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November 19, 2017, 21:18:20 pm


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Author Topic: Automatic tool changer for the lathe  (Read 1378 times)
lloydsp
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« Reply #30 on: November 12, 2017, 18:54:32 pm »

Eddy,
If wires could be properly routed to the head and flexed as required, then there would be no need for batteries!  Cheesy

Lloyd
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EddyCurrent
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« Reply #31 on: November 12, 2017, 18:57:27 pm »

Good point  Grin  Grin  Grin

But wait a minute, what if the electronics required a totally ripple free DC supply  Cheesy
« Last Edit: November 12, 2017, 18:59:23 pm by EddyCurrent » Logged
Bob La Londe
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« Reply #32 on: November 12, 2017, 20:45:09 pm »

Bob,
You do know that redtube is a porn site?

Nope, didn't know that.  Just know Google (who owns YouTube) keeps trying to force me to buy an enhanced YouTube experience.  Must have gotten the name wrong. 

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lloydsp
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« Reply #33 on: November 12, 2017, 21:46:27 pm »

"....what if the electronics required a totally ripple free DC supply?"
--------------
'Tain't no such thing, Eddy, MOST ESPECIALLY from batteries, which possess a specific series resistance, and ALWAYS cause 'ripple' (load variations) with varying loads.

A properly filtered power supply with a large post-filtering capacitor posessing a low series resistance will beat a battery every time!

Lloyd
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dave benson
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« Reply #34 on: November 13, 2017, 05:03:59 am »

Hi Eddy

Yes it's been a interesting  project  'and' on the whole I'm satisfied with the result, But far from content.

When I started out, the goal was to make a cordless\Bluetooth tool changer that was Plug'n Play
for example if you had a job in the lathe which requires changing to  the manual tool post (perhaps you need to do some deep boring)  then you would unbolt the turret install the manual tool post
and continue on without changing tool scripts or fiddling with mach3 at all.

With the batteries, I was figuring on 500 tool changes at the outset, and so to get 864 just means that
I've got plenty of power left to do something else.

What I propose to do is make another two (based on the lessons learned from this build) and flog them off on Ebay and if  They sell I will use the proceeds to build a Beagle Bone Powered version
with a video camera (maybe a Xbox connect) to run Opencv and some python Ai to add →

1. Home switch functionality
2. True Tool identity
3. Tool Change complete confirmation
4. Tool damage and misalignment
5. Collision Detection\electronic fencing 

I've already drawn up the turret to standard Steel\Fasteners dimensions.
I have some cold rolled 12mm and 16 mm plate.
I've ordered  two more housings which have even heavier bearings but are shorter in the snout.

The new ones will have Bi directional control meaning that the turret will select the shortest path for the next tool change.
As part of doing this requires using two pawl's and a (RC servo or a solenoid ) .
The by product of this is that the turret will be rigidly locked in position for both directions.

I did look at 4 axis positioning capability and with the addition of a disk brake, it would be possible
But not very practical, what you would really need is a high torque compact motor and drivers ect.
that fit in the same space, as the present kit, I did look at one compact atmega2560 board and a slew of micro style stepper drivers, and so miniaturisation is possible for the controller but not the stepper drivers as they don't provide the mode I'm using.

One  thing I'll have a look at is to use one of those “One battery for many tools” and charger from the local big box stores, as the battery has visual indication of charge  as well as low voltage cut-out
in this way I could off board the battery and electronics and free up space inside the turret. And as you can see in the cad file image, there's not much room and that's without the LM298 driver.

The tricky bit would be to machine a fitting to suit the battery.
But I  will look into this as the benefits would clearly outweigh time spent making the CB file in the first place.

Dave








 
 


* steel1.png (1144.5 KB, 1000x750 - viewed 8 times.)

* freecad turret model Capture.PNG (41.53 KB, 479x387 - viewed 8 times.)
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Bob La Londe
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« Reply #35 on: November 13, 2017, 15:35:19 pm »

Maybe this is over simplification, but why not setup so you can just add a tool post when you need to do that?  A lot of guys run a t-slot table on their cross slide for gang tooling. 
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dave benson
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« Reply #36 on: November 13, 2017, 23:15:46 pm »

Hi Bob

Here is a shot of the top-slide from the rear, when I was repairing the the top-slide during the lathe build, I added
some extra spigot location holes for the manual tool post, although in practicality I probably wont use it.(no space)
What I have thought about is a rear gang tooling block or a rear mounted parting off tool.

I do like the idea of a rear parting tool for small lathes like this, and I think I will make one.

If you were setting up the lathe for production work, for similar parts, you could fine tune the tool arrangements in the turret and the gang tooling ect. But for me the parts would be one offs so one day I might be doing long thin turning and the next chucking work. 




* space maybe for rear tool post .png (1248.43 KB, 1000x750 - viewed 4 times.)
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