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wbleeker
05-30-2009, 10:08 PM
Hi guys
I have a 12 inch Vertex rotab and a BS1 Dividing head and I want to set them up with steppers or servo's to run off a divisionmaster, I am not an electronics guru! can I have some advice on how to do it please? I haven't bought anything yet, I am waiting for info.
Thanks Will

macona
05-31-2009, 03:20 AM
I like servos. So I would use a small DC motor with an encoder on the back and a Gecko 320. Connect it to the handle shaft with a XL timing belt and pulleys. Use Mach3 to control it.

Something like this might work:

http://cgi.ebay.com/CNC-MINI-Mill-Japan-CIM-60W-DC-Servo-Motor-256-Encoder_W0QQitemZ220407197132QQcmdZViewItemQQptZLH _DefaultDomain_0?hash=item33514aedcc&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318%7C301%3A0%7C293%3A2%7C294%3A50

John Stevenson
05-31-2009, 07:56 AM
Will, not done a 12" vertex but done 8" and 10" which share the same mounting and I have done a BS0, in fact that is in bits at the moment as I had to rob the mounting for another job.

The mounting part is reasonably easy, simple turning and drilling,
One adaptor tube, two halves of an Oldham coupling and a torque disk, O and yes the motor.

Macona offers the idea of a servo and belt drive setup with encoder, we use direct drive steppers for simplicity and ease of use.
It's down to personal choice.

Now controlling it is harder and falls into three camps.
[1] software based
[2] Stand alone build your own
[3] Chequebook engineering and buy one

Take [3] first, which bascically leaves the Divisionmaster which is now done by Lester Caine in the UK.
Best description is on the original web site but it links to Lester under the contact details tag.

http://www.divisionmaster.com/

This is a plug and play provided you motor is less than 2 amps per phase as it contains it's own driver circuit.

Some actual examples in the examples tag.


[2] Read this thread from another Guy in the UK.

http://www.cnczone.com/forums/showthread.php?t=47007&highlight=kwackers

Roughly same as a Division master but roll your own.

[1] can be divided into computer programs like Mach, TurboCNC etc but you need a computer and a driver box to talk to the stepper / servo motor.

Bit rushed explanation but it lays most of the choices out

wbleeker
06-01-2009, 04:21 AM
Thanks a lot both of you, I will check out the local suppliers before I start. As far as I can work out the best of both worlds would be to direct couple a servo motor and use the Divisionmaster for stand alone work and then in the future if I wanted a fourth axis the servo could be just connected in? Also what size stepper or servo would be required? I note that the 6 and 8 inch Vertex rotabs use around 200 oz in and was thinking 300 oz in or better.
Will
Just an afterthought, can the Divisionmaster drive a servo motor or does it only drive steppers?

John Stevenson
06-01-2009, 05:26 AM
Division master can only drive steppers from it's internal driver board but it can output step and direction from the 9 pin D plug on the end.
To use this you would need a power supply and driver box with a servo driver in.

It would be hard to use a servo motor as a direct drive unless you had a real hefty one as servo's get there power at maximum speed, hence the gearing.

.

wbleeker
06-01-2009, 06:25 PM
Got it now, I will get into it over the coming months.
Thanks a lot
Will

macona
06-03-2009, 04:59 AM
Servos have power pretty much all along the board. Them being close loop is what does it. The drive will keep giving the motor more power till it gets to where the motor is supposed to be until it either trips from follow error exceed or too much current.

If I were using a servo, lets say brushless AC, I would use something around 100 to 200w.

For a stepper I would say a double stack NEMA 23 motor.