I can't figure what setting to tweak to improve some prints

[LePaul 331]

I'm not 100% sure combing is the problem some of my recent prints have.

Let me share the most recent ones, where the fill looks a little off (despite 24%) and 0.20 layers. Bottom/Top thickness is 1.2 Shell Thickness 0.8

This cover piece just has these edge artifacts and the surface should've come out smoother

This one, you see the trailing lines which seem to indicate combing. But when I tried a test print with combing off, I got terrible underextrusion

And on this last print, again you see those odd trailing lines on these support leg pieces.

The fill just seems to be lacking...something! If you click on the photo, you can see it in better detail (I uploaded a larger resolution)

Overall these prints are satisfactory but I think they could be better.

[neotko 1,417]

Well more than retract what I would do to have a clean surface it's to close that holes and drill them. The drag marks are because the flat area has 'holes' so the top layer path isn't 'linear' so the head must fill, move, etc etc. Ofc the other problem if you make that tubes solid it's that because the top layer of the screw areas it's taller, it will make the same problem and marks.

Solutions? I would use another slicer version or different and check the travel paths. What I would really do? I would use s3d that allows to have different processes and I would split the 3d object of the top layer and the upper part on another but to do that you need to really know how the program thinks and make the object with that in mind. Also on s3d you can force the head to almost only move from one position to another by using only the perimeters (because you can tell him how much distance it can use to combing and on cura you can't do that).

Another sollution? Use Z hop to avoid the marks, but that will add small blops and make other problems, specially if you print too hot.

Try the last cura beta 1.99, maybe it has some tools to make that cleaner.

Edit: BTW I'm not sure (low res photos) that the scratches are 'scratches' of the nozzle moving or dripping. If it's dripping forget everything I wrote and just print cooler/slower but check that the nonprinting movement speed it's at least 200mm/s

Edited December 2, 2015 by Guest

[neotko 1,417]

Btw your top layers seem to have small cracks. Check the coupler, increasse the flow a little tiny bit or join the top layers underextrusion forum post... I get that look when I use too little top layers or when the coupler start to die...

[LePaul 331]

I do have the full version of Simplify 3D, I just bought that a week ago. I haven't finished the tutorials yet so I need to learn it. I'd be really curious how these print on a different program.

[LePaul 331]

Edit: BTW I'm not sure (low res photos) that the scratches are 'scratches' of the nozzle moving or dripping. If it's dripping forget everything I wrote and just print cooler/slower but check that the nonprinting movement speed it's at least 200mm/s

 

I suspect the later [dripping].  I have been printing at 208C and 40mm/sec

The travel speed is the default 150mm , so I can up that.

I can also lower the print speed to 30 mm/sec on a test piece and report the results.

Edited December 2, 2015 by Guest

[neotko 1,417]

On um2 you should be able yo stay at 250mm/s travel speed without issues as far as I know from others posts.

[LePaul 331]

I have an Ultimaker Original

[neotko 1,417]

On mine I stay at 200mm/s without issues. But I have change the belts to gt2 to have better movement. Mxl belts are a bit worse (little bit) and specially the stock pulleys (that are horrible). Anyhow it should work without problems at 200 I suppose.

[neotko 1,417]

Btw to avoid dripping at all think about moving to 1.75 filament. I print at 207-209C at 70mm/s with 0.2 layers and with 3.2mm retractions I get almost zero dripping. Sorry I always talk about 1.75 but it's really less messy

Edited December 2, 2015 by Guest

[LePaul 331]

I don't have a ton of hours on my printer...probably 100 at top...so I doubt the coupler is the problem either

Either way, you have given me some good ideas to try. I could also try the Beta Cura

[neotko 1,417]

If you have an umo/umo+ to improve the quality try lowering the acceleration from 4000 (default) to 1800-2500, and the Jerk to 18 or something like that. For me 1800 works better because some other mods. That removes some of the ripple effects of the movement and will also make the printer shake less. The 4000 acceleration on my umo+ made it shake like a milkshake. But that's for other topic... =)

[LePaul 331]

Where is that setting (acceleration) and jerk?

[neotko 1,417]

On the ulticontroller. Prepare/Motion or Control/Motion I don't have the printer infront of me

If you like the result use the save memory option.

More on the topic:

https://ultimaker.com/en/community/16398-how-to-tune-your-motion-parameters

And guide about the menus

Edited December 2, 2015 by Guest

[LePaul 331]

Okay, makes sense now, I was looking all over Cura to find them!

[LePaul 331]

 

@Sandervg I would love your input on this!

[xisle 34]

@LePaul

My current UMO settings:

Control->Motion->Accel: 2000

Control->Motion->Vxy-jerk: 12

[JohnFox 25]

Try changing from the metallic filament to something fully opaque. That looks like the stock filament supplied with the UM, works perfectly but I think it shows more print lines than say an opaque white.

[LePaul 331]

Actually it is the ColorFabb PLA/PHA (Shining Silver)

[LePaul 331]

@LePaul

My current UMO settings:

Control->Motion->Accel: 2000

Control->Motion->Vxy-jerk: 12

 

I entered these settings and made sure, in Cura / Expert Settings that Combing was bacl to 'All' (default setting)

I also recalled what @gr5 has posted a few times...

Print slower and hotter! Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers):

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

I have a test piece printing now at 40mm/sec and 220 C (ColorFabb seems to like the cool size, so I opted to go below 225C )

I can already tell that the movements are much more fluid and the usual jerking/thrashing I have grown used to is gone. This is a great tip!

I'll post a photo of the test piece once completed.

[LePaul 331]

Well, problems still exist....ideas?

[tinkergnome 927]

Well, problems still exist....ideas?

 

Is this still sliced with Cura? Then you should use the "No Skin" option for Combing. I suggest this as a starting point:

In addtion: the extrusion looks quite unbalanced, there is serious underextrusion on some parts of the skin. You mentioned in your first post that this happens after retractions... and gets worse after lot of retractions?

I assume that this is somewhere hardware related.... perhaps some backlash in the feeder...? (i'm not familar with the UO feeder...)

Anyway - you should definitely get rid of this first...

[neotko 1,417]

The scratching on the surface it's just the head moving. But you have actual holes between the infill lines. How many top layers or how height are they? I use to need 3-4 top layers at 0.2 & 70mm/s to have a perfectly close top layers.

Also the quality of the top layers depends on the nozzle flat area. Check the nozzle tip to see if it's really flat. But your printer was very new isn't?

An example from my shop. Printed at 60-70mm/s 3 top layers 0.2 207C s3d. You will see it has zero scratches because also, played with the processes to make it look good.

Edit: Also, if you play with the nozzle size and force a 0.38 or 0.39, the nozzle will make smaller movements, and that helps a lot since the flat area will 'flatten' the top layer more making the top layers look better. This won't remove the scratches from the path planning of cura..

Edited December 5, 2015 by Guest

[LePaul 331]

Thanks for your replies, I was at work and using my iPhone 6 to reply is proving to be a frustrating experience.

Yes....still using Cura!

[LePaul 331]

Here's the settings I am using....

[LePaul 331]

Also, the nozzle is new (installed in August, done about 50 hours of printing)