Emco 240 Tool Turret

Hello

I'm busy retrofitting a Emco 240 Lathe (the big brother of the 120 series). And I'm looking for some information about the tool turret.
It's a 8 tool turret driving by a DC motor. It only works one way because there is a blocking mechanism. And there are some sensor for position feedback.

For Mach3 it's seems pretty straight forward to just use a macro to operate the tool changer.
But I'm curious of people done it before for the 140/240/340 machine? I came across the open source toolchanger for the 120, but it doesn't say it works for the 240. I think the mechanism is almost exactly the same though.

Hi,

For Emco lathe it's quite easy to modificate. I have one too in my working place modificated with new steppers,
also a new stepper on tool changer. I think i have a big Emco with 8 position turret.
Just replace the dc motor. Thow it away.

I did replace the turret motor for a stepper motor. The Nema 34 motor 6.4nm fits very good. Then the trick is as follows.
Your turret has a slot mechanisme. Your stepper driver can be slow down in current. So you can do a step over to
fasten the seat belt's of the turret if you want. Then you don't have to worry about exact positions.

The rest is your's.

Hi
Thanks for your reply.
Connecting the stepper is no problem. I will check today if mine can fit a nema34 (think so, since the original motor is pretty big).
But how you arranged everything in LinuxCNC? How you tell the stepper should work for a tool change? macro?

I expected there would be a 24V DC motor like the emco 120 (it has only 2 wires)
I contacted the person who came up with the toolerator3000 and he confirms the 120 only has 2 wires.
Mine has 10 (without the opto sensor board, those wires are the same). The toolerator isn't going to work for me


This the motor



Turret with pulley

Would this work?

wiki.linuxcnc.org/cgi-bin/wiki.pl?Contri...oolchanger_component

It should work for turrets that have no opto sensors and also uses a 'rotate past pawl and reverse to lock' method.

The turret on my 240 has opto sensors (the same as the 120 machine).
Now there is a component for the 120, but the motor is completely different
That's the reason the toolator3000 and 120 component isn't going to work.

With the boxford component I'm able to turn the turret based on degrees. I think it's also stepper motor powered.
Not perfect because when I start LinuxCNC I need to tell the machine which tool is currently loaded. But it's workable.

The emco orginal electronica is quite difficult and old from my lathe. It has a 5 pole stepper for lineair axis.
It has also a dc motor for the chuck. So for me that time when i powered on the machine for the first time in orginal condition
there was a lot of smoke comming out from the main board. So i decided to trow everythin away.

And about two day's later, it was running one a new asynchrone motor for the chuck. Also i placed 3 new stepper motors.
The only negative for me is that the turret moves a little slower then the orginal factory used motor.

Some picture's for forum readers to show how the emco cnc looks like :

andypugh wrote:

If you can work out how it works, I feel sure that we can work out how to work it.

Presumably the original drove for the DC motor still exists? There is no reason to swap a DC motor for a stepper, it isn't like steppers are _easier_ to drive.

Hi Andy

It works exactly the same as a Emco 120 turret. It has opto sensors in the back to check turret position.
Difference is that the 120 uses a small 24DC motor with 2 wires. And mine is a 10 wire three phase motor with 2 speeds.

Nerd wrote:

The emco orginal electronica is quite difficult and old from my lathe. It has a 5 pole stepper for lineair axis.
It has also a dc motor for the chuck. So for me that time when i powered on the machine for the first time in orginal condition
there was a lot of smoke comming out from the main board. So i decided to trow everythin away.

And about two day's later, it was running one a new asynchrone motor for the chuck. Also i placed 3 new stepper motors.
The only negative for me is that the turret moves a little slower then the orginal factory used motor.

Some picture's for forum readers to show how the emco cnc looks like :

Thanks for the information.
I already converted the whole machine with Nema34 steppers and a AC motor (original is DC) with a VFD. Only issue I'm facing at the moment is the turret. Nice machine you got there by the way
This is mine at the moment:



About your email. Changing the motor for a nema34 is an option. I think also fairly easy to do. I've setup a A axis before. And issuing a A axis movement for a tool change is workable. When you reverse the the stepper to lock it in place. Doesn't the drive switch to error mode once it can't move no further? About the speed of changing tools. Can't you replace the small pulley at motor side for a bigger one?

But I prefer that when I issue a tool change command the changer knows which tool is loaded based on the opto sensors. When replacing it for a steppermotor I need to issue a G0 command with the amount of degrees the turret needs to turn. I rather not add the commands to my gcode each time.

1.

Doesn't the drive switch to error mode once it can't move no further?

In a previous asnwer i said, turn the stepper motor driver lower in power, so it can fasten your lock system with a step over.
The adjustment of power of the stepper motor driver you can do with dip switches normally at the front.

2.

Can't you replace the small pulley at motor side for a bigger one?

Yes, I used often use a 14mm shaft pulley belt with 22 teeth on the motor side. "T5-22-15-14"
In Linux you can adjust your rotary step's/revelution. I think it's called "Pitch" in Linux.

3.You can look for Andy's input's. We can learn about this.

4.In my mail i send a g code example like

G0 A50
G0 A-7

This code can be the basis for a Macro to lock your turret in place. 45 degrees is a 8 turret position machine.
So it's getting 5 degrees further and go's dan finally 2 degrees step over.