Re: [CAD_CAM_EDM_DRO] Re: need a transformer

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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