place or glue.
However I'm I'm the hundreds quantity and can't see that working long term. Also slightly defeats the purpose of 3d printing when I could then make it out of cardboard.
I think the key here is the right settings. The machine has demonstrated it can print the structure, just with a lot of stringing.
It's also shown it can print it with hardly any stringing, but the quality suffers. So it's striking the right balance. Either way there will be post processing required.
Edited by djornI'm still a little confused if you are actually looking at preview mode and seeing which moves are retracting moves and which aren't.
If I look at your photo you posted quite a while ago with a black part and a white (gray?) part I can see the black part has 3 thick strings and many thin strings (please look right now real quick). Those 3 thick strings probably had zero retraction. There is no need to actually print the part when playing with this as you can see that in PREVIEW mode *before* you even start the print.
Getting rid of those thin strings are really easy. You buy this tool here or similar - a small refillable butane torch - about 5 euros plus get the refill can:
https://www.amazon.com/Urgrette-Lighter-Refillable-Adjustable-Included/dp/B08MPLVCZC
You can use a candle instead but it's easier with the torch as you can aim it downwards.
You pass this over the thin strings for the tiniest amount of time. Around 1/100th to 1/10th of a second. The thin strings melt and shrivel to nothing and the other plastic doesn't have time to warm up.
You are probably thinking that you can still see the strings or that they will make a blob. They do make a blob but it's smaller than you would think. It's really an amazing tool and you need to try it to understand how powerful this method is.
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The improvement with speed probably has to do with temperature. Instead of printing faster, do you get the same results with lower nozzle temp?
I will have to run another series of results with different temperatures as I think that's having a big effect on the results.
Do I think this is impossible to print. No, but this is definitely a torture test for your machine and will likely break it especially if you don't have a direct drive setup
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gr5 2,176
I suspect you are talking about "stringing". Please post a photo as well.
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