[9 1/2]

X2 file

Hi guys, I'm currently completing my third year CNC Machinist program at our local Pollytech school. I'm attempting to project some lettering on a surface for engraving.
Here's the issue, the projected tool path does not follow the surface, as if the radius of the tool path was larger than the radius of the surface.
The surface is a 10 inch dia disk by .950 thick oriented about the Y axis and the projected tool path appears to be on an 11 inch dia. arc.



My instructor is no help as he is a CNC machinist instructor and teaches only basic 2 1/2 D tool path and geo creation as part of the course (I'm working above the class in this area and just trying to challange my skills)

So find attached the surface and lettering X2 file. I'm fairly well versed in MC but for the life of me ...............

Thanks for your assistance.

Owen

[Superman]

Hi Owen,
There are a couple of methods to program this exercise

1- create the geometry on the surface, then drive the tool using this new geometry

2- create the geometry on a flat plane, driving your toolpaths around this geometry, then wrap the paths on a known radius ( your part )

for both methods -
-start by creating a rectangle to represent the surface laid out flat
in TOP view ( rect. size X=width of surface, Y = circumference ), in this area place your text. your text will end up being vertical and on Z0 plane

method 1- select all entities and roll ( wrap ) around Y axis at the correct radius ( new text will be created on the surface ). Use the new text to drive the tool. ( comp=off, Z depth Z0 incr. = tooltip is on the text, -value cuts below the text, Rotary Axis is on Y, lead in/out= off )

Method 2- select all original text, same settings as above, BUT, Rotary Axis substitute Y with C and input the part radius. ( toolpath verify should show your tool engraving on the OD )

Moving the original text in Y alters the placement of the letters on the OD.
Engraving a point at X0Y0 ( drawn TOP ) will place it at the 3 o'clock postion ( C270 degs from TOP )
BTW. this rectangle represents 360 degrees rotation. So a 1/4 of it is equal to 90 deg. ( file this under "useless info" ).

( I'm working here from memory, at home, please forgive me if I have missed something ).

Steve

[cadcam]

create the leters above the part. go to surface finish project. use a 60 deg engraving tool.
when doing the surface Project use the option of curves and pick your letters. in the are to leave stock on drive surface say -.005 for depth of letters. this will project the letters as a path.

[Superman]

create the leters above the part. go to surface finish project. use a 60 deg engraving tool.
when doing the surface Project use the option of curves and pick your letters. in the are to leave stock on drive surface say -.005 for depth of letters. this will project the letters as a path.

This method will only work for small segments on a larger diameter

Do not use if your engraving geometry covers over a large radius,.:nono:

your geometry will lose its aspect ratio ( stretching in Y ) the further the tool is off centreline

[cadcam]

The smaller the radii the more difficult. on a larger one this will work great.as I have done mold cavitys to large parts. this not going to stretch the geo.
Please review my file as I have set the setup stock so you can see it on the curve and what you will get.

I teach this do this stuff all the time. hope this helps.
Time to leave work and go teach Class.

[9 1/2]

EDIT: Thanks Cadam, I'd not noticed your file attachment.

So I've noticed a few things I'd not done:

You made a solid of my surface and projected onto that.
Is that needed in order to do this tool path.

The tool I was attempting to use was a 00 center drill. You use an "engraving tool" I switched your tool to the centre drill (in your file) and the same problem I was having returned.
What is it about the tool that causes this problem? (center drill v/s engraving tool)



I'll study this further and try it in class tomorrow.

Owen

[cadcam]

Thank you Sir as you will find the issue you talk of wont be that way.

[9 1/2]

Well though i don't understand why my choice of tool effected the lay of the tool path on the curved surface, I got the result I wanted.

Ended up using offset Project and projecting the text onto the curved surface. Created tool paths from there.

I'll keep working on the "project tool path" to try and understand the relationship of the tool and the resultant diameter arc of projected tool path.

peach

[Mike Mattera]

Cadcam made a very good point that's important. Always put your Text/Geometry above the surface and then Project "Down" to the surface. When the geometry is below the surface, it never seems to work right.

Mike Mattera