[Spencoid1]

My home built CNC router that I have been using for years burned out one of the servo motors driven by Gecko drives.
I decided to try one of the motor driver encoder integrated units. I am trying to get a motor from Steppersonline number ISV57T. It is probably made by CMs? The documentation and tuning tools are not at all good. I have downloaded two softwares one of which does not work at all. The other works but the parameters are quite different from those of most motors for which there is a fair amount of videos etc online. Nothing I can find for this particular motor and Steppersonline is not being very helpful

I was able to get some parameters adjusted and quieted oscillations and have good rigidity.

I have the new motor on the X axis but the old motors still on the Y and Z (waiting for more motors)

The problem is that I am not getting round holes unless I turn the acceleration (in Masso) way down to the point that production suffers.

Any hints on what parameters are responsible for acceleration? It is my gess that the new motor does not accelerate as fast as the old ones so if Masso is not slowing them all way down the new motor lags behind. Position accuracy with slow acceleration seems fine although the tool they provide shows instantaneous position accuracy as being really bad. Again the software sucks so it is difficult to know exactly what it is showing. It shows two different values on the Y axis of the scope view and some symbols are overlapped and difficult to read.

[adidoro]

I just found those integrated servo motors on Steppers Online, NEMA 23 Integrated Easy Servo Motor 180w 3000rpm 0.6Nm(84.98oz.in) 20-50VDC Servo Motor aka iSV57T-180S.
Are they good? Have you tune your motors?
I'm tempted to give them a try, have anyone else tested those motors?

[joeavaerage]

Hi,
do you suppose there is a reason they are so cheap?

If you have not had any experience with servos then these cheap ones are likely to give you trouble to set up and use.

Better servos have setup and tuning software that helps immensely.

I'd recommend Delta (Taiwanese made in China) or DMM (Canadian made in China) as good quality, documentation, support and most importantly
setup and tuning software.

https://www.fasttobuy.com/220v-127nm...ol_p28069.html

Craig

[adidoro]

Thanks for replying Craig.
470 for 1 motor with driver (included shipping) is to much for what I afford.
I have no experience with servos whatsoever.

[joeavaerage]

Hi,
yes, the downside is the cost. Delta and DMM cost 25% more than the run of the mill Chinese made stuff but still half or less, than Yaskawa.

Unfortunately, most of the cheap Chinese stuff has no setup software and the documentation is hard if not impossible to understand.
I don't have any reason to doubt they work well enough, its just that they can be such a battle to program if you've not done it before.

The 750W Delta B2 model is only an extra $40 more than the 400W one I linked to, so I buy those, I mean who doesn't twice the power for only just a little bit more?
They cost $438, and shipping to New Zealand another $150.....but they sure kick arse! With the setup software programming and tuning take minutes at most.

Craig

Craig

[adidoro]

Hi Craig,
Indeed, I didn't say it's not worth the money, I just not afford them and for my old DIY CNC that upgrade with 5 motors will triple the total cost at it was made.
Also the NEMA 23 size fit the NEMA 23 steppers that I want to replace with.
Maybe I will try with 1 motor at first, like Spencoid1 did and if it's not good for that, I will not lose a fortune.
Yet I am not sure I will do it. Expected more people have tested those motors before and give us some feedback.

I'll ask you as I have never had experience with servos before, how good are to hold position compared to steppers?
I'm thinking at Z axis, and mostly for rotary axis. Do I need to consider brakes for them?

[Vlod]

I’ve got 8 NEMA 34 Vevor hybrid servo steppers with drivers last year from Amazon. Couldn’t resist for $65 a set.
So far so good. I didn’t do any drivers tuning just plugged them in and it works fine for more than a year now.
I did have similar problems with round holes and cutting side top corner of the hole on exit - actually advise was to increase acceleration. I have increased acceleration more than twice and it worked great for me.

[joeavaerage]

Hi,
the main advantage of servos is speed.

A 23 sized stepper say 100mm long may have a holing torque of 600 oz.in, which is pretty good, but it will fall off the faster it goes, down to typically 75oz.in at 1000rpm.
A 23 sized servo of say 100mm long maybe have a holding torque of 150 oz.in but will still have 150oz.in torque at 3000rpm.

