The real power of
any CNC machine is the Control.
At the introduction of the first Fadal machine we were pressured to
add other controls. It was quite common at the time for
machine tool builders to add virtually any CNC control that the
customer requested. It was difficult, but we resisted and
forged ahead developing one of the best CNC controls every
produced. Feature for feature, very few, even today, can match
all the features we provided. Besides cost advantage of having
our own control, the primary reason for having our control was to be able to efficiently
service the machine. Having one control allows the servicemen to stock all
the parts needed in his service van.
Development of the Fadal CNC- Beginning in 1975, we used one of the early
desktop computers that came in a kit form. It was the IMSA 8080 based on the Intel 8080
microprocessor and used the North Star Disk Operating System. The
very first unit did not have a video monitor, it used a Teletype
via an RS-232 port to display and input information. The IMSAI sold for $599 as a kit, then you had to
build it yourself; the kit came with bare boards and a bag of IC's. The main processor was the Intel 8080A and was
clocked at 2.0 MHz. The system RAM came with 64K and was the maximum
memory available for the time. To start, the programmer used the front
16 toggle switches to set the Bootstrap address, flip the LOAD address switch
and then the RUN switch. With this computer one could step
through all the binary data by watching all the LEDs change.
Just like the really old computers seen in the movies.
The
RUN switch would boot the DOS system and run the Northstar Disk Operating
System. With the DOS running, we could load the NC kernel and start the
Fadal CNC processor assembly code.
The IMSAI used the S-100 bus interface design (common in those
days) which is the same basic design we used as the heart of the
CNCs motherboard bus activity controller; we called it "the
traffic
cop". This is the primary function of the Fadal 1030
board; it controls the flow of communication between the main CPU board
and all the peripheral devices. In the case of the Fadal CNC,
the flows between 1010 axis controller
CPU boards, the M-function board and the Mill interface board.
Once the IMSAI "booted" and loaded what we called the NC
processor, it would come alive, the teletype in its clunky,
mechanical fashion, would simply display "R>" which signified READY.
In the beginning, as the software code advanced, we used the system to
generate paper-tape programs for our machine shop and at the same
time debug and test the CNC functions. In the beginning, the
software allowed us to input a program using the
IN command, list the program using the LI command and punch the
program to paper tape using the PU command.
We had another command that would process the NC program. It
expanded fixed
cycles to single axis Z moves and for milling it used the cutter-radius-compensation
to allow us to output the actual tool path. After creating the
tool path program, we would punch a paper tape for our NC machines.
At the time, most controls did not
have CRC; that's why they were called NC's and not CNC's. It
was a great feature for our Job Shop because we used a lot of
reground endmills.
The two letter mnemonic command structure(LI, CH, PU, etc.) was
eventually increased to cover all functions we needed for the CNC.
It was not until the advent of
the VMC40 around 1984, that we changed the "R" prompt to "ENTER NEXT
COMMAND". Later, we added a Menu system to the control that
simplified having to remember the various commands.
The
year of the very first working Fadal CNC prototype that actually
turned motors was about 1977.
It was a free standing control that looked like an early video game.
In the early 70's many CNC's were basically a self-contained
console.
At the time, one of the most common was the Slo-Syn control that
came out of the 60's; no video monitors, basically just knobs and a
paper tape reader.
About 1980, the first production machine was the VMC45, it had a hanging pendant design.
The keyboard
was to the right of the video monitor and It
was one of the very first CNC's to use a primarly a QWERTY keyboard
interface.
The design only needed a keyboard, a feed-pot and an Emergency Stop
button. At the time, most, if not all controls had many knobs, buttons and
maybe a data input keypad. We based the entire interface on
software rather than hardwired switches. The idea was complete
flexibility where we could add features and easily update in the
field. Sadly no actual pictures
are available.
But the picture to the left is what the very first prototype looked like.
The 1400-1 CPU Board
VMC45 and early VMC40
The 1400 board is the Central Processing Unit of the CNC
control. All CPU boards came with 38K of battery backed memory.
This memory is managed by the main CPU and used to store the following:
• CNC Part Program
• Tool Data – both Length and Diameter
• Fixture Offset Data
• SETP parameters
• Backlash
The CPU board interprets the part program and executes it by issuing commands to
the other boards, it monitors the inputs and proceeds as required
by the program and external feedbacks; simply put it orchestrates all
activity
of the CNC.
The first 1400 board was the original CPU board
designed and used primarily by the VMC45. It was basically the
same as the 1400-1 board as shown above, except the first CPU did
not have battery back memory (the four memory chips above the
purple battery). The original 1400 card (1400-0), used "Bubble Memory"
for permanent program storage, which was very slow and expensive.
There was not a 1610 software module, so the control software was "burned"
directly to the Eproms on the board by removing the Eprom jumper
ribbon cables and connecting to Eprom "burner". To greatly
simplify the software update process, it with the 1400-2
hardware, we designed the pluggable 1610 module.
The 1400-0 CPU was based on the Intel 8080, which eventually ran at 8
MHz;
state of the art in those days!
As the Intel microprocessor improved, we upgraded our hardware and came out
with revisions signified by dash numbers.
Click Here for more
information about the 1400 CPU boards.
