The 'D2W' Research and Development
Here in the 'Designed2Wind' R
& D Laboratory, the 'D2W Stepper Traverser' (from the 'Possibilities' page) has undergone
further development to become the control centre of my latest
winder - 'The Model 8' (also pictured in 'The Gallery').
Prior to the modifications outlined below, the traverse speed and the
winder speeds were set separately. The traverser's onboard circuitry
generated pulses for the stepper motor at a rate set by the speed
Above: Monochrome shot of the Model 8 in action.
The evolving 'stepper traverser'
modifications explained -
However, after some trials and experimentation, the following helpful
innovations have been devised and executed by a professional engineer
a) New 'Synchronized Mode' -
It was determined that winder and traverser could be synchronized (with
pitch ratio applied) if the pulse from the flywheel's magnet and reed
counting setup could be harnessed as an alternative
trigger to the stepper's own pulse generation. With careful
planning, to avoid adverse interaction between both traverser and
counter, and attention to gearing, a very useful 'sync mode'
was arrived at.
In the early stages of development, it was realised that, with the
prevailing mechanical gearing, each step
of the stepper motor caused the
carriage to move a little over twice the target (desired) pitch. So a
circuit was used to halve the reed pulse rate fed to the traverser
and thus cause ONE step of the traverser for every TWO winder faceplate
*Update note: Further engineering of the electronic circuitry has
enabled 'half-stepping' of the stepper motor. It can now be operated
'full step' per TWO rotations of the faceplate, OR switched to
'half-step' per ONE rotation. Either way, pitch and winding
outcomes remain much the same. The main benefit in half-stepping is the
visibly smoother travel of the carriage.
outcomes are readily achievable with a variety of wire
gauges (AWG 42 through to AWG 44 tested).
The traverser can now be used
in either 'synchronized' OR 'separate' (non-sync.) mode via a
newly-added selector switch (topmost red switch at left). Synchronized
mode means the traverse starts, stops, slows, or speeds up in direct
response to the winder's rotation. When the selector switch is assigned
to 'sync' mode, the 'separate' (non-sync) traverse
mode is overridden. Switching between modes can be done 'on the fly'
during winding for added versatility. Such toggling between modes
could be used to introduce more 'scatter-winding', or be used
to operate or speed up the carriage with or without winder rotation in
the set-up phase prior to winding ( i.e. setting of traverse
limits 'under power' so to speak). The white middle switch
left and right to instantly change the traverse direction by
the auto-traverse (see point 'c' notes below). The lower red switch
offers 1) a 'set-up mode' (LEDs 'on'/ stepper 'off') where the carriage
can be moved by hand to trigger the LED's to set 'limits', 2) 'all off'
at centre position, and 3) auto-traverse 'on' at the lowest switch
speed Range (in non-sync mode).
A capacitor value in the original traverser's clock pulse circuit
was increased to lower the overall
speed range available at the speed control when used in
non-sync mode (independent functioning of traverser and bobbin rotation
Option - for varying traverse
limits (turnaround points)
'on the fly'
The limits of traverse are usually established by the setting of the
However, further flexibility was achieved by the addition of a *3-way
momentary/centre-off toggle switch to the control console (see
mid-placed white knob switch
above).* meaning momentary left and right activation with return
to centre 'off' position.
This is simply connected in parallel to the 'arm' micro-switches, but
has the effect of intervening in the auto-traversing process at
the operator's choosing by way of a manual over-ride.
Where would this feature be used?
Consider a coil that is winding unevenly due to deformed bobbins, poor
initial setting of traverse, or other reasons.
The manual toggle-activated over-ride allows the operator to lay up
winds at any particular point of the coil then revert back to
auto-traversing. Elsewhere this feature might be used to scatter wind
with non-sync mode.
Note the speed of traverse remains 'as set' elsewhere (be it
sync. or non-sync.), but manual 'toggle control' allows for the freedom
altering traverse limits 'on the fly' - it might be thought of as
d) Secret Wiring channels
While not a grand technical innovation, the Model 8 has numerous
'secret (unseen) wiring channels' to present as neat a layout as
possible. Channels travel through the roof and walls of the motor box,
across the baseboard, through the winding tension turret, and under the
arms. These channels feed dc. power to the counter, send a pulse signal
from the flywheel magnet to the counter and traverser, carry
wires from the traverser arm micro switches and turret LEDs, and
provide for the wiring loom from the stepper.
e) Wire feed and faceplate detail
A recent upgrade, not shown elsewhere, shows the thinly
slotted wire feed guide now
made from 'Teflon'(TM). At
left of shot, is the calibrated wire tensioner and black speed knob
which makes for easy referencing of tension A closer look also
reveals a past innovation on the faceplate - the quick fitting cut-down
brass 'shelf stops' (see 'Gallery' notes). The 'stop' is
against, and half under, (due to the pin's profile) the
plate to prevent free-spinning of the pickup. The locking effect of the
stop's twin radii, shape and firm fit make for a secure fixing. The
routed faceplate offers relief (if req.) to the pickup eyelets enabling
flush 'seating' of the mounted bobbin.
f) Speed control - a robust custom-built
variable speed control (not shown above) provides set-and-forget speed
settings via a rotary knob.
g) Additional comments -
With the exception of my trusty electronic counter (which can be moved
from machine to machine), and
the tailstock, this is an entirely new home-built machine,
though it embodies many ideas from my previous models. Apart from the
extensive features described above, I note some other departures
in the design from its forerunners.
Model 8 drive is accomplished via a stepped timing belt and toothed
cogs/pulleys, not the '0' rings I have previously used. This was a case
of what I had on hand and does not imply any dissatisfaction with other
drive systems. The headstock is once again a 'found object' machined
fitted with bearings to carry the shaft and faceplate. As always, it is
essential that the latter components rotate smoothly and truly. As
noted above, the speed control is a custom-made device with dial-up
control (not a PWM device) and not the sewing machine foot pedal of the
past. The counter reed and flywheel magnet used on past machines
is again repeated here but given the dual function of providing a pulse
to both counter and
traverser (in 'sync' mode). A measuring scale has been added to each
traverse adjustment arm to assist with set-up. Certainly another level
automation could be invoked with the fitting of an automated
where the machine automatically switches off after counting down from
a preset number of turns. This has not been implemented to date.
The above traverser and its matching winder operate beautifully in
providing versatility in both automated and 'hands-on' control of the
winding process. Minimum traverse distance is less than 1/8", with max.
- about 1.25" in practical terms, though it could be configured for
longer travel. It is quite capable of winding speeds in the approx.
of 450 - 2000+ r.p.m. though my preference is to wind at lower,
than higher, speeds in this range to allow greater attention to detail
with the building coil.
I readily admit that much
of the electronic design is beyond my own ability, therefore I cannot
provide a trained analysis of the circuit (or diagrams). Such credit
belongs elsewhere. Even so, I have made a general outline of the
'concept' here for those with qualification, experience and a specific
bent for exploring their own solutions at the more technically advanced
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