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Author Topic: Just got a lathe to retrofit  (Read 176985 times)

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Offline fdos

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Re: Just got a lathe to retrofit
« Reply #30 on: August 28, 2006, 05:45:48 PM »
Hood

I've seen it (the cpr v's ppr) argued before, and I guess there's no real answer except that I have never seen the count quoted as the actual quadrature output.   In my experience whatever they quote has to be multiplied by 4.

The rating of the Teknix drives is all down to the mosfets.  Same with the Rutex drives I think.

Wayne...

Hood

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Re: Just got a lathe to retrofit
« Reply #31 on: August 29, 2006, 02:38:00 PM »
Wayne
 Had a look at the TekNix manual and it calls it ppr but as you say that it must be multiplied by 4. I think it was just my understanding of what ppr was that was confusing me. Now I know whatever the count of an encoder is advertised it is the line count.
Thanks for keeping me straight on this.
 Now all I need is to get some info on the voltage and current that the motors are using on this lathe, that way I will be able to make a half informed choice in which drives to get. I found some info on the motors on the polish manuafacturers site, gives max voltage and holding torque etc but no mention of current. I emailed asking for a torque/current curve but so far no reply.
Hood

Hood

Offline fdos

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Re: Just got a lathe to retrofit
« Reply #32 on: August 29, 2006, 02:51:43 PM »
Hood

Re Current.

Unless you go for very expensive commercial drives you are not going to exceed the current rating of those motors.

You will be limited by the drives max current rating in the case of the 3 different brands of DC drives available from the usual sources.  ie 20A for Gecko's and whatever the two ozzie brands are rated at.

Lower current will just limit the torque available.

My Hardinge uses just 1nM motors with 2.5:1 reduction at 3300 rpm.  I reckon it will still be more powerful and faster than the original 1.2nM motors at 2000 rpm and 1.85:1 reduction.

It's quite strange that your machine uses servo's at 1:1.   But I guess with that torque available they didn't need any!

I always use steppers at 1:1 but they are a different animal.

Wayne....

Hood

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Re: Just got a lathe to retrofit
« Reply #33 on: August 29, 2006, 03:10:26 PM »
The rutex can go 40Amps but they are a bit more expensive than I like, the ausie drives can go to 25A which I think will probably be more than the motors are at the moment so it looks like my drives will be either Geckos or the Teknix.
 I am not 100% certain that the motors are 1:1 as I never measured the pulleys, but going by the pic above of the motor pulley and ballscrew pulley they look the same size.

 Been looking through the Teknix manual and it explains a lot and has some excellent info for a newbie like me.

Hood
Re: Just got a lathe to retrofit
« Reply #34 on: August 29, 2006, 09:45:57 PM »
You are going to like that lathe :) It is like the Okuma's that I have run in the past with the two tool changers.. I wish I could have that lathe :)

The Teknics drives do look like nice drives :) I have never tested them so please tell me how you like them!
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Hood

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Re: Just got a lathe to retrofit
« Reply #35 on: August 30, 2006, 04:41:04 PM »
Brian
 yes I think I am going to like it but at first I will be very scared of it, never used a lathe that big before so using a CNC one will be very daunting.

Been getting some answers through my friend who has a contact that made these machines and it looks like I am going to need more voltage and current  than either the Geckos or Teknix will give me so looks like the big Rutex drives are my only option. He said it will probably run OK at the lower votages and currents but I think its better to get the right things from the start instead of making do.

Hood

Offline fdos

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Re: Just got a lathe to retrofit
« Reply #36 on: September 03, 2006, 07:09:56 PM »
Hood. you got the big bugger home yet?

Hood

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Re: Just got a lathe to retrofit
« Reply #37 on: September 04, 2006, 02:46:56 AM »
Wayne
 No, its still at my friends place. I actually dont have any place to put it at the moment, I am probably going to rent the unit next door to my workshop so that I have room, I need more space anyway ;)

Hood

ynneb

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Re: Just got a lathe to retrofit
« Reply #38 on: September 07, 2006, 06:23:36 AM »
Fantastic stuff. I must say I am really enjoying the show and tell threads. You guys are generating lots of inpiration.

Hood

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Re: Just got a lathe to retrofit
« Reply #39 on: September 07, 2006, 05:49:23 PM »
Thanks Benny
 This will be a steep learning curve for me, its going to be a lot harder than the mill I think
 I am hopefully going through to see my computurn this weekend and  hope to power it up so we can get an idea of how the turret and toolpost index. Also want to try and find out how the spindle speeds work as they are clutch driven but there are only 5 clutches and there are 6 speeds within each of the four main ranges (2 speed motor + Hi/Lo range )
 Have also taken the lease on the unit through the wall from my workshop so I now have room for it, entry date is 19th of next month but might actually be able to start moving things in two or three weeks :)
Hood
« Last Edit: September 07, 2006, 05:51:22 PM by Hood »