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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 401842 times)

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Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #420 on: January 03, 2013, 01:33:45 PM »
Thanks! I'll check them out.

500 watt is major overkill for my little carousel, but if the price is right, it would probably save enough time to be justified.


I think the list in the UK for a 005-SE is approx £1000 plus VAT, obviously list and what you actually pay is quite a bit different but it gives you an idea of tha ballpark figures.
It often makes me chuckle when I see them listed on eBay second hand, often they are more than you could get one new and paying full list ;D

Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #421 on: January 04, 2013, 05:44:29 AM »
I think your own words sum it up nicely.  You were disappointed that Tormach would not work with YOU to develope 3rd party hardware to run with a standard TORMACH. (;-)

You still don't get it, and you still post your personal speculations about me as if they are facts, so let me help you out with a few ACTUAL facts.

1) The 'development' was already completed long ago, so your latest statement above is also  . . false. Tormach is decidedly low-tech. Their 'engineering white paper' is actually just a list of excuses as to why steppers are 'better' than servos. 'Disappointed', you say? I think they would need to go back to school for a while before they could help me with development, frankly, but 'working with ME to develop' anything (as you claim) was definitely not on the menu. 

2) The objective was only to QC my MACH customizations with theirs. With the single exception of Tormach, every other vendor has been more than happy to cooperate. If you have ever done this, you would know that it is a simple matter of making sure multiple apps don't use the same outputs and other MACH resources and then merging the screens. This in not rocket science, but is apparently beyond Tormach's abilities. I will SPECULATE that Tormach is not so much unwilling as they are unable to cooperate because their stuff is third party and they don't understand it themselves. Using outdated version of software in order to 'avoid new bugs' is an excuse, in my view. They either do not have the talent in house or they do not want to pay for third party review of bug FIXES.

3) You made the accusation that my motivation was to 'sell something to the Owners'. Way off base once again. Several previous InTurn™ models have gone to Tormach owners. Most of these users already had clean MACH installs and had ditched Tormach's stuff. One of them took on the task of integration himself. Two of the new MEGA-Duty models from the last batch went to Tormach owners. One of them has a clean MACH install and the other was looking for a solution. These were done deals and I did not HAVE to do anything at all to 'sell something to the Owners'. My effort was after the fact, by customer request, and would have been an uncompensated support function.

Now let me explain 'Red Neck Logic'; A red neck farts. Just then it begins to rain. Conclusion: farting causes rain. Proof: 'seen it mahseff'. Once the redneck has this 'fact' lodged in his brain cel, there it no way to change it.

Things are not always what they appear. I remain uninterested in your opinion about Tormach and I am still not going to get into a debate with anyone about their policies, but I do ask that you collect some facts and maybe ask a question or two before you shoot your mouth off about my motivations, intentions,  or any other part of my character.   

This thread is not about Tormach, or Tormach fanbois. If you have nothing to contribute to the topic, please lurk quietly.

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #422 on: January 04, 2013, 05:50:01 AM »
Thanks! I'll check them out.

500 watt is major overkill for my little carousel, but if the price is right, it would probably save enough time to be justified.


I think the list in the UK for a 005-SE is approx £1000 plus VAT, obviously list and what you actually pay is quite a bit different but it gives you an idea of tha ballpark figures.
It often makes me chuckle when I see them listed on eBay second hand, often they are more than you could get one new and paying full list ;D

Hood

Ebay is a good resource, no doubt, but you do need to know what you're buying. I've seen the same thing that you've mentioned.

I definitely can't spend that kind of money on a single component for a prototype when I already have a solution in the J2S, but if I sold the J2S setup, that would cover the cost of the AB. The Mitsubishi drives are about ideal for a 4th axis and it seems the AB is ideal for a turret/carousel type application. I guess you just have to pick your poison.

Thanks very much for the info.

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #423 on: January 04, 2013, 06:03:26 AM »

I've gotten a couple of questions about the speed of the ATC, so I thought I'd expand on that a bit.

The gearboxes are rated for something like 2,400 RPM input continuous and there is no 'instant' or 'momentary' rating. The Mitsu servo motor on the arm has a max instant rating of 6,000RPM and I have tested the gearbox and shaft at that speed without any problems. I suspect the only issue would be heat and in this application it is doubtfull there would be any significant build up, but I'll know more about that when I start doing continuous torture testing.

The reason the speed is held back in the first test video is because the arm is not counterbalanced and the whole machine tries pretty hard to jump off the table if it is run much faster than is shown. I had not considered a counter balance for the arm, but it became an obvious punch list item as soon as I fired the thing up with the arm on it . . LOL!!

Some compromise weight will need to be chosen for a counterbalance since the tool weights will vary quite a bit, but anything will be better than nothing in this case.

