AutoJet® Pre-Polymer Spray System Eliminates
Quality Problems and Improves Production Efficiency
Application: Foam cutting processes invariably
result in a certain amount of trim foam. In order to
recycle the material, the trim foam is shredded into
small flakes and is then blown into a blender, where it
is sprayed with a pre-polymer in order to produce
rebounded foam. After this process, the trim foam can be
pressed together in slab stock, which can be cut and
used again in applications such as sound insulation,
seating reinforcement and packaging material.
Problem: The customer was experiencing quality
problems in the recycling process due to excessive
overspray and poor spray patterns provided by
competitive spray guns. In addition, lack of proper
heating control resulted in variations in the
temperature and viscosity of the pre-polymer. These
viscosity fluctuations further deteriorated the spray
pattern produced by the guns, causing quality problems
in the end product. Large, hardened pieces of unbounded
pre-polymer were often found in the foam, forcing the
customer to scrap the product, which can no longer be
recycled.
 Solution
and Benefits: Two VAU variable spray guns were used
in place of the competitive guns and immediately
improved the quality of the end product. Although this
alone satisfied the customer, additional benefits were
achieved by installing a complete spray control and
monitoring system.
The system featured the Model
2250 AutoJet Spray Controller, powered by SprayLogic™
software. The controller monitors and automatically
regulates the temperature of the pre-polymer by means of
a remote controlled heater, ensuring the correct
viscosity at the spray guns.
The Model 2250 controller also monitors the
pre-polymer pressure and flow rate as well as the air
flow to the VAU spray guns. The spray controller
regulates the pre-polymer flow by regulating the RPM of
an existing pump group. A system integrity algorithm
generates an alarm when the nozzles are worn or clogged
and when the air mixing orifices are clogged. The
ability to monitor and adjust the process is key to the
success of the application, because the spray process is
fully enclosed and cannot otherwise be monitored.
When not spraying, the system automatically goes into
continuous circulation mode, a unique feature of the VAU,
in order to keep the pre-polymer at the proper
temperature. The Model 2250 controller logs time and
material usage for each production batch and also logs
minimum and maximum values for temperature, flow rates
and pressures.
The additional control and monitoring provided by the
Automatic spray system has resulted in cost savings due
to reduced use of expensive pre-polymer. Further savings
were realized through reduced cleaning, maintenance and
downtime. The system – with a payback time of less
than one year – has been so successful that future
enhancements to the system are already in the works.
|
