Roundover tooling and toolpaths and previews

WillAdams · November 23, 2024, 5:16pm

Wrote about this a bit at:

To explore it a bit more we look at a couple of tools:

and look into how they may be previewed.

A notable G-code previewer is:

https://tahlinc.com/products/cutviewer.html

Which specifically supports this sort of tooling via G-code comments:

(unfortunately, the developer has passed away, so its status is uncertain — the website is off-line as of this writing: https://www.cutviewer.com/ )

Suggestions for other G-code previewing tools to try would be welcome (but see below).

Here, we will look into creating G-code and files and supporting this sort of tooling.

WillAdams · November 23, 2024, 5:26pm

Draw in some geometry:

positioning it to match the offset necessary from the center of the tool:

and then assign a toolpath to cut to the desired depth (in a single pass so as to make the G-code simpler):

The toolpath and G-code are quite straight-forward:

(Design File: )
(stockMin:0.00mm, 0.00mm, -8.35mm)
(stockMax:219.00mm, 150.00mm, 0.00mm)
(STOCK/BLOCK,219.00, 150.00, 8.35,0.00, 0.00, 8.35)
G90
G21
(Move to safe Z to avoid workholding)
G53G0Z-5.000
(Toolpath: Contour Toolpath 9)
(Toolpath: Contour Toolpath 9)
M05
(TOOL/MILL,0.03, 0.00, 10.00, 41.60)
M6T56142
M03S17000
(PREPOSITION FOR RAPID PLUNGE)
G0X0.000Y-0.254
Z0.250
G1Z-1.575F254.0
X218.999F508.0
Z3.175
M05
M02

The line which we are concerned with is:

(TOOL/MILL,0.03, 0.00, 10.00, 41.60)

which we will need to change to:

(TOOL/CRMILL, 0.508, 3.571875, 1.5875, 5.55625, 1.5875)

(assuming that metric is being used)

which when opened in Cutviewer, previews as expected:

WillAdams · November 23, 2024, 6:25pm

After a bit of research (see the sordid tale at: Using a dovetail tool before a roundover tool causes dovetail tool to be used when roundover should... · Issue #47 · gsohler/openscad · GitHub ) managed to work this out in gcodepreview:

and, it also generates a matching appearance in Cutviewer: