QCAD.org Forum

Hi, using Windows 11 Pro, QCADCAM V 3.31.1.0

Are the feed rates (feed per rev) units in mm/rev or inches per rev

Similarly are the plunge rates (penetration rate) in mm/minute or inches per minute

I guess both of these depend on your unit settings in the document properties or in the CAM Config (mine states mm).

Sorry new user question.

Barry

These values are copied 1:1 to the G-Code output of your post processor (e.g. a feedrate of 100 yields G-Code output F100). Please enter the values exactly as you want them to appear in the G-Code file.

Some controllers support different feedrate modes, for example G94 (units per minute) or G95 (units per revolution). Please refer to your controller manual to see what is supported by your controller. Default is usually units per minute.

And 'units' depend on G20 (inches) or G21 (mm)
One of G20-G21 and G93-G94-G95 are usually included in a header.
Otherwise the controller uses its defaults.

Please note that a standard post-processor may not always include these, but they are highly customizable.
The drawing unit is not directly tied to a G-Code.
CAD is basically unit-less, the unit is nothing more than how you name a value.
Then 1 unit can be 1mm, 1inch or 1km, a light-year .... In short 1.0000... something

Exporting a 10.0 by 10.0 rectangle in G-Code can then in mm or in inches depending G20/21.

Regards,
CVH

Many thanks, being a retired scientist I have have spent most of my life with the unit of time as seconds. Knowing its selected unis / minute certainly helps and seems to be sensible.

cheers

Barry

Hi,

Units per minute is also handy because the spindle speed is universal in revolutions per minute.
Avoiding a factor 60 or 0.01666... in many calculations like chip-load, cutting edge speed and so on.

Regards,
CVH