[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

>