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

[Gene Heskett]

On Tuesday 13 February 2007, altair8800c wrote:
>Charlie,
>
> Some huge Okuma's out there with 6+ pallet changers. These are
>$2,000,000,000+ machines. Very neat to see run.
>
2 Billion Dollars?  Let's just say that is a lot of money.

> -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



-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2007 by Maurice Eugene Heskett, all rights reserved.