Re: [CAD_CAM_EDM_DRO] Re: Acceleration rates..

Hi Jarrett,

Acceleration is often more important than top speed. What is the use of
a machine capable of 400IPM if it needs half of it's travel to get up to
that speed? Twice the acceleration and half the top speed would end up
being quicker overall. What sort of work are you intending to do? If it
involves lots of long straight cuts then acceleration is not all that
important. If you are cutting a lot of detail then acceleration is vital.

I would say that in general you don't want the machine to take more than
0.5 second to get up to cutting speed. Remember when you go round a 90
degree corner one axis has to stop and the other axis has to accelerate
to speed. If you have low acceleration then the machine is going to
crawl if it needs to cut a complicated shape. Get hold of a copy of
Mach2 or TurboCNC and set it up with your expected acceleration and top
speed parameters. Now run a job and see what speed the machine actually
runs at. You will then be able to play with the values to see what
effect they have on the overall cut time.

Les

Jarrett & Heidi Johnson wrote:

>I'm working through some design disicions and trying to get my head around
>mill acceleration. My plan is to mill foam predominantly. I'm wondering if
>acceleration rates are really a concern or not. I would figure that not to
>many people want there system to take 5 seconds from a stand still to
>accelerate to 10 ipm or something but.. what is acceptable? I would like to
>rapid @ ~400IPM and be able to accuratly mill at up to 200-250IPM. The
>system I'm looking to build has a fairly large foot print with a ~200lb
>gantry. Obviously 120 oz-in steppers won't cut it [ pun intended] but..
>should I be able to go from 0 to 250 ipm in 5 seconds?
>Does it really MATTER? Am I looking at the wrong side of the design??
>
>Opinions welcome!!!
>
>Jarrett Johnson
>
>