Attaching Metal Grilles and Screens to Plastic
For many years, metal grilles and screens have been attached to
plastic housings and frames by the use of additional fasteners. These fasteners
may be screws, clips, rivets, hot-melt glue or adhesive. Each of these
processes cost money, require inventory and are subject to fluctuating degrees
of consistency in quality.
In recent years, many manufacturers have designed or redesigned
their products to incorporate heat staking or swaging process. This can
typically be done with minimal expense to new or existing injection molding
tools. In many cases, the final product, when staked or swaged, becomes much
stronger and robust than its predecessor that required hardware for attachment.
Besides the reduction in product cost by eliminating hardware,
there are many advantages, as cited by our customers, for why switching to
staking/swaging is such a benefit to many products.Listed below are just a few.
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Rattles from loose fasteners become non-existent.
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Screens or Grilles do not become loose over time.
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Products become tamper proof.
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Production rates increase with smaller workforce.
As shown in Examples #1 & #2, a heavy duty, construction
grade screen is heat staked onto a plastic Vent Housing. The Housing has 16
heat stake posts equally spaced around the perimeter. A machine operator
locates the housing into a part holding nest, and then places a precut screen
over the surface with posts Upon initiating the machine cycle, the parts become
an assembly within 10 seconds.
As shown in Examples #3 & #4, a black painted grille is
swaged into the rib of a plastic engine frame. The process of "swaging" is
basically embedding the metal grille directly into the plastic. This process is
much more difficult than straight forward heat staking as shown previously. In
this application, the heat stake iron (tooling) must remain only a few degrees
below the plastics actual melting point. Any point over will produce a stringy
mess. With quality tooling and equipment, the iron temperature can be closely
maintained to repeat this assembly with ease. We employ machine controls
with precise tooling to make assemblies such as this routine.
Many other screen materials such as nylon, felt and fabric can be
easily staked as well. To discuss your application and whether heat
staking/swaging is a viable option for you, please contact IMS today.
See these articles for more information:
Heat Staking of Antennas in Handheld Devices
Cell Phones Assembly Machines
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