So the stepper actually has more torque a slow speeds, or more holding torque when stationary than the same sized servo. Steppers have no overload, if you overload a stepper
it just stalls...end of story. A servo will have three to four times its continuous rating as a temporary overload. So the servo above may have a temp overload of 600oz.in, making
the same as a stepper, but only for a few second at a time.

The real advantage of a servo happens at over 500rpm, when a stepper stalls and just runs out of puff a servo just keeps on keeping on. The temporary overload feature means that
servos seem to outperform the rating on the outside....in fact they eat steppers alive!

Since building my new machine where I used 750w Delta servos, I have not bought, nor will buy another stepper ever again. Servos are way more expensive....but in my opinion just that much
better that I will pay the extra.

I know the problem of wanting something but just not being able to afford it....been there done that, and still many times am in that situation. In that case I just do the best I can afford....I mean
what else can you do?

Craig

[joeavaerage]

Hi,
the manufacturers of closed loop steppers will tell you they are faster, more powerful, never miss a step...etc all BS.

A stepper is a stepper and loses torque the faster they go, a closed loop stepper is no better. If a stepper is marginally overloaded and misses a step the drive will insert an
extra step to catch up...but guess what....the extra step is just as likely to be missed as any other. A closed loop stepper will do its best to keep up and sometimes those extra steps
work....but sometimes they do not.

Closed loop steppers do have greater step interpolation than open loop steppers and will fault out if it gets too far behind.....but you are paying a significant premium for those rather
limited gains. Vlods steppers are very good value....and probably worth while, but well chosen and spec'ed open loop steppers will do just as well and for less.

If you really want closed loop performance servos are the way to go.

Craig

[Vlod]

No argument there, servos are way better performing.
On the other hand - do you really need them on home built cnc router considering the price. I guess it depends on expectations.

[adidoro]

Hybrid steppers are not servo. Those motors are steppers with encoder feedback so will hold position like old steppers motors.

[adidoro]

No argument there, servos are way better performing.
On the other hand - do you really need them on home built cnc router considering the price. I guess it depends on expectations.

Servo motors I asked on this topic are not expensive.
On my DIY CNC when I do larger parts 50% of time is wasted on slow travers speed. If I chose a microstep that can allow more speed and torque it will vibrates at low speeds.

[adidoro]

I have just ordered one of these cheap servo for 120$ with DHL Shipping. I will post back when I receive it and make some tests for tuning and installing on my CNC.

[adidoro]

A 23 sized stepper say 100mm long may have a holing torque of 600 oz.in, which is pretty good, but it will fall off the faster it goes, down to typically 75oz.in at 1000rpm.Craig

That is valid for a stepper only in full step mode, that holding torque will drastically drop in microsteping.

[joeavaerage]

Hi,
the holding torque for a stepper is between fullsteps. As it turns out the torque between half steps is as good and in some cases better. So it is entirely reasonable
to consider the full holding torque to be available at 400 steps/rev.

Lets say you have selected an eight microstep regime, ie 8 microsteps per full step or 1600step per revolution. The torque between adjacent microsteps is approximately
1/8 of the holding torque. Lets make it simple and say the the Holding torque spec for this motor is 800oz.in. Thus between step '6' and step '7' you might expect a torque of 100oz.in.
Lets now also assume that 100oz.in is just not able to move the load....so the load remains where it is, you might say the stepper has 'missed a step' but then you issue another step
so the stepper is commanded to move to step '8', and it is at step '6' at the moment. The torque is now about 200oz.in, which may well be enough to move the load. Eventually if the load does not move
you will get a situation where the stepper is lagging 4 microsteps or 1/2 a fullstep. At that time the full holding torque will be applied and the load will almost certainly move.

It is for this reason that microstepping does not result in the increased precision and resolution that most imagine microsteppeing does. In fact 1/2 stepping is about as good a reliable resolution
as a stepper can get. Microstepping does not therefore result in increased resolution, or at least any better than 1/2 stepping, but it does result in increased smoothness of motion.

