Acorn Carousel Tool Changer

[slodat]

Looks great! What spindle are you using?

[DY10CNC]

Hello Michael,

I have been working on an Arduino based tool changer with a 10 station carousel for Tormach style (TTS) ER 32 chucks.

Having seen yours, I am both impressed by the build quality and functionality.
I am inspired to change my approach and go with a similar one to yours.

I would appreciate your help...

Could you please post a screen dump of your input and output pin assignments.

Thanks,

John

[mick41zxr]

No problems John,
Details below, I also tried to include as much detail/notes in the headers of the macros as well.

The carousel ram is set up on a single relay so that NC side of the relay always sends the ram home & the NO brings the carousel into the spindle.
That way if anything fails or on startup the carousel is always at home.

Also note that the proximity sensor to home the carousel is connected in series with the X,Y & Z axis so that the carousel homes to tool 16 on startup.
Any other info needed please feel free to ask. Its pretty simple when you break it all down.

Slodat the spindle is a BT30 off AliExpress.
https://www.aliexpress.com/store/produc ... 2cd0lIHiG2
Spindle is ok, I have not dialed it in for run out or anything yet. I starts to heat up over 6000rpm so I will strip it down & check the quality of the bearings. For long term use I will probably rebuild it with new angular contact bearings & kluber grease.

Regards,
Michael

[DY10CNC]

Thanks Michael,

I am in the process of re-wiring my home/limit switches to free up some inputs.

I ran a modified version of your test5.NC code and it works OK with my setup.

I've a little way to go on the code for the macros, but underway.

Thanks for your help.

John

[mick41zxr]

No problem,
Remember that you can load your *.mac files directly as a job & run them in single block mode.
This can be done in Alt+I mode (diagnostics) to help troubleshoot them.
Regards,
Michael

[Richards]

Your tool changer looks great.

Have you considered the Teknic ClearPath model MCPV servos to simplify the interface and to "hit" each station exactly without overshoot or undershoot? Their Operational Mode 14 allows you to predefine 16 positions and then by simply pulsing the B-input pin to select the desired position, the servo will spin to that position by asserting the A-input pin, i.e., two outputs from the Acorn give you up to 16 positions on the turret. They also offer their "G-Stop" option that eliminates vibration as the servo starts and stops.

I don't have that motor model, so I can't use that Operational Mode. Unfortunately, the MCPV models don't have a Step/Direction mode like the SDSK models, which are normally used with the Acorn for X,Y,Z,A axis control.

Ballpark price of an MCPV model motor is about $400 for the RLN models and about $500 for the ELN, depending on the model, but, given its software, it might simplify your design enough to justify the price. Teknic has a very generous 90-day return policy to allow you ample time to test a motor for your application.

You can probably tell that I have very high regard for Teknic and for their ClearPath servos. After having installed several hundred stepper motors in various process control computers, using a high-quality servo is a pure joy. The steppers did their job and they did it very effectively when sized properly and driven properly. The MCPV models handle the "fine tuning" that made using steppers complex in some applications.

Teknic has videos on YouTube for each of the Operational Modes.

[Gary Campbell]

I'm right with Mike (Richards) on this one. The more and more I use them, the more I am starting to appreciate the capabilities of the Teknic ClearPath product line. I have used the MCVC models only a couple times, the balance have been with the SDSK (Stepper Killer) series.

Where I differ from Mike is that, and mostly for simplicity reasons, would be to use an SDSK motor to provide motion for a rotary umbrella changer. The reasons are:
1) Step and Direction interface is native to the Acorn, no additional hardware or programming is required.

2) Even using the low res ("R" designation) with 800 (native) steps per rev and using my favorite 10:1 planetary gearbox for reduction step resolution for a 20" diameter rotary rack is ~.008". Resolution can be electronically enhanced 2, 4 or 8 times if needed without the torque reduction associated with steppers. The "E" designation with 6400 counts per rev yields a step resolution of .001" Close enough either way for a tool fork.

3) For those that are considering a tool changer of some sort, there is good news on the horizon. I am currently testing and modifying some Centroid supplied (router/mill) tool change macros. For both linear and rotary rack storage. All perform very well and should be easy enough for most that have been paying attention to modify to their own use. We (the beta testing group) are currently waiting on hardware and software upgrades to be implemented to accommodate the ETH1616 (16 inputs, 16 outputs) so that proper toolchange sensor checking can be implemented.

[Richards]

Gary, I think that we agree mostly. My only reservation about using the Acorn to control the tool changer motor with Step/Direction sigals is the loss of an axis. For those needing only X,Y,Z control, that's not a big deal; but, if they need the 4th Acorn axis for an A axis or to mirror two motors on a router's gantry, they would need a tool changer motor that the Acorn only controlled indirectly. Since the positions on a tool changer aren't going to change, the MCPV motors can handle everything with minimal I/O from the Acorn. For instance, using Operational Mode 14, the Acorn would pulse a single output line 5 times for tool number 5 or 8 times for tool number 8. Then the Acorn would turn another output on to signal the MCPV motor to move. The Acorn would then monitor a single input line controlled by the MCPV motor. When the move finished, the MCPV motor would change the state of that line.

Either way works. The SDSK motors work great for axis movement. They would work just as good for a tool changer.

There is one other "gotcha" with Teknic's ClearPath motors. The MCVC motors have fewer Operational Modes than the MCPV motors. The Operational Mode 14 is only available with the MCPV model.

[Gary Campbell]

Right on Mike. I was using the MCVC series as a fractional hp lathe motor for turning on a dual purpose turn and full 4 axis machine. The lathe spindle power was swapped via "knuckledragger transmission" aka. belt swap. Here is a peek at the 2 modes:

https://www.youtube.com/watch?v=_yznJrzd730

https://youtu.be/_yznJrzd730


https://www.youtube.com/watch?v=QPp1itlsbnI

https://youtu.be/QPp1itlsbnI

[mick41zxr]

Thanks Guys,
I haven't tried a Clearpath yet but may do in the future. X,Y & Z are on DMM.
I ran the carousel on a closed loop stepper as I had one on hand & to have some surety that the carousel positions were repeatable.
Ultimately I would like to get the carousel positioning done by 4 bit grey code, but not enough I/O at the moment. Ether 1616 should solve this plus allow for few more sensors to eliminate the time based functions. This should be reasonably simple & intend to use the Velocio PLC to control the carousel positions. Fits in the palm of your hand & already had some pre-built routines to control step & direction motors.
https://www.youtube.com/watch?v=kXEzpmoZm14
Regards,
Michael