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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 402215 times)

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Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #530 on: July 24, 2013, 07:11:11 AM »
Hood,

Thanks for the info and ideas. It will take some noodling to figure out how much of it might be incorprated into future iterations of my ATC.

What you are seeing here is REV 0 of the ATC and only the second prototype of the BT30 spindle. There is more to come. I have designs for a dual arm, a column mounted (and much larger) carousel, a link belt tool storage and a number of other goodies. I am also continuing to improve and expand other products. I have a new CNC rotary table (finally) and an all new tail stock design for the InTurn™ 4th axis (that I am building now) and so on,  so I'm not inclined to discount any ideas that might be useable in any component.

- Steve


Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #531 on: August 20, 2013, 07:29:23 AM »
The ATC is now operational. Below is a quick video fragment that I grabbed before the machine ships out in a couple days. The fragment will eventually be part of a larger video covering the last stages of the mill conversion, but for now, you can get to it with the link.

This video fragment shows a tool CHANGE . . i.e. grabs and stores one tool and then selects another tool, retrieves it and puts it in the spindle. And no more 'smoke and mirrors' trick using MACH axis to drive the motors. What you see is being run entirely by the all new and completely autonomous ATC controller. This video does not show the spindle homing becuase that operation, while finished, was not linked into the tool change macro (M6). The macro now homes the spindle as the first task, then converts the tool numer to binary and presents that at MACH outputs and then signals the ATC controller that there is a tool change needed.

The ATC controller them retrieves the binary number from the MACH outputs and acknowledges to the macro that it will accomplish the tool change.
The ATC controller then operates independently from MACH, including generating the step.dir pulse stream for the drives, and at the end of the tool change, it the sends a 'Done' signal to MACH (to the waiting macro) .

It sounds a lot more simple that it actually is. There are about 1,200 lines of code so far in the all new ATC controller and it is using the newest (4 to 5 times faster) processor. The new processor is 3.3V so that eases the interface problems with the Kflop, which is also 3.3v . . .  mostly.

This scheme is a bit unusual, but it does not rely on Modbus or a plug-in and it will work with any CNC that has 6 available outputs . . . i.e. not tied to MACH. My 4th axis controller is already using the modbus and I decided not to try to have them (the 4th axis and ATC controllers) communicate with each other, nor did I want to attemp multiple simultaneous modbus devices.

In this way, the BT30 spindle and ATC are not tied to the 4th axis.

Also not shown in the video fragment, but now operational, are the two primary safety interlocks. The drawbar cannot release accidentally and the claw cannot release (read 'throw') a tool. Until electric solenoids are retracted, the drawbar actuator cannot move and the claw cannot open. The speed seen in the video fragment is something like 2/3 of the full speed. The claw interlock was not installed yet and I did not want tool holders launched across the shop. But rest assured, both the arm and the carousel can run much faster than shown here.

There are quite a few sensors to integrate (hardware is completed, just a matter of adding the sensors to the software), and of course. This was a particularly difficult project, but it is just the first iteration of the ATC. I have lots of other goodies to add like a dual arm, a much larger fixed carousel and perhaps even a tool belt.





http://youtu.be/QmlAgfIbscQ
« Last Edit: August 20, 2013, 07:31:31 AM by simpson36 »

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #532 on: August 20, 2013, 01:07:53 PM »
Looks like its working well :)
I am not a fan of low voltage signalling and is one of the reasons I always shied away from the kFlop, that and also I am no programmer ;D but looks like its working well for you :)
Regarding the programming, thats why I tend to use PLCs for things like this, ladder logic is easy for me, code is not.

Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #533 on: September 23, 2013, 02:42:17 PM »
Question for spindle experts: Are there any specs on the various tapers which define the power or torque capacity of each size? I have been unable to locate this info.

The time has finally arrived for me to build my own mill. The IH conversion that I had been working on  . . . . for a while  . . . is completed and delivered and I have only a couple of projects to finish up and then I will be  . . at long last . .  turn my attenetion to my own project mill.

Previously the spindle and ATC was BT30. Thus far, I have built several spindles but only one ATC. The converted machine is completed and shown in this video changing tools and cutting steel and aluminum with a 3.5K spindle motor (close to 9k peak).

http://www.youtube.com/watch?v=k2F6100RKOE

For my own spindle, I am leaning toward BT40/CAT40 because my new spindle motor peaks at 15,200 watts and I think that is going to be too much for BT30. Since I have not found any specs, I started looking at the power ratings of available spindles and it seems like 5.5kw (unknown peak) or thereabout is the high end for BT30.

In addition, I have in mind to mount a tool carousel in the spindle to rotate tools toward the InTurn™ 4th axis (this will be in addition to the existing gang tool plates) and again I am feeling like BT30 might be a bit light for that application. Overall the new mill should be impressive. Built on a new cast iron frame, it will have massive ball slides and ball screws (all high precision ground and pre-loaded)on each axis with travels of 38" X, 26" Z and 14" Y. Each axis will be powered by a 750watt Mitsubishi AC servo motor and be capable of about 700IPM. ATC of course and like the previous project, it will have 5 axis capability. I am looking for repeatability and accuracy measure in tenths for this new mill.

