[Inuk]

hey all. looking for help figuring out what seems to be unintended feed rate variances pocketing a hole. I've posted video of what the machine is doing here: [nomedia="http://www.youtube.com/watch?v=RLGqQUdQiX4"]YouTube - Router Aluminum 0021[/nomedia]

Speed seems to vary around circumference of path.

Code generated via VCarve Pro being cut is attached.
Cheers.

PS Ran a timed test over 1000mm. X axis travel rate is 50% slower than Y axis travel rate, even though the same feed rate is specified.

[camsys]

Is this a new problem that always happens, or just a problem on a specific program?
Sometimes servos go awry, or controller system settings are inadvertantly modified.

What's the machine/controller makes?

[Inuk]

The machine is an Excitech with original controller. Problem only seems to occur at very low feed rates.

[dalee100]

Hi,

I don't know your controls, but some controls have ramp speeds that slow the tool going into an arc. Particularly important on open loop systems with heavier tables and fixtures and stepper motors.

It might be just more noticeable at slow feed rates.

dalee

[camsys]

Excitech routers have a Fagor brand controller.

Assuming you have the correct I's and J's there are a number of potential
parameter settings that can cause this sort of problem.

Certain params involve axes resolutions, feedback, and feedback multiplyers, to name but a few.

I would suggest you double/triple check your I's and J's in the program, but I'm of the opinion that there's an issue with a parameter setting.

The last posting also identified accel/deccel type params that are certainly
worth looking into. All in all I'm sure your answer is in one or more parameters
do you have access to support from Excitech?

[Inuk]

Sorry I missed these replies guys. Quite possible I'm loosing my mind ! Ran into the same problem XY speed issue recently and coming back to the Zone to post about it found I'd already posted the question more than a year ago !!! Ok so I've been cutting acrylics where it hasn't been problem, but now I'm back on aluminum where it's more of an issue, so I'm looking into it again. Dalee is right it's more noticeable at the slower speeds, and Camsys I believe it's always been happening but as I say I cut mostly softer mtrls so it's not been an issue.

I can adjust the linear and curve accelerations via a hand held DSP but it doesn't make a difference.

Rerunning the test it appears that neither the X or Y are running at the rate specified by the Code. X is 50% slower and Y 50% faster !

Anyway, I've tried various postprocessors non of which seem to resolve the problem. Curiously the Fcode read can be disabled on the DSP and the feed specified directly via the DSP. Using this method the XY is speeds are equal and alls good, but it would be nice to figure it out and have the speeds specified by the pathing software.

Support is non existent, chinese machine bought used, they don't respond.

Rather late but thanks for your responses !