Engraving

[narvf]

How to specify shape of my tool for engraving? It doesn't matter what i will type in "shape" option of default tool - i will always get warning about no shape for tool and 45o is used by default.
And diameter, how is this related? I have 0.1mm and 45o tool. I would like engrave something on laser laminate (don't know exactly how to name this in english) and it is 1.6mm thin. So i think i need more wide tool like 60o. But where to type it?
Could someone explain this function better? Why sometimes i get engraving "inside" a letter which is great, and sometimes around letter - which also looks very good. But i would like to decide which i want to use. How to determine max depth - is it possible or it's always calculated by tool settings and width of paths?

I've added example files to show what i was doing.

[Nick]

The Shape is defined by the function - Z(w). This means
Depth(depended of width).

Example, cone 45 degree, is the function Z(w)=w
Example, cone 30 degree Z(w)= w*tg(30) === in gcodetools parameters w*math.tan(30/180*3.1415)
Example, sphere Z(w)= r-math.sqrt(r*r-w*w) // where r is sphere radius.

Why sometimes i get engraving "inside" a letter which is great, and sometimes around letter

this depends of path orientation, engraving is done always to the right of the path. You can add middle marker to the path to see it's orientation. So if you get outer engraving - just do Path-Reverse.

[narvf]

Ok, i would like to try, but i don't know where to write this
In "Path to gcode" Depth function?

[Nick]

no in Tool's shape parameter.
Add a Cone tool and edit it's shape parameter using Text (F8).

[narvf]

Will check this at home! Thank you

[narvf]

Well, i think somehitng is not correct.
When i type: w*math.tan(60/180*3.1415) for example the g code is generated. I get message about commeny in comment in linux cnc, but i deleted this line manually. When opened gcode in linuxcnc z depth is 0, not below 0, for w*math.tan(60/180*3.1415) also the same and for 45 also.

[Nick]

Can you attach your svg, and ngc files?

[narvf]

Attached files.
In ngc file i had to delete 9'th line to load this into openscam or linuxcnc.

[Nick]

And what do you think is wrong with the Gcode?

By the way, math.tan(60/180*3.1415) = 1.7319272760572555 = sqrt(3)
hmmm... python thinks that math.tan(60/180*3.1415) = 0 (because 60/180=0 (they both integers)), try to use math.tan(60./180.*3.1415)

[narvf]

Z is alywas 0 so it will not go into the material.
Maybe I don't understand something :/

[Nick]

Ok. The problem is in the "shape"'.
As I've written - in python 60/180 =0 but 60./180=0.3333
because 60 is integer and it suppose the result will be integer and int(0.333) = 0.
So you can ether write w*math.tan(60./180.*3.1415) or just compute tangent of the cutters angle yourself and just write w*1.7(...)

[narvf]

Thank you! Will try this, when i will be in my garage

[narvf]

Thanks, everything is working good

[narvf]

One more question, for 90 degress how this should be calculated? And for 120 degrees.

[Nick]

for 90 degress how this should be calculated

90 degrees bit has a 45 degrees from vertical to cutting line.
tan(45) = 1, so it will be just "w".
For 120 deg - it's w*tan(60) = "w/2."

[narvf]

Thank you very very much!
As soon as i will engrave something good i will let post here

[narvf]

Playing with engraving