Hello Guest it is June 19, 2019, 05:38:47 PM

Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 400257 times)

0 Members and 1 Guest are viewing this topic.

Offline simpson36

*
  •  1,374 1,374
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #210 on: October 03, 2012, 12:34:40 PM »
Steve,

I don't understand the black lever at the bottom of the photo.  I'm assuming this is a positive lock, that prevents the ball gripper from coming down and releasing the tool, but it's not clear how it fits.  I assume the pivot goes into the slot on the side of the housing, but where does the "tang" on the RH side go?

Regards,
Ray L.

My bad. I have the lever in the photo upside down . . or backwards, depending on the perspective. It works exactly as you surmised. The 'beak' if you will, pokes thru the hole at the top and interferes with the ball holder descending into the body, this preventing the tool release. The 'tail' reaches down to the bottom of the body and is spring loaded. The spring is not in the photo because those parts are not here yet. The spring goes in the bottom of the pivot slot just below the pivot pin (also not in the photo).

The claw engages the slot on the adapter and then in the last 1/4" or so of travel, it pushed in the tail of the lever, thereby removing the interlock and allowing the air cylinder to release the tool.

You are uber observant, so I will presume your next question will be why is there a 'tooth' on the 'beak'. The 'beak' is retracted, the plunger is then pushed in (down) by a small air cylinder. The plunger not only 'releases' the ball grip, it also physically ejects the adapter about .060". The next action in the sequence if to the arm to descend with the toolholder in-hand, so to speak.  At this pint in the sequence there are two options:

1) let the plunger up and lower the arm simultaneously and the plunger will raise all the way to the snap ring stop. It will then need to be depressed again by the air cylinder in order to return the tool

2) lower the arm first and then let the plunger up. When the claw is lowered from the pod, the lever re-opens via its own return spring and the 'beak' pokes back into the chamber. Letting the plunger up at this point results in the 'tooth' catching the top edge of the plunger and holding the gripper in the 'open' position. 

In the second configuration, the tool is returned simply by the claw raising the holder into the pod. The claw re-compresses the 'tail' as it raises the last 1/4" or so, thereby releasing the plunger and locking the holder into the pod.

Hopefully that all made sense.
 

Offline simpson36

*
  •  1,374 1,374
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #211 on: October 03, 2012, 12:49:50 PM »
Do you sleep?
Thats looking great.
I disassembled my ball gripper after about 800 tool changes and there were no signs at all of wear or distortion. Starting to test my spring forks to work out those details. Even if I stall on the tool changer (I won't) changing over to the BT30 and air drawbar was the best mod I've made to this mill since I converted it to Mach. Manual tool changes are so… Civilized :)

Again amazing work your doing.

Derek

THX!  At this point I am not considering the ATC design to be proprietary and there is nothing in it (thus far) that is beyond the capabilities of a competent DIY. I may be inclined to share the drawing of the final design claw and pod. Not a promise at this point, but I don't see a patent in the ATC so far, and I am doing it on my own dime, so no NDA on that part of the project.

The current pod actually works perfectly. My concern with the first prototype was the potential for jamming. The current gripper arrangement does not tend to jam, but it needs to be a little more bulletproof. More robust. Probably the interlock lever's 'beak'  should be hardened, which would put it out of DIY.  I have already refined that design a bit from what is in the photo and the areas that need to be stronger can be handled with different materials, but I don't want to spend any more time on it for now since I have a new method in mind. Something of a hybrid between the two approaches. See my response to Ray (Kabibble) for a description.
« Last Edit: October 03, 2012, 12:54:10 PM by simpson36 »
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #212 on: October 03, 2012, 09:57:46 PM »
Steve,

I don't understand the black lever at the bottom of the photo.  I'm assuming this is a positive lock, that prevents the ball gripper from coming down and releasing the tool, but it's not clear how it fits.  I assume the pivot goes into the slot on the side of the housing, but where does the "tang" on the RH side go?

Regards,
Ray L.

My bad. I have the lever in the photo upside down . . or backwards, depending on the perspective. It works exactly as you surmised. The 'beak' if you will, pokes thru the hole at the top and interferes with the ball holder descending into the body, this preventing the tool release. The 'tail' reaches down to the bottom of the body and is spring loaded. The spring is not in the photo because those parts are not here yet. The spring goes in the bottom of the pivot slot just below the pivot pin (also not in the photo).

