Slaving axis (rotating nut, 2 steppers for Y-axis)

@ Todd Zuercher
Hello Todd,
I hope you can help me out.
The main frame is finished and today i leveled the frame with epoxy, so now i have to wait about 7 days until i can start to build the gantry, but i would like to order the electrical parts like steppers(nema23 425oz or 566oz), drivers (Leadshine AM882), power supply (4x 80V 5A) and brakeout board (for testing it will be an cheaper brakeout board but not an chinese one - later i would order the mesa 5i25+7i76).

You said, if i want move at 10m/min with the 2505 ballscrew, i have to rotate the nut with 2000rpm. I used some calculators to check which stepper would be the best, but only with one stepper (3.1nm, 8wire parallel connection, 4.2A at 80V) i got 984rpm (i looked for an stepper with low Inductance)

So, i would need to use an 1:2 ratio to rotate the nut at 2000rpm, but then i have only half of the torque and fear that it will stall when moving (not cuttin) the gantry (will weight about 150kg)

Is that my only option to go for 1:2 ratio with steppers?

I havent bought the 2505 ball screws for the long axis yet, but i have already bought an HIWIN 2005 for the gantry, and it cost me about 150€ with the Nut.
Would not like to sell it and loose some money, but is that my only option? I think with Servo motors the 05pitch wouldnt be an problem, but they are pretty costly..

I dont need to cut at 10m/min, but for positioning etc. it would be great to achieve that speed.

Hope there is some solution.

Thanks in advance!

No eBay APP ID and/or Cert ID defined in Kunena configurationThis isn't necessarily a recommendation just an example of what you can find if you let google be your guide.

Please remember these sorts of no name Chinese knock off components can be of questionable quality, abysmal documentation, and little if any support (read this as "you are on your own sucker" after you buy it.)
Not that they can't be adequate, and serviceable if you understand or can figure out how to use them.

If you feel you may need support to make your setup work (in other words you don't know what you are doing) spending 2x or more for a product from a reputable company, with support in your native language (or better yet in your own country) can be money well spent.

Thanks for your quick reply and help!

I knew about servo motors (still thanks for it), but that will cost too much and much more then to replace the one 2005 Hiwin screw.
I would update to servos in future if the router will make some money, but for now, i think that is nonsense even if the speed would put some smile in my face .
I think then it makes more sense to sell the 2005 and buy the 2010 screw and 2510 for the long axis (thank god i havent bought them already).

Sad that there are no stronger stepper motors like nema34 8.7Nm, which can go over 1000rpm and still have some torque left for fast acceleration, because then i could use 1:2 Ratio, but i think with nema23 425oz that would not work well at 10m/min, or do you think they will handle it to move the 150kg gantry without stalling ?

The problem with steppers is that they have great torque at low speeds (aka stopped) but it dropps off quickly the faster they turn. And the problem gets worse the larger you make the motor.
Have you looked at the torque curve for that your NEMA34 8.7Nm motor? By about 500 RPM it has probably lost about half it's torque and is dropping fast. Don't be fooled by the logarithmic RPM scale many marketing people like to use to show their torque curves on. While most servos can usually provide their rated torque throughout their operating range. And servos don't require the large safety margin of excess torque that steppers need to ensure no lost steps.

Thanks Todd.

Yes, i have read about the low rpm and low torque on higher speeds on big stepper motors.

Today i called the shop where i bought the 2005 ball screw and asked if i can change it to an 2510 hiwin ball screw. They said its not an problem if the ball screw and nut havent been used and opened. I havent use or opened it so i will replace it and then i will have no problem to achieve +12m/min. with 3.1 steppers.

Just one more question: I have read about 2phase and 4phase stepper drivers, but does that mean that 2phase stepper drives works only with 2phase stepper motors (4wires) ? Sorry for the "maybe stupid" question, but this information i find on almost all stepper drives, but couldnt find any information when googling it.
I would like to buy 3.1nm stepper motors with 8 wires and connect them in parallel, but if 2phase steppers (e.g. DQ860MA from Wantai - cheaper but good reviews) works only with 4wires steppers then i have to buy the Leadshine AM882 Digital stepper drivers (more expensive, but very good reviews).

You can use 4,6 and 8 wire stepper motors with wantai drives. You can not use 3,5 or 10 wire stepper motors.
There are 2, 3 and 5 phase stepper motors, 4 phase is refering to 2 separate windings for each phase.