Properties window = Time?

Howdy all~!

I ran a job yesterday, and when I selected the [Properties] menu item, I noticed that it gave me an estimated run time of 18 minutes, (see attached image).

So, I decided to actually time the job, and the time came out much different = actual time was 32 minutes. Nearly Doubled~!
Thus far, it is the only one I have compared the time, but I am curious if anyone else has come across this.

Thanx -

Hi

The docs show this under Axis > Menus

Properties - The sum of the rapid and feed moves. Does not factor in acceleration, blending or path mode so time reported will never be less than the actual run time.

I think it should read ' will always be less than actual run time'

It takes no account of the time it takes to get to the feedrate specified, or the reduction in feedrate required to blend a move between 2 or more axes, or the effect of having a very tight path mode set.

So don't base any quotes that will cost you money on it!

regards

ArcEye wrote:

So don't base any quotes that will cost you money on it!

Thank you~!!! = That is *exactly* where my mind went!!
I've been given my first commission/job & I am trying to determine how much charge for running the CNC and the subsequent follow up of my time.

You can always run it in a simulation, that should be much closer to the real run-time.

But then there is set up time, changing the cutter that breaks half way through .............................................

Check out the thread on the new beta trajectory planner:
www.linuxcnc.org/index.php/english/forum...rams-wanted?start=30

Understanding the changes discussed in that thread will help you understand why the run-time cannot be predicted without actually running through it. Basically when you have a straight line cut leading into an angle, the straight cut must decelerate to match the speed at which the next move starts its move. The forum thread uses a large series of spirals to show how much slower your cut speed is than your Feedrate setting. It seems like the new planner will be better...

I'll check it out, thanx~!