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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 411001 times)

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #50 on: August 21, 2012, 11:00:06 AM »
Denford use this on their spindle interlock to keep the door closed when the spindle is running.

Offline derek

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #51 on: August 21, 2012, 11:18:20 AM »
Right now I have a relay that turns the vfd on and off through Mach. If I routed the air valve in a way that when that relay is energized there would be no power available to the air valve so even if the output was turned on in mach the drawbar would stay put.
Basically a variation of what angel tech suggested a few posts back. I think for my purposes this may be the best route.
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #52 on: August 21, 2012, 11:45:35 AM »
you just replace the existing relay with a douible pole relay and use the second set of contacts to isolate the drawbar air solenoid.

Offline derek

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #53 on: August 21, 2012, 11:51:22 AM »
That sounds too simple :)

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #54 on: August 21, 2012, 01:20:00 PM »
If the relay turns off the drive and allows the drawbar to move simultaneously, there will still be a 'danger zone' if the spindle was running a 7K and the drawbar was set to move. The adapter would release as soon as the VFD was disabled, but it would still be spinning at 7K.

The Tach idea would eliminate that possibility. Also, as mentioned previously, I don't see how you can disable the drive and then change the tools. What would keep the spindle stationary?

It occurs to me that there has to be some sort of home sensor on the spindle in order to change tools that have drive dogs, so unless I am missing something, why not just watch the home signal? i.e. WHILE <continuous home sensor signal>, do the tool change, WEND. The spindle would have to be stopped and any movement would halt the tool change . . .  which would be a good thing, presumably.

I think this is the hot setup for the spindle, so that just leaves every other movement . . .  LOL!  Actually, I have magnetic sensors on the air cylinder, so it will be fairly simple to detect that the rod has reached the correct release and grab locations. If it fails to pick up a tool, it would move past the correct grab spot, and that should be pretty easy to detect also.  

Offline derek

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #55 on: August 21, 2012, 01:36:43 PM »
Good point.
The Delta VFD-m uses an input, usually a proximity sensor for indexing. You can tell it what angle from the sensor you want it to stop at. This is the same drive that David DeCaussin uses on his machine. If you watch the video you can see it stops, then turns to index. Not sure if it locks the position though.  My thinking at this point is to ultimately have the VFD dictate whether or not the draw bar can engage. That may be a dream or something as simple as using an intelligent output on the drive. I'll have to see what I can come up with when I get the drive.
If you don't trust Mach-pokeys-smoothstepper to not turn on (or off ) an output then you can't really trust it for any other method to prevent unintentional draw bar movement.

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #56 on: August 21, 2012, 05:00:56 PM »
Not familiar with VFDs but I use the Zero speed output of my servo drives to enable the drawbar, maybe VFD's have such a feature?
I do mine in the PLC, also have it interlocked the other way so the spindle cant start if the drawbar is energised.
Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #57 on: August 22, 2012, 03:27:39 AM »
Good point.
The Delta VFD-m uses an input, usually a proximity sensor for indexing. You can tell it what angle from the sensor you want it to stop at. This is the same drive that David DeCaussin uses on his machine. If you watch the video you can see it stops, then turns to index. Not sure if it locks the position though.  My thinking at this point is to ultimately have the VFD dictate whether or not the draw bar can engage. That may be a dream or something as simple as using an intelligent output on the drive. I'll have to see what I can come up with when I get the drive.
If the drive can signal, that would be a good option to consider. Most likely I will do my own setup that way, but it is useful to get as many ideas on the table as possible and then pick up the one that best suits each machine.

Quote

If you don't trust Mach-pokeys-smoothstepper to not turn on (or off ) an output then you can't really trust it for any other method to prevent unintentional draw bar movement.
It is not possible to get MACH out of the loop completely since the tool change command initiates in the G-code and (typically) MACH is controlling the spindle. My objective is to have, in addition to an 'enable' function, a positive mechanical interlock that will prevent the drawbar from moving unintentionally, regardless of the source. I suppose the reasoning would be similar to the folks who have their E-stop setup outside of MACH, but still triggerable by MACH.
[/quote]

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #58 on: August 22, 2012, 03:59:16 AM »
Not familiar with DVDs but I use the Zero speed output of my servo drives to enable the drawbar, maybe VF D's have such a feature?
I do mine in the PLC, also have it interlocked the other way so the spindle cant start if the drawbar is energised.
Hood
For my own machine, I will use the drive as you have done. Also I will be using a separate PLC to control the sequencing and watch the various sensors. Did you write your own code for the PLC?

As with my motor controller, I am trying to anticipate what might be out there so that I can accommodate as many setups as possible, and then make the ATC controller configurable. If you click on the lower right image on this page www.theInTurn.com  you will see the configurator for the 4th axis motor controller. Note that certain safety features are optional, like monitoring the signal, and how to react in the event of a failure. Most likely I will do something similar for the PDB/ATC controller and let the user pick the source of the interlock; drive, home sensor, tach, etc.

Do you have a mechanical lockout on the drawbar, or do you rely on the 'enable' function?

Offline Dan13

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #59 on: August 22, 2012, 04:12:08 AM »
LOL... Hood said "Not familiar with VFDs" and somehow in your quote it appeared as "Not familiar with DVDs" ;)

Dan