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anwofi

Achieving best print quality

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Hello,

after reading this blog-post and realizing waht superb quality one can achieve on an ultimaker, i've tried to get the best out of my machine.

As test-object i've chosen the thingiverse owl. I've tried for a 0.075 mm layer thickness and 50 mm/s speed several settings for temperature, infill ratio, etc.

As result i've got an overall satisfying quality. However there are two small issues i'm not sure how to fix. At the head 'small holes' are remaing, also there is a slight overextrusion at the very top of the structure. (fig. 1) Overall there are some minor issues at the print surface. (fig. 2)

Has anyone an idea how to improve the overall quality?

Regards,

Andreas

DSCN0417.JPGDSCN0419.JPG

 

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I have printed the owl at really great quality at 0.1mm layer height, check my albums :)

Can you post the settings used?

What revision of the Ultimaker do you have?

What modifications do you have? E.g. clip at extruder drive for retraction, etc.

What filament (supplier/type) do you use?

Can you supply a simple print of a 20mm cube?

Then it's easier to help :)

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Sometimes smaller layers come out worse for me. I try to stick with .2mm and tune everything for that.

Anyway, my only suggestion is that to fix the top of your owl, in cura, the "bottom/top thickness parameter, under "fill" section should be 2 or 3X the value of your layer height. So if you are doing .075mm layers, make this either .150 (two layers on top of owl head) or .225 (three layers). This will greatly reduce the likely-hood of holes.

I'm not sure if your blobs are due to overhang but if so then greatly reducing the speed will help. I can get almost horizontal printing at 20mm/sec. If you have an ulticontroller and are printing at say 70mm/sec then when you get to the chin of the owl dial it down to 40% (50 * 0.40= 20). This might also help with the top of the head. Else if using cura, then go to the tab with speeds and lower the perimeter speed to 40%.

 

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The lowest I'll ever print is 0.1 mm. I think that if you go lower then that, other variables are becoming more importent. For example at 0.05 mm, the effect of the deviation of the filament-thickness becomes much more important. The filament always variates a little bit in thickness (maybe 0.02 or 0.03 mm through the whole spool). Also when the head is travelling over the object can cause more damage to the print because of the small layerheight. And many more things like this. The bigger the object you're printing, the bigger the layerheight can be to still get a very smooth finish.

Indeed lowering the printspeed improves overhangs but still, because it's a small object, the extruded plastic doesnt have enough time to cool before the 210C nozzle touches it again... Adding a second fan helps a lot!

And optimizing the PLA diameter so that it's JUST enough and you don't get over-extrusion. For straight objects without overhangs a little bit overextrusion of no problem, sometimes even better but with small objects and overhangs it's better that it extrudes only the nescesary ammount of plastic.

 

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For testing surface quality and small layers I made this compressor wheel:

http://www.thingiverse.com/thing:53455

I scale it down to 50% then the print is fast but challenging.

cw1.jpg

click for larger image

I am quite satisfied with this print quality though there is always room for improvement. ;)

The layer height in the picture is 0.05mm, pla-diameter and steps-per-e are standard. And I am using two fans, which helps a lot.

Maybe you try my gcode and test it for yourself. With cura you can use the gcode to see my print profile.

comp_wheel.gcode

If I reduce the layer height to 0.02mm I have to reduce the extrusion, too. Otherwise the print quality is getting worse.

But I do ask myself, Is a layer height lower than 0.1mm really necessary or even usefull? Most of the time I am using 0.15mm layers and this is totally OK for me.

 

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Hey blecheimer, I also have two fans using the fan duct of Ian. But could you please share the stl files for the fan ducts that you use? I'm attaching a heated bed to my UM and want the fan ducts to blow more precise at the nozzle. Your's look perfect!

 

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