What stepper motor should I use thread - Page 5

1. ## High torque (95nm) - not possible with stepper/gearbox?

Hi,

I'm new to your forum. My application is not a CNC machine (its actually a robotic arm), but you guys seems to be the stepper motor experts.

Our application needs a DC Motor (can be stepper or servo - does not matter to me). The output side needs to deliver at least 50Nm (preferably closer to 95Nm) at a maximum of 90rpm.

I typed these numbers into the calculator on the link provided, it just said - out of stepper range, look into servos.

Can a gear box be added? My reasoning is that with a 25:1 gearbox, I only need 4nM of torque since at the motor end I'll then get 4nM x 25 = 100nM) At 4nM the calculator suggested that "my system could be supported by a: Linistepper".

I also don't have a clue where to buy this locally - I just get Chinese suppliers when I google it.

Some guidance will be much apprecaited.

Ollie.

2. Originally Posted by ollie_oasis
Hi,

I'm new to your forum. My application is not a CNC machine (its actually a robotic arm), but you guys seems to be the stepper motor experts.

Our application needs a DC Motor (can be stepper or servo - does not matter to me). The output side needs to deliver at least 50Nm (preferably closer to 95Nm) at a maximum of 90rpm.

I typed these numbers into the calculator on the link provided, it just said - out of stepper range, look into servos.

Can a gear box be added? My reasoning is that with a 25:1 gearbox, I only need 4nM of torque since at the motor end I'll then get 4nM x 25 = 100nM) At 4nM the calculator suggested that "my system could be supported by a: Linistepper".

I also don't have a clue where to buy this locally - I just get Chinese suppliers when I google it.

Some guidance will be much apprecaited.

Ollie.
Hi,

For 50 Nm torque output, not many steppers can offer that much. Oriental Motor USA actually offer a hollow rotary table (driven by closed-loop steppers) that outputs 50 Nm with a maximum speed of 110 RPM. It's ideal for rotarting arms or discs. Mounting holes are provided right on the face of the table for easy mounting. For information on the product, click the link below:

Hollow Rotary Actuators

The product model that will do the job is DG200R-ARAA-3 (pulse-input type) or DG200R-ARAAD-3 (built-in controller, stored data type). The SCX11 universal USB/RS-232/CANopen stored program controller is also needed to provide pulses for the pulse input type products.

Your torque calculation of 100 Nm is assuming that you have a 100% efficient gearbox which is costly and difficult to do. Typically, standard gearheads offer much less efficiency.

Oriental Motor USA also offers a free motor sizing tool (registration required) to estimate your motor requirements:

Motor Sizing Tools

I hope this helps.

3. Hi Gibson22,

I'm with cncrouterparts.com and we have many luthiers as customers. The size stepper motor you should use is based on a couple factors. Machine rigidity is one to consider. If your machine isn't rigid enough to handle the speeds the larger motors are capable of, it isn't really worth the extra \$\$. If your machine is rigid enough for the larger steppers, a Nema 34 will remove twice as much material as a Nema 23 setup would in the same time period. So if you are using the machine regularly, it might be worth going to the larger steppers.

Cory

4. I would like to propose we use a free modeling tool that can deal with all the different designs and answers what if questions quickly and easily. http://visualsizer.com/ has a free professional modeling application that does it all as far as motor selection goes. i am not affiliated with them at all.

Visualsizer has the ability to use its database but more importantly it has a generic motor where any motor not in its database can be used for modeling.

It has a steep learning curve. We can here on the forum provide the basics for the inputs and answer the questions and we can even provide pre populated files for downloads. All the motion profile info can be supplied as generic info per axiz.

I have used the tool and can do a writeup of how to use it. We can discuss the fundamentals that is needed here in a point by point fashion and provide answers that are universal and can be directly entered as starting values. A number of files for download can be created, lets say for small medium and large tool sizes for mills and routers and what ever the community requires.

What say you?

Sent from my iPad using Tapatalk HD

5. ## Re: What stepper motor should I use thread

Hello CNC gods!
So I need some help, need to choose new steppers for my Gerber D200 router. X axis motor failed. Machine is used for hobby work only, so I'm trying to keep it to 100 EUR budget.
Also I think, I should change all motors.