The claw engages the slot on the adapter and then in the last 1/4" or so of travel, it pushed in the tail of the lever, thereby removing the interlock and allowing the air cylinder to release the tool.

You are uber observant, so I will presume your next question will be why is there a 'tooth' on the 'beak'. The 'beak' is retracted, the plunger is then pushed in (down) by a small air cylinder. The plunger not only 'releases' the ball grip, it also physically ejects the adapter about .060". The next action in the sequence if to the arm to descend with the toolholder in-hand, so to speak.  At this pint in the sequence there are two options:

1) let the plunger up and lower the arm simultaneously and the plunger will raise all the way to the snap ring stop. It will then need to be depressed again by the air cylinder in order to return the tool

2) lower the arm first and then let the plunger up. When the claw is lowered from the pod, the lever re-opens via its own return spring and the 'beak' pokes back into the chamber. Letting the plunger up at this point results in the 'tooth' catching the top edge of the plunger and holding the gripper in the 'open' position. 

In the second configuration, the tool is returned simply by the claw raising the holder into the pod. The claw re-compresses the 'tail' as it raises the last 1/4" or so, thereby releasing the plunger and locking the holder into the pod.

Hopefully that all made sense.
 

Steve,

Makes perfect sense, and very clever.  Thanks!

Regards,
Ray L.
Regards,
Ray L.

Offline simpson36

*
  •  1,374 1,374
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #213 on: October 04, 2012, 10:32:45 AM »
Better late than never . . .

Offline BR549

*
  •  6,873 6,873
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #214 on: October 04, 2012, 02:02:10 PM »
(;-) Are yous guys building tool changers or PITCHING machines.

(;-) TP

Offline simpson36

*
  •  1,374 1,374
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #215 on: October 04, 2012, 07:02:28 PM »
(;-) Are yous guys building tool changers or PITCHING machines.
There is definately a security breach around here somewhere . . . .

Offline simpson36

*
  •  1,374 1,374
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #216 on: October 04, 2012, 07:24:16 PM »
Feedback is that people really like to see the raw materials and not just the finished parts. Also, mock ups seem to be popular. It would be nice if there was more participation in this thread instead of my e-mail, but in any case, here are some mock ups of the mechanisms for the arm and the carousel. I am most likely going to use the same gear box for both, although the carousel will be driven by a smaller BLDC servo and a Coplet Accelnet drive.

To Hood; incidentally, the Copley does have the configurable roll-over feature. I have not had time to check out the rest of the related feature set that you described, but it looks like it may be the hot setup for the carousel. The Mitsu J3 has a special anti vibration capability that should make it a good choice for the uber accell/decell of the arm.

http://www.youtube.com/watch?v=8JkFqzwlyiI

The Mitsu motor can blast over 6K RPM momentarily so with the 50:1 worm gear drive the swing should happen in about 1/4 of a second give or take. Any of the 6 tools should be reachable in less than 1/2 second with the little BLDC servo motor. I *might* be able to eliminated the pneumatic release of the tool from the carousel, so I think I am on target for sub 5 second tool changes and be well back from the maximum speeds.
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #217 on: October 05, 2012, 08:01:53 AM »
Nice work!.

It is also amazing to me that people will send you an email or PM but they won't post in the forum so everybody can participate.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

Offline Hood

*
  •  25,844 25,844
  • Carnoustie, Scotland
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #218 on: October 05, 2012, 08:55:54 AM »
Look forward to hear what the Copley's can do :)
Hood

Offline simpson36

*
  •  1,374 1,374
    • View Profile
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #219 on: October 05, 2012, 12:54:50 PM »
Nice work!.
It is also amazing to me that people will send you an email or PM but they won't post in the forum so everybody can participate.

Forums are the place where the small can be giants and the weak can be bullies. People have a bad experience with some a-hole who ridicules their ideas or comments and they don't post any more. With 3,400 reads and the same handful of people participating, I have to believe there are some great ideas out there that we will never hear about. It is foolish and short sighted to trade a moment of bravado for losing a resource, but a lot of people do it.  Great ideas often come from unlikely places.

If somebody posted a comment or idea in this thread and got slammed for their trouble, I'm afraid I would have to go postal on the slammer.