To hang the plaques, I’m going to cut a keyhole on the back. This is done with a keyhole cutter.
The cutting process works like this:
- The cutter does rapid movement to position itself over the hole location
- It plunges into the material to the desired depth.
- It moves forward toward the top of the plaque to create the keyway.
- It stops and moves back to the hole.
- It rapids upward clear of the stock.
HeeksCNC doesn’t have an operation like this but it’s fairly simple to accomplish anyway.
I started by adding a sketch with a single line segment to represent the key way. I selected the sketch and added a profile operation. I set the parameters so the cutter would cut ‘on’ the line and at the depth I needed for the bottom of the hole (-9 mm). In the resulting path, steps 1, 2, and 3 are represented, but then the cutter moves up to clear.
All we need to do is hand edit the g-code to add rapid back to the previous location before ascending.
G90(Absolute Coordinates)
G21(Metric Values)
G17(Select XY Plane)
G54(Select Relative Coordinate System)
(tool change to 1/4″ carbide 2 flute endmill)
T1M06
(hanger)
G00X153.048Y304.802S7000.0M03
G00Z2.000
G01Z-9.000F593.970 (descend into the material)
G01X165.048Y304.802F500.000 (forward cut)
G00Z5.000 (retract out)
M02
All we need to do is add this line before the retract:
G01X153.048Y304.802
Now the backplot (shown in emc2) looks like this:
