Re: [CAD_CAM_EDM_DRO] Re: need a transformer

These are series 1 mills. For Z on both, The servo motors are 100 volt 40lb-in running off of a G320 at 72 volts DC. Using a 2.5:1 reduction. Works out to 20,000 steps per inch. Using a 200 in quad encoder. You can acually run a servo on one axis and a stepper on the others. Just a different drive of course. Thats a big mill you're to driving the knee on. It can be done though.

Ron

Jessie <rebel307@...> wrote:
Ron,
You mentioned you have knee driven Z BP mills. This is a series 2
with a J4 head. The table is 16in by 36in. When these machines came
out, the knee only raised for position and the quill handled
drilling cycles. I have found a few people on the new who
retrofitted them but never could get info out of them. You knee must
go up and down reliably. Is there any way you could give me your
specs? I would go servo for motorvation but I cant justify the cost
in a hobby shop.
For steppers I got all 3 of them new from homeshopcnc.com. They
are 4 wire steppers so I am useing full winding for sure.
Jessie

--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@...>
wrote:

>
> I read a few posts back that you are using a 1700 oz-in motor for

Z. You are driving the knee and you cant get over 5 ipm? There is
something definitely wrong with that. I run two knee driven
Bridgeports with servos. And they get 60 ipm on Z with no air assist
or counterbalancing. One of these had an original stepper system on
it and it would do 30 ipm on Z driving the knee without help and it
was an 1100 oz-in Slo-syn with 2.5:1 reduction, crummy old bandit
controller. Are you running half winding or full winding on the
motors?

>
> 5 ipm on Z would be 100 rpm of the motor with a 2:1 reduction. A

1700 oz-in stepper is stalling at 100 rpm and it has air assist?
Something is definitely wrong. I'd be back looking at the power
supply. Check voltage amps etc.

>
> Ron
>
> Jessie <rebel307@...> wrote:
> Jon and Ron,
> The steppers actually run smooth all the time, when you throw in a
> program is acts as if its overriding your set ramping speeds when

it

> goes to make movements. I tried turning the constant velocity

option

> on and off and it didnt really make a difference. Then someone
> mentioned to me that even in a 1inch rapid is going to try to max
> speed just like in a 20inch rapid. That makes since, in the long
> rapid is has more time to ramp up, short rapid is going to be as

if

> its overriding the set ramping speeds. But now,, throw in a 5IPM

g01

> code on the Z axis and it will stall it.
> I now have the mill setup as a manual to move the table around to
> put the head on. The ballscrews all turn very freely and extreamly
> smooth. The knee without air assist, you can actually roll it up
> then let go and it rolls itself back down. The air assist just
> pushes up on the screw to take the load off the ballnut and

balance

> the load so its the same up or down and does a good job.
> I thought about this, with these motors in full step I would
> still have a .0005 resolution and we all know your not going to

get

> that close with conventional endmills and drill bits, a thou maybe
> but all cutters are going to flex. My idea was to try it in full
> step or half step and see if the lower pulse count per unit would
> solve the trouble. These are hybrid steppers and microstepping

does

> kinda hurt the torque a bit from what I have read.
> Jessie
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@>
> wrote:
> >
> > Another thing to check is the active high or low setting for

step

> or dir on the motor outputs screen. My experience has been the
> motors will run on either one but on the wrong setting they run

like

> heck.
> >
> > Reading the ratios he has, they sould like they are too high.
> I'd look at coupling them direct or even swapping the timing

pullies

> around. Putting the large one on the motor if the motor mounts

will

> allow it. That would still be .0005" resolution at the screw.

Ample

> for most mills. The step motors are large enough if it's the same
> machine I'm thinking this thread is about.
> >
> > Ron
> >
> >
> > Dan Mauch <dmauch@> wrote:
> > Recently ,I have been seeing more and more issues with
> newer computers not having sufficent output on the parallel port.
> The output voltage is about 3.2 volts on them but the Gecko drives
> require 4.2V but I have seen them run quite well at 3.8V.
> > To see if this is the problem look at the end of the cable

coming

> from the parallel port. Locate the pin numbers that you set up in
> the config file for X direction. Place a wire in this pin and
> connect a voltmeter set to about 20VDC. Connect the red lead to

the

> X dir pin and the black lead to pin 18 of the parallel port. Read
> the voltage Then using the jog keys jog the axis in both

directions

> recording the voltage. If is is around 3.2 to 3.3 VDC then that

may

> be your problem. You will need a parallel port booster to up the
> ouput to 5VDC
> > Dan Mauch
> > low cost stepper and servo motors.
> > cases for Gecko drives
> > kits and assembled 3-4 axis drives
> > www.camtronics-cnc.com
> > www.seanet.com/~dmauch
> > ----- Original Message -----
> > From: turbulatordude
> > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > Sent: Thursday, June 15, 2006 6:24 PM
> > Subject: [CAD_CAM_EDM_DRO] Re: need a transformer
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Jessie" <rebel307@>

wrote:

> > >
> > > Jon,
> > > The steppers are on a 2:1 ratio with the screws. That works

out

> > > too 20,000 steps per inch with microstepping and 40,000 on the

Z

> > > cause its geared down even more. The motors when they take off
> and
> > > run, run smooth as silk. I did all the tuning on the geckos,

got

> > > compentation for the bigger motors set, got the trimpot set to
> run
> > > as smoothly as possable. In mach2 enhanced pulsing is on,

motor

> > > ramping is set on the Z as low as possable. On the X&Y it dont
> have
> > > to be so picky about the ramping but on the Z I can set it to
> 5IPM
> > > with nothing but ramping and it still stalls. Zaxis also has

air

> > > assist.
> > > The computer, AMD athalon XP 2000+ 256megs ram. Kernel speed
> runs
> > > smoothly at 45K. Also the computer is setup just for mach2,
> nothing
> > > else installed its on a clean install of XP. I tried slowing

it

> to
> > > 25K and still no help. I havnt got the machine up and going at
> the
> > > moment cause I just moved, need to assemble everything into

the

> new
> > > shop. This computer is an Athalon64 3800+ and it might go into
> the
> > > shop on the mill if I build another machine for personal use.

So

> far
> > > havnt seen the need for a new computer here.
> > >
> > > Jessie
> >
> > If it stalls so easily, I would put a hand crank on it and

verify

> that
> > the axis moves freely.
> >
> > Dave
> >
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> >
> >
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> >
> >
> >
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> >
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