Blobs vase mode short stops

[moschidreamer 0]

Hello

I printed my first vase.Naja, second vase.

It is 60mm high, very small. After almost finished I noticed blobs.

But also noticed that blobs occur because it shortly stops. After reducing speed the short stops dissapear and blobs dissapear too.

In gcode I can not see different parameter during print.

What value makes the short stops in cura? I already made minimum layer timt to 0 and minimum layer speed 0 too.

 

Why it stops shortly but after changing speed it stops not shortly?

 

nozle= 0.4

layer high= 0.2

speed= 30

[burtoogle 513]

Sounds like you have a minimum layer time that is too high and perhaps the lift head option is enabled?

[moschidreamer 0]

Minimum layer time is set to 0.

Layer Speed to 30mm/s.

 

The Model is the  ZYYX vase Thingiverse.

Scaled down to 60mm hight. Maybee too much data points? Because it occours on top of vase where the circle gets smaler and to acheve the speed, more data points to calculate and then stops because of bottle neck (funny, because I truely have probs in bottle neck 😉 )

What I did is to set all accelerations to 500 mm/^2. Without understanding what it does.

But this jerky stops occour while making that smooth circular movement. No fast changes in acceleration or speeds neccesary.

It only occours when I increase speed with this knob on the controller (Fr Value)

After decresase under 100% it,  no more jerky move.

I also changed SD Card, but still happens.

 

Does is have to do with limited data calculation of the Creality controller? To make round shape vase is a lot of changes in direction. I read anything in forum. Like jerky speed problems, but there was no clear solution on that problem. I can not belive that a little vase 60mm high only can be printed witn 20mm/s!

Afternoon I will make a short video of it.

 

@ Ambassador: are you also in VR communities? Somehow I know your name....

Edited March 6, 2019 by moschidreamer

[moschidreamer 0]

Short Update.

Because I scaled down high resolution stl model I think it is realy the data bottle neck of the data trafic.

Slow down and no stops no more.

[NoMeursie 0]

Hello,

 

I have exactly this problem with the current Cura 4.7.1 and my Ender 3 V2. When I try to print a vase (spiralize outer contour), the print ends up to be quite good only there is a spiral pattern of blobs, dots, zits (whatever the name) (see image). Cura does not show them in layer view. While printing, I can see the nozzle stop every half circumference. During this stop, material oozes out of the nozzle which leaves such a dot. I tried a lot of things to avoid this stopping behavior and allow the printer to move with one continuous speed but with no success. No clue what to do. Is it a bug in the new Cura? Or a single setting that I might have forgotten? because it feels like that which is quite frustrating.

 

Anyone that thinks he/she could help? I would greatly appreciate it!!

[gr5 2,167]

I agree that you probably have the same problem - scaling down the number of triangles in your STL should fix the problem.  Could you upload your STL?  I'd like to look at it in meshlab.

 

How to reduce polygons:

http://www.shapeways.com/tutorials/polygon_reduction_with_meshlab

[Asimomon 1]

Hi Everyone,

I randomly stumbled across this thread searching for the solution to the problem.

I am too trying to print an object on my Ender 3 V2 in vase mode and facing zits and filament blobs.

Just like the @NoMeursie has posted the query regarding the zits, I feel I am too stuck with the same zits issue on Cura 4.7.1.

 

I have observed that the nozzle stops at regular intervals while printing the outline and hence oozes out a little that is resulting in zits.

 

I have played with retraction settings, coasting, mesh improvements just to fix this zits/blob issue.

However, what fixes my problem is moving down from the speed of 100mm/s to 40-60 mm/sec using the knob on the printer while printing.

 

On a side note, I am using the scaled down ( 68%) of the original print size of a lamp from Thingiverse.

 

Any ideas?

@NoMeursie

[gr5 2,167]

5 hours ago, Asimomon said:

Any ideas?

Yes!  See my post above.

[nicomora 0]

Hi!

 

Last week I had the exact same issue in my Ender 3 Pro and I tried to simply the models without better results (I need to print this model as fast as I could).

 

However, I solved it completely by sending to print directly from the software via USB.

(I'm using the 32 Bits 4.2.7 Silent mainboard so I don't know if that will influence the performance of USB connection)

 

[GregValiant 1,245]

In Cura 4.7, Creality gave their printer definition files a default Maximum Resolution of .025 which was much too fine for the printers.  There were just too many calculations required and the print head would stutter as the processor tried to keep up.  The fix was made in 4.8 when the Creality definition files were updated (by Creality) to a Maximum Resolution of 0.5.  That eliminated a lot of very short line segments and printing was much improved.  So in Cura, check "Mesh Fixes | Maximum Resolution" and set it to 0.5.  Maximum Travel Resolution is tied into it.  Maximum Deviation can stay at .025.  Also having an effect on circles is the Accel and Jerk settings.  Once they get much over 500 Accel and 8 Jerk (Creality Ender 3 Pro with the 1.1.5 mainboard), stuttering can start.

 

The Arc Welder post processing plugin was developed to change the line segments (that comprise any circle) into G2 and G3 commands.  Instead of the printer/processor having to calculate 200 gcode commands to get around a circle of radius 32 it would be 1 command with Arc Welder.  This has a huge effect when printing via USB as not near as many commands are needed to be sent and processed.  There is a lot of overhead required in the firmware (36kb?) when G2/G3 are enabled so of course Creality simply disabled them and Arc Welder doesn't work on some newer Creality models.

 

At any rate, my printer is an Ender 3 Pro with the 8 bit board.  Printing from the SD card is my preferred method as USB printing from Cura is no longer maintained (no current Ultimaker printers use it).  USB Printing from Cura also has a peculiar drawback due to buffer over-runs (the opposite problem of stuttering) and printing will halt as a Cura generated M105 temperature check gets truncated and is read by the printer as an M1 which is "Unconditional Stop" (Pronterface/Printrun suffers from that same problem).  There is also the problem on Windows systems of Microsoft pushing out updates in the middle of the night causing the computer to re-boot which re-boots the printer and your print that looked terrific when you went to bed is sitting on the build plate like a lump.

[mattw 2]

Yes, this is old, but it still comes up in related google searches, so here is how I fixed it.

 

It is indeed a data transfer problem, but for me it was internal to Marlin. The default Planner Buffer size in the Ender firmware is only 4 lines of G Code! This results in a lot of calls to the disk for little chunks of G Code.

 

When I adjusted the Planner Buffer to 16 or 32, the problem totally went away.

 

So yes, reducing your speed and resolution are potential fixes, but they have obvious drawbacks. Removing the restriction of an overly conservative planner buffer allows you to print faster and finer without blobs ( assuming your control board processor and memory is strong enough to handle the larger planner buffer.)

[mattw 2]

Yes, this is old, but we found another solution to remove the blobs. Just posting answers for future folks that reach this via a search.

 

When we disabled power loss recovery, the blobs went away. Our printer had poor power loss implementation and would write the position to the sdcard repeatedly. The system couldn't keep up.

 

To disable, put "G413 S0" in your preprocess g code.