Ok, so I ordered the Kittaz, put it together, and printed a calibration cube. I love it, it worked great. However, when i go to print a circle, or round objects in general, I get problems with the shape. I have looked for answers online, I’ve calibrated the x-axis, y-axis, and z-axis steps. The surface is leveled, the extrusion steps are calibrated. I have no idea what’s going on, which leads me to believe it could be a software issue? I am using Slic3r and pronterface. Also, when i turn the speed down in slic3r, it doesn’t seem to change the print speed. Any help would be greatly appreciated.
This is likely the result of the part you are trying to print. More specifically… how the part was converted from CAD into a 3D print-friendly file format and then sliced for printing.
The printer gets instructions from the G-code. The g-codes are typically in ASCII text (human readable) files. This means if in doubt that the printer is doing the right thing, check to see what the g-code is doing.
You can find the Marlin firmware g-code reference here:
When printing “circles” there are two ways to do it.
The G2 and G3 commands tell the printer to move in an arc-shaped path. The printer will calculate the circular interpolation of the X & Y axis to perform a perfectly circular move. G2 moves in a clockwise direction and G3 moves anti-clockwise.
But if you were to search your gcode files for G2 and G3 commands… you probably wont find any. This has to do with how files are converted from CAD … they are typically “meshed” into a bunch of tiles (typically triangles). Each tile is technically “flat”. A stereo-lithography file is created (usually a “.STL” but it could be a .OBJ or a .3MF or even a few others).
Your slicer software uses that file (which has a mesh) and slices it into layers. It will generate gcode that follows the path (within the layer) of those flat-surfaces. This means that a circle is really a series of straight line-segments and are not actually “round” because the source file doesn’t technically have any true “curved” surfaces… it’s a mesh created from a lot of tiny flat tiles to simply approximate a curve without actually being a curve.
But this also means that the quality of the circle is dependent on how many tiles were created in the mesh.
Most of the time you’ll see “G0” and “G1” commands. G0 is conventionally used to move the printhead (quickly) without printing (not extruding filament as it moves) and G1 is conventionally used to move at a set feed-rate while also extruding filament as it moves. This is not strictly true. For example the wipe commands that LulzBot uses to wipe the nozzle at the start of a print job uses the “G1” command without extruding.