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used now tend to have a narrow
continuous abrasive band and are
easier to control as they have less
tendency to ‘grab’ the upper leather.
Properly used by a skilled operator, they
are able to provide excellent results. But
there remains one big problem.
While at first glance this operation
might appear to be simple and
straightforward, it is not. The care and
intense concentration required on the
part of the operator in order to
achieve a perfect result every time on
different leathers and last shapes is
extremely demanding. While not in
the same skill category as forepart
lasting, for example, a slip during
roughing can nevertheless ruin an
otherwise perfect shoe.
Roughing must follow the feather
edge of the lasted upper accurately.
Too far in and the sole will gape,
moisture and dirt will penetrate and
the bond weakened. Roughing over the
edge will not only need extensive
repairing later on—if indeed it can be
repaired—but may also lead to the
upper splitting in wear, especially if it is
in the forepart of the shoe. Needless to
say, the flatter and tighter the lasting,
the easier roughing becomes. But,
even so, achieving the right result calls
for a careful touch, and the more so the
lighter the upper material becomes.
Because of all this, upper roughing
has never been a particularly popular
job in shoe factories and finding people
with the right level of ability who are
prepared stand all day doing it has
never been easy. As a result,
maintaining consistent quality has
always been a problem. Indeed,
maintaining the required level of
concentration throughout an eight-hour
shift is extremely hard for anyone.
Interchanging two or more operators in
the course of a shift is one answer, but
they would have to be capable of multi-
tasking and operator balance on the
production line could also be affected.
USM POINTS THE WAY
The answer had to be a machine that
could be programmed to rough the
upper without any manual contact
during the process; in other words, an
automatic rougher. But how do you
replicate all the various directional
movements and adjustments needed to
follow a three-dimensional shoe
bottom? Not easy. An early example
was patented by USM in America in
1982. This employed templates that
guided two contra-rotating wire
brushes, one for each side of the lasted
margin on one shoe. It would do the
right foot first and the template would
then flip over for the left.
It worked well as far as following the
feather edge was concerned in that the
template could be shaped so as to rough
to the edge or fractionally over for
moulded footwear that tended to use
thicker upper leathers. It was, however,
difficult to find the right amount of
pressure to consistently achieve the
optimum depth of rough as the leather
varied and the brushes were repeatedly
sharpened. It was also necessary to
have a template for each size of every
last shape and, while this was
acceptable for volume producers of
moulded footwear, it was less so for
producers of fashion and dress shoes.
Although many of the latter who tried it
returned to traditional hand roughing, it
did point the way to the future.
AUTOMATIC MACHINES
Today’s
automatic
roughing
machines are a far cry from that early
machine. Although they mostly still use
roughing brushes, the development of
CAD/CAM and digital cameras has
made possible refinements that the
engineers at USM could not have
dreamt possible. The modern automatic
rougher has effectively de-skilled this
key operation in the same way that the
CAD revolution has with so many other
aspects of today’s footwear industry.
The program needed to control the
various aspects of the roughing process
is inevitably complex. Creating it,
however, has become progressively
easier and machines are now both
simple and quick to program for
different last shapes and designs. The
CD1 and CD8 models from Molina e
Bianchi S.p.A. of Italy are good
examples. They are extremely versatile
with the CD1 able to accommodate
shoes or boots from size 18 to 52 and up
to 110mm heel height and the CD8 to
rough up the side of the shoe for side
wall sole units. Both use an advanced
‘self-learning’ process to create
programs for each last shape and
design that then automatically control
every function of the machine.
The self-learning system of the CD1
(Figure 1)
uses an optic projector that
progressively places itself auto-
matically onto 64 points around the
bottom of a right foot medium size
lasted upper. The operator manually
19
ROUGHING BRUSH TO LASER
MAY/JUNE 2012 | www.footwearbiz.com
Fig 1 – “Self-learning” program on the CD1 uses an optic
projector to trace and register the profile of the lasted bottom
of the right foot of the medium size in the range.
Fig 2 – On the CD8 the right and left feet of every size must be
traced in order to accurately delineate the roughing line on the
side of the shoe.
CREDITS: MOLINA E BIANCHI