Updating old Meccanica Cortini Lathe to Mach 3

New here but I have lurked for a long time to figure out how to go about doing this. First I am pretty terrible with electronics and this is all completely not in my realm of comfort but screw it I am going for it anyway.

Unfortunately the memory in my old lathe has started to give out and I decided to go for a mach conversion.
http://www.hunt101.com/data/500/Cort...e_overview.jpg
(stupidly I never took an overall picture this is a real old picture of it after someone gave it a terrible gray paint job)

What i plan to keep:

The Zebotronics stepper motors, they draw around 36volts and are 3.5 amp
http://www.hunt101.com/data/500/medi...e_X_Axis_1.jpg
The Proximity Home Switches which are a 12v system but I still have very little idea on how this is going to work out
The circuit breaker for the ac line in
http://www.hunt101.com/data/500/medi..._Breaker_1.jpg
The fuses on the AC line
The AC powered fan under the motor/spindle housing and the other AC fan in the computer housing

What I plan to replace:

The motor drive board to get something more modern in it
All the stepper drives
The breakout board
The monitor and all the controls
Eventually modifying the cabinet to use flood coolant
Eventually modifying the cabinet to be fully enclosed

What I am using for the conversion:

A KBMG-212D Regenerative motor drive
A Gecko G540 board to control everything
A smooth stepper board so I do not need to use old XP
A 48 Volt power supply 8.4 amps
A 12volt wall charger to use to power the home switches
A 1 signal per revolution tachometer sensor for threading with mach
an additional outlet from my gecko box for later coolant modifications
I have a windows 7 32 bit professional tower, that I had for college and havent used in years.
It has 1 gb of ram, 500gb 7200rpm hard drive, pentium 4 3.something ghrtz, plenty of power for it
Some usb extensions to easily plug in flash drives.
I am looking at picking up a usb pendant from VistaCnc
I have a 10" multitouch monitor to replace the old cvt screen
I also have a touch screen mouse/keyboard combo which is small enough to fit up top with the screen coming for computer controls
I hope to just modify the existing face plate up top and cut in the new sleeker displays and keys, there is plenty of room in the box for what I am planning.
http://www.hunt101.com/data/500/medi...trol_Old_2.jpg
http://www.hunt101.com/data/500/medi...trol_Old_1.jpg

Things I know about the machine now:

Machine runs on 230 VDC single phase
The motor is 1/2 hp dc shunt motor drawing around 160 vdc with the stock board, and a field voltage of 180ish vdc, draws around 2 amps under load as far as I measured.
3 zebotronics steppers, not entirely sure on what sizes they are but they draw 3.5 amps max and run around 36 volt peak at rapids.
3 proximity h.e.s. style limit switches running at 12 volts
The tool changer has a 60:1 Ratio that I need to somehow code in down the road but I am completely uneducated on that portion as of now.
The stock spindle speed was 3000 rpms
The stock rapids are a bit over 100 ipm (all metric as of right now)
About what I know

First attempt is to wire up the motor drive board. Before I did this I was not entirely sure if it was a pm motor or a shunt style. I originally wired it as a pm motor because it is easier.

I made sure that all the tabs were set correctly for 230 VAC coming in, and had the output set for 180 VDC. I plan on using the Gecko g540 to control the KBMG-212D board eventually off its 10v setting but decided to wire up the 15v potentiometer to try and get the motor driven by something more modern.

Wiring up the potentiometer I first put a jumper between en and com to get the board to run, then I connected the potentiometer to run the motor in the forward direction. From left to right it was Com, Sig, 15V+ wired into the potentiometer.

Set the amperage jumper to 2.5 amps and put some power into the board to make sure the potentiometer was changing the voltage coming out at the motor end.

I then had to figure out which was hot and neutral leading to the two brushes on the motor, both wires were red so I had to run the motor and put a voltage meter on it and see which way read positive and then reversed it to make sure it said negative when I had it backwards to figure out which was hot and neutral.

