[Coco] [Color Computer] [coco] Coco CNC

[altair8800c]

Charlie,

 Some huge Okuma's out there with 6+ pallet changers. These are
$2,000,000,000+ machines. Very neat to see run.

 -Neil


--- In ColorComputer at yahoogroups.com, "Charlie" <chazbeenhad at ...> wrote:
>
> Hello! 600K a pop? Wow, what types of machines are they?
> 
> I'm a CNC technical leadman for some 16+ years now. My career has
mostly been working
> with English and American built Cincinnati CNC mills. Mostly Arrows
and Lancers.
> 
> -Charlie
> 
> 
>   ----- Original Message ----- 
>   From: George's Coco Address 
>   To: ColorComputer at yahoogroups.com 
>   Sent: Monday, February 12, 2007 12:55 AM
>   Subject: [Color Computer] [coco] Coco CNC
> 
> 
>   Okay!
> 
>   I've been working on my Coco powered "Tiny CNC" machine this weekend.
> 
>   Whew!
> 
>   What a task! I discovered that the axis designations were all
messed up.
> 
>   (You learn a LOT when working in a machine shop)
> 
>   All three were wrong. X, Y and Z were wrong. So I renamed them and
in the 
>   process, I lost the driver(B09 driver) for the REAL Y axis.
> 
>   No problem, I thought. Just rename the X or Z axis driver. Well,
it didn't 
>   work. After two days, I discover several problem with my hardware
that 
>   proved that the port for the Y axis was wired incorrectly, the
cable that 
>   connected it was also wired incorectly and the software to correct
this 
>   error is now lost.
> 
>   No matter about the software. I repaired my mistakes with the
hardware and 
>   now the software to drive the servos works correctly. I can swap
the cables 
>   to each of the servos and it works correctly.
> 
>   Since I've been working at a machine shop, I was forced to buy some 
>   precision instruments such as a dial caliper. My old vernier
caliper was not 
>   acceptable at work.
> 
>   Hmm. I really can't see any accuracy difference except for the
fact that 
>   the dial is easier to read.
> 
>   Anyway..... Math always works......
> 
>   All three lead screws are 32 TPI. The three servos are 200 steps
per inch. 
>   Doing the math, this comes to 6400 steps per inch, or precision to 
>   .00015625.
> 
>   Not bad, but not as good as what I work with at my job.
> 
>   I've learned that offsets and HOME are important. (I did have trouble 
>   figuring into this on my coco)
> 
>   FINDING HOME:
>   Originally and even now, I use brute force to drive the axis into a 
>   mechanical stop. The stepping motor would stall there and hum
until the 
>   software stopped driving it. At that time, I set the software to
assume it 
>   was HOME. Actually, it works! However, it isn't elegant. So I'll
add some 
>   micro switches to the sytem to fix this. Besides, I can move that
switch to 
>   a more convenient place for each project.
>   My coco takes a long time to step these motors to where they are
supposed 
>   to be. Basic09 is a lot faster than RS Basic, but it doesn't hold
a candle 
>   to ML. .....Someday, maybe!
> 
>   I envy you folks that can "whip up an ML program".
> 
>   So far, I can move each of the three axis from home to the limit
and back 
>   and my dial indicator reports a return of exactly zero. This
implies that my 
>   stepping motors, power transistors, software and math are working
correctly.
>   The only problem is finding home. The micro switches will take
care of 
>   this.
> 
>   Backlash on each of the three axis are different. The Y axis is
only about 
>   two steps on the stepping motor. This is incredible!. However, I took 
>   extreme care to minimize backlash when building this thing. I
won't go into 
>   detail on how I did this until later.
> 
>   I've learned at work, that extreme brute force and extreme mass of 
>   machinery is important to get the results necessary. Heavy metal
is good! 
>   However, it's expensive. The machines that I work with cost a TON
of money. 
>   We're talking 600 thousand dollars for a small one. My first 4k
coco was 
>   $300 and took a couple of pay checks to pay for it. So, I won't
expect to do 
>   what those monsters can do. I just want to make some small gears,
sprockets 
>   and pulleys. Later, I want to do some 3D stufff, small things.
> 
>   More later....
> 
>   George
>