Engraving curved surfaces is easy using bCNC autolevel feature.
bCNC is an advanced fully featured g-code sender for GRBL. bCNC is a cross platform program (Windows, Linux, Mac) written in python:
https://github.com/vlachoudis/bCNC
For this example i will engrave a pieze of PVC pipe 50 mm in diameter:
The first step is "scan" the surface to get a "map" of depths.
For this i will use a DIY very simple probe, consisting basically in a switch glued to a 6mm screw, attached to the spindle grant:
Afther opening bCNC, loading your gcode and settig x, y, z origins go to "Probe" dialog.
There you will find the "Autolevel" section.
In this section you can set the parameters needed to "scan" the surface you want to use.
The most importan part is the dimensions and number of scan points you need:
In this case my gcode dimensions is around 27x27 mm.
I checked the max Z depth i will have, being -5 mm.
So my scan dimensions are:
X: -15 to 15 mm
Y: -15 to 15 mm
Z: -6 to 1 mm
I used 10 divisions in Y axis, because curvature is in this axis.
For X axis 5 is enought.
If the surface is irregular maybe you need more points to scan.
You can also set the speed of probing in "Probe Feed".
if you have a lot of points maybe you should speed up it a bit, but you will loose some precision.
You will see a yellow grid representing the area to scan with its subdivisions.
When everything is configured you can start scanning by pressing "Scan" gear icon.
Then your CNC will do a probe at each point, stopping when the probe hits the surface and saving depth value.
At the end of the process you will have a map of depths of the surface:
Now is time to mount the bit used to mill.
You must set the Z=0 for this bit in the highest part of the surface, in this case it is in the center .
Once you get the bit tip in the highest part and set Z=0 in the "Control" dialog you must go again to "Probe" dialog and set this point as Zero for the depth map:
This step is very important, if you don't do it you problably will broke something...
You will se how values change to fit the highest part to 0.
Ok.. we are ready to mill.
This depht map will be used by bCNC as the Z=0 for the gcode, so your flat gcode will be "proyected" to the curved surface.
You can see the video here: https://youtu.be/dgqRBbZXwIA
bCNC is an advanced fully featured g-code sender for GRBL. bCNC is a cross platform program (Windows, Linux, Mac) written in python:
https://github.com/vlachoudis/bCNC
For this example i will engrave a pieze of PVC pipe 50 mm in diameter:
The first step is "scan" the surface to get a "map" of depths.
For this i will use a DIY very simple probe, consisting basically in a switch glued to a 6mm screw, attached to the spindle grant:
Afther opening bCNC, loading your gcode and settig x, y, z origins go to "Probe" dialog.
There you will find the "Autolevel" section.
In this section you can set the parameters needed to "scan" the surface you want to use.
The most importan part is the dimensions and number of scan points you need:
In this case my gcode dimensions is around 27x27 mm.
I checked the max Z depth i will have, being -5 mm.
So my scan dimensions are:
X: -15 to 15 mm
Y: -15 to 15 mm
Z: -6 to 1 mm
I used 10 divisions in Y axis, because curvature is in this axis.
For X axis 5 is enought.
If the surface is irregular maybe you need more points to scan.
You can also set the speed of probing in "Probe Feed".
if you have a lot of points maybe you should speed up it a bit, but you will loose some precision.
You will see a yellow grid representing the area to scan with its subdivisions.
When everything is configured you can start scanning by pressing "Scan" gear icon.
Then your CNC will do a probe at each point, stopping when the probe hits the surface and saving depth value.
At the end of the process you will have a map of depths of the surface:
Now is time to mount the bit used to mill.
You must set the Z=0 for this bit in the highest part of the surface, in this case it is in the center .
Once you get the bit tip in the highest part and set Z=0 in the "Control" dialog you must go again to "Probe" dialog and set this point as Zero for the depth map:
This step is very important, if you don't do it you problably will broke something...
You will se how values change to fit the highest part to 0.
Ok.. we are ready to mill.
This depht map will be used by bCNC as the Z=0 for the gcode, so your flat gcode will be "proyected" to the curved surface.
You can see the video here: https://youtu.be/dgqRBbZXwIA
Hello, this is helpful. On a complex textured surface, it's not always clear where the highest Z point is. Is there a way to find the highest point? It would make sense for the software to set the Z to the highest probe data point. Curious.
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