Hi Dean, I've been using imported stepper motors and drivers (the type you find cheap on eBay) and have been very happy with them. They have generally much more robust designs than the older high dollar industrial controls, and they're much smarter. The new stepper motor controllers have microcontrollers with more complicated algorithms that not only implement some of the design robustness, but also other nice features such as the aforementioned quieter operation. You might also see faster acceleration and/or faster max speed step generation without missing steps.
Whether using servos or stepper motors, a good case can usually be made for buying an old machine, stripping 15+ year old CNC electronics and installing new electronics. Add LinuxCNC and it's an easy way to upgrade a good old machine (good iron) to be much better than it was when new. Upgrading electronics is an obvious choice when the old electronics have already failed and are prohibitively expensive to replace, but I think it's a worthwhile investment in longterm reliability even if the old electronics are still working... for now. If you want to be proactive on the remaining Parker drives, sight unseen, I'd generally recommend opening them up, cleaning the printed circuit boards, and replacing the electrolytic capacitors. Those are the components most susceptible to age related failure. If you want to attempt an inexpensive rebuild of your old Parker drives without being an electrical engineer, I'd replace all of the electrolytic capacitors and then replace any semiconductors that are charred. :-) Typical damage occurs to large power transistors near the outputs. From my experience, that's the repair technique often used by the aging CNC repair specialty shops. Good luck, Bruce On 02/08/2015 11:40 AM, Dean Posekany wrote: > A little background : > > About six years ago, as I was just starting to design my shop-built > gantry machine, I came across a SUPER deal on Ebay for six sets of drive > components. Each set included a line filter, Parker OEM300 75V, 7.5A > power supply, Parker OEM750 stepper driver and a stepper motor. I didn't > know a whole lot about this stuff a the time, but I knew it was a deal I > couldn't pass up. So, they became the drive system for my CNC build. As > it turned out, only five of the six drivers worked. Thas wasn't a > problem (especially for what I'd paid for them) because my gantry is > only (at least for now) a 3-axis machine. But, six years later I've lost > two additional OEM750's and I'm now running on my last three. Another > failure and I'm down and its decision time. > > Here's my question for the worldly experience of the group. I'm retired > and this is a serious hobby machine and I don't have a great deal of > money that I can throw that this. So when the inevitable failure of the > next stepper driver occurs, what would you do? Repair the OEM750 > (~$280)? Or would you look at replacing the Parker hardware with > something else like Gecko or maybe go the Mesa route? I've really been > pleased with the stepper performance I get from the Parkers and the > software stepper generation that Linuxcnc gives me is more than fast > enough for the work I do. The repair is expensive and the drives were > released in 1997. So they're 18 years old. I just don't have enough real > world experience with this stuff to feel like I can make a good decision. > > If it was your problem, what direction would you go? > > Thanks in advance for your thoughts. > > Dean > > ------------------------------------------------------------------------------ > Dive into the World of Parallel Programming. The Go Parallel Website, > sponsored by Intel and developed in partnership with Slashdot Media, is your > hub for all things parallel software development, from weekly thought > leadership blogs to news, videos, case studies, tutorials and more. Take a > look and join the conversation now. http://goparallel.sourceforge.net/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ Dive into the World of Parallel Programming. The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
