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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 407835 times)

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Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #520 on: July 21, 2013, 09:36:26 AM »
Running a job on it at the moment but will take a couple of vids of it later on to let you see whats happening.
Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #521 on: July 21, 2013, 09:37:18 AM »
I just looked at the video fragment ans I probably should add a couple of comments:

The arm flexes up and down. This is inentional. The drawbar not only releases the grip, it also physically shoves the toolholder out of the spindle by a small amount. The arm flexes to accomodate that movement

The carousel is a bit loose. That will be tightened up during final assembly, but some play will remain intentionally to allow for minor misalignments.

The arm shaft will eventually be cut off flush with the bottom of the arm.

The arm shaft will have a corrogated rubber bellows covering it.

The arm will have a cover to keep swarf off the sensors.

The arm will move a little bit faster in the final version.

Edit: Oh and one last thing . . .  the carousel will rotate . . . so that the machine can use more than one tool  . . . :D

When I get some more pods made up, I will do another video showing an actual tool CHANGE and also the spindle homing, which is working, but not shown in the video fragment.
« Last Edit: July 21, 2013, 09:49:53 AM by simpson36 »
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #522 on: July 21, 2013, 10:04:03 AM »
Well, as you might agree, the software is the real challenge, especially now that I have completely lost my mind and decided to go forward with porting to the Kflop. I can tell you now that I used your name in vain more than a few times for recommending the Kflop as a 'plug and play' MACH accessory and using the word 'easy'. Note to self: When Ray uses the work 'Easy', be afraid . . be very afraid.

 The HimmyKabibble vernacular exchange rates:
"Easy = Doable, like walking on water or spinning straw into gold."
"Difficult = requires intervention and assistance from advanced civilizations"

Eventually, I did get things working. It is quite a powerful system, but they really need to hire you to write some manuals like you did for MACH. I will be starting on that port in a few days so if you hear your name on the wind with colorful adjectives attached  . . . that would be coming from the East, most likely . . .  ;)

Steve,

That explains the odd burning sensation in my ears lately!  But, when did I ever say bringing up a KFlop would be "easy"?  :-)

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 #523 on: July 21, 2013, 10:38:41 AM »
Ok Steve, here are the vids, first shows me offering a tool up to the spindle so you can see the dog getting pushed up and then dropping in.

http://youtu.be/784P5uA9lro

As you will see the toolholders have the bearings but also a brass disc, this acts as a brake so they dont rotate in the tool arm until the dog engages. When the dog drops in it obviously turns the holder and this would soon cause friction if left in that position. However when the tool is clamped it is pulled up to clear the disc and instead the bearing is then in contact with the tool arm.
You should see all that in this vid.

http://youtu.be/fuxOCikZxU8

Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #524 on: July 21, 2013, 04:26:09 PM »
Hood,

First, THANK YOU for the vids. Thats a piece out of your busy day and it is much appeciated.

I looked at a lot of attempts at R8 tool changers before I concluded that this was not a road I wanted to go down. Likewise, when I looked at the various tapers, I saw only fixed dogs on the spindle . .  and I looked at a lot of those spindles and changers.

The spring loaded dog seems like a brilliant solution. However . . .   it appears that each tool holder has its own bearing/brass ring brake assembly as a permanent fearture.  Is that correct?

- Steve

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #525 on: July 21, 2013, 04:45:23 PM »
Yes thats correct, it needs the brake so that the tool will not turn with the friction of the dog pressing on the flange before it rotates round to the slot. Also it is needed so that when the tool is released at 200rpm it will stop spinning very quickly.
The bearing is needed as the tool arms are  always holding  the tool and if it wasnt there it would either have to be loose in the arm which would present problems with it entering the spindle nose or if the arms were made tighter then you would get rubbing and friction and it would seize in no time.

The toolchange is actually damped down on my machine, it was done by the previous owner and I decided just to leave it that way but original toolchange time was I think 0.9 seconds and something like 2 seconds chip to chip.


Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #526 on: July 21, 2013, 10:33:39 PM »
Well, I was all excited for a while there, and I will say that the system in ingenious in side stepping the alignment issue  . .  which is a BIG issue. However, requiring all custom tool holders is not on the menu so while I can be amazed and admire the creativity in the solution, it is not an idea that I can use as it goes contrary to one of the primary deisng goals: use standard commercial/indusrial tool holders.

I looked at some of the 'pseudo' CNC toolholders such as the stuff from Tormach and some other similar stuff, but those are really aimed at the hobby community that does light duty work, can tollerate down time and prioritizes cost over performance (for the most part) and that is not my focus, so all of those type solutions got the boot.

Quite obviously, your setup is not hobby level and is well thought out and proefessionally executed, particularly is one considers the time frame in which is was built. However, while I have to admit that I would love to have one  . . because it not only performs, but the cool factor is off the charts, it is not an idea that I can run with becuase of the proprietary nature of the scheme.

Thanks for taking time to show the system and explain the operation. I found it 'fascinating' as Mr Spock would say.



Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #527 on: July 22, 2013, 03:24:52 AM »
You shouldnt need custom holders as your tool arm moves out the way and the only time you would need the spindle rotating would  be on loading and thus I am sure you could incorporate a wear disc/brake of sorts into the arm. You would have the spindle stopped when unloading a tool and thus no need for the brake to stop the tool spinning when released from the spindle.
The only reason the bearing and brake are needed on the Chiron is the basket tool changer setup as the arms hold the tools at all times, even when machining, and thus the bearing is needed. Add to that the fact that the whole setup of the basket toolchanger was to make super fast tool changes and have no need to actually stop the spindle then you can see why it was required to have these custom holders.
 At the time (late 80's) I think most toolchangers were talking 10 plus seconds per tool, the Chiron must have been amazing at under 1 second, even 25 years later it is still amongst the fastest around. Another big benefit that was/is touted by them is if something happens to a tool arm then no big deal as you still have all the rest you can work with until time can be found to get that repaired, on a standard style changer you are stuck until you get the changer repaired or have to resort to manual tool loading. Again probably no big deal for me or your customers but in high volume production that could save a lot of money.
 When I got the Chiron two of the positions were missing and the previous owner had used it that way for 8 or 10 years as the type of work he did often only required 3 or 4 tools, so that kind of shows that Chirons  talk of no downtime due to a tool arm failure holds true.



Hood
« Last Edit: July 22, 2013, 03:27:46 AM by Hood »
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #528 on: July 22, 2013, 10:44:39 AM »
Ah but the million dollar question is...














Have you been hit by an arm yet ?


lol.

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #529 on: July 22, 2013, 02:37:14 PM »
Nope, only the wifes elbow :)
Hood