Re: Max feedrate

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "andrewyslee
<andrewlee@s...>" <andrewlee@s...> wrote:

> Hi,
>
> In Flashcut feedrate/ramping setup, one has to input values for the
> max. feedrate for the x-axis, y-axis and z-axis. Then there is
> another "general setting" one for "max arc feedrate and one

for "pt.

> feedrate - linear". Am I correct to assume that this is the overall
> linear interpolation max feedrate? If so, I wonder if there is some
> connection between the max. feedrate for the x, y, z feedrate and

the

> max. linear interpolation feedrate
>
> Eg. if max feedrate for
> x = 15 ipm
> y = 15 ipm
>
> Should one set the max linear interpolation feedrate to be also 15

ipm

> or since linear velocity may be a vectorial addition of the x
> velocity and the y velocity, it should be set higher, example,
> 15 ipm X squareroot 2 or something like that?
>
> Thanks

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I'm kind of new to Flashcut & CNC myself, but when I was setting up
my machine I discovered that it will only tolerate about 1/3 the
seperate axis feedrate when doing a 2 axis move. Test it yourself
with a simple G code program like:

G01 X5 Y3 F (fill in your test feed rate)
G01 X0 Y0

and check to see if steps are lost. I got the circular interpolation
figure much the same way, having the machine do a 2" circle drawn in
Cad and converted to G code until I found a speed that didn't drop
steps, which was only about 1/6 of the fastest single axis move
possible.

Once you get the fastest feedrates for these 2 settings, you'll
probably want to derate them to %70 of their values for reliability.
Now that I have the machine setup right, it will run hours on end
with no step loss.