Building a CNC Lathe

[northwest]

Would this encoder be suitable:

Incremental Rotary Encoder DC5V Encoder 100 /600/2000/5000 P/R Incremental Rotary AB Two Phases 10mm Shaft - AliExpress 1420

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

Or this one:

Page Not Found - Aliexpress.com

and what is PR?

 

[Dr.Al]

Would this encoder be suitable:

Incremental Rotary Encoder DC5V Encoder 100 /600/2000/5000 P/R Incremental Rotary AB Two Phases 10mm Shaft - AliExpress 1420

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

Or this one:

Page Not Found - Aliexpress.com

and what is PR?

In encoders, P/R is Pulses per revolution (i.e. resolution - if it's 3600 P/R then it's giving a 'tick' every 0.1°)

 

[Munkul]

Interesting

I know Hood has mentioned these SZGH controllers before, I'm interested to see if they would be a good retrofit to an old knackered prototrak mill or something like that.

 

[Hood]

I use a 2500 line encoder, so 10000 PPR as far as the control is concerned. It is actually the one that I had on the conect
A lesser count would also work but wouldn't go too low.

 

[Hood]

Interesting

I know Hood has mentioned these SZGH controllers before, I'm interested to see if they would be a good retrofit to an old knackered prototrak mill or something like that.

Depends, the servo drives need to be step/direction and I think prototrack may be analogue. If so then new drives would be required.

 

[m_c]

If you're going to use a servo to drive the spindle, provided you couple the servo to the spindle 1:1, then I'd just use the servo drive's encoder output.

Although if you are going to go for the full spindle positioning option, I'd maybe invest in a newer toothed belt/pulleys profile though, as IIRC the original just used an old fashioned trapezoidal profile, which isn't the best in terms of positional accuracy.

 

[Hood]

If you're going to use a servo to drive the spindle, provided you couple the servo to the spindle 1:1, then I'd just use the servo drive's encoder output.

Although if you are going to go for the full spindle positioning option, I'd maybe invest in a newer toothed belt/pulleys profile though, as IIRC the original just used an old fashioned trapezoidal profile, which isn't the best in terms of positional accuracy.

It may depend on the servo drive but I know the Allen Bradley and Telemecanique ones I use can scale the output of the encoder pass through, so that is not usually a problem. I originally had the pass through encoder outputs used on it but then went with a separate encoder to see if the chuck positioning at stop worked better (with CSMIO) it didn't so...

 

[m_c]

It may depend on the servo drive but I know the Allen Bradley and Telemecanique ones I use can scale the output of the encoder pass through, so that is not usually a problem. I originally had the pass through encoder outputs used on it but then went with a separate encoder to see if the chuck positioning at stop worked better (with CSMIO) it didn't so...

You can scale the encoder output using various methods, but if the controller relies on the index pulse for initial synchronisation, any mechanical gearing is going to cause issues when trying to do things like threading, as you can't scale the index pulse.

 

[Hood]

Worked fine for me so I think you must be able to.

 

[Hood]

From memory I think this is the setting.

 

[m_c]

It all depends on how the controller handles synchronisation. Some just use the AB count and continually keep track, whereas others use the Z/I pulse as a trigger for synchronisation.
Unless you know how the controller works, I'd advise against gearing a servo spindle.

 

[Hood]

As far as I am aware the control uses the Z for sync'ing the spindle for start of threads etc.
As I said earlier on (post 12) I personally would use a separate encoder but if using a drive such as the Allen Bradley I previously used then it would work fine even with a divided output.
I had mine geared 2:1 as far as I can remember, just depends what spindle speed you want, I just kept it about the 2000 or maybe 2500 rpm so gearing was the best option as no point in having a servo motor capable of 5000rpm if you are only ever going to use it to 2500rpm.

 

[northwest]

Bit further forward, the Tray and some of the structure came back from the Powder Coaters:



It's a start and we are off running now. I have it on the bench, sort of In front of me so getting things sorted is easier than scrabbling around on the floor. Hopefully the Spindle servo will arrive soon and I can set to getting it mounted. Need a couple of Ball Screws next, one for the Y axis and a second the full length of the Z. I have been reliably informed that with just the one Ballscrew on the Z axis the carriage tries to twist when heavy drilling or boring so I will pre-empt that by putting a second ballscrew the full length of the bed but at the back and drive it from a pulley at the tailstock end. Rather helpfully one of @Hood s pals is running something similar and he has said it will be okay if I go over between Christmas/New Year and take a look at his setup. I am pushing the boat out a bit here but the controller is supposed to be here tomorrow! Fingers Crossed!

 

[mtt.tr]

Well done,
Took a gamble on a Chinese controller with mpg £250 be rude not to try

I'm also awaiting parts for my beaver conversion dont my laser cutters know how important I am!!

 

[m_c]

Well done,
Took a gamble on a Chinese controller with mpg £250 be rude not to try

I'm also awaiting parts for my beaver conversion dont my laser cutters know how important I am!!

Who are you?

 

[mtt.tr]

Who are you?

don't break my illusion

 

[minimutly]

Well done,
Took a gamble on a Chinese controller with mpg £250 be rude not to try

I'm also awaiting parts for my beaver conversion dont my laser cutters know how important I am!!

Nice, keep us posted!

 

[mtt.tr]

Nice, keep us posted!

I will try to document it, not my strongest attribute I vary rarely take pictures

 

[northwest]

Well, the Controller DID arrive this morning, despite the Fedex Tracking saying it was in Stoke on Trent! It came well packaged with plenty of Styrofoam (More about that in the Dogs thread!). I was a bit surprised at just how BIG it is, Proper, Industrial Strength thing, hours of fun working this out:-) Christmas reading "Instruction Manual - CNC Controller" Going to have to make a new housing for it:



Remembered that I DID buy a MPG for it, Manual Pulse Generator- Twiddly wheel thingy to everyone else, you can just see it at the bottom on the Left:

totally missed the keyboard layout, a recipe for disaster, WHY can't we have just ONE standard?

 

[mtt.tr]

Who are you?

Think they are on here parts arrived today. That is a 1 day turnaround.