I’ve been wanting to try out relief carving on my CNC machine for awhile now, but hadn’t found a decent set of tools to do it.
Vectric VCarve looks awesome, but it’s pricy! The desktop version (which would be fine for my needs) is USD$349. That’s more than my CNC machine cost to build. Luckily, there are some smart people who made, perhaps less pretty, but fully functional software to do the task.
I found this image searching google images for “depth map”. There are plenty of images available. There are also tutorials out there for taking a 3D object like an STL file and converting it to a depth map, though I haven’t tried that yet.
I hooked up the DW660 cut out tool and used this Milescraft V Groove Router Bit. The specs don’t list the exact angle, but it’s somewhere around 60 degrees, so that’s what I used.
I then screwed a scrap piece of about 3/4 inch thick wood, I think pine, to the spoil board. I drilled and countersunk the screw holes to ensure the bit wouldn’t hit them if it passed over that section while homing.
I changed the settings for Gcode Header to
$32=0|G90|M04 S1000 and Postscript to
M05 to match what I normally use on the machine. Also disabled G-code arcs and made sure comments are suppressed (the software I use to send the gcode does not like the comments). Also change the units to mm, since that’s what all the other software expects.
I used these settings for the image:
- Image height: 100mm
- Depth color: Black
- Tool diameter: 6.35mm
- Tool end: V
- V-Bit Angle: 60
- Scan Pattern R then C
- Feed rate: 600mm/min
- Plunge feed: 180mm/min
- Stepover 0.5mm
- Z Safe: 1mm
- Max depth: -8mm
What I should have done was generate roughing gcode to cut out the bulk of the material in thiner, faster layers. But I didn’t do that. It would have had 2 advantages:
- When the cutting first started, it plunged the bit 8mm deep and started cutting at a fairly fast speed. That burnt the wood and burnt the tool, probably dulling it quite a bit. I’ll have to be careful about that in the future.
- Would have let me use a much higher feed rate for the final pass. With the settings I used, this too over 3 hours to cut.
Running the job
I loaded the gcode into LaserWeb, homed and zero set the machine at the bottom left corner of where I wanted to cut, with Z at the surface of the wood.
Then I raise Z and hit the check outline button to make sure it is fully on the wood. Then run the job.
I’m pretty happy with my first attempt at this. I can see a lot of room for improvement, particularly in making it faster without burning the wood by cutting too deep. I might also have to adjust the controller’s max Z rates, since I think that was limiting the overall speed. Using a ball tipped bit instead of a V bit would also speed things up, since the stepover wouldn’t have to be quite as small.