PSM International unveiled a patented lightweight insert for cam covers, air intake manifolds, and other thermoplastic injection-molded applications at the April 12-14 SAE 2011 World Congress in Detroit.
"Engineers are looking for weight savings—even 20 grams per component is meaningful—so this aluminum product is our contribution to weight savings on a vehicle," said Ian Atkinson, Managing Director-Europe for PSM International.
A conventional inlet manifold can use as many as 15 inserts. "You need an insert to provide thread strength and other performance criteria that you can't achieve by screwing directly into plastics," said Atkinson.
Employing the aluminum Tri-Step inserts on a plastic inlet manifold eliminates approximately 60% of the weight that is associated with conventional brass inserts or steel inserts, Atkinson said.
A weight-conscious plug-in electric vehicle could use 50-plus inserts to fasten the battery housing and battery cell frame. "The more thermoplastic components on a vehicle that would have used traditional brass or steel inserts, the greater the potential for a more significant weight savings if switching to the Tri-Step inserts," said Atkinson.
The Tri-Step, which can be installed using either a preheating process or an ultrasonic heat-generating process, features a unique design that essentially eliminates both insert misalignment during installation and insert spring-back.
Explained PSM International's Global Technical Director Paul Martin, "The patent addresses the geometry of the insert and the geometry of the hole it fits into."
From a process perspective, the Tri-Step is a time-saver. "Installation speed and time is improved by one-third on average," said Atkinson. "Because aluminum has 40% better thermal conductivity than brass or steel, the heat prep time that's needed prior to the insert's installation is reduced. The insert also cools more rapidly after installation. This in turn results in an energy savings."
The first production application of lead-free inserts is en route. "We now have Tier 1 customers who will be specifying the aluminum Tri-Step insert for OEM components for next-generation projects," said Atkinson.