cnc winder controller board

[David King]

2 axis stepper kit?

Im thinking that maybe one of these stepper kits from probotic might be a reasonable and cost effective starting point.

2-Axis CNC Stepper Motor Driver Kits

It's two 2 Nm (280 in/oz) steppers with a pair of stepper drivers (3A @24V) and a power supply.

I'm not sure you could do the whole bit yourself for less using new equipment and I don't see much used equipment for sale on ebay these days.

Any reason to up grade to the 32 or 40V systems?

[-Elepro-]

that system is good but not cheap.... wait and check ebay every day

for power supply is enough a transformer with a diode bridge rectifier and smoothing capacitor..... motors don't need stabilized voltage.....

about voltage, 24 volt is enough (but more is not worse ).... (motor speed depends on voltage)

did you receive my reply private message?

bye

[-Elepro-]

i'm working on tensioner....
Escluding the load cell because it is not cheap...

...I am undecided about:

- a solution with felt tensioner controlled by a solenoid driven by a pwm pic output..... but without any kind of controll feedback.....

- a solution where the wire wraps a turn around a pulley on the shaft of a DC generator... a mosfet controlled by pwm signal from pic adjusts the load on motor (and brake torque).... voltage on load go at A/D converter and value compared with set tension value.... comparator output adjusts pwm duty cycle....


first solution is simple and easily doable

second solution has feedback.... but it's too hard to find perfect generator with right brake torque and with linear current/ brake-torque characteristic curve (at speed variation too) ....

I'm afraid that a complicated solution like second could be worse than first....

suggest?

[David King]

I think the solenoid is already too much trouble, just a thumb screw and a spring over the felt is more than enough here. If your windings seem a bit loose, just tighten the screw 1/4 turn and try again. If anything goes dead with the solenoid system then the whole tensioner becomes useless.

I really like the feedback loop on the DC generator, that's probably overkill but just so cool. Use a DC motor with lots of poles and very low inertia. Probably a disk drive motor, the spinning disk armature kind.

Why not just use a passive dynamic brake with a potentiometer? It's got to be more reliable than the felt. You want a motor that's not too "notchy"

Swiss made Escap tape-drive motors have the magnet inside a spinning armature. Totally smooth and 60-75% efficient despite having brushes...

[-Elepro-]

here is main motor test....

111 turns at 800 rpm... ac-deceleration in 40 turns
note same position at start and at end....
big leds counter is the old one.... it work with magnetic sensor on shaft.... i hope it will retire soon

YouTube - cnc pickup winder - main motor test

[David King]

It looks good. Is it really as loud as it sounds on the video? My 3 phase motor is nearly silent at those speeds.

My shop is in the basement of my house and I really like to keep the noise to a minimum just for my own sanity. It's bad enough having to run planers, tablesaw, bandsaws, + a dust collector, milling machine and lathes all day. I've rebuilt all of my machines to get them as quiet as possible so now my focus is to start with the quietest machines I can find.

[-Elepro-]

about noise... it'is not silent but not much loud.... in my machine is amplified by sheet metal. box and my crummy mechanics.....
in video seems many loud than it really is.....

here's a video of start pause stop and resume functions
300 turns - 400 rpm at max speed - ac/deceleration in 20 turns

YouTube - cnc guitar bass pickup winder - start pause stop and resume functions

[David Schwab]

Very cool! The project is coming along nicely.

[-Elepro-]

thanks David....
now i'm starting to program traverse motor control.... but it already should be in my mind.... i hope....
then i'll think for tensioner..... I am undecided beetween solenoid with felt or dc-motor.....

[-Elepro-]

maybe i found motor for tensioner.... and anyone has it at home

[-Elepro-]

about tensioner...... i made some test with my motor and 1" pulley....

without supply it has a detent strength smaller than 5 grams
with 1 ampere current it has a detent strength of about 50 grams

what about this values?

if you want try, it is a hard disk brushless motor...

YouTube - cnc pickup winder - tensioner. - detent torque

[-Elepro-]

traverse works well.... random and alternate pitch are very cool features

soon some video....

about tensioner i have decided for the solenoid (with mosfet and pwm control) with felt (and without feedback)

[-Elepro-]

and this should be board

[-Elepro-]

and here's my tensioner

[peskywinnets]

As it goes, I'm just about to put together a CNC winder.

Previously, to wind coils (not pickups) I was using an old 48V DC fan motor, controlled by a PWM speed controller I threw together. On the fan I mounted an encoder disc with 192 black stripes. I then knocked up a little circuit which counted the blackstripes from the fan motor using a PIC...the PIC then pulsed a stepper IC, ultimately feeding a stepper that had some plastic helix rod on its shaft. (for traversal)

it worked well for winding small coils (traversal was near perfect)...I used a small spreadsheet to calculate the black stripe pulses per stepper motor 'step' needed to keep the stepper motor traversal wire feed correct - I then programmed the PIC with the data over a serial link using the UART tool as a pseudo-VT on my PC.

Then I came to wind a Guitar sustainer driver on the above rig. These drivers use much thicker wire (0.25mm vs 0.063mm for a pickup)...therefore need a lot more tension to pull against the driver to keep the copper wire taught as it feeds on to the bobbin - that fan motor didn't provide enough torque

so I thought...why not use a stepper - they have bags of low end torque. This set me off on a path of investigation. I stumbled across a bit of half finished Mach3 plugin (CNC software I use) off the manafactuer's site....



but it was only part working ...but I've manged to kludge it so it will to fit my modest needs.

For the hardware, I was initially going to use this for donor parts....



stripped down here...



& stripped down further here...



But I've now realised that the printer chassis isn't 'flexible' (meaning not enough side mounting options for the steppers to mount onto), to satisfy my needs....nor does the belt traversal arrangement have sufficient resolution. So last night I started milling a very basic stepper holder out of 12mm acrylic to get me up & running quickly.

To get a flavour of what's possible, someone used a similar setup (though he didn't go the scrap heap challenge route that I have!)...

http://www.machsupport.com/videos/movies/coilwinder.mpg His is a glory of engineering ability ...all aluminium & shinyness...mine will be the engineering equivalent of AmyWinehouse... aesthetically challenged! (ok, so he's not winding a coil, but rather tubing/fishing line But just imagine a driver/pickup bobbin on the end of that main motor in the video!!)

Since steppers don't have a high rpm, I'm interested in the 4:1 pulley gearing mentioned earlier in this thread.... but where do you go to get such kits? (what are they even called!)