Power supply: switching 30V home made, should handle at least 800W, can be easily modded to 40 volts, should I?
Ebay TB6600 drivers with some modding
Current motors M063-LS09 running in series mode
3.2V, 3.25A, 0.98Ω, 4.6mH, holding torque of single winding 115 Oz-In, holding torque of both windings 190 Oz-In.(Being a cnc newbie I have no idea witch one is actually used with micro-stepping driver. )
Torque curve in unipolar mode (max 150 Oz-In):

Rapid speeds: (figured it out by trial and error)
X:1500mm/min
Y:1000mm/min
Z:800mm/min
Y gantry weight about 30 Kg
X gantry weight about 10 Kg
Porter Cable router 1.2KW spindle with custom ER 20 chuck (God I hate Porter Cable, it was cheaper to buy ER20 MT2 chuck, give it to local machine shop to cut and thread and get full ER20 collet set, than get a single Porter Cable collet here in Europe.)
I'm looking for faster motors, but having limited knowledge, I came to conclusion that more torque not equal faster, but less inductance equals faster. Can't upgrade to larger motors due to space shortage.

Possible options:
1: Longs Nema23 3pcs Stepper Motor 23HS9430B 425oz in 3A Dual Shaft CNC Cut | eBay
Rate Voltage(V) 4.8
Rate Current (A) 3
Phase Resistance ( Ω ) 1.6
Phase Inductance (mH) 6.8
Holding Torque (oz.in) 425

2: UK Free Act 3pcs Nema23 Stepper Motor 23HS6620B Dual Shaft 185oz in 2A 56mm | eBay
Rate Voltage(V) 3.6
Rate Current (A) 2
Phase Resistance ( Ω ) 1.8
Phase Inductance (mH) 2.5
Holding Torque (oz.in) 185

3: 3pcs NEMA 23 Stepper Motor 1 26nm 2 8A 4 Wires 6 35mm Shaft DIY CNC Router Mill | eBay
Holding Torque 1.26Nm(178.5oz.in)
Rated Current/phase 2.8A
Phase Resistance 0.9ohms
Voltage 2.52V
Inductance 2.5mH

4:UK Free Act 3pcs Nema23 Stepper Motor 23HS8630B Dual Shaft 270oz in 3A 76mm | eBay
Rate Voltage(V) 3
Rate Current (A) 3
Phase Resistance ( Ω ) 1
Phase Inductance (mH) 1.6
Holding Torque (oz.in) 270

5:AU Free Act 3pcs Nema23 Stepper Motor 23HS8430 3A 270oz in 4LEAD Single Shaft | eBay
Rate Voltage(V) 3
Rate Current (A) 3
Phase Resistance ( Ω ) 1
Phase Inductance (mH) 3.5
Holding Torque (oz.in) 270

Having limited knowledge i'd go with option 1 or 5.

Thanks for help!

6. ## Re: What stepper motor should I use thread

Those rapids are pretty slow, so maybe just get the motors from Openbuilds. They are 175oz-in and I am able to get up to 5k rapids with 1605 ballscrews (48V supply, 3.5k on a 24V supply)

7. ## Help request: stepper accelerated wheel

Hello. I need to spin a 48oz wheel mounted to a stepper at 1200 rpm. Time required to achieve maximum acceleration is not critical. For example, 5 or 10 sec, etc., is fine. The assembly would be oriented horizontally (like a turntable), and the wheel would not be interacting with any other parts. I realize a regular motor would give the same result, spin wise, but I'd prefer to use a stepper for (undisclosed) control reasons. Any assistance you can provide in selecting the right sized stepper would be most appreciated. Thanks.

8. ## Re: Help request: stepper accelerated wheel

Originally Posted by Inexorable
Hello. I need to spin a 48oz wheel mounted to a stepper at 1200 rpm. Time required to achieve maximum acceleration is not critical. For example, 5 or 10 sec, etc., is fine. The assembly would be oriented horizontally (like a turntable), and the wheel would not be interacting with any other parts. I realize a regular motor would give the same result, spin wise, but I'd prefer to use a stepper for (undisclosed) control reasons. Any assistance you can provide in selecting the right sized stepper would be most appreciated. Thanks.
You need to measure the weight of the wheel, perhaps the friction of the bearing (if significant) and then apply the calculator below.

techref.massmind.org/techref/io/steppers.htm#Estimating Will help you estimate the combined size of the drivers, supply, and motors. It's NOT about the size of stepper /only/; its about the combination of driver, supply and motors /together/.

9. ## Re: What stepper motor should I use thread

hello

I read through this forum but to be honest my limited knowledge about the subject prevents me from understanding some of the terms listed and how to deal with them.

I built a 3m by 1.8m cnc machine and had it up and running until I decided to upgrade my 700W spindle motor to a 3.5kW one complete with a VFD.

