Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: guynamedbathgate on September 08, 2007, 06:16:44 PM

Title: ATC for lathe
Post by: guynamedbathgate on September 08, 2007, 06:16:44 PM
any one out there ever tried to make a rotary type tool changer for a small lathe project. I saw one for an emco mini mill size one once and I have no idea where I could even get one. but I thought about maby being able to make one using a sherline-cnc rotary table. Any one out there ever tried this or thought about it.
Chris
Title: Re: ATC for lathe
Post by: poppabear on September 08, 2007, 09:04:31 PM
Yes, I have it is easy to do, If you dont mind doing some VB scripting for your M6. You will also need to decide how your gonna stabilize your turrent once it gets into position.

scott
Title: Re: ATC for lathe
Post by: DAlgie on September 08, 2007, 09:09:47 PM
I talked about this awhile ago here http://www.artsoftcontrols.com/forum/index.php?topic=304.0
   DaveA.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 08, 2007, 09:29:32 PM
well how did you end up locking it.
Chris
Title: Re: ATC for lathe
Post by: DAlgie on September 08, 2007, 10:05:16 PM
It has a tapered pin in the rear of the turret, driven by a large electric solenoid. The design of the pin is a copy of an italian turret that  a Clausing Clochester Storm lathe uses. One important detail is to have the software 'vibrate' the turret a very small amount to help the pin settle in it's home, this design uses a stepper motor, so I would forward/ reverse the pulses just as the pin goes in to lock it. I haven't built it yet, but have all the materials and hardware ready to do it, probably will happen in six months or so.
   DaveA.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 08, 2007, 11:47:16 PM
well Id love to see pictures as you make progress. any pictures would help really.
Thanks
Title: Re: ATC for lathe
Post by: cowpoke on September 09, 2007, 10:24:02 AM
Am retrofitting an Index NC lathe which already has an 8 position turret.
Since I know nothing about VB programming, has anyone done a macro for controlling the turret they would be willing to share?
TIA,
Claude
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 09, 2007, 01:09:38 PM
yes someone enlighten us as to what it would look like ???
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 10, 2007, 04:17:38 AM
Each and every tool changer is different, the software is custom written for each one, without knowing how it works and how the signals are laid out its not possible to even guess.

Tell me more about the turret, I will then give you a guide on how to program it.

Graham.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 10, 2007, 11:12:27 AM
I just got one off ebay so I havent recieved it yet but here is what the seller told me about it.

"Do you know how a rear hub on a bicycle works? The turret works in a similar way, in that it makes use of pawls. You have six pawls, each 60 degrees apart. Originally there was a 12vDC motor on there. One would supply 12v to the motor, and the turret would rotate. It would rotate the turret until it has completely passed the pawl. Then, the polarity of the voltage is reversed, and the voltage being supplied is cut in half. THis makes the motor rotate the other direction, backing the turret against the pawl. The motor doesn't cook because it is being supplied with only a few volts. I think it's a pretty clever arrangement myself, and leaves no room for positioning error. The turret is rotated via worm gear already, so it's pretty rigid to begin with. I think a step motor is better suited for the job because it doesn't require any extra circuitry (other than your typical stepper drive). "

obviously Im going use a stepper motor instead of a dc motor.
Is that any help.
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 10, 2007, 04:18:02 PM
Hi Chris,

That gives me something to work with, here is a rough guide as to how to do it:-

Set up the turret as a normal linear axis, work out the number of steps to give you one 60 degree move.

Set up a DRO on a screen to hold the tool that's in use. Set it to oem code 1050 or what ever you have free.

Now put this code into M6start.m1s macro, in your current profile :-

Graham.

Title: Re: ATC for lathe
Post by: guynamedbathgate on September 10, 2007, 04:35:13 PM
few that s a mouth full. I cant wait to try it. when I get it all setup I will let you know how it went. will be at least two weeks or so.
Thanks alot though Im not so sure Ill ever do enough scripting to get the hang of it.
Chris
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 10, 2007, 04:38:04 PM
I am not sure it will work, as I have no way to try it out at the moment, I will set up Mach lathe and try to get it to work on screen.

Graham.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 10, 2007, 04:45:53 PM
I do have a question now that I look at it. not that I understand it much at all anyway. but If its set up as a linear axis. wont it try to turn in the wrong direction  if I want to go from say tool 6 to tool 3 as it will be returning linearly. or what. I guess my question is what command in the script allows it to roll over back to tool one.
just trying to understand what Im doing is all. I do find this to be fascinating
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 10, 2007, 04:48:08 PM
sounds great. let me know how it goes. I appreciate it alot.
I like this forum alot. I got yelled at on the Practical machinist forum for being a hobbyist. people are alot nicer and tolerant over here.
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 10, 2007, 04:48:45 PM
No the code only runs the turret one way round, there is no short path coded into it.

Graham.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 10, 2007, 04:52:15 PM
I understand.
Chris
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 10, 2007, 05:13:55 PM
I have turned the macro into a .ZIP file for ease of updates, down load this one and give it a try.

I have just set up Turn and tried the latest version on it and it is working OK.

I have set it to work on the X axis so you can see numbers change.

It moves 100 units per tool, so if you enter T0101 to start with it moves to X110.0000 then to X100.00.

Looking Good

Graham.

Title: Re: ATC for lathe
Post by: guynamedbathgate on September 10, 2007, 08:54:44 PM
Im sorry where is this zip file Im supposed to down load.
Chris
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 11, 2007, 02:54:39 AM
Hi Chris,

it is now 9 posts down the list.