Wired them up to the board and tried to drive it... I heard the power going into the motor and it spun slightly, needless to say I was disappointed but then started looking for more wires and found the two that made the field for a shunt motor. I put connectors on these two wires and plugged them into the f slots, didnt know which was which, because they were the same color again, but just went for it. First plug in had the motor spinning the other way, figured I should just switch the field wires again and it did the trick. Started spinning correctly and had good power. I put a reflective strip on the spindle and read the speed with my tachometer and seen that full out it was running at 3400rpms which is great because I am putting 20 more volts into it then the old board could.

Very successful for day 1, Next up will be wiring in the ac fan and an estop switch on the motor side, as well as mounting the new motor drive board. I decided to keep the bus bar in there and want to use the wires already run through the body to handle all the connections from the gecko g540 board, and the new tachometer that I need to put on the spindle for threading.

Pictures of the outdated spindle control
http://www.hunt101.com/data/500/medi...oder_1_Old.jpg
http://www.hunt101.com/data/500/medi...rive_1_Old.jpg
http://www.hunt101.com/data/500/medi...rive_4_Old.jpg
(old ohms resistor under motor)
http://www.hunt101.com/data/500/medi...or_Brush_2.jpg
(picture of the top brush it still looks to be in good condition)
http://www.hunt101.com/data/500/medi...rive_2_Old.jpg


Pictures of the wiring and new setup
http://www.hunt101.com/data/500/medi...rive_8_New.jpg
(just the drive board with jumpers set correctly for my setup)
http://www.hunt101.com/data/500/medi...rive_6_New.jpg
http://www.hunt101.com/data/500/medi...rive_4_New.jpg
(AC line coming in from the other side of the lathe)
http://www.hunt101.com/data/500/medi...rive_5_New.jpg
(AC side wired in )
http://www.hunt101.com/data/500/medi...rive_3_New.jpg
(potentiometer and jumper wiring)
http://www.hunt101.com/data/500/medi...rive_7_New.jpg
(full wiring of the board with the shunt motor field wired in on the bottom left and the motor outputs on the top left)

A small video of the first bit of success
http://youtu.be/I0zEDEMSR54
(lets see if this linking works)

Next step is to setup the mach in my computer and try and get the drive board going with the steppers, then stripping out the stepper control cabinet to put in the new components.

Update my computers mother board fried out today funnily enough. I ordered another computer off ebay for $80 its pretty much the same computer funny enough so if something happens I have parts as an upside.

Also this one has linux installed in it and I will make a partition for windows 7 but I can also start looking at emc2 when I get confident enough with it.

Looks like a manly lathe & will be very useful when you get it going. With the amount of time & money you're investing, replacing those outdated stepper motors should be a priority. Modern hybrid steppers are relatively cheap & would match your Gecko much better than those old 36V motors.

Keep the pics & updates coming!:)

Why not use what you have? Just tie it in with a BOB. How about a pic or two of your drives? Also just hook up a contactor to your estop allowing you to remove ALL power in an Estop situation?
If you are going to change, do as DB suggests, new motors and all.

Just a quick comment on Mach single pulse/rev indexing & threading. If your plans include threading steel of any useful sizes, start planning to modify your spindle drive to have a *VERY* stable speed & lots of grunt at the lower end. Your shunt wound motor & modern regen drive may be a lot better than my PM motor/KB SCR drive but I'm having troubles getting consistent results...and this is after building a 4:1 reduction belt drive system for my 3/4 hp Baldor motor. That 3000 rpm speed you mentioned is great for small work in aluminum but pretty much guarantees it'll be far too wimpy at the low end.

Your Z-axis stepper drive's speed & acceleration have a big impact on threading success as well. The faster/stronger it is, the better success it'll have tracking fluctuations in the spindle speed. That's the other flaw in mine, the Z motor isn't powerful or fast enough.

Not trying to throw a stinky wet blanket on your project, just add some info for you to think about early-on. Mine was built up by scraping the bottom of the barrel for cheap parts & pieces and it does a great job for a lot of things; threading just ain't one of 'em.:(

Something to keep in mind with that shunt-wound motor... Most people don't realize there is a safety risk with shunt wound motors - if the field connection is broken while the motor is spinning, the motor will NOT stop, as a series-wound motor will. It will, instead, accelerate very rapidly, and, unless there is enough friction or load to prevent it, can, under the right circumstances, continue to accelerate until the rotor literally explodes. Make sure the field wiring is VERY secure.

