Re: [CAD_CAM_EDM_DRO] Re: UCMI Interface

William Scalione wrote:

> Jon,
>
> Lets see if I understand you right.
>
> My cnc router will do cuts at 300ipm but I need to slow it down
> as at that speed corners will be rounded sometimes 1/2" or more.
> If I change the acceleration numbers in the ini file, will that help
> with my problem?

There are a couple of ways of managing this. You have the acceleration
parameters in the .ini file, which should be set pretty close to the max
acceleration the machine is actually capable of, otherwise the EMC
will be rounding the corners even more than necessary. So, yes,
finding the highest acceleration that will not cause problems like
losing steps or tripped servo amps is the first thing to do.

Then, there is the G61 (exact stop mode) modal G-code, which
means that the machine is to come to a complete stop anyplace
where a blended move won't pass exactly through the endpoint.
This will slow down your program quite a bit, but there will be no
rounding of the corners whatsoever.

Without the G61, whenever the machine starts to decelerate an axis
at the end of one move, the other axis begins to accelerate. For
slow moves, this produces very little rounding. For rapid movement,
the rounding can be quite large.

Finally, you can change the program so that the ends of each line
have a several inch section at low speed programmed as a separate
G-code block, which will give the best performance, as you are
specifying what you really want the machine to do, vs. allowing EMC
to guess at it.

Maybe the G61 will work fine for your needs.

Jon