The top of my prints gets smudged

[3dprintworld 0]

Hello,

I am new to this forum and new to 3d printing. I recently got my Ultimaker 2. ../

I have two questions and problems.

In order for better understanding, I'll do it with pictures

First problems is the bumps that occur when doing a slight overhang. The thing is I have seen people print this same model on an Ultimaker 2 and it looked far better than mine. http://www.thingiverse.com/thing:297846

I used 0.04 mm quality. Don't know what is the problem. Could it be that the belts are lose? Or maybe i need to change some other settings.

The second and more serious problem I have is with smudge on the top of my prints. It's as it the printer forgets to print in the last 20 layers.

 

[illuminarti 18]

On the small parts, the issue is that the plastic doesn't have time to cool between layers. You need to set a minimum layer time of at least 5 seconds so that the print slows down a bit. You may also want to enable 'cool head lift' in expert settings, or better still, print several items at once, so that the head can go do something else while the first part is cooling.

On the overhangs, I'm not sure. It might also be temperature/speed related - especially since the layers are so thin, and the overhang is quite steep. It might also be related to infill settings. What speed are you printing at, and are you using infill? It should print quite well with 0.8mm walls (shell) and no infill.

Also, are you sure you really need to print at 0.04mm? That's very, very thin, especially for something moderately large like that figurine. I rarely see the need to go below 0.1mm layers, and still can't usually see the layers.

 

[braddock 1]

This is my model, and a photo of my print

http://www.thingiverse.com/thing:297846

Illuminarti is correct about small objects, the one I printed is about 150mm tall. Make sure fans come on after the first layer, and print at 210 to reduce heat induced blobbing.

Your print looks quite small in the photo, how big is it?

Illuminarti, there's massive different between the visible layer heights of 0.06 and 0.1

0.1 is far too course for the majority of prints I do, perhaps for certain prototypes where surface detail is not important, but not for organic sculpture with things like skin, wrinkles etc

0.04 does provide a better surface than 0.06 but the hit in print time makes it not so viable.

I'd print at 0.01 if I could! I want as close to an injection molded finish as I can get!.

 

 

[illuminarti 18]

Braddock, if there's very fine detail in the mesh that is only resolvable with the thinnest of layers, then yes I agree that thinner layers will make a difference. However, they will also increase print times and can cause problems of their own, due to the capillary effects when extruding very small volumes out of the nozzle, and the lack of inherent rigidity in the thinnest of films of plastic.

However, for surfaces that do not have the very finest of details in the z-axis, I find that 0.1mm layers on a UM2 already give a very smooth surface without visible layering. For instance, the dragon print that I did - the layers are pretty much invisible. So, if the only concern is getting rid of visible layering, then I don't think that going thinner than 0.1mm buys you much on a UM2. (On a UM1, I generally print detailed organic prints at 0.06mm, as I do find a benefit there).

As a further consideration, I think that for anyone like the original poster who describes themselves as 'new to 3D printing', I'd encourage them to start at 0.1mm layers, or even thicker: simply because you can get results that much faster, without losing much effective resolution. There's so much to learn about how the settings interact, that I think there's a lot of value in getting experience with prints that place less demand on the printer's set up, while completing much faster. Only with a good grasp of the basics would I recommend new users experimenting with especially small and/or fine prints.

 

[3dprintworld 0]

Thank you for the reply. My minimum layer height is 5sec. I printed this with 225 C and 30 mm/s and 10 or 15 % infill.

The part is scaled down 60% because at the time Cura 14.03 wouldn't slice it. Braddock helped me find a fix. I used Cura 14.01 and sliced it without any problems. I think there were problems with the slicing because it started skipping layers above the head.

I will try printing it again. Full size part. 0.05 mm layer height, 30 mm/s, 205 C with no infill.

One more question. What do you guys use for spool holder. I find that the one provided by the Ultimaker 2 can be improved.

I know I am a beginner but I can't work with simple parts. I wanna see the limits of my printer . Plus the complicated things are far more interesting to build. Thank you Braddock again for this amazing sculpture.

 

[dkaygee 0]

This one is nice

https://www.youmagine.com/designs/low-friction-um2-spoolholder

 

[braddock 1]

I printed my own spool holder that runs on bearings and sits under the printer.

You could try printing at 0.06, it'll go a bit faster and there's not a huge advantage in printing at 0.05

If you print at 205 make sure you watch the first few layers, for me, anything below 210 can cause under extrusion, but this depends on the material somewhat.