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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 401853 times)

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Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #390 on: December 30, 2012, 09:40:49 AM »
Those are the biggies. The rest is, as you pointed out, to keep the machine from chewing its own ankles off.

I would try to design in a failure point to prevent that.  On my ATC, the weak point is the attachment of the tool "forks" to the carousel, which are Nylon screws.  If a major jam were to occur, those screws would simply shear off, and the tool holder, and folk would fall on the table.  The only failure I can see right now with any possibility of breaking anything would be if the PDB tried to engage while the spindle was running in reverse.  Since I've never once had to run in reverse, this one doesn't concern me.  

Running in reverse does present some additional problems. I have a big face mill that runs in reverse, hard tapping of course involves reversing the spindle and I also run certain grinding cups in reverse depending on the setup.

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If the PDB were to engage while the spindle is running forward, the drawbar would simply unscrew, dropping the tool and collet.  Not good, but not catastrophic.  Even then, the spindle brake *might* be enough to over-load the motor and stall the spindle, though I have no intention of testing that theory....  

You have the luxury of designing and building for your own use exclusively. I have to imagine the stupidest thing a person could possibly do and then try to prevent it. Her in the States, everything you buy has twelve pages of warnings and one page of actual operating instructions. First you have to say 'do not use this toaster in the shower' and 'do not eat the insulation' and 'do not put the large hot coffee between you legs and then drive out into traffic'. Each one of those idiotic warnings is part of the settlement from a law suit. It is hard to explain to people on the other side of the pond how rediculous out legal system is here.  
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Once I get a spindle sensor on the machine, these issues also go away, as neither the PDB
nor ATC will be allowed to engage unless the spindle is confirmed stopped.

Regards,
Ray L.

A HAH!  You are soooo busted my friend! You have more sensors to add.  I'll just puit that beer back on the shelf a bit longer, thank you very much!   >:D

« Last Edit: December 30, 2012, 09:43:03 AM by simpson36 »
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #391 on: December 30, 2012, 09:44:55 AM »
You have the luxury of designing and building for your own use exclusively. I have to imagine the stupidest thing a person could possibly do and then try to prevent it. Her in the States, everything you buy has twelve pages of warnings and one page of actual operating instructions. First you have to say 'do not use this toaster in the shower' and 'do not eat the insulation' and 'do not put the large hot coffee between you legs and then drive out into traffic'. It is hard to explain to peopel on the other side of the pond how rediculous out legal system is here. 

Steve,

I'm on your side of the pond - Santa Cruz, CA.  The best warning I ever saw was for a Toshiba laptop.  They warned you not to drive nails through the battery pack!  The drawing accompanying the warning was priceless!  It was someone pounding what looked like a railroad spike through a battery pack.

BTW - *I* don't have to imagine "the stupidest thing a person could possibly do".  I'll usually manage to do it myself at some point....  :-)

Regards,
Ray L.
Regards,
Ray L.

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #392 on: December 30, 2012, 09:45:35 AM »
Steve,

BTW - I'm also in discussions with a machine manufacturer, to potentially design a PDB/ATC system for several of their machines, loosely based on my current design.  There are, of course, a number of things I would do differently on the second go-round.

Regards,
Ray L.

We should throw in together. I'll do the mechanics and you can do the controls. I don't like that part so much . . .

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #393 on: December 30, 2012, 11:26:14 AM »

Probably a good bit of that code is for communicating with the mother ship and I won't have that feature . . . :D

Nah the mother ship only sends a signal out and waits for one back to know its done :)

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The pair of Mistu drives will help a lot in reducing the coding and the sensor count as they will fault in some of the situations and they have a position reached signal that will serve as the sensor for several of the steps. In taking advantage of that, the controller would not be able to pinpoint a failure quite as accurately, but the operator can snoop around a bit to figure out what stopped the party.



Yes the lathes turret is kind of like that, only have two sensors on it, one to say its clamped and another for un-clamped, the drive handles the rest and will fault out if it doesnt get there which in turn will fault out Mach. There is also a feature in the drive where it can send an analogue voltage to indicate which position the encoder is at but I decided I didnt need that.
 The Chiron just has so much I/O and that is why the ladder is so long, there is a prox on the clamp, two on the main up/down cylinders and 2 on each of the tool cylinders. The ladder makes it easy to make sure one step can not be started before the other is complete.

Those are the biggies. The rest is, as you pointed out, to keep the machine from chewing its own ankles off.

I would try to design in a failure point to prevent that. 

 Sad thing is its not so simple with a lathe as the turret needs to be sturdy to stand up to the cutting forces and that is why it can do so much damage. A 10inch chuck spinning at 2000rpm colliding with the turret will not have a weak point other than a spindle getting bent or a turret getting ripped off or possibly both :(

Hood


Offline poppabear

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #394 on: December 30, 2012, 03:06:08 PM »
wait a minute, I did NOT know there was Beer involved in this!!