The Fadal CNC MP Design -
The second generation pendant was called the "CNC 88" for the Intel
8088 processors. With that
we added dedicated switches and knobs for the operators convenience and
to help our salesmen compete with the Fanuc machines. After a
while, it was renamed the MP control, which basically was
the same internally as the CNC 88, the new faceplate was done mostly for a fresh look.
The MP signifies Multiple Processors and does better describe the
architecture
of using
many CPU's to do the work that one CPU can not do efficiently.
It is a design that is commonly referred to as "Distributed" or "Parallel Processing"
architecture, and
is technically defined
as "a distributed system that consists of multiple autonomous computers that
communicate through a computer
network. Where as the computers interact with each other in order to
achieve a common goal". A computer
program that runs in a distributed system is called
a "distributed program", and "distributed programming" is the process of
writing such programs. Today's Dual Core and now the Quad Core
processors all operate on this principle.
With the Fadal CNC on a standard machine there's five CPU boards working
together. The Main CPU, the X,Y,Z and Spindle CPU boards; all working
together and independently in conjunction to make the machine
function. This
design allows for maximum speed with minimally powered CPUs.
With this design the control can do five things simultaneously;
something a single 64-bit control could never do because it is
limited to only one function at a time.
Servo Performance:
At the time we introduced our control, the typical CNC controlled
the axis servo at rate of approximately 2 millisecond
intervals. That means correcting the servos position 500 times per second.
With a three axis machine and a single CPU it can only adjust
the position error 167 times per second, per axis!
The result is a "sloppy" servo system in what is called the position
loop.
With the MP design, the position loop of each
axis is adjusted at 1 millisecond intervals which was far beyond most controls then, even by
today's standards it
is considered exceptional.
Control Throughput:
Throughput is defined as the speed and volume that the CNC
can process the high level NC code, convert it to a low level set
of positions commands and execute them to cause machine motion. With the MP
design, the main CPU is processing the high level NC code while at
the same time the axis CPU boards are executing low level motion
commands. Originally the Fadal CNC could process between 10 and
100 NC blocks per second. It depended on the complexity of the
NC block; simple G1 moves are processed faster than CRC (cutter
radius compensation) type moves
that requires much more calculations than simple linear moves. As
the CPU processor improved, so did the control throughput.
With the 1400-4 version CPU, we got up to 1000 block per second
throughput for simple XYZ linear moves.
Historical Interests -
First show with the VMC40:
In 1984, we had our first booth at the LA WESTEC show for the
VMC40. It was only about 6' x 12' in size, just enough for a
machine and a desk. We were just down the isle from the
ACROLOC booth. At the time, they sold one of the most popular
machines and they had a booth that was about 200' x 200', they
really put on a show. They even had the LA RAMs cheerleaders
signing autographs and a mill that was upside down and 40' in the
air. I was told it was to show that with their machine you could
drill a hole anywhere, but the cheerleaders got most of the
attention!
One morning as we were walking up to our booth we came around the
corner and saw a dozen Acroloc guys standing around our machine with
one of them standing at the control, pointing and talking. We
stood back and listened to him talk, at one time we heard him say
that "This design was the control of the future"... We
competed directly with them, they had one of the fastest tool
changer with a 2 second chip to chip time, but because of the tool holder
design, it couldn't mill as good as we could and they never offered
a 10,000 rpm spindle. Needless to say their
booth size got smaller and smaller over time.
Advent of 1000 blks per second:
In the early 90's, we were getting our booth ready for one of the
WESTEC shows, and as always it was pretty chaotic as all the other
exhibitors were scrambling to finish the last details. Anyone
who has been an exhibitor at a convention knows exactly what I mean.
We noticed one of our biggest competitors was setting up a demo to
show a machine cutting a part at 250 blocks per second. At the
time, the Fadal CNC could run at 100 blocks per second. Not
wanting to be "out done" at a show and in the true spirit of
competition, the control design team got together and did some
brainstorming about how we could squeeze out the maximum speed of
the control. This was Tuesday morning and the show started
Thursday, so we had little time work with but a good "fire drill" is
always a good thing now and then. With a bit of creativity, we
ended up reorganizing the control code and found we could get 1000
blocks per second. So we rewrote the code, tested it,
developed a working 3D demo and printed up all the show display
signs and material. Then took it all down to Westec, set it up
and starting running. We finished Thursday morning just as people were
walking in for the first day of the show. It ended up being one of
the biggest and best demos! Few people had ever seen a control
cutting at 1000 blks per second. Needless to say our
competitor was not very happy that we took the wind out of their sails...
We often get asked "Who was first Fadal or HAAS?"
I can tell you first hand it was Fadal. One of our earliest
customers was Gene Haas. At the time, his company was called
Haas Brothers and they bought a VMC40 to make indexer parts.
It was about machine number 25 that they bought. After the
installation, I spent three days training him in his shop.
It was about a month or two later that I asked Harry Nash, his
salesmen, how Gene was doing because I hadn't heard a thing from
him. Harry said that he stopped by Genes' shop and the machine
was in pieces "all over the floor". After that we decided it
best to limit Gene's visits to our factory. We remained
"friendly competitors". Gene used to come over to Fadal when we
were in North Hollywood quite often, maybe a little too much...
Overtime
the Fadal CNC was used by so many different people and in every
imaginable industry.
Even today it's amazing to hear who has bought them and where the machines ended
up... One thing is sure, most customers love their control,
still to this day!
