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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 401850 times)

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Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #120 on: September 21, 2012, 09:47:42 AM »
Update: I have settled on an arrangement for the ATC and completed the preliminary design.

So far, I have built one prototype tool storage 'pod' (for lack of a better term) for testing and while it works as expected, there *might* be a tendency for the release mechanism to jamb in the long term, so I have made some changes, adding to reliability but also to the cost, as is usually the case.
 
After reviewing a lot of existing ATC configurations, both DIY and commercial, I chose to not move the entire tool storage device and instead use a single swing arm to transfer tools from storage to the spindle. here are some design goals which are met with the design thus far:

1) safety - accommodate sensors at each step in the process for monitoring purposes.
2) configurable - choice of 6 tool turret or unlimited number of tools via chain belt
3) self contained - optionally the ATC (with turret only) can be mounted entirely on the mill head (credit to Hood for this goal),  
4) Tool tapers are completely covered and protected by the tool storage 'pods'.
5) positive mechanical retention of the tools in the storage device - no reliance on material spring - i.e. nylon 'fingers' or equiv.
6) tool release from storage pod is initiated by the swing arm 'claw', and then only after the claw has firm control of the tool.
7) fast - have not quantified this yet, but definitely not 10 to 20 seconds as typical DIY changers require.

Feedback always appreciated, especially if you have a favorite ATC arrangement and can cite the advantages. I will post a photo of the prototype storage pod a little later today perhaps.

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #121 on: September 21, 2012, 09:58:43 AM »
Sounds like it will be nice, are you having a dual sided arm or just using a single arm?
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I am likely not going to have to bother getting the knee on the Beaver servo'd in preparation for a toolchanger,  now as I will likely be buying a Chiron FZ12 Mill shortly, going  to see it on Sunday so I can see if I reckon the motors I have will fit. Now they are fast, something under 1 second toolchanges. ;D

Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #122 on: September 21, 2012, 10:13:06 AM »
Sounds like it will be nice, are you having a dual sided arm or just using a single arm?
,
I am likely not going to have to bother getting the knee on the Beaver servo'd in preparation for a toolchanger,  now as I will likely be buying a Chiron FZ12 Mill shortly, going  to see it on Sunday so I can see if I reckon the motors I have will fit. Now they are fast, something under 1 second toolchanges. ;D

Hood

Single arm mounted on the head. The swing is over 180 degrees making articulation rather complicated, so the arm will probably be servo powered. Expensive option, but one that also provides for accurate positioning and also for sensing jams, collisions, or empty tool pods.

The arm will raise and lower on a single linear slide via pneumatic cylinder. I am unsure at this point where to put the sensors for vertical movement.

I doubt there will be sub second tool changes, but 5 seconds would be great.

The tool change speed will be improved significantly in a configuration where the turret is carried on the mill head, but with a tool change possible at any Z position, special attention will need to be paid to tool clearance in the g-code to make sure there is room under the head for the new tool to swing in. Have not looked at that Gorilla yet.
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #123 on: September 21, 2012, 10:21:20 AM »
Looking forward to seeing what you come up with!  I'm finally getting off my lazy a$$, and getting back on my ATC - a 10-tool carousel that will handle TTS initially, and, hopefully, eventually move to 30-taper.  I considered a "remote" carousel and transfer arm, but it seemed to get too complex too quickly.  My current carousel design is really quite simple, with only two air cylinders for actuation, also fully inter-locked.  I'm using a Geneva driven by a simple gearmotor for tool selection.  With luck, I should have it working in another week or so.

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 #124 on: September 21, 2012, 10:22:54 AM »
On the topic of 'Any-Z-position-tool-changes', it has just occurred to me that if there is access in MACH to the tool table, the operator could enter the highest point on the workpiece stock and the ATC controller could raise the head to safe level for the commanded tool after checking the available Z travel. If the travel is exceeded, the machine could fault or suspend and wait for operator intervention.  