Indeed in the early days of steppers it was astronomers that invented microstepping, no doubt trying to get increased resolution, but even if they were thwarted in regards to resolution they got smoother motion
which they greatly value so as the motor does not jiggle their telescope.

Craig

[adidoro]

Hi,
the holding torque for a stepper is between fullsteps. As it turns out the torque between half steps is as good and in some cases better. So it is entirely reasonable
to consider the full holding torque to be available at 400 steps/rev.
Lets say you have selected an eight microstep regime, ie 8 microsteps per full step or 1600step per revolution. The torque between adjacent microsteps is approximately
1/8 of the holding torque.
Craig

Exactly. I should specified about holding torque in no motion when the motor need to hold that position, in microstepping is dropping that holding torque. So the myth about stepper is good at holding position is only valid in full step mode, in microstepping will not have that holding torque when not moving.

[mactec54]

I have just ordered one of these cheap servo for 120$ with DHL Shipping. I will post back when I receive it and make some tests for tuning and installing on my CNC.

You will not get much from a 180W servo motor, if your machine is small and light weight then it may work for you, but don't expect much from 180W servo motor you will most likely have to do a gearing of 2:1 or more

[adidoro]

You will not get much from a 180W servo motor, if your machine is small and light weight then it may work for you, but don't expect much from 180W servo motor you will most likely have to do a gearing of 2:1 or more

Well, received the motor yesterday. Fortunately my old USB to RS232 didn't work to tune the motor, so I was forced to place it on my CNC and give it a try.
About expectations, I expected to move my axis with 15000mm/min (590in/min) because 3000 rpm with 5mm ball screw give me that number and it did.
Before with stepper motor 3A 60V I was able to move that axis with 2500mm/min without losing steps. Was set on 1600 microsteps.
The servo at default configuration is on 4000 pul/rev so it is now at 800pul/mm resolution. I also increased the acceleration from 200 (as it was for stepper) to 1000 and working great.
I just tested a loop 100 moves length of travel max of my X axis (540mm) and performed well at max speed.
Also compared to stepper is pure silent without noise and vibration.
Over all I'm happy with it, so I ordered 5 more motors for all of my axis and USB to RS232 cable for tuning.
I forgot to mention the advantage being nema 23 size for easy replace and integrated driver = less wires (less problems)
That is for now, after upgrade all my motors and maybe fine tune the servos, I will come back with more details.

[hoochiekoo]

Hey adidoro - any updates on iSV57T-180S? I am also considering replacing my steppers (that are just not doing the job on by 48"x30" gantry router) with these but... It seems too good to be true and there's precious little information online from real world users (except some videos on it being used for driving a lathe leadscrew - nothing on CNC application). How's it working for you (now, some 6 months later)? Holding up? Did you end up using the RS232 cable to reprogram any parameters (if so - what and did it help)?

On one of the YT videos - a guy seems to demonstrate that it doesn't have all that much standing torque (it keeps coming back to position but it seems it's kinda "soft" at holding it). Does it work ok for Z axis (propping up a hefty spindle)?

Anything you care to share would be appreciated - like I said, I'm really thinking of pulling the trigger on this but... Can't find much information about them from (CNC) users... Thanks!

[adidoro]

Hey adidoro - any updates on iSV57T-180S?

For now I am happy with the motors as a replacement for my old steppers.
I did use the cable for tuning the motors, but nothing special, just the auto tune to determine the inertia of each axis, and worked well.
They don't hold position well with a pulley like in that YT video, but on the ball screw after tuning, I can't rotate the ball screw with my hand and it's holding the position. I have a Z axis that goes down by itself because of weight on power off and this servo can hold and move with speed and precision this axis too.
For rotary axis with a 2:1 pulley reduction didn't work, can't hold the position. Maybe with a larger reduction...
In conclusion for linear axis where there are ball screws, I'm happy with the motors and they are a good replacement of stepper motors, for that price. They run smooth with more speed and acceleration than a stepper. You just need to change all of your motors, don't combine them (stepper on one axis and servo on other) because you risk to run into original poster problems.