Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: TT350 on October 20, 2007, 08:49:44 PM
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My question to you is I would like to convert my lathe
to cnc.
I’ve been talking to another Tormach customer that has
been playing with cnc routers and such for years and we
come up with an idea that I would like your opinion on.
We have been kicking around the idea of putting my lathe close enough to my
Tormach so we could put some amphenol plugs on 2 of the axes motor control
wires so that I could unplug the Tormach and plug up the lathe axes to the
Tormach cabinet and use your Mach lathe software to run my lathe.
I could have a cnc lathe and save a lot of $.
If this is would work I mite even put a 3 phase
motor on my lathe and let Mach control the
lathe spindle speed as well.
Thanks for your time
Chris
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I don't know if there is a limit to the number of profiles you can have in Mach, but you can certainly have two. ;) If you wanted to run the lathe, change the connections and open your lathe profile. I don't know if Tormach has any propritary settings or configurations. If they do, might put a kink in things.
Brett
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If it can be done it would make it simple to setup and very
cost effective.
If spindle encoder output if fed back to the PC and no threw the
the circuit boards in the cabnet I'll be set!
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You will have all sorts of wring to unplug/plug such as limits, motors, index etc etc. It could be done but to be honest it might not be the best way. You are going to need motors anyway so the extra cost of a breakout board and two axis drives would be money well spent in my opinion. For steppers Geckos seem to work well but there are others out there altough I would be carefull what you opt for.
If you go this route then it would just be a case of setting up Mach turn and swapping the parallel port cable over, you could probably even get a two port switchover to save having to unplug it all the time.
Hood
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It could be done but to be honest it might not be the best way.
I agree with Hood.
Brett
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I'm really don't know anything about all the other stuff that goes with the system.
I know what a VFD is, I've put one on a three phase motor and programed it before
but all the other things that it takes "brake out boards drives and power supplies"
I have read people posts but it's not my cup of tea.
If some one could put together a recipe of parts it would make it easer.
All that stuff is in the Tormach cabinet.
After loading the Mach lathe program why can’t
it use the same printer port?
Why can’t one just open Mach lathe after the motor tuning setup for the lathe and unplug the
and plug in assigned axes and limit’s switch’s?
My be I’m not seeing the hole pitcher here, but it seam’s
to me that the electronics in the cabinet is sending commands to a motor,
what would it care if it’s a lathe or a mill?
Now I do know that Tormach comes with it’s own version of Mach, maybe it won’t run on a regular
version?
If there was a place where I could go and get everything
at from company and build a system that would make it
easer.
Saving money is only a small part of this is.
All that stuff in that cabinet really intimidates me.
I just don’t know what to buy.
Chris
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First off dont be intimidated, its really quite easy once you get your teeth into it.
Well you could do as you say and maybe the Tormach makes things simple by having plugs for everything that is outside the cabinet such as limits, index, speed control etc. If it does then you can set up your lathe to use these but I think it might be a pain to do it that way. If it doesnt use plugs for everything then it will be a major pain as you will have to wire your lathes limits, index etc to the Tormach breakout every time you want to use it and hen swap everything back when you want to use the mill.
You can use the same parallel port in the computer but if you have two distinct machines then you will have to connect the parallel port to one machine or the other. Please note this is if you are not going to try and use the same drives etc.
If you do use the Tormachs drives etc you may run into problems unless the motors are the same on mill and lathe. The drives need to be set to the current of the motors with a resistor and also there is a pot on the drives for adjusting resonance. So if the motors are not exactly the same you may hit problems and even if they are the tuning pot may need to be set different from motor to motor.
There are a few places that you can buy complete control hardware from but its more expensive that way. For a basic system you will need a power supply, breakout board, stepper motors, stepper drives and limit switches. You can easily build a power supply as they dont have to be regulated so all you need is a suitable transformer a suitable capacitor and a rectifier.
If you decide to go down the self build route you will get all the help you need from the guys on this forum.
The version Of Mach in the Tormach shouldnt really be a problem as I would think it only varies in screensets and maybe a few macros but as long as you can open MachTurn from your Tormach computer then you can set it up how you like.
Hood
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I plane on putting the same motors and limit switches on the lathe that the Tormach uses.
I will put Amphenol plugs in the cabinet so all I have to do is unplug the mill motors
and switch's plug up the lathe motors and switch's.
This way all the stuff in the cabinet matches.
Amphenol makes plugs big enough to put all the necessary
wires all in one big plug.
I really appreciate ever ones help.
I know I my seam a little hard headed
but if I build a new control system
and I basically will end up with 2 control
cabinets and 2 PC setups.
I’m a one man shop and can only run one at
a time. Now as I get better I may need 2 separate
systems.
Thanks for all your input
Chris
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Not hard headed at all :)
You wouldnt need 2 PC setups just two hardware setups, the one PC could control both machines.
From your description though it seems that maybe it is possible tyo do as you are wanting, ie all external harware is connected via plugs. If this is the case then my only worries would be the motor resonance adjusting but really that shouldnt pose too much of a problem. The spindle control might be an issue depending on how the Tormach and your Lathes spindle will be connected but again as long as you are careful with the settings there shouldnt be a problem, just have to make sure you get it right as you dont want the mills spindle starting by accident.
I am a one man shop also but I hope to be able to run both machines at the same time and be away doing another job :D
Hood
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http://www.youtube.com/watch?v=BnKmLGP6lIg
I would like one of these as well.
It looks like it was made by the owner.
I was chasing forum threads on one of these and there
was talk of there being some detailed plans for one,
but so far I haven't been able to find them.
