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Just typed out a long response, looks like it was lost...sorry about that!

Here is a new one: www.sterlingint.com/lathes/optoform-80

Here is a used one, sold: caeonline.com/buy/machine-tools/precitech-optoform-50/9133282

Optoform 50. Two air bearing linear slides, and one air bearing spindle. Machine uses something like 10CFM of compressed air.

I have never actually seen one, so I don't exactly know. Drive is Delta Tau controller. Delta Tau no longer--it is now Omron. machine made in 1990's, and has been used for grinding interocular lenses. Interocular lenses are the lenses used to implant in people's eyes following cataract removal surgery.

We wish to make contact lenses with these things.

I did ask about the drive: 0-12 volts is what I was told, however I would be surprised, and probably 0-10 volts driving custom-made Kollmorgen motors. "Everything" about the lathes are outdated, and why I asked about where to start with the conversion of the program to Linux CNC.

Linux is a DIY system, and since they take weeks to respond to our requests, I would rather be on my own than depend on them.

With the slides being air bearings, pretty sure encoder feedback with some sort of velocity feedback because cutting torques are really small. ALso t he machine has a vibration isolation base using some sort of air bearings. Best surfaces in the business...

Definitely not stepper motors.

Regarding macros. I have decades of experience designing and making contact and optical lenses--even before the advent of computers. We just did not have enough money for the custom programs. All of the programs date back to Sir Isaac Newton--about 400 years with updates due to computing power.

Pretty sure the program itself is relatively straightforward with the needed changes in the control language from Delta Tau to Linux CNC.

All you really do to make contacts is generate curves. These are relatively small curves, usually in the 6.00mm-15.00mm range. There are some complex curves, however, I believe these are handled by the host computer, and either downloaded or the host computer generates the code for the lathe itself. I just do not know.

Due to taking months to get any service, we are slow with information. Pretty sure the lathe runs on DOS.

  Hi,First post, I have zero experience with LinuxCNC, I came hear to get educated.I previously did a CNC conversion of an old round column mill using steppers and Mach3 (about 10 years ago). I'm an electrical engineer by training so hopefully that will help.I have a new 8x30 knee mill and I want to try LinuxCNC this time I have near zero direct experience with Linux. To be clear this is for hobby use so I would like to use low cost components wherever I can get away with it, I won't be making NASA type stuff just hobby stuff so if the machine approaches 0.001" repeatability I will be very happy. I'm swapping in ballscrews at this time.System as I envision:

• Four x  T6 ac servos, AFAIK the controllers for these accept step and direction pulses much like a stepper and take care of closing the loop and are provided with some form of tuning software (yet to be tested).
• 8 limit switches
• Spindle speed encoder
• Scales possibly up to four
• Eventually I will make a custom control board for jogging etc, but hope to use GUI for the short term

Hopefully someone can answer my preliminary questions:

1) For a CPU board, what is powerfull enough?   I have a RPi, not sure if that is even close to powerfull enough. I also have more of a PC type SBC EPIA Nano-ITX not sure if it can run Linux?  Suggestions for a suitable CPU board please?

2) I can randomly start reading posts, however if there is a starting from zero tutorial somewhere, please provide a link and hopefully I can come back less clueless with more focused questions?

3) What version of Linux should I be loading on the CPU board? is it free?

4) Suggestions for required break out board, someone suggested Mesa 7196S, not sure if there is better or cheaper. I'm all ears?Image of my old custom control panel that I made for my RC mill quite some time ago.Thanks in advance
 

Hello everyone:
I've been disconnected from this topic for a few days but I haven't had time!!! remodeling at home!!! hehe housework.
Just yesterday I returned to linuxcnc, my ec500 hardware and the nema 34 closed loop stepper motors and DM860H drivers to perform a small closed loop test. I must say that I would have preferred motors with lower resolution encoders but all the closed loop motors from ebay and aliexpress have 1000 pulses or 4000 counts per revolution, another difficulty has been the voltage level of the encoders is 5V so I have used the free pins of the MPG port +/-WHA +/-WHB which are 5V tolerant (they are differential, something really good because all the closed loop motor encoders that I saw also have differential outputs), I don't know what quality level the differential driver connected to the MPG port will have, I haven't even looked at it, on the other hand, there are the basic configurations for the *.ini and *.hal files that Scott provides us, first I have done certain tests in open circuit and the motors truly reach incredible speeds, this is where I have found problems because the speeds in the sample *.ini file are of the order from 125 <-> 166 mm/s = 7500 <-> 9000 mm/min; which from my ignorance, depending a lot on the construction of the machines, it is quite difficult to reach these speed values, now the problems have been in terms of the relationship between speed and loss of steps since, for example, above 1500mm/min I lose counts in the encoder, my calculations would be the following, you can correct me if I'm wrong: for a spindle with a 4mm pitch it would be 1500mm/min / 4mm = 375 rpm, 375rpm/60 = 6.25rps and 6.25rps*4000 = 25000 counts/sec, which I already say from my ignorance seems quite little to me but I lose counts above this speed, otherwise it has been gratifying to be able to perform a closed loop control using Linuxcnc I was able to adjust the pid without problems, I have seen a pretty good video on the Youtuber size83 very well explained by the way and based on Remora's notes for a closed loop configuration.
Hello Scott, I have made some changes to the qdc module since I had not used the MPG port pins and I had incorrectly configured dir signal continues to occur, I tested your changes in the bugfix branch and I have not seen any improvement in this regard, then I will upload the *.ini and *.hal files since now I am from the phone.
I don't understand why the editor doesn't allow me to add a video, I did it a while ago and it worked, it doesn't matter, I'll leave you a link to the test video