Regards,
Ray L.

it looks like it has at least a 100 line encoder... That plus index would work great for theading..

Quote:

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Originally Posted by samco

it looks like it has at least a 100 line encoder... That plus index would work great for theading..

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Yep, for you guys that are fluent in LinuxCNC. Sigh, I can only dream.:(

heh - it isn't rocket surgery... :) Linuxcnc can do encoder counting through the printer port (I have an emco with the stock 100line + index working) On a decent computer - that should count to a minimum of 6000rpm.

Isn't there hardware you can get for mach the allows for multi line encoder threading? Smoothstepper maybe?

sam

I really love this forum so many responses from people that actually know what they are doing.

The reason for me keeping the steppers is that they are already run through and have been running fine, so my initial thought is to not mess with success and keep running them until they start giving me problems, especially because the Z stepper is in a hell of a crammed spot and I dont know if I can get a new nema stepper to just bolt right up and fit in the spot so I rather wait for them to die before I go revamping them. That being said the encoded stepper motors really look interesting to me if I was going to replace them I would probably go that route. This machine has been a great little lathe for me and has made me a good amount of cash in its short lifetime with me I dont mind splurging on her if I feel I can wire up the expensive new toys for her. The italians who built this made an incredible piece of iron for such a little lathe, there is really no vibrations with the solid base, rugged cabinet, and still near perfect box ways on it, so I dont mind dumping money into it for quality parts as they die off.

Also good to know about the threading stuff. This lathe was originally setup to be a threading monster, it was incredibly good at it in both metric and standard thread sizes in any material I tried with it, probably because of the more complicated encoder, but it did a very good job threading hard materials even with a wonky motor drive board, it would speed up then free spin down to rpms a bunch until it found its sweet spot but it would thread nicely even as it did that. The new drive board doesnt have that free spin lag that the old board had it doing which is awesome to me as of now. We will see how the 1 signal mach encoder goes, the new computer i bought to replace the fried one has linux in it already so I plan to keep both OS in it and maybe play around with emc2 when I have time in the future. Maybe I can one day wire the 100 count encoder back up but I dont see how its possible at the moment especially because there are 9 damn wires leading from that encoder and I have no idea where they all need to go.


As far as the estops go. I have one estop that I am wiring up on the controller side (right side) of the lathe that does cut all ac power to the entire thing. I have space for another estop on the motor side (left side) that I am going to wire in there just because I have holes for it and gives me another option if I am off to that side of the lathe and need to stop the spindle. Also with the old drive boards, there is a lot more pins coming out of them then there is going into the modern breakout boards that I was seeing and they do not deliver as much punch as the newer gecko drive so I decided to upgrade that as I was switching over to mach, again I will update the motors themselves if they start to have problems and force me to figure out how to mount newer motors to the lathe.


Also thanks for the tip on the shunt wound motor I did not know that. They connections are a plug on style and are pretty tightly on there, the drive will be mounted in that cabinet as well so it should not go anywhere hopefully. I have never had any experience with a shunt wound motor before and didnt even know that it existed until I read the manual that came with my drive board so any info on them would be helpful. In fact i would be lying if I said I had any extensive knowledge on any electric motor type.

I will have more pics up of the mach setup and the stepper drive cabinet as all the components come in and I start putting them together stay tuned and thanks for all the replies any information is helpful to me on this.

Ok another small update.

I received the second computer to replace the initial one. I am happy that they are the same computer, I stole the ram out of the dead computer, the floppy drive, the second cd drive, and the hard drive just because I could. The second computer I got had linux mint installed on it so my initial concept was to plug in the hard drive with windows 7 in it and change the load order to load windows first. It started to work then went blue screen of death, tried to recover it and no good blue screen of death again. So I formatted the hard drive with windows and tried to reinstall windows 7 again. It did not like that and I had to do a little research online, where I found that windows doesnt like to make a partition if linux is sitting on a hard drive, so I had to go back in and turn off the linux hard drive before I was able to install windows. After that I was able to turn both hard drives on and change between the operating systems if need be. After that I put mach into the computer and left it at that.
http://www.hunt101.com/data/500/medium/Computer_2.jpg
(old computer stripped out)
http://www.hunt101.com/data/500/medium/Computer_1.jpg
(new computer loaded up with additional features just because why not?)
http://www.hunt101.com/data/500/medium/Computer_3.jpg
(side by side new one is the non dusty one)
New computer details now
intel duo core processor 2.66 ghz
4 gb of ram now
2 hard drives, one with windows 7 32 bit the other with linux mint 17 I think
2 cd drives and a floppy drive.


