UM2 print quality querie, with pics!

[braddock 1]

Hi guys... after 2 days with my new machine, Im very happy with it overall. I have noticed though, that it prefers printing objects, with the majority of the surface area either vertical, or facing upwards... hopefully my pics will explain this better.

I've begun cutting my models up to suit this orientation, and sticking together afterwards, but this isn't always possilbe.

I'm assuming it's mostly due to cooling, temperature etc, but the inside walls are always perfect. Any outside wall past a certain degree, facing the build plate comes out a bit messy.

 

 

[braddock 1]

Forgot to mention, printing at 20mm / second and 0.04mm height.

My prints are long... looking for best quality, regardless of time for these small objects.

40 micron looks amazing!

 

[illuminarti 18]

Overhanging parts are always going to be very difficult because most of the outer filament bead on those layers is being laid down over thin air, so it's going to tend to droop, if it extrudes at all. You're already printing slow - you might try changing the temperature, or even printing thicker layers. With very thin and slow layers, you start to get various capillary and surface tension effects - particularly when extruding overhangs where there's nothing underneath to attract and hold the freshly extruded plastic in place. Printing thicker layers, or faster, might help overcome the resistance of the plastic to actually leave the nozzle, and paradoxically give you better results.

Given that your print resolution is limited to 0.4mm in the X-Y plane, 0.04mm in Z is probably more than you really need. I never go lower than 0.06mm.

 

[braddock 1]

Cool thanks... What you've said makes total sense, and yes, it is basically printing on thin air, so I'll keep trying different options.

Cheers.

 

[valcrow 145]

This is pretty normal, most of the overhanging bits tend to get more droopy filament placement and causes roughness. Though yours seems a bit more pronounced than normal, maybe try printing a tad cooler. Especially with .04mm layers, you might just be causing those areas to heat up and curl.

I've found for me, slicing and orientating your parts to ensure that most of the surfaces are printed no more than a 45 degree incline will ensure that the surface finish will print nicely.

relevant robot skull printed at .04 like yours.

Congrats on your new machine!

 

[braddock 1]

thanks valcro, I did reduce the temp to 200 on a couple of these. What temp do you generally print at?

Yes, already cutting up differently for my next go.

Nice detail in that head.

Cheers.

 

[valcrow 145]

I print at 218 on small layers 0.06mm (i rarely go down to .04, you almost don't notice the difference from .06 and it takes longer, and first layer is more challenging)

And around 220, 223 at .09mm and 1.2mm respectively. (someone said keep to multiples of 3 for layer height...and I just kinda stuck with it, it's been working.)

My Silver PLA recommends a higher temperature than normal PLA... It's still kinda viscous at around 225.. I have some traffic red PLA from colour fab that drips at 215... So adjust accordingly.

 

[tommyph1208 55]

Did you try printing stuff with support? Either automatically generated by Cura, or you model some into your models yourself...

Removing support and getting a nice surface finish is not always easy, but it might be a solution for you in some cases