Tag: CNC-3018XL

The CNC-3018XL fit into its new home with the Run/Hold buttons toward the front:

Which is rotated 180° from its previous orientation, putting Quadrant I and the most-positive coordinates in the left-front corner. Rather than stand on my head while trying to use the jog keypad upside-down, I reversed the axis directions by changing the GRBL Direction port invert mask value from its previous 4:

$3=7

Because the home switch positions haven’t changed, reverse the Homing dir invert mask from 0:

$23=3

The XY origin remains in the center of the platform, so the G54 XY offset didn’t change. The Z offset puts the Pilot pen tip 10 mm above the platform, which will change as you (well, I) touch it off on the paper:

G10 L2 P1 X-169.0 Y-149.5 Z-44.0

Jog to the left rear corner (with Z at the home position) and set the G28 park position:

G28.1

Jog to the right front corner (also Z homed) where (manual) tool changes take place:

G30.1

Configure bCNC for manual tool changes without probing at the G30 position:

The machine will move to the tool change position at each Tn M6, the operator (that would be me) inserts tool pen n as needed, pokes the Run button, and watches it draw pretty pictures in a resolutely techie manner:

For completeness, the current GRBL settings:

$$
$0=10
$1=100
$2=0
$3=7
$4=0
$5=0
$6=0
$10=1
$11=0.010
$12=0.020
$13=0
$20=1
$21=0
$22=1
$23=3
$24=100.000
$25=2000.000
$26=25
$27=1.250
$30=1000
$31=0
$32=0
$100=401.284
$101=400.000
$102=400.000
$110=3000.000
$111=3000.000
$112=3000.000
$120=1000.000
$121=1000.000
$122=1000.000
$130=338.000
$131=299.000
$132=44.000
$#
[G54:-169.000,-149.500,-34.450]
[G55:0.000,0.000,0.000]
[G56:0.000,0.000,0.000]
[G57:0.000,0.000,0.000]
[G58:0.000,0.000,0.000]
[G59:0.000,0.000,0.000]
[G28:-335.000,-3.310,-3.450]
[G30:-1.000,-297.000,-1.000]
[G92:0.000,0.000,0.000]
[TLO:0.000]
[PRB:0.000,0.000,0.000:0]

The weird $100 X axis step/mm value is correct, because QC escapes are a thing.

After fixing the X axis drive, the CNC-3018XL table moved properly again, so I measured its overall alignment:

The +Y side (on the left in the photo, keeping in mind I’ve rotated the axes) turned out to be 0.7 mm too low, so I made a set of riser blocks to level the tabletop:

The 10 mm height would ram the tip of a Pilot pen about 10 mm below the tabletop surface, were it not for the spring-loaded pen holder:

The 0.7 mm difference in height levels the tabletop:

The OpenSCAD code produces an SVG outline I intended to use for a foam pad, but then I found a quartet of springs that worked even better:

So it’s now aligned within ±0.3-ish mm across the surface, with the unflatness of a slab cut from a 1955-era Formica kitchen countertop accounting for most of the difference in a swale from Quadrant III across the origin to Quadrant I.

Which a check plot using an old file shows will be Flat Enough for my simple needs:

Having the camera alignment remain exactly spot on came as a pleasant surprise:

The faded cross to the left came from the table’s previous position; there’s no positive index between the countertop slab and the underlying T-slots.

Part of the motivation for these blocks was to verify PrusaSlicer automagically handles filament / color changes between two objects, as long as OpenSCAD hasn’t unioned them as part of a common transformation. Not having to cut out the socket around the text simplifies the code from what I’d been doing with previous objects.

The OpenSCAD source code as a GitHub Gist: