Failed print - too thin details?

[shurik 87]

Well, very simple. Why the cow has no forward legs? I removed some of the supports. On the legs, they were messy. Other than that, the print was fine.

 

Layer: 0.06mm

Shell: 0.8mm

Fill: 20%

Speed: 30mm/s

Bed: 60C

Temp: 210C

:?:

 

[illuminarti 18]

If the supports were 'messy' then probably they didn't print right, so when it was time to print the legs, there was nothing for them to print on, so they added more 'mess'. Make the supports thicker, and add more cross bracing.

Personally, I'd print it with feet flat on the bed, and just add some supports under the stomach to get it started. And I wouldn't bother printing with infill, as I don't think it needs it.

[gr5 2,172]

What he said.

And I wouldn't bother printing with infill, as I don't think it needs it.

And will print much faster.

 

[shurik 87]

Right, the supports got messy at some point. But why did they? Why the other didn't? The ears and their support columns were all right. The upper parts of the problematic legs were printed OK, too.

I printed a hippo staying on his feet, with standard Cura supports, but still, the belly got very rough, even after sanding.

With the cow, I tried to find an optimal angle, to minimize the supports and printing in the air. Not very successful yet.

 

[illuminarti 18]

The supports are very thin, and very long, so the head exerts a lot of torque on the support columns if it catches them higher up - or just from the pull of freshly extruded plastic as the head moves onwards in its path. Also, the 45º overhang angle of the support columns is probably too steep to really print well. I generally use 3mm columns at 60º.

I think the reason that the upper parts of the legs print is because the support is denser in that immediate area, and has finally accumulated enough 'mess' to provide some sort of stable base to print on.

I certainly wouldn't use Cura's standard support to do it - just add Meshmixer supports, but with it oriented horizontally. It looks like, topologically-speaking, it's a wingless dragon - and that printed just fine with no infill, and feet flat on the floor:

http://www.extrudable.me/2014/01/02/the-guy-with-the-dragon-part-2/

 

[shurik 87]

OK, will try one day to re-print the cow.

Now, a new question, somewhat relates to the original one, so no new topic for it:

It's these:

http://www.thingiverse.com/thing:88849

UM Blue, 0.1mm, 50mm/s, initially 230C, 60C bed.

After this disaster, I am printing it now on 200C with 30mm/s. The result is considerably better but very ugly yet.

Going lower than 200C is very risky with UM Blue - it loves higher temperatures and underextrudes heavily even on 210C on a more straight layers.

So, like with the case of the aforementioned cow supports, I do not know how to print thin vertical structures.

BTW, tried the overhang test by gr5 and it printed almost perfectly from every direction. But here, there are these ugly blobs of plastic almost everywhere, except the two edge walls. Why? How to get rid of them?

 

[illuminarti 18]

Do you have retraction turned on? And speeded up? For this you need 1mm minimum travel, 0mm minimal extrusion, combing off (in expert settings), travel moves at 250mm/s, and retraction speed tuned to 5.5mm at 35mm/s.

And even then, it looks like a tricky print, given just how thin and overhanging some of those bars are.

 

[illuminarti 18]

Also, what version of the slicer are you using... it's possible that this would be affected by the 13.04 issues with generating over-detailed tool paths.

Does the head move constantly and smoothly on each island that it prints, or is it stuttering?

 

[shurik 87]

Hi,

Thanks for the assistance!

The retraction settings are all default. Will try to play with them according to your recommendations tomorrow.

Latest Cura 14.03 is being used, the head moves are smooth. as far as I can say.

 

[gr5 2,172]

The retraction settings are all default.

 

I think the default is retraction off. At least it was at one time. So that's definitely not good.

Grab the bowden and lift it at the print head and push it down again. Mine won't move at all. But when my UM2 first arrived it moved up and down by about 1mm. Measure how much it moves up and down and then add 4.5mm and set that distance to your retraction. Originally I used 5.5mm retraction but now that the bowden is immobile I use 4.5mm retraction. Other than that use the settings Illuminarti recommends. Exactly those settings.

One more thing - 60C can cause ugliness if the fan is off. Consider having the fan come on at 100% relatively soon - maybe by 1mm. By default I think the fan doesn't come onto 100% until 5mm.

This is a very difficult print and I'm not confident you can get it much better but after trying everything Illuminarti said and after doing 100% fan on a lower level, consider trying .2mm layers to see if that helps. Sometimes you can get better results with .2mm when you have overhangs (and sometimes it's worse).

210C should be cold enough for this color blue and 30mm/sec should look noticably better than 50mm/sec. So do that also.

 

[cez_etc 0]

I'm not entirely sure this model is supposed to be printed without these blobs. I guess it's named "Coral Cuffs" because the random blobs make it look like coral? Even in the picture on thingiverse some tiny blobs are visible.

 

 

[shurik 87]

Well, I have a small coral piece brought from Eilat once. It has certainly no blobs. :-)

With all the recommended retration settings, the result was noticeable better, but very far from perfect yet. Indeed, when examning other prints on Thingiverse, almost all have similar <lack> of the quality. Is the model doomed to be so?

On another note, all these massive retractions caused excessive grinding of the filament, up to the point when I had to remove it by force and cut off the chewed piece.

 

[illuminarti 18]

Hmm. Retractions with those settings shouldn't cause grinding on the UM2; I've done http://www.extrudable.me/2013/12/17/highqualityultimaker2/ without any issues. I'll try printing that piece tonight and see how I get on.

 

[gr5 2,172]

You want the spring in your feeder at the minimum force so make sure that the white square marker is all the way up. The white marker is visible from both the rear and from the side of the feeder - it should be as high as it can go. There is an adjustment screw set into the top which should be loose - it should be adding no pressure to the spring.

