Knee mill CNC retrofit using Anaheim
 

Is anybody out there using Anaheim Automation's "DPJ72LC" LC Series on their
knee mills?

From what I've seen the product looks fairly capable and cost effective.

I'd appreciate any comments.

Lucky Strike wrote:
Is anybody out there using Anaheim Automation's "DPJ72LC" LC Series on their
knee mills?

I'm not familiar with that company but for my own Knee mill retrofit, I
chose www.jraco.com It's a small company, but they give great service.
I have over 4000 hours on the control now and it has been extremely
reliable doing a ton of 2.5D and 3D work. It uses a proven Galil based
motion card that just plugs into a PC. JRA wrote a G-Code compiler that
translates from G-Code into the Galil motion language. The motor drives
(Servo Amplifiers) are from AMC http://www.a-m-c.com - I had to put all
the pieces together on the mill etc., but it resulted in a good machine.
The JRA system supports a handwheel (MPG) that makes setup a breeze.

One minor criticism of the program is that the peck drill cycle is a bit
non-standard and I still can't generate the entire G83 code from my CAM
software - maybe your CAM software can? For me, it requires a simple
manual edit which is a bit of a pain, but not a big deal. I don't do a
lot of drilling. Let me know if you want more info.

yada yada - just a happy customer

Cheers, Peter

On Sat, 29 Jan 2005 08:30:44 -0500, "Lucky Strike"
wrote:

Is anybody out there using Anaheim Automation's "DPJ72LC" LC Series on their
knee mills?

From what I've seen the product looks fairly capable and cost effective.

I'd appreciate any comments.

I looked at the above mentioned product. It is a stepper system. I
would avoid making a machine with steppers. Gecko Drives makes servo
drivers that use step and direction signals on the input side. For an
80 volt 15 amp driver you would spend $114.00. Of course, you will
need three drives. US Digital sells inexpensive encoders that will
work with the Gecko drives. And there are several step and direction
software packages available. Some for free and others, like MAXNC, for
a pretty good price. I have bought and used the MAXNC software that I
used to drive a small stepper driven X Y stage. The software worked
well and was easy to setup. But I had problems with the stepper motors
losing steps. To avoid losing steps the stage could not move faster
than 30 inches per minute. Gecko has an engineer who will gladly help
you decide what size motor to get, either servo or stepper. Just my 2
cents worth.
Cheers,
Eric R Snow,
E T Precision Machine

I agree, avoid stepper systems, they're yesterday's newspaper. Servos
avoid all the resonance headaches and have faster travels than a stepper
system of equal power. The saving grace of steppers is they're cheap,
but you know the old saying -- Good, fast, cheap, pick any two.

Eric R Snow wrote:

On Sat, 29 Jan 2005 08:30:44 -0500, "Lucky Strike"
wrote:


Is anybody out there using Anaheim Automation's "DPJ72LC" LC Series on their
knee mills?


From what I've seen the product looks fairly capable and cost effective.

I'd appreciate any comments.


I looked at the above mentioned product. It is a stepper system. I
would avoid making a machine with steppers. Gecko Drives makes servo
drivers that use step and direction signals on the input side. For an
80 volt 15 amp driver you would spend $114.00. Of course, you will
need three drives. US Digital sells inexpensive encoders that will
work with the Gecko drives. And there are several step and direction
software packages available. Some for free and others, like MAXNC, for
a pretty good price. I have bought and used the MAXNC software that I
used to drive a small stepper driven X Y stage. The software worked
well and was easy to setup. But I had problems with the stepper motors
losing steps. To avoid losing steps the stage could not move faster
than 30 inches per minute. Gecko has an engineer who will gladly help
you decide what size motor to get, either servo or stepper. Just my 2
cents worth.
Cheers,
Eric R Snow,
E T Precision Machine

On Sat, 29 Jan 2005 08:39:21 -0800, Eric R Snow
wrote:

It is a stepper system. I
would avoid making a machine with steppers.

Why?
--
Cliff

bud sorry a bridge port i have reto with
anaheim automation works very very extreamly well 100 part never mised a
beat!!!!!!!

Cliff wrote in news:1eaov0tta9pt4shgd5eqsa0lcnk1s5btuh@
4ax.com:

On Sat, 29 Jan 2005 08:39:21 -0800, Eric R Snow
wrote:

It is a stepper system. I
would avoid making a machine with steppers.

Why?

They are open loop for one.

Dan

Tim Killian writes:

The saving grace of steppers is they're cheap,
but you know the old saying -- Good, fast, cheap, pick any two.

My vote is also for servos over steppers except for slow, low-torque apps.

And steppers are not cheap, if you compare based on performance.

On 30 Jan 2005 01:50:24 GMT, Dan Murphy wrote:

Cliff wrote in news:1eaov0tta9pt4shgd5eqsa0lcnk1s5btuh@
4ax.com:

On Sat, 29 Jan 2005 08:39:21 -0800, Eric R Snow
wrote:

It is a stepper system. I
would avoid making a machine with steppers.

Why?

They are open loop for one.

Dan
The biggest problem with steppers is that the torque drops drastically
when the motors are close to their maximum rpm. And the max rpm is not
very high. In slow speed applications a properly sized stepper is a
good choice. They can be run open loop, which means no position or
speed feedback. And they have lots of torque at low speeds. Also,
because of the way they are made, the accuracy of positioning when
moving one complete step at a time is very good. All error is
corrected every 4th step. When microstepping more error is likely but
will still be corrected every 4th complete step. So if the motor is
being micro stepped at ten microsteps per full step then the error
will be corrected every 40th microstep. Microstepping is accomplished
by using varying voltage to the windings. Instead of energizing one
winding, or a pair of windings, all the windings are supplied with
varying voltage which will prevent the motor from locking at the
natural steps built mechanically into the motor. You can imagine this
by picturing an iron pendulum suspended between two electromagnets.
With the electromagnet on the right energized the pendulum will swing
over to it. But if the left hand electromagnet is energized the
pendulum will be attracted to it. by varying the energy supplied to
the electromagnets the pendulum can be held at any position between
the electromagnets. This is how the microstep drives work. A printer
is a good example of a stepper driven system. A stepper driven machine
tool the size of a bridgeport is a bad example. Even though a servo
driven system is much more complex electronically than a stepper
system the advantages of high speed and positioning accuracy of the
servo system outweigh the simpler stepper system.
ERS

On 30 Jan 2005 01:50:24 GMT, Dan Murphy wrote:

Cliff wrote in news:1eaov0tta9pt4shgd5eqsa0lcnk1s5btuh@
4ax.com:

On Sat, 29 Jan 2005 08:39:21 -0800, Eric R Snow
wrote:

It is a stepper system. I
would avoid making a machine with steppers.

Why?

They are open loop for one.

For many applications, with the proper controls & sizing,
they seem to work fine.
As a retrofit on a BP for light duty use ..... seems it's worked
a lot ... cheaper too, right?
--
Cliff