i thought these forums were set up to help people, o replies
well it look like i am on my own and not even a welcome to the forum
Hi to everyone on the forum
i hope i can make sense with my questions because until a month ago i did not know anything about cnc but have learnt a small amount since and i am looking to learn more.
i have a large frejoth turret mill that i have had for 15 years but recently it has a worm gear and bevel pinion damaged and now has no feed so rather than scrap a good mill i decided to look at converting it to cnc, i understand that most people would say just buy a cnc machine instead of retrofitting a knee mill but i don't want to scrap it ,also i am a electrical fitter mechanic of 35 years with a lot of time spent in a machine shop so the hardware fitting servo motors and making drives is easy for me and have a lathe as well and i love a challenge.
The things i would like help on is what size and specs of servo motor would i need and if any of the chinese servo motors and drivers are any good if so which ones.
Also what would be the best choice for a motion controller considering it is going to have an output for a vfd and also many inputs and outputs for other functions,also i would like the board to be usb interface and the highest frequency available and can i use a 4 axis motion controller and only use the 3 axis and have a spare axis for later uses.
i have many questions but i don't want to ask to many stupid questions until i learn more and there is defantely a lot more to learn.
thanks in advance for any help
kind regards mechhamo
Similar Threads:
i thought these forums were set up to help people, o replies
well it look like i am on my own and not even a welcome to the forum
Hi and welcome. I am only new here too, its fairly quiet. I check in about once a week, so dont stress!
I dont know much about your machine, and cant help with the spec for servo's. I am working with my father to do CNC conversion and I chose the DMM stuff. Initally I was planning to use LeadShine (shinese) servo's but the shipped cost to Australia was not much different to DMM and the info and support from DMM sold me in the end.
Re. Motion controller. From what I have read, if you are using Mach 3 then the SmoothStepper is the most popular. I chose SmoothStepper and CNC Technics Break out Board. PMDX Break out boards are also popular, but alas I could not get a response from them and they seem disinterested in selling outside the US. Its shame because I wanted to use the PMDX gear.
If you are using LinuxCNC, then I have read the MESA motion controllers are pretty good.
Like you, I am on a learning phase. I have an electrical/electronic background, so the mechanics are struggle for me. But I have learned a lot from my little chinese 6040 router and from helping a mate fix a half million dollar machine that manufacturer couldn't fix (which I fixed twice purely as a massive frig you to the manufacturer after they told me I had no chance).
The *best* choice is a cslabs csmcio-ip-s industrial controller.
It is what I have for my lathe refit - around the best lathe refit in the world (afaik).
It is quite expensive for all-in multi axis lathe use.
But a multi-axis lathe is always expensive by nature.
My retrofit bits cost over 12k€ wholesale (4+7 - 2 toolchangers).
The best cheap option is a pokeys unit.
Limits 4 axis 125 kHz.
The pokeys has lots of io, great support, great drivers.
Thanks heaps fellas, it looked like i was not going to get any help at first but thanks again,also thanks for the advice on using a smooth stepper and break out board and the advice on the dmm servo motors and drives i checked out the price in au dollars as you said there is not a lot of difference slightly dearer but will be better quality and better support so i think i will stay away from the chinese gear.
my mill has a table 52" long and i think i will go with the 1.8kw dmm ac servo motors and drives.
i plan on using a vfd to control spindle speed with mach3 does the hardware you spoke of have the ability for this as well as proximity switches.
kind regards wayne
If you decide to go with a ESS, have a look at this option.:
https://www.cncroom.com/interface-bo...tf38kbqjaoa052
Its a nice neat package with lots of I/O. No problems with the transaction at all.
This is what I got ( newbie ) and I went with the Ethernet version as USB can be prone to interference issues is some cases.
My original motion card was AKZ250 which is USB and generallly is ok , but the ESS is alot better.
'smooth is the word'....
Steve
Last edited by Sterob; 09-30-2018 at 09:22 AM.
