smooth bottom surface on factory testprint

[laserb 0]

On the factory testprint (that comes with the ultimaker 2) the bottom surface is completely smooth. Does anybody know how they did this?

 

[illuminarti 18]

Just level the bed with the head a touch too close to the glass, and print at a fairly high temperature (and get a bit lucky).

 

[tmrevlje 1]

Hi laserb,

well the first layer touches the glass buildplate, which is basically the only reason the bottom surface is so smooth and shiny well at least to my knowledge.

 

[gr5 2,172]

I always recommend .3mm bottom layer for new people because the thicker the bottom layer, the less accurate you need to get a nice print. But if you want ABSOLUTELY PERFECT bottom then you need to level not just to accuracy of paper but 1/10 that and you need to do .1mm first layer. Print nice and slow and have the bed nice and warm (>40C e.g. 50C). You will have to tweak those screws many times to get it perfect. Forget the levelling procedure - that just gets you close. To get it perfect you have to play with the screws alone while doing skirts or bottom layers and getting it perfect.

But you can get pretty damn close with .3mm bottom layer if you have leveled it properly.

 

[laserb 0]

ok, thanks guys for the replies!

I was looking more closely on the edges of the bottom layer and it looked "melted" and no layering is visible. So the high temp advice seem to be correct. Therefore my basic strategy is to have high filament temp on the first layer so all the strings are melted together. Which means for the first layer:

*) high temp on the nozzle

*) high temp on the builplate.

*) no fans

*) high speed

And after the first layer back to normal settings.Does this seem ok? Any advice on settings? (I'm printing i PLA.)

 

[gr5 2,172]

Yes to everything except speed. You want low speed to allow the plastic to heat up fully before exiting the nozzle.

 

[jameshs 42]

Agree with George - no matter how big the part I normally print the base layer at about 20mm/sec - feels laborious at the time, but results in a good stick and a good finish (on cold glass).

 

[yellowshark 153]

This may be a printer thing but I cannot say I agree on the extruder temp being high. These days I run the 1^st and subsequent layers at the same temp. I found that dropping the temp from, say, 220 to 210 would take some time to stabilise and would see the temp dropping below 210 during the process and I always wondered what that was doing to the pressure during the process, apart from the possibility of under extrusion whilst it was below my target temp. It has never caused me a problem although reading this thread might just tempt me to try it again as a verification.

 

[gr5 2,172]

My ultimakers both overshoot on temperature - even changing by just 10C they typically overshoot by 5C. So when I raise or lower the temp I first go to 5C closer than goal - let it overshoot and slow down and then just when it is about to stop or just as it hits the goal temp I set it to that goal temp.

For example lowering from 230C to 210C I set goal to 217C, wait for it to overshoot to about 209C, then as it starts rising to 210C I set the goal to 210C.