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Offline nobby

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just bought a little baby cnc 280mm square davinci style thing
« on: January 29, 2023, 04:04:03 PM »
hello please - been off grid for a fair few years.....
just bought a little machine \/ see pic some german tiny 280mm square thang
the bloody thing has 5 phase 10 wire motors - damn
do they go straight in the bin?
the drivers and controllers 1997 ish - rs232 straight in the bin?

had an old nema 23 hanging about and the bolt pattern is just a bit too small

47mm nema 23 - the machine has positec vdrm 564/50 lna at  60mm bolt spacing
do i simply slot the cheapo nema 23 motors

am i going for 56mm nema 23's with 8 wires and going bi polar parrallel?

anyone in the uk got any little dual shafted little 8 wire nema 23's x3
6mm to 6.35mm blums to do aswell =

bloody thing
nice quality

got one of them network nvem controller break out things, are they worth the hassle

the machine has a 24 volt spindle in it already and a group of relay type things for door open and emergency stop and that but I just need emergency stop and spindle control?


thanks
« Last Edit: January 29, 2023, 04:17:33 PM by nobby »
Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #1 on: January 29, 2023, 07:20:45 PM »
Hi,
my first mini-mill which I used for eight years had five phase Vexta steppers and they are superb. Admittedly my steppers only had five wires and the
drivers (direct off-line) had the colors marked, so it was easy. I tuned them to do 2400 rpm through an integrated 10:1 low lash (<2 arc min) planetary
gearbox direct coupled to the ballscrews. Once I got them dialed in they were perfect, never missed a step unless I did something stupid.

The natural resolution of a five phase stepper is 500 pulse/rev, compare that to a two phase stepper of 200 pulse/rev, so the 5 phase wins hands down there.
You try and get ANY two phase stepper to do 2400rpm. I did use 3000 rpm at one stage, but they got just too hot so I dialed them back a bit. The drivers
are direct connected to incoming 230VAC supply. The drivers themselves put out about 150VDC so that's why they can go so fast.

I paid big dollars for them second hand nearly ten years ago now, and they lasted all the eight years on my mini-mill. I managed to blow one up when
I put it on my new fourth axis on my new mill a while back.. I have no regrets, those little motor did thousands of hours for me, and they were old when I got them!

The bottom line is that five phase steppers are all high quality premium steppers, reuse them if you can. There were only a few manufacturers of them, Vexta (Oriental Motor),
Largher and Pacific Science are the ones I remember, but I seem to recall Sanyo-Denki made them as well. All top tier companies.

I have four Vexta RKD514L-C drivers if you need them. 230VAC input, 5phase full step and half step output, up to 1.4A/phase. They are old now but still Japanese quality.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'

Offline nobby

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Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #2 on: January 30, 2023, 03:18:34 AM »
Reading between the lines
I am reckoning that all servo motors are 10 core 5 phase motors, 500 pulse, maybe, I had a set of minas a4 and they did have the 60mm bolt space, anyhoo. There were some 41mm long 8 wire NEMA 23s on that popular auction site for 7 bucks each free post. So I shall run them bipolar parallel. Cheap. I have some drivers, easy.
Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #3 on: January 30, 2023, 04:15:03 AM »
Hi,

Quote
I am reckoning that all servo motors are 10 core 5 phase motors, 500 pulse, maybe,

No. Old school servo motors are a brushed DC motor fitted with either a tacho-generator and/or an encoder. No pulses.
Brushless DC servos have three phases around the outside of a permanently magnetized rotor and use trapezoidal commutation. No pulses.
AC servos have three phase windings on the outside of a permanently magnetized rotor fitted with an encoder. They use Field Oriented Control,
ie have a smart drive providing three phase sinusoidal excitation to the winding. No pulses.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'
Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #5 on: January 30, 2023, 02:12:47 PM »
Hi,
all steppers lose torque the faster they go, its just the physics of how stepper motors work. The inductance of a stepper motor determines how bad that torque degradation
will be. The lower the inductance the better. What inductance are those steppers you have pictured?