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #125 on: September 21, 2012, 10:25:06 AM »
The toolchanger I was planning was similar with the exception that the arm was going to be dual sided and it could swing round take a tool out, drop swing 180 and raise and place the new tool in. It would really have neeed three levels though as the toolchanger would be higher.

Regarding the sensors, the Chiron has them on the cylinders, there is a cylinder for each tool, each having a prox sensor top and bottom and then two more cylinders either side that lower and raise the basket.  It looks at first a very complex set up but  when you study it is actually quite simple and seems reliable as the only thing my friend has had to do in the 15 or so years he has had it is replace pipes as the originals started splitting.

Heres a vid of the style on the Chiron.
http://www.youtube.com/watch?v=97KQ5DKSuNw
Hood
« Last Edit: September 21, 2012, 10:26:48 AM by Hood »

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #126 on: September 21, 2012, 10:36:06 AM »
I considered a "remote" carousel and transfer arm, but it seemed to get too complex too quickly.

Agreed. However, the goal of unlimited tools eliminates a moving storage device as a possibility. Moving a carousel is easy enough, as you correctly point out, but moving a 6 or 7 (or more) foot long chain belt and associated drive mechanism would be impossible by any practical method that I can think of. Another consideration on this aspect is the cover s for the tool storage. Since the arm moves up and down, I think I can sidestep needing an opening access door . . . .  hopefully . .  maybe . .  

Quote
My current carousel design is really quite simple, with only two air cylinders for actuation, also fully inter-locked.
how are you sensing a successful tool change

Quote
I'm using a Geneva driven by a simple gearmotor for tool selection.

Simple and effective for a carousel.  NG for the chain belt option, but a servo drive could be moved over with out much difficulty and the programming would not need to be significantly different . .  perhaps even handled by a config param.


Quote
With luck, I should have it working in another week or so.

A week!  Jeez, It will take me a week to figure out how this new coffee maker works . .  :D
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #127 on: September 21, 2012, 10:42:46 AM »
Heres a vid of the style on the Chiron.
http://www.youtube.com/watch?v=97KQ5DKSuNw
Hood

THAT is the single coolest toolchanger EVER!  :-)

Regards,
Ray L.
Regards,
Ray L.

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #128 on: September 21, 2012, 10:45:32 AM »
Its something else when you see it in the flesh ;D

Hood
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #129 on: September 21, 2012, 10:48:53 AM »
I considered a "remote" carousel and transfer arm, but it seemed to get too complex too quickly.

Agreed. However, the goal of unlimited tools eliminates a moving storage device as a possibility. Moving a carousel is easy enough, as you correctly point out, but moving a 6 or 7 (or more) foot long chain belt and associated drive mechanism would be impossible by any practical method that I can think of. Another consideration on this aspect is the cover s for the tool storage. Since the arm moves up and down, I think I can sidestep needing an opening access door . . . .  hopefully . .  maybe . . 

Quote
My current carousel design is really quite simple, with only two air cylinders for actuation, also fully inter-locked.
how are you sensing a successful tool change

Quote from: HimyKabibble
By the carousel position.  The whole carousel drops down, moves under the spindle, then raises up to insert the tool.  If the tool does not correctly enter the spindle, the carousel will either hang up, and throw a fault, or the tool "fork" will break off, which will not be detected, but should be both VERY rare, and relatively harmless (I hope).

Quote
I'm using a Geneva driven by a simple gearmotor for tool selection.

Simple and effective for a carousel.  NG for the chain belt option, but a servo drive could be moved over with out much difficulty and the programming would not need to be significantly different . .  perhaps even handled by a config param.

Quote from: HimyKabibble
Actually, no reason why a Geneva can't be used to move a belt just as well....


Quote
With luck, I should have it working in another week or so.

A week!  Jeez, It will take me a week to figure out how this new coffee maker works . .  :D

Quote from: HimyKabibble
Well, I started on it a couple of months ago, but it's been on the shelf for a while.  I got the geneva, carousel disc, and all tool holders done and working - that all took just one day to machine.  I just have to make the mounting arm and housing.
Regards,
Ray L.