New Ultimaker2 user questions

[bcuz07 0]

Hi guys, I received my ultimaker2 yesterday and printed the um robot and coffins cube from sd card supplied.

Went well and I'm sure settings can be adjusted to print them even better. Very happy with the machine

I printed a custom insert for a case which is 180mm long in the x direction and seem to get a strange result on the top surfaces (probably underneath aswell - but not sure). This was printed on the fast print setting

Please see pictures in link below:

https://www.dropbox.com/sh/ry9pvg5mm96ctor/AABBA5MGBQDSJyt0_E3i5Cnfa?dl=0

[gr5 1,021]

The top surface shows 2 issues: underextrusion and play.

Play: This is trivial to fix. Play (aka backlash) can be caused by loose belts or by too much friction. In either case when one of the servos (can't tell if it's X or Y from the picture) moves to a certain position, the head doesn't quite make it all the way there and stops a bit early. Since you have a new UM2 it's probably not friction but you can turn off power and push the head around and make sure both axes are about the same. More likely you have a loose belt. The long belts have spring tighteners so it's probably not those but check those first - squeeze all 4 long belts and make sure they are all equally tight. Most likely the problem is one of the short belts. To tighten, loosen the for screws that hold the motor in place, then push down on the motor hard with one hand (like maybe 2kg force) while tightening the 4 screws (they are in slots so you can slide the motor up and down a bit). Then feel the tightness of the short belts.

Underextrusion: Not enough plastic coming out on that top layer. I don't see underextrusion on your side layers. It could be simply you need one more layer - you want at least 3, maybe 4 layers to get a good seal on the top of your part. The first layer comes out a little low and it takes a few layers until it's all at the right height. So top/botttom thickness should be 4X your layer height. If layer height is .1mm then top/bottom should be at least .4. If .2 then .8. Other fixes for underextrusion are printing hotter or slower (you may be approaching the limit of the volume of filament it can squirt through that tiny nozzle hole). Hotter to make the plastic thinner (less viscous - more like honey than toothpaste) slower to lower the pressures and forces involved.