Next step will be to get the ethernet cable to link to the smooth stepper drive and then get the steppers wired to the gecko g540 board and get them moving in mach, hope to start on this in the morning.

Linked the smooth stepper board to the computer no real drama there just followed the instructions and copied and pasted the files into the correct area of mach and all was well until I get this error message
http://www.hunt101.com/data/500/medium/computer_4.jpg
if anyone knows the work around for this I would be very grateful, I need to do some research and head scratching to get rid of this little annoyance. I have an estop setup but its not set to do what that is asking and it lets me through the message its just a small pain Id rather get rid of if anyone knows.

After the smooth stepper board I enabled the charge pump to get my gecko g540 to go green and be ready to run steppers.
http://www.hunt101.com/data/500/medium/computer_5.jpg
http://www.hunt101.com/data/500/medium/g540_1.jpg
http://www.hunt101.com/data/500/medium/computer_6.jpg

Here is the old components in the cabinet.
http://www.hunt101.com/data/500/medi...anel_1_Old.jpg
Up at the top bus bar are all the stepper wires connecting into the old board. I am using the wires from this terminal location.
http://www.hunt101.com/data/500/medi...anel_5_Old.jpg
http://www.hunt101.com/data/500/medi...anel_8_Old.jpg
(back side of the first pic)

http://www.hunt101.com/data/500/medi...anel_2_Old.jpg
(some large capacitors and a large power supply I believe)

So i am not exactly sure which wire goes where but I know that they are 4 wire stepper motors and figured I would just plug the wires in the same way I take them out of the bus bar. I wired up the three steppers and when I jog I get a little movement. I need to adjust the jog amount and the motor tuning section to better work with these, this was a metric machine and I just left the settings that were already there, I need to start stripping the cabinet out and then working on getting the motors running as they should.

Update...

Got the vistacnc pendant in and it is a very nice product. Wired the steppers together, I seen how they were wired in the bus bar and just assumed that the black and brown wires should still be on the outside, was just a guess. I then plugged them in black, green/yellow stripe, blue, brown. I tried to cycle the stepper and it would go one direction and then go back a little. So i decided to check continuity between the black wire and the green/yellow wire, there was none... So i checked between black and blue and got the beep noise on my tool so I switched the blue and green/yellow wires and boom it works as it should.

A few questions now
I have no idea how many steps I need per inch or mm or whatever mach has. Should I put a dial gauge along the side and jog it once to see where it lands then calc out to see how many steps I need per inch? Also I know the machine was set as a metric standard so I am assuming the ball screws are metric pitched as well, should I keep with that or convert it to inches because everything I do is in inches for the most part.

I hope to tune the steppers in tomorrow then hopefully get the spindle under control from mach tomorrow as well. Then the next step would be the limit switches which are an entirely different animal

http://www.hunt101.com/data/500/medium/Computer_7.jpg
(new pendant and my touch keyboard/mouse pad pretty cool little $15 gadget)
http://www.hunt101.com/data/500/medi...r_Wiring_1.jpg
(Wiring to the soldered connector. I have the covers and everything to complete the vga connectors and will do it as I mount the box and computer into the cabinet)
http://www.hunt101.com/data/500/medi...r_Wiring_2.jpg
(all three plugged in temporarily)

A short video of the z and x axis moving.
http://youtu.be/8Fte6NFzBM4

Another update for the day.

It took a long time with my process but I got the motors tuned in!!! Basically I knew the phase angle on my steppers but that is really it, I did not know how many steps per rotation they were or what pitch my ball screws were running so I was going at it blind. What I did was set up a dial gauge on a magnetic base and just picked 20000 steps per inch and set my jog to 0.005" to see what I would get. I was getting over 0.01" of movement so I cut it in half to 10000 steps per inch and got a little under 0.005" so I went for 12000 and got closer so I just went up and down a bunch until I found a happy step amount to get an accurate reading.

