Precise and consistent insulation and jacketing RAW MATERIAL MANAGEMENT
is the chief advantage of the MaguireÒ
Weigh Scale Blender (WSB) for manufacture of wire and cable. In the plastics
industry, the Maguire WSB is already far and away the world’s most widely used
dosing system with more than 30,000 units now at work in molding and extrusion.
Now companies in the wire and cable industry are discovering that this
gravimetric blender is the most effective means available to control the
critical cost factor of raw materials for insulation and jacketing, including
both compounds and colorants.
Capable of being mounted directly over the throat of an extruder, the Maguire
blender controls raw-material metering by weighing each recipe batch.
Recipe ratios can be varied from 0.01 to 100% with simple thumb-wheel settings.
In operation, the blender sequentially dispenses all ingredients, in their
targeted recipe proportions, from separate hopper bins into a weigh chamber.
From there the batch falls into a mixing chamber, then is fed directly into the
processing machine. In subsequent batches, small corrections are made
automatically.
The key benefits provided by this “gain-in-weight”
gravimetric system are:· Reduced
material consumption. The Maguire WSB exerts precise control over the
metering of all materials into the extruder, including compound and costly
colorants and additives. Automatically self-adjusting to compensate for
variations in extrusion rate or bulk density, the blender maintains batch
accuracy within 0.1%. This renders unnecessary such wasteful practices as
“over-coloring” to compensate for process variations or for the unreliability of
conventional feeding equipment.
The resulting savings in material costs alone can enable a
manufacturer to achieve payback on the cost of a Maguire WSB in less than
twelve months, and for high-throughput operations, the payback time can
be considerably shorter.· Gain in
operational efficiency. Essentially a means of compounding raw
materials right at the extruder, the Maguire WSB frees manufacturers from the
cost premium and inventory commitment associated with using pre-colored
compounds, or from the labor and batch variations of pre-mixing raw materials
off-line. The operational streamlining made possible by the Maguire WSB is
particularly valuable for companies that supply customers on a just-in-time
basis.
· Improved
quality assurance and accountability. In addition to the
quality-control benefits of maintaining recipe consistency throughout a job run
and (thanks to extensive built-in recipe storage capability) from one run to the
next, the precise control over ingredients provided by the Maguire WSB is
particularly important for manufacturers serving high-specification markets.
The formulation data generated for each batch by the blender controller is
readily accessible for meeting documentation requirements such as those for
ISO-9000 operations.· Expanded
factory automation. The wealth of data generated by the blender
controller has even broader potential for manufacturers looking to establish a
system of plant-wide (or even multi-plant) monitoring and control. Maguire has
developed various softwares for networking blenders and even for linking
blenders with other machinery, translating between their different controller
languages.
Optimizing Electrical Performance through Color
ControlColor, a necessity for visually coding wire and cable and,
increasingly, for product identity as well, is in fact a necessary evil for wire
and cable manufacturers. The pigments in color masterbatch can interfere with
or degrade electrical performance. In the downstream test of dielectric
integrity commonly performed on wire-coating lines, insulation with too much
colorant of erratic color dispersion will fail the test by “sparking-out.”
By increasing the accuracy and consistency of colorant
dosing, the Maguire WSB enables wire and cable manufacturers to reduce colorant
levels, not only to save costs but to enhance the electrical performance
of the product in the spark test and in subsequent end use.
Because wire and cable manufacturers must frequently change
colors, the Maguire WSB also represents an opportunity to boost productivity by
speeding color changes. Particularly important in this respect are the
automatic calibration capability of the blender, its ease of set-up, and the
speed with which it can be cleaned out.
First Low-Cost System for True Extrusion Yield
ControlWhile the accuracy and consistency of the Maguire® Weigh
Scale Blender (WSB) makes it possible to save on colorant cost and enhance
electrical performance, wire and cable manufacturers can raise control to even
higher levels with Maguire’s new LineMaster™ AC software. Adding only $5,000 to
8,500 to the cost of a WSB, the system provides true extrusion yield control,
defined as uniform weight per length of product. This translates into
consistent coating thickness, elimination of rejects, and raw-material economy.
The Maguire WSB is
a gain-in-weight blender that sequentially dispenses ingredients, in
targeted recipe proportions, from separate bins into a weigh chamber. In the
LineMaster AC system, this batch is then fed into a loss-in-weight hopper
mounted at the extruder throat. The hopper load cell provides updates on
material consumption once every half-second to the WSB, mounted atop the hopper
or on a floor stand. Using this input, LineMaster AC software simultaneously
adjusts extruder throughput and hauloff speed to control yield. The high-speed
responsiveness of the hopper makes the system effective even with frequent
ramp-down / ramp up cycles, such as for reel changeovers.
