[lokii]

I am upgrading my lathe to CNC, it's an Ebay special!

Here's a pic


The Mill attachment is pretty much useless as it's might as well be made from cheese, so I taking this off. I'm also building a better frame with a built in coolant system. Structurally the lathe is not bad, but the electrics leave a lot to be desired.

The is similar to the Grizzly G0602 lathe, just a little bigger with an 11 inch swing a 28 inch between centres. So I'm getting a lot of how to do the conversion from those threads, which I thank the authors for posting them.

I hope to order the steel for the new frame next week, but this week I am concentrating on pulling the lathe to pieces to check what's ok and what's not.

I am toying with one idea, which I am not sure how to do, so I'll pose the question here.

I want to make the spindle an axis, so I can turn a piece then mill it with a live tool on an auto tool turret. How can I do it?
I'm thinking a servo motor with the appropriate rpm and power, but I'm sure someone will say otherwise.

I'll post some more pics as I go.

[T.W.O.]

Hello

You have a lot of plans. Do you have more than 7 days in a week?

Spindle axis: Would it be a good idea to do it with a dual drive? One with a normal motor for turning and one (detachable) with a steppermotor for milling.
Building a toolturret with the possibility of a live tool: Following threat is a good start. • turret bouwen(updat 2-2 nieuwe film draaitsnijden )

greetings

[lokii]

You have a lot of plans. Do you have more than 7 days in a week?

I wish

The Milling machine is in the design stages, and the can't really be built until I have a working lathe, so the lathe is the priority.

But, thanks for another link

[lokii]

Given what I want this lathe to do and what I have learnt from my other thread http://www.cnczone.com/forums/genera...tor_lathe.html, I took the cover off the headstock today to see what is used to measure to spindle speed.



Sorry, it's about the best shot I could get.

You can see an encoder with slits cut into a disc and an optical switch.
This sends an output to the LED display, on the cover, which in turn shows the spindle speed.



This is a similar disc to the one on the spindle.

I have two options the first is to use a single motor to provide both my lathe spindle & my C-axis, or second, use a separate servo motor in addition to the spindle motor.

I'll try the first option initially, and if it doesn't work I can still go for the second, what don't want to do is go for the second option only to fine I didn't need to, and the first option would have worked perfectly.

As, I don't think I'll be able to add three outputs to the encoder wheel on the spindle, there's only one at the moment. To get the indexing output I'm going to have to make a second encoder wheel, with only one single slit cut, and fit that to the spindle, to achieve the indexing output. Hopefully this should give me a working encoder on the spindle.

The Spindle motor is going to be a 2.2kW 240V AC induction 1500rpm 4 pole single phase motor, driven by a Mitsubishi E700 VFD. The E700 has sensorless vector control. If this combination works, great, if not I'll go with plan B and add a separate servo motor to provide the C-axis.

[Al_The_Man]

I have two options the first is to use a single motor to provide both my lathe spindle & my C-axis, or second, use a separate servo motor in addition to the spindle motor.

The E700 has encoder options for vector control and orientation and even a positioning module for step, dir positioning by the look of it.

The Spindle motor is going to be a 2.2kW 240V AC induction 1500rpm 4 pole single phase motor,

I hope you mean 3 phase motor and not 1 phase??
Al.

[lokii]

The E700 has encoder options for vector control and orientation and even a positioning module for step, dir positioning by the look of it.

I hope you mean 3 phase motor and not 1 phase??
Al.

The E700 seems to be the best one I can find at the right price.

As per the motor this is where I found it ACP&D Limited - CW Series - Single Phase Induction Motors, and yes it is single phase.

My electricity supply is 240V single phase, do you recken same "kw" but three phase. If so I'll go with that, just single phase costs less.
But as always, you get what you pay for.

[Al_The_Man]

The idea of using a VFD on 1 phase is that it converts to 3 phase to allow the advantages of using a 3 phase motor, you most certainly will run into issues trying to run a 1 phase motor on that VFD.
Al.

[lokii]

Ok cool.

I had a look at the 3 phase version of the same motor and it's actually cheaper than the single phase, so much for single phase being cheaper.

[lokii]

Been looking at various servo & stepper drives, and came across Geckodrive.
I have no experience of them, it's just I can get them in the UK.

I was looking at the G540 4 axis step motor drive, as it's got an output for a VFD.

Anybody used them, are they good or bad?

On the Encoder front, I found these people www.ifm.com they have some encoders at a very reasonable price.
If the encoder in the lathe doesn't quite work out I'll give these a try.
They have an option for an encoder wheel, so I can place one on the lathes spindle and measure direct, just got make an appropriate bracket for it.

[m_c]

Charter Controls import Geckodrive bits - Charter-controls
Just search for either Gecko, or the drive model number.

[lokii]

Charter Controls import Geckodrive bits - Charter-controls
Just search for either Gecko, or the drive model number.

The link for them is on the Geckodrive website, I don't suppose you know if they're any good?

The Geckodrive stuff that is.

[The Blight]

There is an entire section dedicated to Gecko drives. These are some of the most popular drives to use on hobby cnc machines, and I myself use some (not the G540 though).

Gecko Drives - CNCzone.com-The Largest Machinist Community on the net!

Look around a bit, and you will find several topics on that specific unit. Doing a search in the benchtop machine forum will also turn up several hits.

[m_c]

As said, Gecko have their own forum on here, and are very popular.

I've just replaced the controls on my lathe with G251s, which is the same drive as what's used in the G540. They've still be used in anger, but they've performed well so far while setting everything up.

[lokii]

Thanks guys

I've been reading the Gecko section, and I think I'll go with a Gecko drive.
But looking at what I want my lathe to do, I'm going to have to go with servos.

So it looks like I'll be getting the G320x and a Pico systems universal controller.
Any other suggestions/recommendations for a controller would be nice