I took a video of the z axis before I got it completely tuned in. I did the x axis later. I am sure I can get a little more accuracy out of it using a 0.0001" gauge but I will do that if I run a few parts and are unhappy with the tolerances I am getting. The steps per inch is a strange number because the ball screw has to be metric, its like 10.309something rotations per inch and I dont know the steps per revolution of the motors.

http://youtu.be/A29cbyhGsGM

http://www.hunt101.com/data/500/medium/computer_8.jpg
(final tuned steps per inch, The ipm speed and accel are very conservative because I didnt want to whip the thing around while trying to tune it in, I had it humming at around 100ipm a little faster and I was shaking the stand which I might try and support a little more if I want more rapid.)

In the mill profiles of Mach 3, there is an axis calibration tool. It works very well. IIRC it is not in the lathe profile. I have used the mill profile many times on different lathes during calibration just to use that tool.

Fastest, wish I knew that before I spent all that time lol I will probably give it a shot if I dont like the accuracy I have now when I do a few test parts.

Small update.

I got the spindle motor running off mach now. Thankfully I asked a member here how he wired the g540 to the kbmg-212d, that I have, and he quickly showed me what I was doing wrong and boom I have a working spindle off mach. Of course there is no tach on it yet so I first tried to adjust the ratio on the pulley screen and it did nothing to my spindle speed, not sure why. So instead I just adjusted my max speed to get myself in a decent range. Of course I assume I will only take my machine to 3kish rpms so I made 1500 rpms pretty close and watch it dip a little as I go slower and go a little faster as I speed it up. I am planning on getting a tach on the spindle before I attempt anything like threading so I am pretty happy with where its going. I made a video but forgot to show the spindle stopping which it does very nicely and quickly now. Also I put the speed up to around 3500 rpm and didnt record that either. Got some real neat vibrations from that speed its a little to fast.

http://www.hunt101.com/data/500/medi...r_drive_12.jpg
(picture of the motor drive with the 10v power supply on the power strip that goes into the g540 (hot to pin 9, neutral to pin 7), the common is shared between the g540 (pin 7) and the kbmg-212d common which is what I was having problems with originally trying to spin it. The signal line is coming directly from the vfd out on the g540 (pin8), eventually when I have everything getting pretty I will make a switch to switch between potentiometer and mach control, I also need to wire in an ammeter as well on that side.

http://www.hunt101.com/data/500/medi...r_drive_11.jpg
(wiring on the g540 side)

Small video of the motor spinning
http://youtu.be/n-J1I0cn9x4

I want to run a small simple part to see how everything is going under load next then I plan to start putting everything in its place and doing the real wiring that is a little neater and starting to wire up the old proximity switches, which is a bit of a daunting task to me right now...

I'm happy to see you making such good progress. Any updates? Have you got the macros for the toolchanger working? I guess that's sort of the next step.

The homing switches on my Cortini are inductive, with the rated driving voltage 10-35V dc, 200mA. There is a little sticker wrapped around the cable for the switches inside the back connector block, on the cross-slide next to the X-stepper motor. I am using a C10 BOB for mine, and according to the manual, there are ways to connect the switches directly to the BOB inputs, using a resistor. These limit switches should not be too scary... :) I hope.

Any updates lately? Have you got it all up and going properly? Interested parties want to know! :)

Hi

I'm from France and i'm very to order the same lathe as you have in the past !

Many thanks for sharing your information, with your topic i have retrofited kbmg-212D same as your and really happy with this upgrad, thanks a lot !

But for now i have 2 question without founded answear over the web.

First are in the documentation this is writted 1Hp, in your topic you write 0.5Hp, i'm lost on this point for now i have selected 2.5A same as you but i think for 1Hp this is 5A, qhat do you think about this ?

Second are really important because i don't have suficient informationa bout stepper used for turret, i have found that is zebotronic M56 but don't know max current, i see on your pictures some engraved value on this stepper but can't read, have you a way for found better pictures or have this information ?

Another thanks for this sharing !

Best regards, Aurélien