The Difference Between Heat Staking and Swaging
Manufacturers in a wide range of industries rely on heat staking and heat swaging to assemble and join plastic parts. In the past, technologies like ultrasonic welding and hot plate welding were some of the most popular, but modern advances in thermal press technology and materials have made both heat staking and swaging more attractive than ever.
As consumer electronics, medical devices, and automotive parts got smaller and more complex over the years, the processes manufacturers use to join them have become more advanced. Heat staking is one of these processes, and heat swaging is another.
Both processes address the same engineering issue – using a combination of temperature, time and force (and motions for servo-based equipment) to mechanically lock two components together. However, they differ in the specific mechanism they refer to, and that makes each one particularly useful for certain applications.
Heat Staking vs. Heat Swaging
Heat staking is a process in which a machine applies heat and force to a plastic boss (post) over a set period of time and/or distance. The plastic boss, which protrudes from one component and fits in (or through) a mating component is re-formed or “staked” in a downward motion to changes its’ shape to fit securely inside or to retain the mating component, as required.
Unlike plastic molding processes, heat staking relies on heat and pressure to form a new shape to ensure the tightest possible grip between components. In a proper heat staking process the plastic material is never heated to its actual flow temperature, so some of the energy needed must be mechanical in nature.
Heat swaging operates on a similar principle, but instead of forcing the protruding plastic boss (post) to change its shape in a downward motion to fit the mating component, the wall that retains the component changes shape in a lateral motion. Typically, thermal assembly machines do this by “rolling” the wall(s) inwards and using a combination of the heat, time and force to ensure a precise, consistently repeatable result and a tight grip on the assembly, as required.
Choosing the Right Process for Your Application
Modern thermal assembly machines have “application specific” custom interchangeable tooling, so you should be able to quickly and easily switch between heat staking and heat swaging of different products without issue. Investing in a higher quality machine will make tooling changeovers easier, saving time and boosting productivity on the factory floor.
In general, heat staking is ideal for locking multiple components into a plastic housing or assembling multiple layers of components into a plastic body. Examples of components well-suited to heat staking include automotive LED taillights, medical devices, consumer electronics devices and automotive Infotainment systems.
Heat swaging is the best option for situations when the main component is harder than the frame surrounding it or if the part being retained is a lid with no holes for heat staking posts. For example, when attaching a metal grille to a plastic frame, manufacturers cannot expect a frame-mounted protruding plastic boss to hold up to the metal grille it is supposed to support.
Instead, metal grilles, glass displays and devices with a lid need to either be embedded directly into the plastic frames or have the frame walls swaged over to hold and retain them securely. Swaging is the most efficient and reliable way to achieve this result.