Possibilities
    The purpose of this site is to set the reader thinking, and provide encouragement and inspiration. I didn't learn to build these machines overnight, but I did have a lot of fun exploring the possibilities (. . .and the odd failure and frustration too!). You may start with a very simple winder, but by refining and modifying your ideas, you can arrive at a very satisfying conclusion. Five years ago I considered buying a commercial machine to get into pickup winding. Today, I wouldn't have it any other way than to use and enjoy the machines that were born in my own small and humble workshop. 

A fully optioned variable speed (inter-linked drive/auto-traverse with preset tension) home-built machine.

 A Stepper Powered Auto-Traverser!

The machine pictured above relies on a mechanical cam traverse which 'locks in' the traverse distance - meaning a new cam is required for each change of traverse length.
It has long been a challenge, for me to design a *stepper motor controlled traverser with computer control (CNC -no cams!).
Recent experiments (April, 2003) have brought this closer with some insights and revised outcomes along the way.

* For readers unfamiliar with stepper motors, these are commonly used in a range of computer controlled (CNC) equipment including printers, plotters, robotics, etc. Web searching will prove informative elsewhere - space prevents detailed info. here.

Early prototype
My early prototype traverser to test feasibility

Some time back I had built a stepper motor controller board, but hesitated about executing the actual traverser design, and gaining the associated computer skills needed to write a program for slaving the whole set-up to a pc.
In the process of designing a geared cog and rack traversing unit, I pondered further the issues of having to input data via a pc. for each changed parameter involved in winding and/or associated adjustments.
I wondered, 'Wouldn't it be easier to offer direct 'hands-on' adjustments in real time without dependency on a pc. at all?'
While I admire the achievements of those who have taken the pathway to pc-based programming, (and it remains an as-yet untapped option on my winder), I chose the latter approach as my starting point - to offer direct 'hands-on' adjustment on a 'stand-alone' winding machine.

After much R&D and generous input by a knowledgeable friend, our combined efforts provided the following features -
So what does it look like  . . .?

'The Designed2Wind Stepper-Powered Auto-Traverser'-
                                                                                                         
labeled traverser      
    Component List :
    1. Base, circuit boards inside
    2. Retractable drive assembly
    3. Wire guide (black, rod end eye)
    4. Function switch
    5. Speed control
    6. Traverse distance adjust (left & right)
    7. Feed arm angle adjust
    8. Tensioner
    9. Tension adjust knob
    10. Right LED (left not numbered)
    11. Carriage
    12. Outfeed Wire guide
   


      Note: Photos above and below show traverser unit only - no coupled winder displayed.

The picture above depicts the view as the traverser faces the operator. The winding machine would be located on the farther side of the traverser, where the traversing wire guide (component no. '12') would automatically travel left and right on the moving carriage as wire is drawn to the bobbin.  In these pictures, for photographic convenience, no power was connected - no LEDS illuminated. The light grey ('gray' for U.S. readers) traverse adjust 'arms' are formed from laminated PVC which allows for hidden internal wiring channels that carry wires to the circuit boards in the base/box below. A custom fitting inside the box permits easy flexing of cables as traverse arms are adjusted.
In lower photo, lens barrel distortion falsely suggests misalignment of components such as the nylon blocks which are, in reality,  'in parallel' and not 'out-of-plumb'. The end-on view (end section more clearly visible in 'prototype' photo nearer top of page) of the carriage is an' inverted L-shape' so that the white nylon blocks 'nest' within this upside-down angular section and are bolted and further braced to ensure stability.
 

 
     
            Above: rear view of traverser shows LEDs, nylon 'glides', and outfeed wire guide on moveable carriage.


At far right :
 
In this photo, the carriage assembly has been removed to reveal the FOUR micro-switches bolted to rebated and channeled  pvc 'arms'.
Here, the gap between switches is clearly visible, and a 'bumper block' on the carriage (not shown) would fit between the switch arms allowing  traversing, then switch activation - about 3 mm. (1/8") at min. The lower pair of switches is responsible for 'change of direction switching'. The topmost two are 'failsafe' switches - in the event that the 'CoD' switches fail, the fail-safe backups will shut-off power to the traverser preventing damage to the gearing and mechanism. Fail-safe switches were thought to be a useful innovation even though in practice the change of direction switches have performed reliably. Mounting is done with 2 mm.bolts.
The lower switch arm is 'hook-shaped', and under normal use will activate on its own. Should it fail however, by flexing just a little further, the upper switch arm is activated. Operation of this system requires careful and accurate switch mounting. Some readers will foresee, the fail-safe only stops the traverser. The winder will keep drawing wire, even if to one side of the bobbin, but the traverser is at least protected until the operator intervenes. An audible 'fail-safe' alarm could be fitted to monitor such malfunctions. To date, as I mention above, the failsafe system has not been called upon and the unit operates most reliably.
Look closely and you can see the wire channels in the laminated pvc. arms. The indicator LEDS are just visible atop the motor box. Each lights for one direction of traverse and indicates the 'turnaround point' (or switching point) when triggered.
This is particularly useful in manual set-up mode where the motor is turned 'off' and disengaged, and the carriage (or appropriate arm) is moved by hand until a LED triggers. This illumination reveals the change of direction, or 'turnaround' point for set-up.

The overall traverser design presented various problem solving issues . I refer to but two such issues by way of example -
 
eg.1. the sliding motor mount must offer a very firm and accurate sliding motion. Any slack here will upset the smoothness of traverse changing as the drive reversal copes with unwanted  slack, 'play' or 'backlash'. This was detected on an earlier 'model' where 'fit' was on the slightly 'loose' side, and had to be promptly corrected!
eg.2. the manual speed control offers a very good (ample) range for the intended purpose, however all steppers have their limitations and here (on this unit), maximum motor speed is reached well within the pot's (speed control's) operating range. This is only to say that on the above unit, max. effective stepper speed is achieved short of the 'full throttle' potentiometer position.

As with other projects on this site, this is not a conclusive nor prescriptive model for others to duplicate/emulate. I only offer this as a stimulus to the reader's thinking, and hope that it may generate further exploration and enthusiasm for others.

Updated Information! The above traverser is now integrated into the Model 8 auto-traversing Winder (see R & D Lab. Page)
 
*All text and photos above are copyright property of spinner@designed2wind.alphalink.com.au - 2003, and may not be redistributed, or otherwise copied/ published, or reproduced for mass-circulation without written permission of the author.

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