Since the control system for the ATC will be so simple  :P,  I may as well add a speed parameter per tool position. In this way the arm speed can be programmed to be appropriate for the tool. It occurs to me that this may actually net a significant improvement in the overall throughput.

Question for Hood and/or anyone else who has a commercial ATC; is the operating speed of the ATC fixed at a certain rate or can it be altered per tool? If not, then can it be altered overall?

The servo drive is easy enough to change speed, of course, but the air cylinders would be a bit more complicated to speed control. Anyone have some ideas on how to accomplish that?

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #424 on: January 04, 2013, 06:18:33 AM »


And one last comment on the TB30 spindle;

The spindle is reassembled with the new die spring and initial testing shows it to work perfectly. There is considerably more travel and also more options as far as setting the forces. Currently it is set to a calculated force of approx 1,400lbs and there is an additional .050" travel after release of the tool.

This compares with . .  if I remeber right . . about 1,000lbs with the bellevilles and a scant few thousanths of travel after release.

I did not rebalance the spindle, so I can't comment on that aspect, but I don't forsee a problem there. If anything, at a few pennies under 20 bucks, I would be inclided to buy another spring and just balance the spring itself and call it a day. This spindle will run at max 7,500 and I will bench test it at that speed once I get the drive system built for it.

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #425 on: January 04, 2013, 06:58:40 AM »
Regarding the AB drives, not sure if I made it clear when I said disabling the sercos turned them into Indexing drives. What I maybe should have said was drives capable of Indexing. You can use them as normal servo drives with either position (step/dir, encoder follower etc)  or analogue input. You can also use them as Indexing drives, in fact you can use them as both with an input to change between modes. Example an input could switch between Indexing mode and Position mode (Step/Dir or Follower) or between Position and Analogue or Analogue and Indexing etc.

The advantage I have is I am using these drives for myself so I can afford to use second hand ones and I refuse to pay too much for them, that may change is I was really desperate for one but at the moment I have quite a few spares and the most I have paid was under £300 for the 22Kw ones. There are lots of the smaller drives (3Kw and under) for £300 or so but being a poor boy (as I was informed in another thread ;) ) I wont buy at that price.
 Your problem with this approach is you are putting a product to market so even though picking up a cheap one for your proto may be an option, you would have to consider the new cost for your product.

Regarding speed, I dont have any commercial changers with the exception of the Chirons and it is air cylinders. They are adjustable like any air system is and have actually been reduced from default. Tool change is supposed to be 0.9 seconds tool to tool but with the Up/Down cage being slowed it is approx 1.8seconds.

The lathe did have a turret on it when I got it but it was hydraulic and worked by rack so really just one speed unless you adjusted the flow rate. The turret I made to replace that has the servo and I have limited the rotation to what I think is suitable and wont put too much stress on things, I could have turned the speed up to probably 5 or more times what I have. Heres a vid showing the speed I settled on.  http://www.youtube.com/watch?v=hRTfxuXf6yk

Hood
« Last Edit: January 04, 2013, 07:08:16 AM by Hood »

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #426 on: January 04, 2013, 07:09:39 AM »
Meant to ask, what is the cost of the Mitsu drives? Say the 400watt ones.
Hood
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #427 on: January 04, 2013, 09:18:04 AM »
The servo drive is easy enough to change speed, of course, but the air cylinders would be a bit more complicated to speed control. Anyone have some ideas on how to accomplish that?

Steve,

You have to do it be either throttling the air flow, or damping the motion.  I would think you could make an adjustable air flow valve by making a needle valve actuated by a small stepper or servo - perhaps an RC servo?  You might be able to adapt something from an automotive idle air control valve, or perhaps even a fuel injector and a simple PWM control. 

Regards,
Ray L.
Regards,
Ray L.
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #428 on: January 04, 2013, 09:33:57 AM »
Steve,

Thinking about it some more, I think a solenoid-controlled needle valve driven by a simple (even software) PWM would be the way to go.  Simple to implement, and should give very good control.

Regards,
Ray L.
Regards,
Ray L.

Offline BR549

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #429 on: January 04, 2013, 11:40:45 AM »
Nice try stevo BUT " your" words proved my point .   IF you look back through your posts the main objective was to sell someone on the site your wares. AND it was hard to sell your wares to Tormach users as long as Tormach LOCKED you out of the picture.  Then you were pissed because Greg would NOT work with you so you could access his customer base

Then there is the ME syndrome. Basic genetic flaw in a LOT of engineers who think the world cannot revolve without their guidance.

I dought that Greg needs your help with anything concerning his CNC products. He is light years ahead of you already .

But you Have a good one anyway, YA hear

(;-)TP
« Last Edit: January 04, 2013, 11:55:17 AM by BR549 »