Bridgeport Series II Interact 2 CNC Mill
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These pages detail my progress in converting an old Bridgeport
Series II Interact 2 mill to EMC2 CNC Software based CNC PC control.
I bought it from a local seller who placed a Craigslist
ad (see pictures from the ad). He advertised
a Bridgeport CNC mill with a non-working display. The price was $500, plus
$500 for a large quantity of toolholders. I figured that the price
was right and bought it. At that price, the worst case scenario
would be that I would be unable to restore the mill and would part
it out. I would probably get my money back from toolholders alone
(35 of them). While searching for more information about this mill,
I save
some pictures of other similar
milling machines. An additional impetus to act quickly was this
thread from CncZone, where a potential buyer was asking questions about
the same mill that I was looking at.
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I rented a low boy trailer.
Pick up was relatively uneventful and the mill
looked okay. I had help from Machinery Movers Chicago.
The trip back, unfortunately, was not without a disappointment. I
was stopped by the police and accused of exceeding weight allowed by
my drivers license. I was told my trailer will be towed until I get a Class C license. Fortunately, I had a laptop with me and looked
up and showed them the Illinois statute, which permitted me to drive
up to 25,000 GVWR vehicles. I was still fined for
lack of some stupid sticker, but was let go. So, now I say, beware of Sugar Grove, IL police department.
I was extremely fortunate, because my friend generously offered me to
use his warehouse to hold the mill until I clean up my garage enough
to place the milling machine. I dropped it off there.
Since the mill was taller than my garage door, I had to remove the head and chip
guard from the mill. I documented
every
single
wire
that was
disconnected.
A mere six weeks later:), I rented a car hauler trailer and
took it home. Again, my friend, his son
and his son's buddies helped me a lot. All faces in pictures are
blurred for privacy.
Check out some pictures of servo motors and their guts and original look of inside the control cabinet. Also check out the Bridgeport Series II Interact 2 Schematic. Those, like me, desperate to get a manual, look no further: Bridgeport Series II Interact 2 Maintenance Manual PDF and more manuals.
An attempt to diagnose problems with the original control, pointed
the finger to Hendenhain TNC151 control. A CNC control is like a PC
and, as you know, PCs go bad after a few years. I was quoted some
outrageous amount for fixing this control (3,000-5,000 USD). I
figured that even if I fix this control, all I will have is an old
control, and next time another capacitor leaks I would again have to
pay thousands. At this
point I decided to junk my control, took out the control and servo
drives. I sold
those
parts
(with proper disclosure) on eBay and
recouped the cost of the mill from just that stuff.
My first undertaking was building of a homemade CNC power supply. I made it from a toroid donut transformer, a capacitor and a rectifier. It was easy and pleasant. I was reusing mounting brackets from servo drives.
After removing stuff from inside of the cabinet (see emptied out cabinet, I started wiring the control cabinet anew. I tried very hard to have all wiring labeled and to go through wiring channels.
Being a computer programmer, I tried to do one thing at a time: for
example, first I tried powering a servo motor with a DC power
supply. Next, I wired in a servo drive and connected a DC servo to
it. That way I could test stuff and get myself familiar with the operation
of this machine and its components.
At that point, more fun began: I purchased a PPMC drive from Jon Elson's PICO Systems. This an
interface between computer on one side, and servo drives, encoders
and control buttons on the other. It was not dirt cheap, but well
worth the money and Jon provided excellent product support. I also
bought three
E5 Optical Encoders
from US Digital. The model I selected provided 4,000 pulses per
revolution,
which amounts to resolution of one pulse per 0.000025 inch move
(this does not directly
translate into accuracy of the machine, just shows that there is
plenty of resolution).
I made adapter plates to mount
new encoders to the existing servo motors. That was somewhat
painful, because I had to drill a large 43/64 hole for the motor
shaft, and I could not do it accurately enough. My solution was to
drill the big hole approximately where it should be, and then
re-zero my coordinate system relative to the big hole. I really
wished that I had a CNC mill working. It was time consuming, but I
made all the plates.
Then something exciting happened and I
hooked up a Linux PC to the mill.
Being a long time Linux user since 1995, I was very happy to use the
OS with which I am most familiar.
After a day of not understanding of what is going on, the PC
connected to the PPMC device and was able to read encoder readings
and send signals to the motor. For testing purposes, I unhooked a
belt from the Y axis motor (which I could easily see when sitting
near the cabinet), so
there was no danger from the motor moving, even when it was
moving uncontrolled, in a wrong direction, could not stop etc.
A lot of time was then spent wiring limit switches, E-STOP,
and home switches.
I also wired the computer for Ethernet and added a webcam.
Finally, I could move the axes from a GUI. I programmed my first G-Codes and voila, the table MOVED exactly as programmed!
Finally I started writing some perl scripts that generate G codes and wrote a G code file to drill bolt holes. YouTube video.
After the mill became functional, I spent some time looking at the
Troyke CNC rotary table
that I bought on eBay for $149. It is currently a completed project. The
table has a resolver instead of an encoder, and so it needs to have
a resolver to encoder converter.
The next mini project was to mount a nice 17 inch monitor that was
thrown away at my employer's place, and therefore I had to CNC a set
of monitor mounting
brackets.
One sunny August day, I stopped by a garage sale and purchased a
new in box Saitek
P880 joypad that I set up with EMC2. I can use this joypad now to
jog the mill in a super convenient way. It is even better than the
original jog control, which I intend to restore to full function
anyway.
This is how the mill looked in September.
My last and, possibly, final project for this mill is to
motorize the knee, in
order to provide a greater vertical "envelope", in order to accommodate
short, as well as long, tools.
