In addition to continuously improving our molding capabilities, Hi-Rel Plastics & Molding, Inc. have years of experience in proven advanced molding technologies like
Heat Insertion is a user friendly, low maintenance, repeatable method of permanently embedding a
metal component into a thermoplastic product through the use of precise time, temperature, and
pressure. The most common example of heat insertion applies to internally threaded metal
fasteners (inserts). The insert O.D. is manufactured with various knurls, teeth, grooves and
undercuts which are designed to accommodate displaced plastic to prevent rotational torque or
tensile pull out.
A manual or pneumatic press has heated probes with a tapped face to accept various size
insertion tips. The insertion tip is designed to rest on the top surface of the insert as well
as piloting down into the internal thread. Once contact is made moderate force is applied to the
insert.
The pressure for force being applied to the insert is set so that it cannot "cold press" into
the part. Heated via thermal conduction the insert does not begin to install into its mating
hole until it reaches the melt point of the thermoplastic material. Once the proper melt point
has been achieved the heated probe advances and drives the insert to a flush or above/below
flush specification.
The insert does not begin to install into its mating hole until it reaches the melt point of the
thermoplastic material. Once the proper melt point has been achieved the heated probe advances
and drives the insert to a flush or above/below flush specification. Heat insertion achieves the
high strength values of a molded in insert while offering the benefits of post molded insertion.
Heat insertion allows the fabricator to install an unlimited number of inserts of various sizes
on multiple planes simultaneously. Heat Staking is also a user friendly, low maintenance, cost
effective, repeatable method of mechanically attaching plastic to plastic and plastic to
non-plastic products. The process combines precise pressure, temperature, time and cooling to
reform a plastic stud, tab, wall, or protrusion over a mating component to retain or
mechanically lock it in place.
Generally, the mating component is a dissimilar product such as printed circuit boards, metal
brackets or stampings, bezels, light pipes, RF shields, or non-compatible plastic resins.
Physically and visually the heat staked assembly appears to be an extension of the molding or
fabricating process.
A manual or pneumatic press has heated probes with a tapped face to accept interchangeable
process tips. The tip is manufactured with various contours, conical cavities, knurled patterns,
or specific profiles. Once heated via thermal conduction, the tip is used to melt, form, and
solidify the plastic stud which protrudes through a hole in the mating component. The molten
stud under heat and pressure compresses and takes the shape of the tip cavity. At this point our
unique "freeze out" feature rapidly cools the tip and solidifies the plastic under clamping
pressure. This ensures a tight assembly and excellent tool release from the plastic which
prevents sticking or stringing on the forming tool.
Until recently, the majority of staking was done with ultrasonic welding. With today's
sophisticated microprocessor based temperature controllers, precision dwell timers, and other
combined technologies, heat staking offers many advantages, such as the ability to
simultaneously perform many stakes on varying planes of a product as well as independently
control each staking point.