Heat Set vs Press-In vs Molded-In Thread Inserts – Key Differences

Heat Set vs Press-In vs Molded-In Thread Inserts

Selecting the correct insert installation method is essential for achieving optimal performance in plastic components.

The most common types of installation methods include:

• Heat set inserts

• Press-in inserts

• Molded-in inserts

Each method offers different performance levels and production advantages.

Heat Set Inserts

Heat-set inserts are installed by heating the insert and pressing it into a plastic component.

The heat softens the plastic, allowing it to flow around the insert's external features.

Advantages

• excellent torque resistance

• good pull-out strength

• reliable installation in thermoplastics

Heat-set inserts are widely used in electronics housings and plastic equipment enclosures.

Press-In Inserts

Press-in inserts are installed using mechanical force.

They usually include helical knurls or barbed features that grip the plastic.

Advantages

• simple installation

• low production cost

• suitable for high-volume assembly

However, press-in inserts typically provide lower torque resistance than heat set inserts.

Molded-In Inserts

Molded-in inserts are placed in the mold before plastic injection.

During molding, molten plastic flows around the insert and fully encapsulates it.

Advantages

• maximum pull-out resistance

• superior torque performance

• long-term durability

Molded-in inserts provide the strongest threaded connection for plastic components.