The problem I'm facing is that my carriage now weighs about 14KG (about 31lbs) and my openbuilds NEMA23 motor cant lift the spindle anymore for Z-axis movement. X and Y axes still work fine, both are also using NEMA23s.

The Z axis holds the spindle motor and drops it fine but cannot lift it, i can lower the spindle motor and keep it still but cannot get upward movement, when I try it just tries to spin upwards but ends up slipping downwards.

What I want to know is if I upgrade to a NEMA34, will I be able to fix this? Do I need to upgrade my driver as well for this stepper? I'm using a 24V power supply with 36amps capacity and this driver from amazon couple onto an arduino uno.(Witbot CNC Shield Expansion Board V3.0 +UNO R3 Board for Arduino+ A4988 Stepper Motor Driver With Heatsink Kits for Arduino)
https://www.amazon.com/Witbot-Expans...bot+cnc+shield

10. ## Re: What stepper motor should I use thread

Originally Posted by mokhabarat
hello

I read through this forum but to be honest my limited knowledge about the subject prevents me from understanding some of the terms listed and how to deal with them.

I built a 3m by 1.8m cnc machine and had it up and running until I decided to upgrade my 700W spindle motor to a 3.5kW one complete with a VFD.

The problem I'm facing is that my carriage now weighs about 14KG (about 31lbs) and my openbuilds NEMA23 motor cant lift the spindle anymore for Z-axis movement. X and Y axes still work fine, both are also using NEMA23s.

The Z axis holds the spindle motor and drops it fine but cannot lift it, i can lower the spindle motor and keep it still but cannot get upward movement, when I try it just tries to spin upwards but ends up slipping downwards.

What I want to know is if I upgrade to a NEMA34, will I be able to fix this? Do I need to upgrade my driver as well for this stepper? I'm using a 24V power supply with 36amps capacity and this driver from amazon couple onto an arduino uno.(Witbot CNC Shield Expansion Board V3.0 +UNO R3 Board for Arduino+ A4988 Stepper Motor Driver With Heatsink Kits for Arduino)
https://www.amazon.com/Witbot-Expans...bot+cnc+shield

Second, using an A4988 with a NEMA 23 motor tells me the driver, not the motor, is probably the issue. In other words, just upgrade the driver and it will probably start working just fine. My adapter and THB6064AH kits would be a perfect fix IF you can solder an electronics kit together. Otherwise get a TB6600 (hopefully not from eBay / China) or a DM542a or something like that. DO NOT buy a TB6560 (shudder)

But finally, the much easier fix is this: Add antigravity. Meaning, add a rope from the top of the Z axis, up over a pulley, down to a weight which is the same as the weight of the spindle motor. Or add a long spring with about the same force. The extra weight may reduce your acceleration on the X and Y axis, but it will solve the Z problem.

11. i'm sorry i didnt mean to hijack a thread, i just thought this might be the appropriate place to post!

Thank you for your reply. i will definitely try the antigravity hack!
as for using a different driver, can i get the inputs for the new driver from the A4988 outputs? just wire that driver to the new driver? if I can't then would I have to change the drivers for the other motors as well and get their inputs directly from the arduino board? since the driver I'm currently using plugs directly into the arduino and as far as I know its outputs have a higher voltage and amps than the pulse signals going in which will probably fry the new drivers if plugged in directly right?
Originally Posted by James Newton

Second, using an A4988 with a NEMA 23 motor tells me the driver, not the motor, is probably the issue. In other words, just upgrade the driver and it will probably start working just fine. My adapter and THB6064AH kits would be a perfect fix IF you can solder an electronics kit together. Otherwise get a TB6600 (hopefully not from eBay / China) or a DM542a or something like that. DO NOT buy a TB6560 (shudder)

But finally, the much easier fix is this: Add antigravity. Meaning, add a rope from the top of the Z axis, up over a pulley, down to a weight which is the same as the weight of the spindle motor. Or add a long spring with about the same force. The extra weight may reduce your acceleration on the X and Y axis, but it will solve the Z problem.

12. ## Re: What stepper motor should I use thread

Originally Posted by mokhabarat
As for using a different driver, can i get the inputs for the new driver from the A4988 outputs? just wire that driver to the new driver?
The adapter and driver I linked two would exactly replace one of your drivers. You unplug the little A4988, and plug in the adapter, then the other end of that cable connects to the new driver. You wire the motor, and motor power, directly to the new driver and away you go.

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