Re: Help a confused newbie out please
Posted by
Alan Marconett KM6VV
on 2002-11-12 13:01:24 UTC
Hi Caudlet,
You're right!
If your part program ran you into the limits, you WANT to evaluate WHY
you ran into the limits! My example would be that my Sherline's work
envelope can sometimes hamper my moves. I've got the rotary table on,
and I want to do a "retract" move that sends me up to the '+' limit of
my 'Z' axis. It hits the stops (what stop, the saddle nut runs into the
end of the ways). Probably my first and most important limit switch to
add! Nothing wrong with the part program particularly, except that I
exceeded my work envelope. The 'X' axis in the Sherline mill has Allen
head cap screws to limit the travel, better I think then my old
Sears/Sherline mill (which had none), but a HARD stop none the less.
I'm thinking I can somehow add a limit switch bracket under these screw
heads, and I've yet to figure out the other axis. (open to suggestions
for the mounting of limit switches on the Sherline!).
I recall that FlashCut has envelope parameters, something that I
initially put parameters into my STEP4 controller program for, but never
implemented. These, I believe, are quite "physical", and need to be
referenced to machine coordinates (limit switches). It will also
involve moving from G53 "Physical coordinates" to G54-59 (coordinate
system). I'm also STILL learning, and haven't ventured very far into
using the coordinate system, although I've implemented it.
Yes, a known reference point on the stock (don't machine it away!) is
excellent, and what I like currently to do. And If I've got it correct,
using the home switches for G53 "physical" coordinates (home!), and then
touching off the stock in G54 (coordinate system) will give me (you
too?) a set of offsets to reference to (can't machine 'em away)! This
will require home/limit switches. Yes.
For reference points that MUST (and before I get home/limit switches) be
machined away, I'm thinking a toolmaker's button (maybe in this case a
little SQUARE post) that can be mounted out of the way could be used for
a G53 home, and then the stock would be in G54. 'Till I get those pesky
home/limit switches mounted!!
FWIW,
Alan KM6VV
caudlet wrote:
You're right!
If your part program ran you into the limits, you WANT to evaluate WHY
you ran into the limits! My example would be that my Sherline's work
envelope can sometimes hamper my moves. I've got the rotary table on,
and I want to do a "retract" move that sends me up to the '+' limit of
my 'Z' axis. It hits the stops (what stop, the saddle nut runs into the
end of the ways). Probably my first and most important limit switch to
add! Nothing wrong with the part program particularly, except that I
exceeded my work envelope. The 'X' axis in the Sherline mill has Allen
head cap screws to limit the travel, better I think then my old
Sears/Sherline mill (which had none), but a HARD stop none the less.
I'm thinking I can somehow add a limit switch bracket under these screw
heads, and I've yet to figure out the other axis. (open to suggestions
for the mounting of limit switches on the Sherline!).
I recall that FlashCut has envelope parameters, something that I
initially put parameters into my STEP4 controller program for, but never
implemented. These, I believe, are quite "physical", and need to be
referenced to machine coordinates (limit switches). It will also
involve moving from G53 "Physical coordinates" to G54-59 (coordinate
system). I'm also STILL learning, and haven't ventured very far into
using the coordinate system, although I've implemented it.
Yes, a known reference point on the stock (don't machine it away!) is
excellent, and what I like currently to do. And If I've got it correct,
using the home switches for G53 "physical" coordinates (home!), and then
touching off the stock in G54 (coordinate system) will give me (you
too?) a set of offsets to reference to (can't machine 'em away)! This
will require home/limit switches. Yes.
For reference points that MUST (and before I get home/limit switches) be
machined away, I'm thinking a toolmaker's button (maybe in this case a
little SQUARE post) that can be mounted out of the way could be used for
a G53 home, and then the stock would be in G54. 'Till I get those pesky
home/limit switches mounted!!
FWIW,
Alan KM6VV
caudlet wrote:
>
> --- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> > Hi Jerry, Jim,
> >
> > On the subject of "loosing position/counts", if the stepper(s) are
> > stopped abruptly with out deceleration, they WILL loose position
> (the
> Guys: I guess I am confused. I am trying to visualize a situation
> where I would want to continue on with a program that has just driven
> my table into the limit switches. At that point I think I would like
> to take a deep breath, move my table back to home then check the code
> that caused the problem. I understand the issue that once you lose
> your place with an open loop system you are pretty much SOL on
> getting things back to absolute 0,0,0. I always try to set my
> material up so I have a known reference point by using an edge feeler
> or conversly setting my machine to some 0,0 point and moving the
> material to be back at zero using the offset method.
>
> Like I said, I'm confused so help me out.
>