Feed Rates - Over The Speed Limit

Hi All,

I'm just getting comfortable running Mach3 with my new DIY CNC Router table. In general things are working well. I've had some good and repeatable experiences cutting quite a few 2D parts. So at this point I thought I'd try some 3D carving.

Here's where my question comes up. When I cut 2D tool paths at 160 in/min., I see the feeds rise up to 160 in long straight-a-ways like they should. Now when I run a 3D tool path at 160 feed rate, the long straight cuts can climb as high as 600 in/min.!!!

I've checked the G-Code. The line right before these fast cuts says, F160.0. Yet it will climb to my rapid setting of 600.

I'm thinking it MUST be something with Mach3 settings.

Any help would be appreciated.

-- Bernie

I believe you are seeing the 'rapid' (G0) rates. This depends on the Mach3 tuning settings.
Your F160 only applies at G1,G2 and G3 feed rates.

There are no Mach3 settings that would do this.
I agree with Neil, that I think you're seeing rapid moves, not cutting moves.

Thanks guys.

I'll investigate a little deeper and see what I can find.


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