The classic way to try to overcome the reducing torque is to use the highest possible voltage drivers and power supply.
I think 24VDC is a joke....those steppers are likely to stall at 100rpm. If you used 60VDC or 72VDC or better 80VDC then they might get to 1000rpm.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'

Offline nobby

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Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #6 on: January 30, 2023, 05:51:38 PM »
groovy
so my mach3 license works still as does my sheet cam tng
now, is there a new button i see in sheetcam that auto opens mach3 with the part i have just post processed?
cant seem to get it to do it?
also have a
SCHMERSAL AZR31T0/24V
https://az343058.vo.msecnd.net/productlargeimages/31b7f7c3122a4fda88d3dcfbb2b10d26.jpg

relay thing
the spindle itcontrolls is only 24v
so does it want a 5v signal from the breakout controllery thing through this relay
do i run th estop through it
and do i set it up as it was stock for a door switch

dont know how to do the spindle control yes as havnt done that before
motors bought
mach3 set up and sheet cam - remembered how to get a 2d file into that and into mach

hmm
pray tell, i want to model prismatic lettering and mill it in a hdu type of stuff to then take a mould from as=nd cast them in resin and led back light them
what 3d cam software should i be looking at?


Offline nobby

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Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #7 on: January 30, 2023, 05:56:05 PM »
also what is the total cost involved in mach 4
how much is the software
how much is a controller
3 axis will do
thanks
Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #8 on: January 30, 2023, 06:22:21 PM »
Hi,
if you have a Mach3 license then it still works and makes sense to carry on.

I use Mach4 and have done for eight years, and in my opinion is vastly better. That does not mean that it cuts more accurately or faster but rather
its about the ability to customise your machine. Mach4 is definitely better for that. Having said that for a three axis machine you don't really need any
of the Mach4 goodness, Mach3 will work.

Mach4 costs $200. No upgrade from Mach3, its a totally new product. Mach4 requires an external motion controller, I'd recommend an ESS ($190). Note the ESS
can use either Mach3 OR Mach4, so even if you decide months from now that you want Mach4 the same ESS will work. You'll need a breakout board, or maybe more than
one if you want a lot of IO.  A C10 is $23.00 and has 17IO's. A C25 is $29.00 and has 34 IO's. Note neither the C10 or C25 have a relay for the spindle nor a PWM circuit
for the spindle, you'd need to do a little electronics to add those. There are many breakout boards that work with an ESS, right up to an MB3 ($180) from CNCRoom with
51 IO's, all the relays, PWM circuits, inputs, differential motor outputs 'you can shake a stick at'.

I would suggest if possible to reuse your existing five phase steppers. If you post  some closeups we may be able to learn enough about them to get them working.
As I posted earlier I have 4 'kick arse' 5 phase Vexta drivers that'll make your machine sing. I'd sell the lot for $200, remember I'm in New Zealand....so it might cost a penny or two
to get them to wherever you are.

Note sure what the gadget is that you linked to, can you post a pic of the circuit diagram on the side?

I use Fusion, a paid subscription, but is available free to hobbyists. There are other CAD/CAM that would do what you want, I think if Tweakie reads this he will know the
one I'm thinking of, I cant remember it offhand.

Craig
« Last Edit: January 30, 2023, 06:24:35 PM by joeaverage »
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'

Offline Tweakie.CNC

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Re: just bought a little baby cnc 280mm square davinci style thing
« Reply #9 on: January 30, 2023, 07:25:21 PM »
I use Fusion, a paid subscription, but is available free to hobbyists. There are other CAD/CAM that would do what you want, I think if Tweakie reads this he will know the
one I'm thinking of, I cant remember it offhand.

Craig

If it's any help, I use Vectric Aspire which I think would be ideal for the construction of prismatic lettering and casting moulds etc. https://www.vectric.com/products/aspire

Tweakie.
PEACE