Re: Automatic tool changing ?

[Ray Henry <rehenry-at-up.net>]

At 12:53 AM 6/24/2000 -0400, johnd wrote:
>
>The Milltronics tool changer is not the best design - it has some inherent 
>flaws (undersized gearing, if you aren't careful on manual change, tools
fall 
>out, etc.).  There is an arm that pulls the tool out and inserts it into the 
>spindle, and I don't think it has the capability of random tool location.  


John 

How does the arm do that:  
  does it grab a tool from the drum at the same time it grabs the tool in
the spindle or does it just take one at a time?  
  do fingers extend to grab the tool or does the arm rotate into the tool
holder?  
  is there an intermediate position for the arm?  
  is there a second arm that places the tool in the drum?

>The way the 
>Milltronics changer appears to work is through a 4 (or 5 for 20 tool) bit 
>wide signal from the main controller board into the Acroloop board.  The 
>beauty of this is that the Acroloop board can be standalone and it has built 
>in two-axis control capability, in addition to 24 DIO's.  So maybe up it
to a 
>6 bit wide signal, from the PPT to accommodate the misc IO functions, and 
>that would leave 18 outputs to handle Spindle CW/CCW, Lube, Flood, etc.  

Using the Acroloop board, if it has it's own memory, and if it remembers
how to do all of the logic (ladder?) might be decidedly easier than
building your own plc within or alongside tkemc.  

But the problem then becomes how to communicate between the EMC and the
Acroloop.  You might have very little control over the way the board talks.
 You would need complete specifications for the channel(s) it can use as
well as the syntax and semantics (Fred's words) of its language.

Once you've got those specs, we'd have find some device for your pc that
will provide the channel to the Acroloop board.  Ethernet, parallel,
serial, ISA, whatever, and configure it to match.

After the channel we'd need to build something (probably a file or set of
files) that could translate EMC's language into the Acroloop's language and
connect the EMC to the correct channel.  

And last, we might have to add a few words to the EMC vocabulary so that pc
and Acroloop can tell each other what to do and what has been done.

I'm reasonably certain that there are folk on the list who would be able to
take on part or all of a project like this.  I can help some with the
channel and some with the gui, but for me the rest would be a bit like
translating French into Mandarin. (I know nothing of either!)

If you choose the "keep the Acroloop" approach you jump right into the
middle of the interoperability problem that was a large part of the robot
chat (great stuff) last week.

>I'm still learning!

I think it was Robert Heinlein, probably plagiarizing Mark Twain, probably
plagiarizing ?? who said, "We learn from experience, if at all." 

Ray