I printed with this exact same light blue UM filament a very similar object and didn't get excessive grinding. Illuminarti also. I did over a kilometer of retractions! Each piece of filament when in and out of the extruder an average of 8 times. All for one print. No grinding problems.

Could it be your extruder motor is tilted? There is a nut in the wall of the UM2 holding the panels together but it is under the extruder motor and for some people the motor is pushed away from the wall by a millimeter or so. This causes the shaft of the extruder to tilt such that when you extrude you get a spiral pattern up the filament. I would expect this to be more likely to grind up the filament on multiple passes.

 

[illuminarti 18]

The Coral Cuffs printed pretty well for me, I think:

 

30mm/s at 230ºC, 0.1mm layers, in Faberdashery Bling-Bling Gold PLA.

 

It really is a tough print - many of the edges of the voronoi spaces are less than 1mm thick - Cura can only manage a single-pass wall in many areas, even though I specified 0.8mm shell thickness. So a little roughness on some of those sections is inevitable, and a little droopiness on a couple of the longer bridged sections. But you have to look pretty hard to see the problems.

 

[shurik 87]

Thanks guys!

Checked the extruder. The white marker was always at the top. Its screw was not tight but I unscrewed it a few turns more, just to be sure.

Perhaps, will try to re-print the Coral once more, but not today - my wife is increasingly unhappy about the "plastic junk" piling up in the house. Let us wait.

The picture by illuminarti isn't that clear, but the quality there seems to be obviously better than mine. It might be partly because the UM Blue tends to produce more bulbs than Colorfabb white, for the same settings. The Faberdashery might be even better, didn't try it yet.

And yes, when printing this, the outstanding bowl of illuminarti came to my mind. Is this small bracelet more difficult? Can't believe it!

 

[illuminarti 18]

Here's a better quality photo. The defects visible in the photo are really not noticeable in the finished print - the whole thing is only just over 2 inches across - and they'd clean up quickly with a scalpel - the basic structure is pretty sound.

 

[shurik 87]

Well, unfortunately, I have to revive the topic.

After replacing the feeder with the one suggested by Bas (http://umforum.ultimaker.com/index.php?/topic/4393-ultimaker2-feeder-system-improvements-and-ideas/?p=50304), all kinds of cloggings and black strokes during the prints are gone.

However, the retractions issue didn't go away at all.

This time, the task was to print bunny #2 from here - http://www.thingiverse.com/thing:291323.

It didn't play well:

 

The filament was chewed flat and the plastic stopped flowing out the head.

Then, I tried to increase the spring force a bit, since it was at the minimum possible, so now it is like this:

 

The results were even worse - it spopped printing even earlier.

The filament:

The settings were set as recommended:

UM Pearl White, 210-220C, 0.1mm, 30mm/s.

I'm getting desperate with this. Please, help.

:(

 

[shurik 87]

Anyone, please?

 

[Dim3nsioneer 557]

Shurik, I really like your emoticon...I could watch it all day long and laugh... B)

And now on topic: I just had two print which resulted in grinding with the orignal feeder. However, I have a quite new UM2 and thus the spring is the weaker one. Do you have the stronger spring? I think the tension is just (still) too big. If you have many retracts within a short time, the filament gets heated up due to the pressure and is getting weak and flattened.

I've set the minimum travel before retracting to 5mm and the minimum extrusion before retracting to 0.5mm. Especially the second one makes sure the feeder has a new piece of filament to chew on.

 

[cor3ys 28]

Hi Shurik

I have printed the bunny and some others ok for my wife on my UM2, the only difference is i am using iroberts feeder but that should not make any difference. I get no grinding of the filament.

Settings i am using are as follows.

Temp: 205 degrees

Bed: 60 degress

speed: 40

Retraction: standard setting in Cura

Faberdashery filament

 

 

[shurik 87]

Hi Dim3nsioneer,

Danke zehr! Heh, I should've put that smiley from the beginning.

Do you suggest that the spring in my UM2 (from February) is too strong? Should I ask for a replacement one?

cor3ys - your prints look fabulous! I also try to use the Faberdashery filament, with slightly less appealing results on these prints, so far.

Will try to use the suggested settings. Worst case - will print irobert's feeder, what else...

Many thanks!

 

[Dim3nsioneer 557]

I think to remember gr5 having written that the change took place in March). Maybe replacing the spring might indeed soften the issue if it doesn't solve it. However, I'm just gathering experience with the UM2...

[shurik 87]

All right!

Used the default retraction settings, 225C for the UM Natural White, 230C for Faberdashery Bling Bling Gold, 30mm/s.

Yo-ho! Finally, it worked. The filament did get chewed up, but not to the point of blockage.

Many thanks for all your suggestions!

Now, another problem:

There is twice shift to the left on the bunny's ears. The pulleys are tight. What could it be? I do not like it.

Dim3nsioneer - I'll put another desperate smiley if there'll be no answers in a few days... :-)

 

[gr5 2,172]

You should really start a new thread. One of your axes slipped - which one was it? X or Y? Do you remember how the bunny was sitting on the bed? It's important to know which axis needs fixing.

There was a sudden shift. There are several causes but when the shift is sudden like this it is usually caused by a pulley that is slipping. Usually one of the short belt pulleys (there are 2 short belt pulleys for each axis) or a long belt pulley (4 of those) but much more likely the short belt pulleys. And most likely of all the pulley on the stepper motor. So figure out which axis it was, then remove the cover for that stepper motor. It's just one screw to remove a corner panel over a stepper motor. Then push the head around until you can see the tiny set screw and tighten the hell out of it. I believe it is a 2mm hex wrench. don't strip it!

If you can't get to the set screw then you have to remove the motor and if you do that then you should take the time to mark the pulley and the shaft so that if it moves again you can prove which one slipped.