Printer does dots instead a circle

So my printer started doing dots instead of full circles.
I want to print a heart shape, and first thing the printer does are these 4 dots - on each side the same thing. First that, then continues in complete line to make a heart shape.
Thought its got something to do with layer height but doesnt.

Im using cura for a long time now, and it never happened before. I even thought I drew something wrong in Autocad, but of course that wasnt the issue.

Im printing in pla, layer 0.35, speed 5 first/25 later/15 outer layers/20 infill, heatbed 80/75

Any ideas?

EDIT: does even more dots as the model gets higher and then goes over them in a straight line. The thicknes of the wall is 1mm, nozzle iz 0.5mm so shouldnt be any problems there.

EDIT2: tried the g-code from slicer - almost the same thing.

EDIT3: im thinking my model is to blame, but 1mm is the thickness of the wall everywhere on the heart shape so I dont see why it first draws a few dots (like a small infill first), then the rest of the shape.

Edited 3 time(s). Last edit at 12/02/2016 01:36PM by Sardi.

Looks to me like your bed isn't level and your nozzle may be too close to the print surface, otherwise might be your print settings.

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Ormerod 113

No, everything is ok with that. I figured it out that it has something to do with setting in cura - shell thickness. It was at 0.5 (as my nozzle is 0.5mm) now Its at 1mm (and thats my wall thickness) so we will see what happens now.

Do you mean that it prints the dots then prints the heart shape over top of them. Or, does it only print dots for the semicircle? If it's the first, then it's just the way slicers interpret the models, tiny gaps in circular shapes that sometimes get filled during perimeters and some times skipped. Since the slicers break the circles into lines rather than arcs. If it's the latter I don't have any idea.

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lockezio
Do you mean that it prints the dots then prints the heart shape over top of them. If it's the first, then it's just the way slicers interpret the models, tiny gaps in circular shapes that sometimes get filled during perimeters and some times skipped. Since the slicers break the circles into lines rather than arcs.

Exactly this.
Really amazing that the slicer would break circle into lines when it just needs to draw two layers one next to each other.

Lifting shell thickness to 1mm only made the first couple of layer without that dotty infill, after cca 8th layer the dotty infill comes back and there is nothing i can do about it.

Ive printed one model with slicer and one with cura.

Slicer sees circles as arcs, as the circle part of the heart is completely rounded, where at cura you can see that the circle is actually composed of many short straight lines that create a curve.

It usually only does things like this when the model is designed with the shell thickness. If you can make it solid and print with 0 infill and no top and bottom layers it won't typically.

You can also try exporting a higher resolution model, .01 or .001mm. The problem isn't really cura pursue, it's more that when you translate an object to a stl, the model is broken into flat polygons. The more resolution you give the stl the more polygons, and the closer the flat polygons will be to an arc. The way 3d modeling works we never see truly round objects on the screen just flat triangles with shading textures that make them look round.

Tried exporting the best possible resolution for my model but to no effect on slicing programs.

But I might just google to find out how to create/export a filled 3d solid in autocad. Never done that before so I would like to try it one time to see what happens when you dont need infill.

Edited 1 time(s). Last edit at 12/03/2016 04:11PM by Sardi.

It is almost certainly to do with wall thickness and extrusion thickness. I don't recall whether you can alter the extrusion thickness in Cura (this is NOT the same as nozzle diameter). If you change the perimeter extrusion thickness OR the wall thickness of the heart a little (0.1mm or less is probably enough), you should see the issue disappear.

Dave

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dmould
It is almost certainly to do with wall thickness and extrusion thickness. I don't recall whether you can alter the extrusion thickness in Cura (this is NOT the same as nozzle diameter). If you change the perimeter extrusion thickness OR the wall thickness of the heart a little (0.1mm or less is probably enough), you should see the issue disappear.

Dave

You were right. On a couple of sites Ive read that 0.01mm is enought to get rid of the problem I had.
I went by changing the wall thickness by 0.1mm and there were no dots what so ever.