( Greg )
Every kid would love to ask for a pony, if they thought they could get it they
would ask for a unicorn. Reality however usually proves this to be impractical
to impossible.
Everything is changing today at a hyper accelerated pace. Back in the day
Motorola produced the 68000 CPU, it was used in all sorts of equipment from
Apple PC's to Okuma machine controls. I would guess that that CPU was still
being used to manufacture products 20 years after debut.
Today PC cpu and chip sets are what a 3-5 year life cycle before going OOP.
Same with many ARM CPU. Look at the Arduino and how many generations have come
down the road. Most new version have moved to 3.3V and are no longer compatible
with 5V shields.
Even if someone did come up with a backplane card rack for most of the
interface cards, that main CPU board would have to be updated nearly constantly
because key components would become un-obtainable. Todays global manufacturing
tries to run as close to true JIT as it can.(JIT="Just in Time") companies want
as little space and capitol tied up in inventory. When I worked an Apple PC
assembly line they were so JIT focused they only kept 4-6 HOURS worth of
components in the facility. This meant that trucks were delivering Mem, HDD's
ect. were being unloaded every few hours and being reloaded with boxed product
ready for market.
Several Chinese machine tool builders have offered LinuxCNC as the control to
reduce the overhead of building the machine. I believe it would be used more if
tool builders were sure they could not be held liable for a system they sold
that had been modified by the buyer.
GRBL has come along way - and it was a project to fit a stripped version of the
early EMC/LinuxCNC into cheap Arduino hardware. the current v1.1 IIRC had to
strip down the boot loader and some other items to still be able to squeeze the
optimized assembly code into the Atmega328p chip. What did GRBL have to give up
to fit in an Arduino? Tool table capability {G43}, Tool radius comp {G41-G42},
Minimal look ahead buffer, No program storage - its all drip feed via serial,
no program editing, X-Y-Z only no additional axis, no spindle feedback
(tapping), requires second device to stream G-code and operate the control. Now
I like GRBL and it has the honor of being the founding code which virtually all
extruder type 3D printers is based. I hope someday there is a port for a rotary
axis, I would love to use it to engrave on cylinders using X-A-Z.
For now though, the movement towards SSerial and interface from control PC via
Ethernet allows all sorts of flexibility.
As for HP-GL, I had to work with HPGL for tool paths for several years and it
was a complete disaster. Mathematically a "line" has no physical width, not
exactly so in HPGL so you will have gaps, broken chains, lines intersecting not
at there endpoints and all arcs are output as splines. While at the scale for a
HP pen plotter this worked out, for CNC use it was a dismal failure of epic man
hours wasted trying to get each file into a usable state. I hope HPGL is
banished from the face of the earth long before G-code begins to fade. I agree
that G-code is far from perfect, but there is no other method out there that
even comes close. Early AutoCAD had the same sort of dysfunction issues by the
use of the "polyline" construct.
Lastly - May I ask the status of LCNC v2.8? Is there any potential release date
on the horizon?
Thanks ( /Greg )
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