Messages

11

General Mach Discussion / Re: Emco Turn 120P

« on: May 02, 2008, 03:48:54 PM »

Hi Mike

Things have moved on a bit..but not enough, work keeps getting in the way

I decided to go for AC spindle drive (Hitachi as I have other machines with it) so a 2kw motor and inverter, this all works fine up to 3k rpm
the axis are still on the Emco stepper drive, as long as they work I will keep them.(thanks for the info on replacement cost...cant see me using them)
 
I have chopped the card frame in pieces and interface to the stepper cards from a custom breakout board , I used the same driver circuit as Emco used
to drive the stepper. 7407 all this has been proven...
I then changed the control box as it now lives under the machine in the back (box is actually upside down/back to front)
this gives me ample room for a comell ITX board, inverter and two stepper drives with original transformer on top.

I finished the mechanicals and sensor fixing last weekend, so part of this weekend will be wiring the thing up
I need to finish the custom breakout board as it uses a cubloc for the extra signals. in their wisdom cubloc has been made using a 2mm pitch connector, not quite suitable for Vero board, so I need to engrave a conversion board (CNC mill)

I still need to sort out the collet chuck which I would love to automate (have lot of repetitive work from bar) hence the cubloc

I am also keeping an eye out for smoothstepper as it may help in the speeds (no lathe support yet)

I'll see if I can post a few pics latter on the weekend

what stage are you with the control?, is there a reason why you design your own stepper drive ? (other then 5 phase)
apparently Berger larh does sell them, if you ask nicely, I do not know what price


JB

12

General Mach Discussion / Re: I Bought My Motor Invereter Package From Therse Guys In The UK

« on: April 29, 2008, 02:43:19 PM »

another good place is Newton Tesla, family run, they often setup the inverter if you tell them what motor is on the other end
I have bought 2 sets from them so far (motor and inverter) and an extra motor, all for good pricing and loads of support when you need it

http://www.newton-tesla.com/


no connection with them just a happy customer

13

General Mach Discussion / Re: machine safty issue

« on: April 02, 2008, 05:01:56 PM »

The mach manuals clearly states that machines are dangerous, it further explains about the charge pump circuit and safety circuit
If implementers decide to go without.... that is their decision

That said I agree a discussion is needed, and here is my particular point:

It is not always best to remove power from drives in a case of emergency.
Rotating parts of the machine with a large mass (think lathe chuck ) take longer to stop if the mains is removed from the inverter drive. In this case removing the “run” signal will stop the chuck faster.
In some cases a special program can be started in the inverter to de-accelerate as fast as possible (either simple Dynamic or DC braking)
A lot of commercial machines simply remove the control signal first and then a few seconds later (after the designed stop time) they remove the power from the drives.
Others are a bit smarter and remove the supply immediately only if they where moving.

The same thing counts for stepper / servo drives if they move the machine parts so fast that mass can continue the movement.

The machinery directive is clear in that each machine function needs to be evaluated separately and as a then whole, what is safe for one machine or function is not for others.

My lathe:
As it has speed both on the chuck and carriage I have decided to interrupt the control directly by the Estop circuit and have a timer circuit take out the suply to both drives a few seconds later

Only the spindle drive has the above treatment on the mill, the power to the axis drives are simply removed (moves to slow)

I found the www a great source of info (Google “machinery directive”) and also reading machine safety component manuals (RS website)

After that use that rare thing called common sense….


 

14

Show"N"Tell ( Your Machines) / Re: 5 axis Spinning Lathe: machine and control panel in progress

« on: March 27, 2008, 04:54:51 PM »

can't get a better endorsement I would say

15

General Mach Discussion / Re: Emco compact 6 retrofit

« on: March 22, 2008, 06:18:30 PM »

Hi Luis
have a search on the forum and you will find my posts which are about a similar machine (120P)

from your pics I can see the Berger Lahr 5 phase steppers, they are incredibly strong and are run of 100V drivers (Emco)
as mine where OK I opted to leave the drive and steppers in the machine, I simply soldered a LS7407 on a breakout board and send it stepping signals
it comes with an drive overload at 3600mm/min 
They are noisy though....

the spindle motor is a Siemens again incredibly strong and fast (3Krpm) the DC drive should be Emco you need 3 phase mains for that to run
you can obtain DC drivers for it, but they are quite costly, and if they are signle phase feed they only come to 190V which only gives you half the speed (1500RPM)
So here I opted for a standard 3 phase AC 4 pole motor to be run from a single phase inverter, get a good matched pair and crank it up to 80Hz and your back at
around the 3000 RPM on the head (All be it with reduced torque), at 50Hz you get about 1500
In the UK you can get a 2.2Kw set for about 500 pounds

I am Currently designing the controls for this with a cubloc as there are so many signals to deal with
current tally is 2 LPT ports and 36 signals on the cubloc..... but then my whichlist is big
Colet, barfeed, part catcher, conform the current machinery directive


JB

16

Tangent Corner / Re: Perfect reason to own a CNC lathe

« on: March 20, 2008, 04:43:12 AM »

reading my post again, I fear that it may imply that's me sharpening my pencil but it's not so
I only found the vid....

I have however programed my machine likewise 

JB

17

Tangent Corner / Perfect reason to own a CNC lathe

« on: March 19, 2008, 07:10:40 PM »

I finally found a legitimate reason to own a CNC lathe


http://www.youtube.com/watch?v=EKL6elkbFy0


How did I ever do without it

JB

18

General Mach Discussion / Re: Emco Turn 120P

« on: March 18, 2008, 07:45:49 PM »

are you in the US or another 120/208Vac Country ?? this would explain the transformer box, used to kick up the voltage to 240/440 ??

19

General Mach Discussion / Re: Emco Turn 120P

« on: March 17, 2008, 05:42:20 PM »

Thanks for the info, will have a search at J&Ls slow website

on the control side, I have managed to interface to the original stepper drivers,
the next step is to talk to the other bits like the tool turret control and some of the aux controls
non of this worries me to much (i work in electronics) altough I occasionally need to look in some very old books to understand what emco has designed
in the late 80ties (8088 micro, BDT64C transistor......Ooooold school)

I noticed that the machine favours high feed rates as low stepper speeds make a lots of noise.....
does that tally with your experience of them ?

grey controller box?? I have the machine on a stand, and a controller box on a stand
that is all as far as I can see.. if was a 3 phase machine

Ah yes the controller front panel is also surplus to requirement....
 

20

General Mach Discussion / Re: Emco Turn 120P

« on: March 16, 2008, 04:52:30 AM »

Hurco... got my Inventor training at their place (toolbox software) was rather distracting those monster machines

Thanks for responding, you may be able to tell me where I can find tool holders for the turret
I have two units for boring bars/drills and a busch
I have no OD tooling...which limits my options a bit .

I will have a set of controller cards free to be sold later on(say a month or two)... if that helps the other guy
still use them to work out the original wiring and circuits

also for sale is a full DC drive units (motor/electronics/main stage with chokes)

JB