Graham.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 11, 2007, 06:44:39 AM
got it.
Title: Re: ATC for lathe
Post by: poppabear on September 11, 2007, 02:42:14 PM
I put a thread on a Generic ATC here:

http://www.artsoftcontrols.com/forum/index.php?topic=4191.new

Scott
Title: Re: ATC for lathe
Post by: Ian Ralston on September 11, 2007, 05:20:24 PM
My Boxford TCL 125 has a ratchet type, stepper driven, 8 position turret. I used a simple G code subroutine to get it to index. Y axis was left as linear, (Mach doesn't care) and worked out the number of steps to get the 45 degrees. So the subroutine indexes the turret, say 50 degrees, then reverses the turret to stall the stepper against the ratchet (no problems the driver limits the current) 
G code call is:-
M98 Ln P123 (Where n is the number of times I want to index and P123 is the subroutine.
Subroutine is:-
O123
G91 (Incremental distance mode)
G00 y-10 (Index more than 45 degrees)
G00 y2 (Back up to stall on ratchet)
G90 (Back to absolute distance mode)

M99 (Return from subroutine)

The Boxford turret has no means of telling Mach which tool it is using and because of the ratchet, it is strictly sequential.

It works for me!

Ian
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 13, 2007, 08:38:46 AM
Grahm I posted the script in the M6 macro.
I played with it a bit this morning. but all I could get it to do was go to
X110   when I entered M6 T0101 ( it did not stop and crawl back to X100 like I think it is supposed too)
after that it would not do anything else. and if Is set the tool number manualy in the toolbox to say 5
then entered an M6 T0301
I get an error message saying "tool number to low"
I guess I will play with it a little more.
I do need to drop a dro for the tool number still like you suggested but I am off to work so Ill play with it more later.
Chris
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 13, 2007, 03:56:36 PM
ok well I messed with it a little more and Ive discovered a little more about whats happening. so Ive placed a DRO and set it up for the x axis. what seems to be happening is when I  enter a tool change command it will move the apropriete increment say 110 units then the dwell light will pop on for over two whole minutes. then after that eternity in computor time. the controller backs up th e10 necessary increments to lock the tool changer. I was just being impatient.
Is there a dwell built into this macro that I could have inadvertantly set to two minutes or is that some setting issue. Im just running it on my laptop that does not have the drivers installed to test it. I have not changed any settings from the original instal so Im not sure what it would be.
Chris
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 13, 2007, 06:39:06 PM
Hi Chris,

if you look in the macro code you will see "G04 P250" this is a 250 micro second delay if you have your general config set for micro seconds, you must have yours set to seconds, all you need to do is change the P250 to P.25

Graham.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 13, 2007, 06:58:37 PM
ahh good. because at first I thought it was making mach freeze up and I was clicking on this and that and closing the program till I finally saw the little dwell light on and it hit me to wait it out. Its just one of those things you gotts step back and think about . thanks I will implement this emediately aand continue with the testing
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 13, 2007, 08:22:35 PM
ok. update time.
got it working perfect on my desk laptop. went down to the shop to do the same thing with the computer that will actually be running the thing and naddah.
I copied everything. even used the same xml file and I cant get it to do a thing. installed the most recent version of mach and still nothing.
anybody know where to start?
guess I gotta sleep on this one and maybe it will come to me.
Chris   :P
Title: Re: ATC for lathe
Post by: Chaoticone on September 13, 2007, 08:44:41 PM
Check your Macro for that profile on that machine. Also check in general config to see that the tool change options are set the same.

Brett
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 14, 2007, 08:14:13 AM
I got it working. Basicly I just started over again. I rewrote the Macro. re-added the button to the screen and of course, restarted the computer. so far so good I guess. cant wait till the dang thing gets here so I can set it up and test it.
Thanks alot everyone.
Chris :)
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 14, 2007, 11:42:55 AM
Hi Chris,

Glad to here you are getting something out of my long, hard struggle with the program  :o . OK 15 minutes  ;)

It will still need some tweeking but the basics are there, let me know when you get the thing ready to run and I will guide you through any mods.

Graham.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 29, 2007, 02:12:26 PM
OK got the toolchanger up and running and for the most part the macro is working just fine. Only one problem. is that when I change a tool I assume the macro changes the mode from absolute to incremental mode. where would I add a line to have the macro change the controler back to absolute coordinate mode once the tool change was complete. cause its playing crazy with my tool offsets.
Chris
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 29, 2007, 02:17:56 PM
only other thing I would change is to have the tool changer back up onto the paw a few more steps than what it is going past the paw. as it stands I have to set the steps to the paw slightly less than the actual distance to insure that it backs up till it makes contact. this creates a cumulative error if Im changing from say tool 1 to 6. but if I set it to exactly the right number it will go to the next paw. then go past a set number of steps and then back the same number of steps. this does not account for any lash in the drive so it does not back up snug onto the paw.
Title: Re: ATC for lathe
Post by: Graham Waterworth on September 29, 2007, 06:09:52 PM
Hi Chris,

Here is the latest version with the mods you asked for, anything you altered in the original will need to be changed.

I have added the return to absolute mode and a variable to set the lock back to pawl distance.

Graham.
Title: Re: ATC for lathe
Post by: guynamedbathgate on September 29, 2007, 09:44:38 PM
works great now. thanks
Title: ATC for HESTIKA
Post by: BosniaCNC on December 07, 2007, 07:21:31 PM
 ???
Title: ATC for HESTIKA
Post by: BosniaCNC on December 07, 2007, 07:23:26 PM
 ???