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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 400591 times)

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Offline BR549

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #130 on: September 21, 2012, 11:08:24 AM »
Certainly is an advantage to a double sided swing arm. I dought you will make fast tool changes with a single side arm . You have to get the old tool put it in the slot then rotate to the new tool and load it.

The double allows hot swapping the tools, it is as fast as it gets.

Super fast tool changes always add complexity to the tool changer.   Thinking out loud when the machine is running in auto what is the difference between 5 secs and 35 secs ??  It is no longer YOUR time being consumed with teh TC. You can be off drinking coffee(;-).



Just a thought, (;-) TP

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #131 on: September 21, 2012, 11:20:50 AM »
Quote from: HimyKabibble
Actually, no reason why a Geneva can't be used to move a belt just as well....

Geneva drive for a belt is doable, but lacks high speed random access, needing to stop at each position in sequence, including empty pods. With an intelligent drive such as the one described by Hood, you can simply command the drive to go to a spot and not have to track the position as you would with a Geneva.

I also wonder if it might be possible (in a practical sense), to have variable width tool 'slots' on a chain belt. i.e. why have the same real estate consumed for a 1/4" drill bit as a 6" face mill? I have not given this much thought yet, but if it is doable in some reasonable way, it could make the difference between getting 20 tools on getting 25 tools on the same belt.

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #132 on: September 21, 2012, 11:24:26 AM »
Heres a vid of the style on the Chiron.

Friggin' AWESOME!  Straight out of Star Wars. . . . .  I think I got some wood watching that vid . .  (not sure how that will translate internationally . .LOL!)

Anyway, given a 50k budget . . .  and a staff . .  I might be able to come up with something like that . . . . however, if I fall somewhere between that monster and Tormach I shall be well pleased.

Offline Dan13

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #133 on: September 21, 2012, 11:27:41 AM »
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

That's one cool tool changer. Definitely the fastest I have seen.

If the basket can't rotate then setup is not an easy task, trying to reach the tools on the rear.

Dan

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #134 on: September 21, 2012, 11:36:00 AM »
Certainly is an advantage to a double sided swing arm. I dought you will make fast tool changes with a single side arm . You have to get the old tool put it in the slot then rotate to the new tool and load it.

Certainly a valid point. I looked at a dual arm . . .  longingly . . .  salivating . .  however, while both arms work, they also both swing and a 360 degree sweep is required. A single arm requires only about 200 (approx). There just was no enough room for a full sweep and still be mounted on the mill head, so I had to choose.  

Quote
Super fast tool changes always add complexity to the tool changer.   Thinking out loud when the machine is running in auto what is the difference between 5 secs and 35 secs ??  It is no longer YOUR time being consumed with teh TC. You can be off drinking coffee(;-).

So . . .   is fast important or not important?  ??? With my planned arrangement, there will not be anything approaching 'super fast', but as you point out, it will also not be super complex nor super expensive. So between a Smart Car and a Lamborghini, I'll be happy to end up with a Camaro . .  although actually I like the Challenger much better.

Making 30 parts in one hour instead of 25 parts would be significant enough for my purposes. I only have one product that I make a few hundred at a time.


Just a thought, (;-) TP
[/quote]
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #135 on: September 21, 2012, 12:07:20 PM »
Steve,

Like Terry, I too question the real-world value of a super-fast toolchange time.  I can't imagine that it would save more than a few minutes per day at the cost of significantly increased complexity, and opportunity for disaster, due to higher speeds, and generally higher precision required.  I think you can quickly get to the point where doubling speed will take 10X the time and 2X the cost, to make it as reliable as a slower, simpler machine.

Re: the speed of a Geneva, this, too, I think is a bit of a red herring.  Perhaps a high-speed Geneva will always be a bit slower than a max-performance direct-driven mechanism, but I think the overall difference in toolchange time would still be small.  I'm running mine VERY conservatively, and it runs under a second per tool pocket.  So, even with a 24-tool carousel, max seek time would be 12 seconds.  I'm sure I could easily double that.  Beyond that point, you have to start worrying about the tools flying out as the thing moves.  The biggest job I ever did only used about 12 tools, and that one took hours to run, so an additional 3 minutes in seek time would be lost in the noise.

Certainly doing a variable-tool-size chain-driven machine is quite do-able, but, again, at considerable cost in terms of complexity.  You'd have to not only program each tool length, but now the "pocket" width as well.  And, setting up a job will mean a fair amount of disassembly/re-assembly to move the tools to their required positions.  Or, have pre-configured slots of different sizes, but then you have to deal with mapping tool numbers so each tool lands in an appropriately-sized pocket.  My biggest tool is a 4" face mill, so I just sized all the pockets accordingly.

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 #136 on: September 21, 2012, 01:18:47 PM »
Heres a vid of the style on the Chiron.

Friggin' AWESOME!  Straight out of Star Wars. . . . .  I think I got some wood watching that vid . .  (not sure how that will translate internationally . .LOL!)

Anyway, given a 50k budget . . .  and a staff . .  I might be able to come up with something like that . . . . however, if I fall somewhere between that monster and Tormach I shall be well pleased.

Ha ha yes it translates almost word for word, seeing it on you tube is cool but seeing it when standing right in front is amazing and to think they have been doing that same toolchange since at least the mid to late 80's, the one I am likely getting is I think 1987 or 88.

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #137 on: September 21, 2012, 01:21:16 PM »

That's one cool tool changer. Definitely the fastest I have seen.

If the basket can't rotate then setup is not an easy task, trying to reach the tools on the rear.

Dan

It doesnt rotate Dan and although I havent seen a tool holder being changed I would imagine you just call an arm to drop but not call the main cylinder to raise up.

Hood
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #138 on: September 21, 2012, 01:31:22 PM »


Heres a vid of the style on the Chiron.
http://www.youtube.com/watch?v=97KQ5DKSuNw
Hood

Very cool ! I saw these at IMTS.
I especially like the part load/unload gripper set up as a tool.
Thanks Hood,
Russ

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #139 on: September 21, 2012, 01:35:09 PM »
Steve
Heres a site that  gave me  ideas  when I was dreaming about how I was going to do mine, now I dont have to (assuming I buy the Chiron ;D ) May give you some food for thought, I especially like the hinge down holders.
http://www.miksch.de/en/tool-changing-systems.html

Hood