The Best Steppers/Servos Setup Thread

[m_c]

I'm guessing all the leadshine and other Chinese AC servos on ebay are naff?

Some of them are perfectly good. Kinco is Chinese. Leadshine is good.
The big thing is making sure whatever you buy will do what you expect it to, and comes with reasonable documentation.

[Skiprat]

I bought a full set up of hybrid closed loop stepper motors and associated drivers etc (Purelogic and leadshine) from Zappautomation a few years back and have had nothing but praise for the setup and zappautomation.
Closed loop does exactly what i wanted and i think i oversized the hybrid steppers but at least i can sit on the machine and take a ride...obviously only done under the influence of alcohol ..

Tommy

[andy_con]

there are lots of things like this over ebay

http://www.ebay.co.uk/itm/CNC-AC-Ser...gAAOSwMgdXyS7x

and even cheaper stuff??

http://www.ebay.co.uk/itm/EU-Stock-N...4AAOSwoBtW58KV

I don't mind spending a few quid to get good results

[m_c]

there are lots of things like this over ebay

http://www.ebay.co.uk/itm/CNC-AC-Ser...gAAOSwMgdXyS7x

and even cheaper stuff??

http://www.ebay.co.uk/itm/EU-Stock-N...4AAOSwoBtW58KV

I don't mind spending a few quid to get good results

750W would be overkill for a Triac. I'd aim for 200W, or maybe 400W.

The second link is actually a closed loop stepper system. Technically it is servo system, however it won't have the same performance as what's more commonly referred to as a servo system.

I had been hoping DaveK would of chimed in with his views on the generic Chinese servo systems, but I guess he's too busy playing with his new toy...

[Davek0974]

Hi all,

I got my servo's from AliExpress direct from China, they are fitted to a Bridgeport mill(ex manual style machine) I got 700W on X&Y and 400W on Z.

Having only used steppers until this job, i was not expecting them to be as good as they were as the Nm figures do not compare with steppers at all. I used a CSMIO IP-A with 10-0-10v control.

The issues i had/have are all tuning related really - the manual i was sent by the guy was in strong Chinglish so not really much use to a beginner like me. To get a really good tune i am convinced i need to alter the parameters in the drives but cannot do this.

The tuning in CS Labs plugin is all i have so worked with that. It is a time consuming process, forget the auto-tune ;) Apart from a slight resonance on the Z drive I have it running really well now, very little following error and good acceleration, top speed is pretty low at 2500mm/min but this is only an old Bridgeport so no point in flogging her to death. Acceleration was more important to stop corner-rounding in Mach 3's trajectory planner.

I must admit that i had the 400W on the bench to play with and even running at maybe 5 rpm i could not stop the shaft rotating no matter how hard i grabbed it, the torque is phenomenal and start / stops at speed are sharp enough to make the motor jump off the bench!

I could probably have fitted smaller motors on the mill, they have 2:1 reduction drives but this size seemed a good price :) I think they were about £400 for 700W with drive and 5m cables.

I would love to fit them to the plasma cutter, may do one day.

[JAZZCNC]

The issues i had/have are all tuning related really - the manual i was sent by the guy was in strong Chinglish so not really much use to a beginner like me. To get a really good tune i am convinced i need to alter the parameters in the drives but cannot do this.

Ok I've been watching and stayed out of this until now because don't have any experience with Triac's or there power requiements but need to make this clear to defend chinese servos.
Dave I'm not having a go at you so please don't take it this way just want to point out for sake of others that the parameters can be changed in the drives to give better tuning. Yes it's fiddly process with lots of parameters and the Chinglish manual doesn't help or make it simple but this is why they are so cheap.
If folks want simplicity in tuning then buy branded name but expect to pay the same amount of money for one axis as you would 3 axis worth from China and still have spare change.!

To the OP.
In terms of performance then servos are no comparison to steppers in most cases. However that doesn't mean Servos are always better for the application. IMO for DIY level Mill or router then steppers are perfectly fine. Much simpler with far less hassle for not lot of money.

I can tell you with absolute confidence because I fit both on nearly all machines I build that the AM or EM drives give excellent performance which I've yet to see beaten for the money. Reliabilty so far after fitting good few hundred has been 99.9% with only one none starter. By that mean never had one fail in use and only one which didn't work out of the box.

The Cslabs Controllers are Top notch which ever you use and again you won't get better.

Regards Steppers then provided you buy ones with sensible spec in terms of inductance etc then they all pretty much work the same.

What I will say is that on Denford and Boxford router conversions I've done where all has been replaced with New steppers, AM882 drives and Cslabs controllers the performance difference is Night and Day turns the machine into different animal.

[Davek0974]

No worries Jazz, i fully realise that you get what you pay for :) All it needs is a knowledgeable person to identify the Pid parameters in the manual and sort out what does what :) Trouble is they dont even call them Pid :)

One drive not mentioned yet is the hybrid stepper-servo - a stepper with an encoder mounted and a suitable drive. I nearly fitted these on the Bridgeport but fell for servo's instead. They do sound interesting though.

[Zeeflyboy]

I bought a full set up of hybrid closed loop stepper motors and associated drivers etc (Purelogic and leadshine) from Zappautomation a few years back and have had nothing but praise for the setup and zappautomation.
Closed loop does exactly what i wanted and i think i oversized the hybrid steppers but at least i can sit on the machine and take a ride...obviously only done under the influence of alcohol ..

Tommy

I'm also running closed loop leadshine steppers and drivers, very happy with them.

[andy_con]

so these?

http://www.ebay.co.uk/itm/CNC-Leadsh...EAAOSwsN9XA89p

[Zeeflyboy]

Yes, looks to be the same as what I'm using.

They are nice, work great for me... but then I've never used servos so can't comment on that front. Even if you just view them as normal steppers they are a good (if not the cheapest) option in my opinion, they are quite literally plug and play with no tuning required at all and are very quiet, smooth at all speeds, stay very cool in operation and have the must-have features such as stall detection and error signal.

It was quite fun playing around with the closed loop system before installing them. You can fit a coupling to the shaft and then try to prevent it from rotating as an experiment. Long before it will throw a fault and disable the drive, you can see a sort of rubber band effect.... where a normal stepper would have thrown steps, these keep trying to fight you and then just ping back into place once you release them.

In theory the closed loop stuff also has better torque curves, acceleration and speed due to the controller having a better idea of what position the motor is actually in, along with higher efficiency and lower noise.

Edit:

Quite an interesting read on closed vs open loop steppers where they've actually done some lab testing http://www.motioncontroltips.com/tor...epper-systems/