cnc winder controller board

[David Schwab]

yes, this is the problem in winder with vfd for coil motor... you should have a sensor on shaft to control traverse motor in synch... and this is needlessly complicate....

I was referring to a purely mechanical traverse, with no CNC. You would have adjustments for the coil height and then set the speed of the traverse. It wont match up with the winder speed, so it will be semi random.

Or am I missing something?

[David Schwab]

I was just wanting too slowly decrease friction during the wind in a linear fashion from start to finish. I'm not sure if that is even useful.

Or keep the tension constant and vary the speed. Then it gets more complicated.

[salvarsan]

Interesting. It never occurred to me to try vary the tension mid-turn in time with the rotation but since we know precisely where the coil ends are at all times via the stepper motor, it would be possible to alter the tension without sampling it at all.

Servo tensioners do it with a torque sensor on a pulley, nearly as direct as it gets.

Alternatively, you might belt-drive a cam from the spindle at 2X the winder
speed and have it add or remove tension from the felt pads when the wire
is at top dead center on the bobbin edge.

I don't see the point of that since tension from a friction pad is going to be constant regardless of the speed that the wire is being pulled through the felt pads (provided it's always moving and not subject to the initial friction which is higher.)

That's why, in a simple felt tensioner, you add a 1-2 ft length of wire
between the felt pad and the bobbin. It distributes the stretching due to
tension.


-drh

[-Elepro-]

The newer type have moving parts where the wire wraps a full turn around a wheel or pulley that's connected to a small DC generator/motor. Depending on the resistive load across the motor you can vary the tension on the wire with a good deal of accuracy.

this could be interesting.... i tried it now with a small motor but now i must understand how the braking torque depends on speed, acceleration and resistive load...

I was just wanting too slowly decrease friction during the wind in a linear fashion from start to finish. I'm not sure if that is even useful.

i don't understand how this could be useful

[chevalij]

Sampling at 1600 Hz is easy, controlling at that freq. probably isn't feasable. I think the best bet is just to average the samples and adjust tension based on the average every 1/2 second or so.

As for adjusting the traverse control, you can feed the rotation freq. into a DAQ or cheap PLC and have it output the traverse pulse. Using software you can use any multiplier you like. You could also use a pot and input a variable voltage into the PLC that you would use as the multiplier. At traverse rates slower than the revolution, you use a counter and output a pulse based on the counter sum. Example, count to 3, output a pulse, reset the counter, repeat.

[salvarsan]

Sampling at 1600 Hz is easy, controlling at that freq. probably isn't feasable. I think the best bet is just to average the samples and adjust tension based on the average every 1/2 second or so.

The tension changes too rapidly per revolution for facile digitial control; again, the felt
tensioner followed by a sufficient length of wire is better than good enough
in addition to being inexpensive.

If you ignore 'facile' and 'cheap', there are a few other extravagant methods
such as stages of piezoelectric membranes to induce tension.

As for adjusting the traverse control, you can feed the rotation freq. into a DAQ or cheap PLC and have it output the traverse pulse. Using software you can use any multiplier you like. You could also use a pot and input a variable voltage into the PLC that you would use as the multiplier. At traverse rates slower than the revolution, you use a counter and output a pulse based on the counter sum. Example, count to 3, output a pulse, reset the counter, repeat.

Good ideas there. Worst case, you only need advance the traverse
twice per revolution. At the reasonable limit for handwinding, 3000rpm or
50Hz obligates 100 position changes/second. This is manageable for a
simple wind but more difficult for a programmed scatter wind.

-drh

[chevalij]

Good ideas there. Worst case, you only need advance the traverse
twice per revolution. At the reasonable limit for handwinding, 3000rpm or
50Hz obligates 100 position changes/second. This is manageable for a
simple wind but more difficult for a programmed scatter wind.

-drh

Of course, you could ignore the pot input and just have the software vary the traverse pulse timing. You could base it on time, revolution, just about anything. You can have varying TPL for every layer if you wanted to get extravagant. I don't think 3000 rpm is still in the handwinding realm Then again, any plc control of this level is also into full blown automation.

[salvarsan]

I don't think 3000 rpm is still in the handwinding realm

I've read it claimed but I don't think it is usual practice.

Call me a wimp, but I'm comfortable between 300 and 1200 rpm.


-drh

[David King]

I tell you what, if I don't have to sit there and watch it and hold the wire and feed it back and forth -then I don't care how slow an automated winder goes. It can take 2 hours or 12 hours per coil for all I care. (And think how much more a "slow wound" pickup could be worth..)

2k RPM is pretty darn fast for a longer coil like a Jazz bass. The wire (42 awg) will stretch out just from centripetal force. I had to crank my tension way up and the result was very diminished returns. I think 1.2k rpm is just about fine. 43 works better for me at the higher speeds.

[Achiles]

What you say about this:
Machine Control Specialists, Inc. - Coil Winding MCS1 Control
Machine Control Specialists, Inc. - Coil Winding MCS4 Control

[salvarsan]

Traverse

I think we may be losing sight of how important the automated traverse is.
If you have one, all manner of complicated wind patterns can be programmed in.

If you don't have one, the discussion is academic.

While many industrial winder firms sell wind controllers, they are probably priced near $3k-$5kUS.

Design and construction is complicated enough that it may need its own online book:
Build Your Own Automatic Traverse For Pickup Winding.

-drh

[David King]

I agree. There have been a few things that have come up on CNCzone that looked promising but never the details or a completed example.

One starting point might be this E-leadscrew for hobby lathes which is fully programable and doesn't rely on G-code or a PC to get the instructions going. It's just a keypad with a set of opensource software (or firmware?).
The basic kit is about $250 so not exactly cheap but it also does more or less everything we want with 1 or 2 axis control. I.e. winder motor and traverse stepper motor.

Here's the yahoo group for it:
E-LeadScrew : Lathe Electronic Lead Screw R&D

[chevalij]

Well, yesterday I started buying parts for my new winder. It will be (if all goes as to plan), completely software controlled. So far, all I've purchased is a new motor, motor controller and some DAQ hardware. I already have Labview software, from 6.0 to 8.3, so software isn't a big deal.

I've got a couple linear stepper motors,a nice linear rail assy. and a few small power supplies sitting around. I have a small milling machine in the basement and access to GREAT machinists, so I think it'll fly.

My plan is to have it controlled from my laptop. It's not going to be a quick project, but if anyone is interested, let me know and I'll try and keep a running report of my progress.

[David King]

I found this module that will convert stepper motor instructions to 0-10V spindle speed instructions to a VFD. This should allow my 3 phase winder motor to play with whatever system we come up with I think.
CNC4PC

[David Schwab]

I agree. There have been a few things that have come up on CNCzone that looked promising but never the details or a completed example.

One starting point might be this E-leadscrew for hobby lathes which is fully programable and doesn't rely on G-code or a PC to get the instructions going. It's just a keypad with a set of opensource software (or firmware?).
The basic kit is about $250 so not exactly cheap but it also does more or less everything we want with 1 or 2 axis control. I.e. winder motor and traverse stepper motor.

Here's the yahoo group for it:
E-LeadScrew : Lathe Electronic Lead Screw R&D

That looks interesting!