Hi,
That might have been the case but for some reason that companies support of their products has diminished badly of late.The *best* choice is a cslabs csmcio-ip-s industrial controller
They certainly have a good reputation with Mach3 but their Mach4 plugin is patchy at best. Given the cost of the CSMIO's
I think there are better supported controllers out there. Maybe CS-Labs support will come good again but I wouldn't trust it
at the moment.
Craig
Hi,
I use an Ethernet SmoothStepper but I rejected the CNCRoom breakout board as the inputs and outputs have already been assigned by
the break board manufacturer.
I use two Homman Designs BoB's instead. That allows me to assign the inputs and outputs to my satisfaction. The boards themselves are
surface mount technology so are only about 3" x 4".
Another alternative that retains flexibility in your hands are C10's from CNCforPC at only $23 each.
Note that these options ( Homman and C10's) don't have dedicated PWM to analogue outputs. That suits me I prefer to make my own,
electronics is my thing.
Craig
Hi joeavaerage thanks for the advice on the bob board i would like to configure inputs and outputs myself as well but i am not great at electronics so i would like to have a vfd output,it appears that the smooth stepper is the best choice it just depends on what bob board you use i suppose ,can anyone give me advice of the best breakout board to use with smooth stepper controller.
regards wayne
I wanted the neat package the MB2 offered and didn't feel the need to configure the I/O any particular way, so the CNCRoom package seemed right for me.
You'll just have to do some reseach of the options Joeaverage has mentioned Wayne, and try to pick one
I had some pics of my install but my HD died and it seems terminal......
. Good luck.
I'm an Instrument Fitter too and I too was wary of the spring connectors. I understand why they used them. They save space and they apply strong constant spring pressure to the terminal.( maybe they are cheaper too?...lol)
I use boot lace ferrules and depressed the terminals with a small terminal screwdriver so I got good insertion depth. I guess the springs may loose holding power over time, but they seemt to be ok so far.
When I am fault finding at work , the first thing I do is check all the screw terminations anyway, and I DO find the occasional one loose, whethers its human error or otherwise...no way to tell, so have some I trust issues with both methods....lol
Horses for courses......
Let us know how you go anyway.
Steve
Hi,
value for money the C10's are hard to beat.
It would require a couple of extra components to make a PWM to analogue output and you would preferably use
a MOSFET or BJT to switch a relay rather than relying on the TTL output IC of the breakout board to switch it.
If you wish to go that way let me know and we could cook up some simple circuit for you.
Compare 3 X C10's @ $23.00 = $69.00 vs $200 odd for the MB02......electronics may not be your forte....how about cost accounting?
Craig
Biased opinion:
W7, Mach3, ESS, 2 Homann Designs BoBs, Gecko drivers, 3:1 reduction motor to ball screw. NO internet connection!
I am using 500 W brushed DC motors on all axes. The power required (per axis) is rarely above 100 W. 1.8kW sounds like a massive overkill to me.
Spindle is a KBWT-26 DC drive to a Baldor 600 W brushed DC motor. Unlike the Chinese VFDs and 3-phase motors, this combination is totally bomb-proof. Driving 10 mm carbide cutters I would rarely get to 300 W.
Cheers
Roger
Hi,
biased opinion:
Windows 7 Embedded, Mach4, ESS, 2 Homan Design BoBs, Vexta 230VAC input 5 phase stepper drivers, Vexta 5 phase steppers with 10:1 low lash (2 arcmin)
planetary reduction, C5 20mmX 5mm ballcrews, Bosch Rexroth 15mm linear rails/cars. High speed spindle 800W Mechatron and Delta VFD, low speed high torque
spindle 1.8kW Allen Bradley servo ( 3500 rpm 6.1Nm cont).
Craig
Hi rodger my reason for the 1.8 kw ac motors is because ac motors are less efficient than a their dc counterparts, and i will be milling engines with a lot of weight and mass to move, as well as i do not want to waste money on undersized motors but like you said i could get away with 1 hp motors (750 watts) considering the ball screw pitch will be 20mm with a gear reduction of 2,1 i think it would be ok.
another reason i went with ac motors is less maintenance and no interference from the contact of brushes and commutator as well as not been limited with torque and speed there is no doubt that ac servo motors are a better choice.
regards wayne