The spindle will feature precision pair of angular contact bearings and labarynth seals with a positive pressure purge on the spindle cartidge this time around (9,000 + RPM spindle) and each ball screw will also have pairs of ABEC3 angular contact bearings. People have been asking for more detail and for some design data so I am planning to spend more time with the video camera on this build and show the actual design and fabrication of some of the parts and pieces, including the bearing blocks for the ball screws and some other interesting stuff. The IH conversion has a lot of this stuff, but I did not have time to cover any of the details in that build.

So, if anyone has some info on the capacities of the various taper sizes, please post them.  
« Last Edit: September 23, 2013, 02:44:23 PM by simpson36 »

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #534 on: September 23, 2013, 03:22:02 PM »
Looks like its working well :)
I am not a fan of low voltage signalling and is one of the reasons I always shied away from the kFlop, that and also I am no programmer ;D but looks like its working well for you :)
Regarding the programming, thats why I tend to use PLCs for things like this, ladder logic is easy for me, code is not.

Hood

I can think of a lot of reasons to shy away from the Kflop, but it is a very powerful board and given some programming experience, it can be made to do some impressive stuff. The biggest obstacle with the Kflop is lack of documentation. There is no programmers reference, etc. so the learning curve is practically infinite. I will say this for the Kflop; while it can be challenging to get it to do what you want, once you have it working, it is a rock. It just rolls on day after day without a hitch. Smoothstepper was always flakey and had 'moods', but the worst problem was that if there was an issue, it was pretty much permanent because the user had no way to fix it (regardless of programming knowledge) and the manuf was in no hurry (as in months, years) to correct anything.

To comment on 'low voltage signals' I think pretty much all modern processors are 5V or less, more recently 3.3v or less, so there is always going to be a conversion somewhere between the processor and the 'outside world' where signals need to run hotter to cope with massive intefference generators like high voltage wiring and electric motors and solenoids all over the place. Differential signals are actually low voltage if you compare them to the typical 24V industrial control signals. In any case, once you have the isolation and voltage conversions in place, it really becomes a non-issue and you don't even think about it.

There is still a lot of improvements and feature additions to be done to the ATC controller, but I went with a separate processor for the ATC.  The Kflop is primarily doing the motion control duties and the programming for that device is pretty much done . .  .  thank goodness.

I would liken 'programming' vs 'laddering' to your lathe having tool posts both in front of and behind the spindle. I suspect such an arrangement would be mind boggling to most people, but you have gortten used to the complexity over time and have learned how to make use of the capabilities that come along with that complexity. Likely you would feel quite handicapped if you had to make due with a single toolpost after having two. Programming is the same way . .  all that is needed is an inexhaustable supply of tollerance and patience . . . .   and a Whisky Sour . .  or two . . .  :P



Offline derek

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #535 on: September 23, 2013, 03:29:35 PM »
I couldn't agree more about the Kflop. Unfortunately for me I had to abandon it. Which really disappointed me as it seemed like the possibilities were huge. The C programing was just going to be too heavy of a lift with my current workload. I opted to go with the UC-300 controller which has been working really well for me. In the next couple of weeks I'm going to offload my ATC functions from the Pokeys to the        UC-300. It has plenty oh IO for the job.

Derek

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #536 on: September 23, 2013, 04:12:50 PM »
I was looking for info the last day as I had just made a spindle drawbar force gauge up and was wondering what I should be expecting to see, turns out I am well down on force if the numbers are correct, ie my gauge is right or Chiron chose to  keep in line with what is said to be the norm.
Anyway not sure if this is actually what you are looking for but have attached it anyway.


Regarding the 5v, yes most if not all processors etc will be 3.3v but the difference with the CSMIO compared to the ESS/ SS/ kFlop etc is the low voltage is all contained in a nice little box and only 24v for I/O is external.
Yes there are differential signals, whether that be the encoders ins ( or step/dir outs if using IP-S)  but they are inherently noise immune.
Thing is however I never used 5v for other I/O, was all 24v so that meant I had to convert when wires came out of the controller and when wires went in, was a PITA.

Regarding the SS, I never had any flakiness with even the USB ones but I do agree on Gregs lack of fixes, I waited probably 3 or 4 years for the step/dir spindle to get fixed and it never happenned and now I have moved on, just wish I had taken the jump a year or so earlier to the CSMIO as it is just in a different class.

Hood

Edit, just realised I read your spindle question wrong.
Anyway i can give you some numbers  for the Chirons spindle in a bit once I find the info.
« Last Edit: September 23, 2013, 04:19:36 PM by Hood »

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #537 on: September 23, 2013, 04:29:30 PM »
Ok here are some numbers
30 taper
Max RPM 6000
Cont torque 18Nm
Peak Torque 80Nm

Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #538 on: September 24, 2013, 01:09:56 AM »
Ok here are some numbers
30 taper
Max RPM 6000
Cont torque 18Nm
Peak Torque 80Nm

Hood

Are these BT30 maximums or specs on your spindle?

Numbers indicate approx 11.5kw.  How does that compare with your spindle motor?

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #539 on: September 24, 2013, 03:00:45 AM »
That was the original Siemens motor as supplied by Chiron. It works out at just over 11.4Kw.
The motor I have on now is only 3800 rpm but torque is 28.5 cont so that works out at 11.44Kw.
I am in hopes of some time managing to make a gearbox up to increase the rpm but whether I will ever get round to it I have no idea.
Hood