Heat Staking

Heat Staking is a pulsed-heat process to join two or more parts out of which one at least is made of plastic. The process is to deform the plastic material using heat and force at a set process time. The bond is made by partially de-forming the plastic part in order to fix the other.

Heat Staking makes it easy to bond metal to plastic and is commonly used in high volume/low cost applications such as automotive, IT and consumer appliances.

Heat Staking Applications

Shaping Plastic Using Heat and Pressure

The plastic is deformed by heating it to a temperature above the glass transition temperature. Super-heated air or a thermode is used for this. Pressure is then applied to create the stake. After the stake has been formed, the plastic should be cooled down again below the glass transition temperature. Cooling is performed under constant pressure to ensure good fixation of the parts. Compressed air can be applied for cooling when a thermode is used.

Heat is used to facilitate the creation of the stake. Heat control is critical, especially for glass-filled plastics which often have a process window of less than 10 degrees Celsius. When the temperature is too high, the glass fibers come out of the plastic which leads to a rough surface and adhesion to the thermode. If the temperature is too low, the plastic will crack due to cold deformation.

Heat Staking Benefits:

Similar and dissimilar materials may be joined: metal to metal, plastic to plastic, metal to plastic
Accurate control operating within a small process window
Local heating resulting in no damage to surrounding materials
Processing of glass-filled materials
No mechanical vibration
Many heat-stake shapes possible through custom designed tools