800X800 Build - Little to no knowledge of what I am doing…

[JAZZCNC]

While I wait for a few deliveries I am starting to think about motors and controllers. I do not fancy trying to sort out an Arduino, I have looked at the Openbuilds Black Box controller, Duet 2/3 but the Spark Concepts xPRO V5 looks like a good choice for plug and play.

None of the above is my replay. All of them are a bad choice for a good router, ok for a 3D printer may be but for a router then I wouldn't touch them for a number of reasons.

#1 They use USB which is flaky and unreliable. Ethernet is the only way to go if you want a reliable router.
#2 They use GRBL control software which again is ok for 3D printers etc but for a router, there are much better and easier options.
#3 The drives are inbuilt and weak, if one goes down you lose the whole board.
#4 The all-in-one solutions often suffer from heat issues which shortens life spans
#5 The all-in-one solutions can be limiting on upgradability and they are not much easier in respect to wiring than separate components so the Plug n play aspect is a bit of a gimmick.

How do I figure out what size stepper motors to use? I have allowed for Nema 23 brackets but I don't know what torque I need, from what I understand bigger is not always better… I am using 1610 ballscrews all around and the gantry weights around 35kg without the spindle.

Don't fry your brain trying to work out motor sizing etc, you don't need to reinvent the wheel as it's all been done before by 100's on the forum so just go with what works for a router this size, which is 3Nm to 4Nm NEMA 23 or 24, they are both the same bolt spacing only the outside dimensions are different, 23=57mm 24 = 60mm.

However, the key to a good machine is not just the Nm rating of the motor but the inductance of the motor and PSU voltage plus the quality and type of drives you use. This is exactly why the above All-in-one setups are less than ideal for a router as you'll see when read further down.

The drives and voltage used are key to performance and reliability. Stepper Drives come in 2 main types Analog or Digital.

Analog drives are old technology and best avoided for several reasons which mostly revolve around how they handle resonance which can cripple the performance of a stepper motor.
Digital drives are far superior in how they handle resonance and current, this results in much smoother running motors and more power across the speed curve. This really is a night and day difference and can't stress how important it is to avoid analog drives.

Next up is PSU and drive Voltage, Voltage is the key to speed and torque from a stepper motor and for best performance from a typical 3nm or 4nm stepper motor, this is around 60Vdc, however, because of how steppers work they effectively become dynamo's when de-accelerating so when sizing stepper drives you need to leave a safety margin of about 10% on the Max voltage the drives can handle.
So if running 60V PSU then you need drives with a max voltage of 70V.

This is exactly why Bigger isn't always better and why often a Nema23/4 motor will outperform the same size or larger Nema 34 motor when running the same voltage. Large motors have much higher inductance and in a nutshell, this means they need much higher voltage to get the same performance as a smaller motor. The mistake new users nearly always make is running too low voltage with large Nm high inductance motors.

This is also why the All-in-one controllers with inbuilt drives are not good for routers running NEMA 23 motors in the 2nm to 4nm torque range, even if they say can handle 6A motors.
Because they only run on 24Vdc they can't possibly give the performance because without the volts they can't push the current through the motor's windings unless the motors are very very low inductance. Like I say for 3d printers which are using Nema17 size or less which have very low inductance they are ok, but for a good router, they are useless.

Now, stepper technology in the last few years has transformed, and now the BEST by a long way and not much more expensive than a standard stepper system is the Closed-loop stepper system.
These use digital drives with advanced electronics that connect to a stepper motor which is fitted with an encoder on the back which monitors the position and feeds this back to the drive which corrects for any positional error and if the error goes out of a set range sends out a fault signal.

IMO this is the only way to go these days because the difference in price between a standard stepper motor/drive setup and a Closed-loop system is not very much and they are light years better.

Controller wise then Ethernet-based controller is the only way to go if you want high reliability and best performance. USB is flaky and easily affected by electrical noise and I wouldn't touch it for a router that runs high-frequency spindles etc.
Likewise, GRBL based control software which requires G-code senders, etc are a faff about and are often not optimized in how they calculate cutting trajectories, etc which gives smooth motion and performance.
Compared to dedicated control software and hardware combinations like UCCNC software with an AXBB-E controller they are positively still in the stone age.

All these things work together to give a balanced machine, get one wrong and the machine will be compromised in some way, get a few wrong and you can easily cripple the performance.

Often (99% time) it's a false economy trying to save money with All-in-one or cheap kits as they are just not very good and the upshot is eventually you end up ripping them out and starting again. Bite the bullet and do it right the first time and you'll save money and a lot-a-lot of stress.

The setup I would recommend and actually fit on machines I build is this below. ( I can also supply these if you decide to take this route)

AXBB-E ethernet controller with UCCNC software.
4.5NM Lichuan Closed loop stepper system with 70Vac drives.
60Vac torodial transformer

This setup combined with your 10mm pitch screws will give you first-class performance and reliability/repeatability. With velocity well in excess of 10mtr/min and provided the machine is constructed correctly with a suitable spindle will easily allow you to match correct cutting parameters for most tools and materials, which wouldn't be the case with a lesser setup.
Not cutting correctly results in poor tool life, broken tools, poor finish quality, and lost material when the shit hits the fan not to mention the all-important loss of time doing it all again. Proper hair pulling stuff is avoided which all add's to the savings and hair long term.

Trust me on this don't rush out and buy the first thing that looks easy or cheap because it won't be it never works out well. Even If you can't afford the correct components, wait and save up until you can, don't be tempted to buy rubbish just to get it up and running.!. . . You will regret it, I've seen it time and time again.