1. Does this machine have Trak sensors? These are devices that ride along the table (X) and saddle area (Y) and have cables that attach to the system. These are electronic Trav-a-dials.
2. These systems were very popular back in that time (late 80's early 90's). The motors are brushed DC servos. The amplifiers probably take an analog control voltage proportional to the desired axis velocity. This could be +/-10V, +/-5V, or a single 0-5V or 0-10V signal combined with a direction bit. 3. There's two ways to go I think: A. See if you can get the old motors and amps to work. If so, and you are inclined towards a "science project", use one of the systems Andy described in his reply. B. My best advise would be to see if you can adapt a standard NEMA 34 (or 42) stepper motor to the mounting scheme on your machine. If so, build a new system and eBay the old one. I recommend this course of action due to my concern that eventually brush wear will kill the existing motors, and you'll be back in this same position too soon. 4. To do the Z axis, you need a quill drive mechanism. Jon Elson has (I think) pictures of his that he made from scratch on his web site. If money is no object (!), Elrod Machine has a kit: http://www.elrodmachine.com/Z%20Axis%20CNC%20Quill%20kit.htm Or you can CNC the knee, but this is tougher due to the power required. Thanks, Matt On Wed, 8 May 2013 02:05:05 -0400 Ron Bean <bucketwo...@rbean.users.panix.com> wrote: > When I asked about this before, I had hoped someone would have seen > one of these before. Since that didn't happen, I opened it up and > took some pictures. > > This is a Bridgeport mill with a 2-axis CNC controller and a 3-axis > DRO, owned by a member of Milwaukeemakerspace.org > > The front panel looks like this: > http://www.panix.com/~rbean/temp/bridgeport/front-panel.JPG > All program entry is through this control panel. There's no obvious > way to connect it to a computer. > > Label on the back panel: > http://www.panix.com/~rbean/temp/bridgeport/back-panel.JPG > The connectors labeled X, Y, and Z are for the DRO. > [Note the connector for the cassette-tape interface, which we don't > have] > > Label on the power supply: > http://www.panix.com/~rbean/temp/bridgeport/power-supply.JPG > Note the date: 9/89 (~25 years old) > The servos and encoders plug into this box, and there's a cable from > here to the control box. > > In addition to the power supply, this box contains two boards labeled > "X" and "Y", I assume these are servo amps: > http://www.panix.com/~rbean/temp/bridgeport/servo-board1.JPG > The big thing in the middle is a heat sink, with power transistors on > both sides of it. The data connection is on the other side, through a > hole in the plate it's mounted to. > > Visible chips include: > TSC426CPA dual power mosfet driver > TSC427CPA dual power mosfet driver > HP 2601 line receiver optocoupler > HP 2531 optocoupler > > Another view of the board: > http://www.panix.com/~rbean/temp/bridgeport/servo-board2.JPG > > Here are two views of the servo encoders: > http://www.panix.com/~rbean/temp/bridgeport/encoder1.JPG > The chip is a DS8830N dual differential line driver > http://www.panix.com/~rbean/temp/bridgeport/encoder2.JPG > The chip is a HEDS9000 optical incremental encoder > > Here's the label on one of the servos: > http://www.panix.com/~rbean/temp/bridgeport/label1.JPG > http://www.panix.com/~rbean/temp/bridgeport/label2.JPG > Unfortunately it's very hard to read, and it appears that the vital > info was not filled in. Here's what I think it says: > > DC MOTOR > 60 V A RPM > DUTY > CUST P/N 14969 REV D > I G P/N 4020D-143 > S N 4320 > ASSEMBLED IN MEXICO > BY INDIANA GENERAL > HPL 730-352 > > Finally, here are the two logic boards inside the control box: > http://www.panix.com/~rbean/temp/bridgeport/logic-board1.JPG > http://www.panix.com/~rbean/temp/bridgeport/logic-board2.JPG > > (I just realised these pics are upside down :-) > Each board has a MC6809 CPU and a whole bunch of 74LS-series logic > chips. I think the chips in the yellow packages are resistor > networks. Also visible on the 2nd board are: > Intersil ICL232CPE dual line driver/receiver > MC6850P UART > MC1411P (7 darlington drivers) > And some other stuff I couldn't identify. > > The owner says the machine is usable, but one axis stops working > occasionally (I don't know which one). He'd like to get it working > reliably with a way to input programs from a computer, and add a Z > axis servo. > > Questions: > Are these servos likely to be usable? > > Are the servo amps likely to be usable, and if so, what kind of input > might they be expecting? > > [Do servo amps want step and direction inputs, or something else?] > > Do servo systems like this use a combination of data from the DRO and > the servo encoders, or is the DRO separate? > > If you wanted to modernize this machine and add a 3rd axis, how would > you go about it? > > We've gotten some interesting but questionable suggestions from > members who were born around the time this machine was made... > > Some people assume it must use Gcode internally, and there must be a > way to load Gcode into it from a computer. I think both are unlikely, > although I suppose it's possible. The connector between the power box > and the control box "looks like" a serial port, but I doubt it. The > idea of somehow loading data through the cassette tape interface > seems unlikely to be worthwhile, despite one member's insistance that > it would be a reasonable thing to do. In any case, that wouldn't get > us a 3rd axis, nor would it explain why one axis occasionally stops > working. > > Several people have suggested replacing the servos with big steppers, > on the theory that stepper drivers will be cheaper than servo > drivers. I don't know if that's a reasonable thing to do or not. > > One member works for a company that's about to throw away a somewhat > newer conversion kit (perhaps only 15 years old instead of 25), and > he's asked them to consider donating it to us instead. That's working > it's way through their bureaucracy, I'll believe it when I see it. > > Any other suggestions or comments? > > > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200-page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. This 200-page book is written by three acclaimed leaders in the field. The early access version is available now. Download your free book today! http://p.sf.net/sfu/neotech_d2d_may _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
