I'm fairly certain that there are members on this board that can answer a stepper drive question.
I'm fairly experienced with closed loop servo drives systems, having installed and tuned up several styles over the years. Steppers are a different beast altogether for me, in that I can make them work, but frankly never really cared with the what and why, or how they work, as long as I could get them to do what I needed.
We're building a bunch of multirotor (autonomous aerial survey platforms) craft from FR4, and since I wanted to keep the crud out of our real machines, I assembled a small CNC router from an assortment of odds and ends, and slapped a Mach 3 control on it. It worked just fine with a 135 oz/in drive system, but was slow with a max rapid of around 70 IPM before it started to skip steps in rapid moves. I recently replaced the drive with a 460 oz/in set of steppers, thinking that the higher torque would gain me a faster rapid speed before I would see skipped steps. Both drives are configured as micro steppers with 2000 steps per rev, and with the ball screws, it works out to around 10560 steps per inch.
With the larger drives, I can still only go 70 IPM before I start skipping steps. My guess is that the torque is falling off at speed, so I'm just not gaining anything. The low end torque is insane. I can push against the gantry now, and it will slide me across the floor rather than skip steps, so the reliability should be better at cutting speeds. I'd really like to gain higher rapids though, since the drill cycles on the nest take forever.
Do I need to add gearboxes to help me achieve the higher rotational speeds on the ball screws, or is there another way to increase the rapid speeds and not skip the steppers.
Yes, yes, I know I can skip the steppers and go to a real drive, but Mach 3 doesn't support it, and I don't want to toss a chunk of $$$ at this until the project justifies the additional expense.
I do have access to a much larger router with a vacuum table that needs a new drive, and it would be a far better retrofit candidate.
Thanks,
Stu
I'm fairly experienced with closed loop servo drives systems, having installed and tuned up several styles over the years. Steppers are a different beast altogether for me, in that I can make them work, but frankly never really cared with the what and why, or how they work, as long as I could get them to do what I needed.
We're building a bunch of multirotor (autonomous aerial survey platforms) craft from FR4, and since I wanted to keep the crud out of our real machines, I assembled a small CNC router from an assortment of odds and ends, and slapped a Mach 3 control on it. It worked just fine with a 135 oz/in drive system, but was slow with a max rapid of around 70 IPM before it started to skip steps in rapid moves. I recently replaced the drive with a 460 oz/in set of steppers, thinking that the higher torque would gain me a faster rapid speed before I would see skipped steps. Both drives are configured as micro steppers with 2000 steps per rev, and with the ball screws, it works out to around 10560 steps per inch.
With the larger drives, I can still only go 70 IPM before I start skipping steps. My guess is that the torque is falling off at speed, so I'm just not gaining anything. The low end torque is insane. I can push against the gantry now, and it will slide me across the floor rather than skip steps, so the reliability should be better at cutting speeds. I'd really like to gain higher rapids though, since the drill cycles on the nest take forever.
Do I need to add gearboxes to help me achieve the higher rotational speeds on the ball screws, or is there another way to increase the rapid speeds and not skip the steppers.
Yes, yes, I know I can skip the steppers and go to a real drive, but Mach 3 doesn't support it, and I don't want to toss a chunk of $$$ at this until the project justifies the additional expense.
I do have access to a much larger router with a vacuum table that needs a new drive, and it would be a far better retrofit candidate.
Thanks,
Stu