Gap Spacing Precision

I have been trying to print the gear bearing by emmett. http://www.thingiverse.com/thing:53451.

I haven’t been able to print it without the perimeters of each gear part becoming bonded to the adjacent part. It seems like the edge of the extrusion isn’t being placed in the correct location.

This is on a stock Taz 2 printing with abs. Is this a hardware problem or software? I am at a loss. The printer generally builds parts to the correct dimensions with the exception of hole inner diameters, but holes seem to be a common issue.

Has anyone had this problem with a Taz?

Here is a picture:

Here is the g-code.
; generated by Slic3r 1.0.0 on 2014-04-29 at 20:02:17

; layer_height = 0.22
; perimeters = 2
; top_solid_layers = 3
; bottom_solid_layers = 3
; fill_density = .2
; perimeter_speed = 60
; infill_speed = 115
; travel_speed = 180
; nozzle_diameter = 0.35
; filament_diameter = 2.77
; extrusion_multiplier = 1
; perimeters extrusion width = 0.22mm
; infill extrusion width = 0.50mm
; solid infill extrusion width = 0.38mm
; top infill extrusion width = 0.22mm
; first layer extrusion width = 0.35mm

G21 ; set units to millimeters
M107
G28 ; home all axes
M203 X192 Y208 Z3 ; Speed limits to minimize skipped steps when moving really fast courtesy of forum.lulzbot.com user 1013
G90 ; use absolute coordinates
G92 E0
M82 ; use absolute distances for extrusion
G1 F1500.000 E-1.00000
G92 E0

G92 E0
M104 S0 ; turn off extruder temperature
M140 S0 ; turn off bed
M107 ; turn off Extruder Fans
G28 X0 Y0 ; home X axis Y axis
G1 Y250 ; kick out bed
M84 ; disable motors
; filament used = 1947.4mm (11.7cm3)

And the Slic3r setup.
config.ini (3.31 KB)

I had a heck of a time trying to print that with my TAZ 3, and in the end I had to make a custom one with a bigger gap than the stock model. The literal sticking point seems to be the middle meet point of several of the gears. I think it’s partially a Slic3r issue, and partially maybe some additional filliament calibration needed on my end. I did finally get a working one though as my first Taz 3 part

It has been a real pain. Mine actually fuse at all the gear interfaces. I have tried it with the medium and fine Slic3r setups as well as Cura. It seems like there is physical limitation with the Taz.

There’s a couple of Slic3r settings that need to be changed:

; perimeters = 2 Change this value to 1.
; first layer extrusion width = 0.35mm A smaller first layer extrusion width will help prevent the edges from touching and sticking together
; layer_height = 0.22 A higher layer height will be easier to print. Once you have things printing well, you’ll be able to turn this down and can manually adjust your extrusion widths under Slic3r > Print Settings > Advanced

You’ll also want to have a higher Z axis homing height- Very similar to the last 2 images in this picture:

judging soley from the picture, it looks like you’re over extruding a very tiny bit. You can turn that down, by adjusting your extrusion multiplier slightly, say to 0.98.

Try this gcode file out and see how it works for you.
fast_bearing.01.gcode (4.34 MB)

Thanks for the info. I will give these settings a try.

I tried the changes you suggested in slic3r. It was still smashing the parts together. I was running out of time so I gave your gcode a shot.

Here is the part build with the posted fast bearing gcode.

It looks better but is still stuck. :slight_smile:

Mind posting a picture of the underside?

Sure. I will post it tonight. I don’t have the part with me.

I did increase the z home gap by .oo2 inches before this print. It is now at .005.

I know this part can be printed because I’ve done it before. I think the ideal clearance is somewhere in the .3mm range.

Check this out:

http://devel.lulzbot.com/ATTIC/novelties/gear_bearing/

There are a variety of clearances there.

I will give that a try as well. I wasn’t able to measure the clearance on the Thingiverse file so, maybe it is just too tight.

Here is the bottom of that part.

Raise the Z axis endstop adjustment to start with a higher first layer, a good full turn should probably do it. That should help keep the first layer from blending together, as long as it’s still able to stick to the bed well.