I am interested in the old electronics . Sent a PM . Thank you
It's been a while since I've posted here. A little history; I have a Series II with a V2XT that I picked up from Bridgeport Controls in Bristol. It has been a workhorse for me for 20 years. I've had a few issues such as the original 286 Motherboard finally dying but overall it has treated me well. It's an FMDC machine and it has a network card that allows me to DNC from the file server and run large programs.
About a year ago, the Y-Axis ballscrew starting making crunching sounds and I discovered an oil line that had rubbed through in the saddle. After a fairly extensive regrind of the ways and finding a good set of ballscrews, I was back running. Turns out the screws were 5mm (not 0.200) pitch and I can't change the FMDC parameters...
So... I found a fairly nice BOSS6 machine out there and went on a 1,500 mile round trip to get it. I now have a correct Y-Axis in my FMDC machine and am starting on the journey to put an EMC - MESA - A/C Servo kit together.
I've been reading throughout this forum and seeing what others have done and am inspired by the creativity of this crowd. I'll include some pictures but for now I'll ask the standard question:
"Does anyone need any of the old electronics?" Steppers, boards, etc. I'm not going to waste time on e-bay, just pitch them if nobody has an interest. It was a fully working machine when shut down so let me know.
Last edited by RichWood; 05-07-2012 at 04:02 PM. Reason: Add Pictures
I am interested in the old electronics . Sent a PM . Thank you
I could use a spare stepper. PM sent.
I've gotten several inquires about the BOSS-6 parts, many of which have been picked up by Keith this past Saturday. He got the steppers, the LSI Cage cards, the transistor packs, the drive cards and the user interface panel. If there are any other components you guys need, let me know but it's pretty slim pickings.
Progress continues ... So far, I've been doing cosmetic clean up while researching and buying some parts. I decided to build a wheel sub-frame so I can move it around the shop while the build is in progress. I may not live on it forever but the shop is getting pretty tight and the BOSS-6 is sitting in the only bay of my garage.
For electronics, I've got a quote for Parker MPP0922C AC Servos and Copley XTL-230-18 drives. In addition, I am looking at 16" Magnescale SJ700A-040 5 micron resolution for feedback on knee position. I have some NEMA 34 Steppers around that I am targeting to drive the knee movement. The purpose of this is to normalize the TLO's as others have done on this forum. I figure I'll use the side access panel on the knee that is beside the knee-lift shaft. With reducion gearing, it should have sufficient torque.
My first thoughts were to go with +/- 10V but it seems the world is heading to Step-Direction. I bought the Mesa 5I25 with both 7I76 & 7I77 daughter cards to give me both options.
If you guys have some thoughts / suggestions, let me know. This is a blank slate project at this point.
Last edited by RichWood; 05-21-2012 at 01:26 PM. Reason: Sp
The HOBBY world is largely going to step/dir, primarily because mach3 is a step/dir controller. In the grand scheme, step/dir is actually a step backwards from +/-10V analog. The analog command requires the control loop be closed in the controller. This means the controller always knows where the machine is. The step/dir is a bit of a blind trust thing where the controller sends the proper pulses to the servo drive and hopes the servo drive does its part.
In a properly designed and operational system, it makes little to no difference on a knee mill. Most folks go the step/dir route because it is far easier from a tuning, wiring, troubleshooting standpoint.
As far as I know, EMCshould work fine for either so it's really a preference thing for you.
Especially when you plan to use a stepper motor?
Why do you even need an encoder if you use a stepper motor?
If you are planning on "closing the loop", you cannot - not with a stepper motor. All you can do is verify it stepped when it was supposed to. For that, all you need is an inexpensive encoder.
If you want to close the loop, do it with a servo - it will be silly to do it with a stepper. You will have spent the money for feedback for little benefit.
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." Antoine de Saint-Exupery (1900 - 1944)
Thanks for the input. I suppose I should drop back and give a few more explanations (goals) and then incorporate the feedback.
The BOSS6 machine is secondary to the V2XT which is now running nicely after all the troubles. I'm spending way too much time playing with it but it's a hobby/business after all. The painting and wheels are examples of going to extremes. The basic goals are:
- To make a second machine that is at least equal to if not much better than the V2XT.
- To learn what makes these things tick. I'm fairly comfortable with the other machine but the FMDC is a "black box" and quite dated. EMC sounds like a real challenge but once you surface, the end should be worth it.
- Build it from "Made in USA" components.
About the knee ... My thoughts were to use a stepper because I have one. It would need a couple of stage reduction, likely homemade, which will introduce quite a bit of backlash. It will drive the Acme screw through the bevel gears, all of which I'm sure has some wear and/or nonlinearity. All these add up to something beyond "count the steps." The thought was to lower it past the target point then raise it slowly while reading position from the scale. Again, I'm collecting ideas and will converge on a path forward.
The Parker's and Copley's have been ordered (4 sets, brand new). I have visions of a fourth axis, beyond what I lashed up on the V2XT machine. That was a stepper that ran a canned program from a BasicStamp. The Stamp triggered by toggling the mist coolant line. I don't think I'm original here on that one...
As to "Made in USA", I suppose that speaks for itself. Certainly, of late, the news is that China is hacking its way thought our corporate databases and stealing us blind. It's ironic that the companies that have sent jobs overseas are now waking up to the fact that now they are getting plundered. I'm not going to go all political on this forum, just explaining my goals.
Iíll keep posting progress to the forum so I can pay back for the excellent information that Iíve found here so far.