New Microwave Technology for Uniformly Heating, Drying, and Curing Coatings and Laminants

Heating is the most fundamental process in industrial manufacturing. It is used
for drying, promoting chemical or physical change such as bonding and curing,
and many other purposes. Despite this, heating remains one of the most difficult
processes to control. It is slow and imprecise when implemented in the
conventional manner of heating the surface of a material by convection or
conduction.

In surface heating, the process time is limited by the rate of heat flow into the
body of the material from the surface as determined by its specific heat, thermal
conductivity and density. Surface heating is not only slow, but also non-uniform
with the surfaces, edges and corners being much hotter than the inside of the
material. Consequently, the quality of conventionally heated materials is variable
and frequently inferior to the desired result.

Imperfect heating causes product rejections, wasted energy and extended
process times that require large production areas devoted to ovens. Large ovens
are slow to respond to needed temperature changes, take a long time to warm
up and have high heat capacities. Their sluggish performance makes them
unable to respond to changes in production requirements making their control
difficult, subjective and expensive.

Conversely, with microwaves, heating the volume of a material at substantially
the same rate is possible. The heat energy is transferred through the material
electromagnetically, not as a heat flux. Therefore, the rate of heating is not
limited and the uniformity of heat distribution is greatly improved. Heating times
can be reduced to less than 1 percent of that required using conventional
techniques.

Historically, the primary technological drawback to using microwave energy for
industrial processing has been the inability to create uniform energy distribution.
If uniform energy distribution is not present, regions of the target material are
underexposed, i.e. wet, and other regions are overexposed, i.e. burned. This is
analogous to the hot spots and cold spots generated in your microwave oven at
home when heating or defrosting food such as a potato or frozen chicken.
Industrial Microwave Systems (IMS) has changed all of this by introducing the
first technology to evenly heat / dry planar materials such as coating and
laminants to microwave energy. As a result, IMS’ patented technology translates
the benefits of microwaves to continuous flow processes by creating a uniform
energy distribution.