Here is an ATC prototype I did for Tormach a while back.

http://www.youtube.com/watch?v=vcWUZJ35yL0&feature=youtu.be

Scott
Commercial Mach3 & Mach 4, Design/Build/Retrofit CNC and Industrial machines.
http://www.ss-systems-llc.com/

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #395 on: December 30, 2012, 05:14:08 PM »
wait a minute, I did NOT know there was Beer involved in this!!

Here is an ATC prototype I did for Tormach a while back.

http://www.youtube.com/watch?v=vcWUZJ35yL0&feature=youtu.be

Scott

Interesting. If I read between the lines in your video description, things did not go well with Tormach on this project.

I have it in writing from Tormach's engineering manager that their MACH software is 'locked down' because Tormach does not believe users should be allowed access the 'flakey' MACH software in their own systems for fear they will mess up the 'motor parameters'.

As you know, in MACH parlance, 'locked down' versions have nothing to do with keeping users out and there are no motor parameters in MACH. These statements indicate to me an unfamiliarity with MACH which lead me to speculate that Tormach uses outside sources for some or all of their development. You have now confirmed that.

Offline BR549

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #396 on: December 30, 2012, 05:27:17 PM »
Ray I believe Tormach's stance is to LOCK OUT access to the motor tuning parameters  Steps Per, Vel and accel. From  support stance I cannot find fault with that.

Also they do give you the option of unlocking it for you BUT they will not support you after that point. Can't argue with that either.

Scott, you were NOT in process when the bet started, DING DING, DQed (;-)

THere ARE others that are in process but are bashfull.

(;-) TP

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #397 on: December 30, 2012, 05:29:43 PM »
Steve,

BTW - I'm also in discussions with a machine manufacturer, to potentially design a PDB/ATC system for several of their machines, loosely based on my current design.  There are, of course, a number of things I would do differently on the second go-round.

Regards,
Ray L.

I am supposed to be semiretired, but most of my time is still consumed by consulting work, mostly under DNA and in such arrangements, by contract, liability transfers to the client. Selling a product that I manufacture directly to an end user is a whole other animal.

If I am able to get the proper insurance, I will make the spindle and ATC available to end users, otherwise only to manuf who will assume liability under their umbrella.

I am aware that you are on the same side of the pond, that's why I figured you can appreciate the paranoia. The insurance industry is as nuts as the legal system. A well know insurance company gave us a TD because . . now get this . .  they decided that the 4th axis constitutes 'automation' and they do not underwrite 'automation' because 'automation' *might* be used to make guns or gun parts. WTF  ???    Gotta be lawyer prints all over that one.   


Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #398 on: December 30, 2012, 06:22:41 PM »
Ray I believe Tormach's stance is to LOCK OUT access to the motor tuning parameters  Steps Per, Vel and accel. From  support stance I cannot find fault with that.
Also they do give you the option of unlocking it for you BUT they will not support you after that point. Can't argue with that either.
I think you were addressing my post, so I will respond. Incidentally, you forgot to mention that warranty is also effected if an owner signs Tormach's waiver to get access to their MACH software. Do you find fault with that I wonder.

You can believe what you want. As I said, I have Tormach's official response in writing and I have quoted directly from that document. If you want to see the actual e-mail, just ask and I will be happy to post it so that 'interpretation' is not needed.

I don't care to get into a Tormach debate, but I do want to clarify one thing. In my inquiry, did not suggest Tormach change their policy (regardless of how condescending *most* people think it is). I offered to spend MY time reconfiguring MY software to eliminate any possible conflict with their setup, and that no Tormach customer needed to be involved nor inconvenienced nor given access to anything. The process would be one engineer (me) consulting with an other engineer (Tormach's) to provide QC for the benefit of Tormach owners.

Their response (again in writing) was that they are " . . . not excited about helping third parties, particularly those [who's products] compete with Tormach's".  They inked me to their 'Duality Lathe' as if that was in any way competitive with or equivalent to the InTurn™. My current controller also accommodates a servo driven spindle with universal hard tapping macros included. Tormach has no equivalent that I am aware of.

The simple solution is to ditch the entire Tormach setup and do a fresh install of MACH and put the InTurn™ stuff over it. Tormach only succeeded in aggravating their own users  . . and me. I am asked a couple of time a week what machine I reccommend for use with the InTurn™ 4th axis. Venture a guess?

Offline BR549

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #399 on: December 30, 2012, 06:31:18 PM »
Sorry but I support Tormach's policy. It would be the same if I bought a new car then took it apart to change engine parts to make it more sporty and more HP. 

Of course you would not because you want to sell the Owners something. (;-)

AGAIN we should just agree to disagree, (;-) TP