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chris

Excelent bottom and top surface

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Hi guys,

by now I get more and more closer to my Ultimaker every day. Thats nice and makes me happy. But I got a question regarding the bottom and top surfaces. What quality is possible. Today I printed my first companion cube (had it from thingiverse) and the sides were awesome. Really smooth surfaces. Looks great. But bottom and top looks like a mess. At the bottom you see the 45° lines. It´not filled 100%. But what to do, to get it filled. And the top is not so smooth, too.

Has anybody some input for me to improve my top and bottom surfaces to perfection :-)

Thanks in advanced.

Greetings Chris

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Most likely you are under-extruding. It's quite common, because it still gives perfect outside surfaces. What you could do is adjust your steps per E, set it a bit higher, this should increase the extrusion amount.

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and set bigger bottom&top layer tickness

I usually set to 4 or 5 layers to be 100%fill to make sure you have no gaps.

Actually, with Cura, the 0.6mm top always seems to get a 100% infill, no matter your layer thickness (it calculates the amount of top/bottom layers from that setting and your layer thickness)

It was a bit of an experiment, but it works really well. Even at 0.05mm layers you seem to need about 12 layers of solid infill to get a good closed infill. But at 0.2mm layers you only need 3.

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Thanks for the answers,

@ Daid: I don´t completly understand what you explained. Should I play with the top and bottom Layer thickness, or is it the best to leave it at 0,6mm?

Another thing, wich "destroys" my surface, especially the top, are the little lines from the extruder travelling. In the expert settings (Cura) I don´t tick "Retract on jumps only". In my understanding, that meens that every travel will be retracted, isn´t it. The printer do the retraction, when it´s traveling, but there are still lines! What to do.

Thanks Chris

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Interestingly I had exactly the same problem with the same model.

As Daid said, it was due to under extrusion, possibly due to printing a bit too cool for the speed, or possibly because I'd just put in a new roll of filament which I should have measured the diameter of.

I'm trying slic3r next time I print it because it allows for a few more settings in terms of speed and layer count on 'top' areas. Ideally I'd love to be able to have one profile for part of the object and another profile for another part. In the cube for example the bulk of it can be done quite fast and with minimal fill, but I'd like to change the top 20 layers or so to be printed more slowly and at a different fill.

I don't know if Curas project planer can do this. If not I could post process the GCode, or merge two different gcode files produced at the two different settings.

Anyone else doing this?

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I've been doing that jcosmo. I find that reducing the layer height on the final layers gives a much better surface. k'slicer also avoids many of those travel line problems. unfortunately there are 2 ways to get a 'perfect' surface, and no slicer properly implements them at present.

1) tilt your model slightly (print on a triangular raft) so that the top surface is angled. for 50 micron printing, tilt at about 15 degrees for perfect surfaces. currently you have to adjust the model for this - or use repG to adjust the rotation and then add support, but the support will mar the bottom surface now..

2) print first half of model at one layer height (say 0.2mm), then the last part, including top surface or any detailed part, at 50 microns. currently you have to c&p two files to get this.

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