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I think Steve Blackmore on the Mach Yahoo group was going to be building or has built one, seem to remember he was going to post details but could be mistaken.
The one on my lathe is original and hydraulic controlled and only moves in one direction.
Hood
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If you run up on a link post it if you don't mind.
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Been searching through the Yahoo group and all I could find was Steve mentioning that he was going to be starting again on his project, that was back in 2005 though and no mention since :(
I did a quick google and found this, might be of some help.
http://www.issintl-inc.com/latheturret/
Hood
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That's funny! I just save this to my deck top LOL!!!
Thanks!!
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Well I've been doing some digging and found out that a spindle encoder is required to be able
to do treading and from what I found out it hooks into a brakeout board or something.
So I really don't won't to go monkeying around with the boards in my mill.
I have decided build the whole thing from scratch so I need you guys to
help me with what's needed as far as brake out boards drives and power supply.
My plan is to put steppers on it,1200oz on the Z and 640oz on the X.
If some one could put me a shopping together that would great!
Thanks again guys
Chris
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How big is your lathe?
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14x40 import.
This is my lathe. http://www.billstoolcrib.com/CT1440.htm
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You could probably get away with smaller motors but depends on what you are gearing them I suppose.
You will need a power supply, you can make one quite easily out of a transformer a capacitor and a rectifier. Bob Campbell has a good pdf on this, see here http://campbelldesigns.com/files/power-supply-part-1.pdf
You will also need a breakout board, some drives and some limit switches. I like Gecko drives for steppers, have tried some others but the Geckos are way ahead of the others I tried. Then again the other ones I tried were cheap crap so ........
Limit switches can be of many types but if you want accurate homing then optical ones are good. Its easy enough to make your own optical limits up, bit of work if you use coolant as you will need to make a case for them that is waterproof but if you dont use coolant then just some shields should do.
Hood
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What size steppers would use for the Z&X? Ball screw leed .200 on the Z and .125 on the X
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are you gearing them or direct drive? what kind of rapids are you wanting?
Reason I ask is I have 916 oz/in on my Bridgeport Boss , they are geared 2:1 but they have more than enough torque, they would have enough torque to direct drive them. The rapids I get are 2500mm/min (100IPM) which is more than enough for the short travels on the mill and is the reason I have not changed to direct drive.
Hood
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My plane is to go direct drive, 100 IPM is plenty fast enough.
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Well I would say that the 916oz/in I have would be more than adequate for your needs on the Z and probaly smaller needed for the X. If however you did run into problems then you always have the option of gearing as Direct drive would put your rapids in the range of 200IPM and you are saying 100IPM is more than enough.
The only experience I have of Lathes is the one I am doing at the moment but its a different beast altogether as it uses AC Servos and I have my doubts whether the Torque figures of Steppers and AC Servos can be compared for like for like. I have 10NM motors on the Z Axis which is about 1400oz/in this however is a big lathe that I have taken 20mm off the diameter of 75mm stock in one pass with no problem, but as I said whether the torque of AC Servos and Steppers can be compared I doubt.
Hood
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Well I would say that the 916oz/in I have would be more than adequate for your needs on the Z and probaly smaller needed for the X. If however you did run into problems then you always have the option of gearing as Direct drive would put your rapids in the range of 200IPM and you are saying 100IPM is more than enough.
The only experience I have of Lathes is the one I am doing at the moment but its a different beast altogether as it uses AC Servos and I have my doubts whether the Torque figures of Steppers and AC Servos can be compared for like for like. I have 10NM motors on the Z Axis which is about 1400oz/in this however is a big lathe that I have taken 20mm off the diameter of 75mm stock in one pass with no problem, but as I said whether the torque of AC Servos and Steppers can be compared I doubt.
Hood
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Who makes the most accurate limit switches,
Optical or mechanical? I would like to put 2 of the 4
I will need for accurate homing.
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Optical switches are the most accurate, all other things considered. However, you really don't need great accuracy on the Z axis, a mechanical switch there is just fine. A lathe needs high homing accuracy on the X axis because you keep all the tools set, or at least the main ones anyway, roughing, finishing, parting off. So, you need to have good accuracy on the X axis so that these tools will always be set to maintain your diameters, different stock materials will slightly alter your finish diameters though. The Z axis, on the other hand, you usually set the Z zero point off the end of the stock with each new job, so the Z axis does not need to be as accurate.
DaveA.
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Thanks Mr airplane :) Where do I buy the best ones?
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You can easily make up optical switches especially if you will not be using coolant. For that all you need is something like this OPB916B (go to rswww.com and type it into the search) and a 220ohm resistor.
If you need coolant proof then you will have to make up some form of box and plunger arrangement.
Industrial Hobbies used to make nice ones complete but dont think they do them anymore but you may still find pics/info on their site about them.
Hood
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The more I dig the more I find, this DIY cnc thing has a LOT to choose from.
I've made my mind up that Gecko is the most popular drive out there so I'll
be useing those.
Has any one used any CNC4PC.com stuff?
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I am using a cnc4pc parallel port opto card that is a few years old. It doesn't have any bell or whistles like leds for I/O state. The motor steps and direction plus PWM for spindle speed all come from outputs from this card via LPT1. I had planed on using the inputs for an encoder/MPG and did test it but with a shuttle pro for jogging I just don't see a need for it but I do send the Index mark through this card.
The LPT2 is heavy on inputs so I used a opto22 G4PB16 with it. You can get a good deal on them off eBay. Also I don't think the opto22 stuff is fast enough for motor steps or direction with regards to timming sync. Pics of my lathe can be found here http://www.machsupport.com/forum/index.php/topic,4618.0.html
Drew