Re: [CAD_CAM_EDM_DRO] Bridgeport CNC Mill???

Hi Hanermo

>
> > He would go from a single source of very expensive parts (the original
> > Anilam stuff, which is what I referred to) to a single source of hw, the
> > pico systems stuff, that ONLY works on EMC2.
>
> No matter how you go you end up single sourcing parts. For instance if
> you went for Gecko drives, no others would be physically compatible.
>

Well, not at all.
ANY step/dir drive, of several hundred vendors at least, would work.

>
>
> > However..
> > EMC is limited in terms of hw speed, unless you go into the expensive
> > stuff, just as you said.
> > The mentioned servo loop update time, 20 khz max, is low for high
> > resolution stuff.
>
> I think you are confusing pulse rate and servo update rate. 1KHz servo
> rate is plenty fast enough for this application. Resolution is not
> affected by the servo update rate.
>

Corrected ... servo update rate at 1 kHz is enough BUT,
EMC sw servo control is not (as teh max rate is far too low in software).
So, again, it is not by any means necessarily clear-cut, simple, easy
and or cheap.

>
> Higher resolution means that your
> encoder counter hardware has to run faster. Both Mesa and Jon's hardware
> will count at several MHz.
>

Yes they will.
Neither is a recognised industrial supplier, with compatible funcionally
identical hw available from several sources.

>
>
> > The high end stuff is not well documented, and making any changes into
> > the screen stuff is hard, practically impossible, unilke with mach3
> > screen designer.
>
> IMHO that is the biggest disadvantage of EMC. No two machines have the
> same requirements and it is very handy to be able to customize the
> screen layout to suit.
>

Agree 100% !

>
> For instance on my mill I have one page dedicated
> to different forms of probing and center finding. I do a lot of one-offs
> so this is really handy. It would be useless for a production machine.
>
> > EMC installed base for higher end stuff is very, very low.
>
> How high end are you talking? There are some serious EMC setups out
> there but there are also a lot of more mid-range installations. Would
> you consider my lathe high end? It is a Colchester Triumph 2000 with
> 10HP spindle and 3 speed electronically controlled gearbox. Servos are
> about 750W and have 1000 line (4000CPR) encoders. It works extremely
> well on EMC (with 1kHz update rate). I also have two electronic
> handwheels so it can be used like a manual.
>

This is a basic lathe. Just more powerful than most hobby / small shop
lathes.
Any servo-contolled industrial lathe, with a big spindle, is going to
work very well with EMC2 OR with mach3.
This has long been demonstrated with multiple examples amd has never
been in doubt.

Nice lathe, btw !

Advanced is anything on a lathe with multiple axes;
more than 4 axis mill,
with servo-indexed spindles,
live tooling,
multiple spindles,
multiple turrets
and so on.

>
> The mill running Mach3 is a converted Series 1 CNC Bridgeport. It has 3
> handwheels.
>
> > Plugins are few and far between.
>
> What exactly do you want to do? EMC's Hardware Abstraction Layer
> combined with ClassicLadder allow you to do a heck of a lot. For
> instance it easily controls the sequencing needed for the electronically
> controlled gearbox.
>

I want to have several axes.
I don´t need to run more than 4-5 at a time, + 2 spindles.
I need this for grinders, live tooling on lathes, indexed spindles,
multiple spindles, indexing in general, an on and on and on ...

Building the hw is easy..

> > As an example, I am using 100-200 kHz hw update rate and will be using 1
> > Mh to 2 Mhz, in the near future.
> > On a lathe, with a Centipede, and mach3.
>
> That is pulse rate, not servo loop rate. 1MHz servo update rate would be
> insanely fast. Not even an ultra light voice coil actuated positioning
> system would need that.
>

Servo loop rate in this case is 100/12 kHz, or about 10 kHz, and pulse
rate is 100 kHz and up.
Agreed, pulse rate needs to be high, and servo update above 1 kHz is
plenty good enough, as you said.

For example, the SS 1 kHz update rate is plenty fast enough. SS problems
are elsewhere..

>
> One really big advantage of EMC with servos is that you have true closed
> loop control.
>

I see no significant real need for this.
It is very nice to have.
I wish I could get this, with mach3, easily.
Yet, tens of thousands of commercial controls, and tens of thousands of
m3 users, run machines just fine without it.

It is NOT a *significant* big benefit.
Very nice to have, but thats all.
This is similar to the hard tapping thing ... nice to have, but not a
real true lack, for any except maybe a minute fraction of users.

> Even after an estop it knows exactly where the machine is
> so you can resume machining immediately without having to re-home. This
> sounds pretty minor but for a home/small workshop this is quite
> important and encourages safe working practices.
>

Certainly !
However, safe working practices are a matter of user training, not hw.
Just like excess interlocks, they get defeated when they become too much
of a hassle.

>
> With my lathe, if I
> want to reach in to clear some swarf or pick up a part that I have just
> parted off I usually estop the machine. I seldom estop my mill (running
> Mach3) because of the hassle of re-homing. If I suspect something is
> going wrong with some code on the lathe I'll immediately estop it. With
> the mill I'll hesitate. That has resulted in some nasty crashes.
>

With my lathe, I press space bar.
It holds it. Instantly.
I then run from there, with another press of space bar.

This is because I am running the Centipede.
If I was running PPdriver with mach3, the delay would be variable, and
quite long, in many circumstances.

Also, depending on what you do, sometimes feed hold in m3 is
non-intuitive .. you might be feed/rev mode for instance.

There is not question that an instant (e-stop) machine stop,
maintainging machine ref: is highly desirable.
In this particular case, EMC2 has a big advamtage of mach3.

The need for this is not great, but the desirability is, very much.
Of the approx. 50.000+ commercial users of mach3, who have paid for it,
there is no great clamour for instant feedhold / referenced e-stop.
It would thus appear that less than 1%, or 500, users have a real need
for it, as it is not even anywhere on the radar.

This is a biut like the inverse kinematics thing.
If you have it, nice, but in reality anyone who can do 5-axis cam, doe
not need it.
And the guys who do multi-axis stuff can even manage it without
high-expense cam, mostly running (like me) indexed 3+1(spindle) axis stuff.

>
> Les
>

[Non-text portions of this message have been removed]