Hot Bar Reflow Soldering & Bonding Heads

AMADA WELD TECH bonding heads are available in a range of force capabilities and configurations to accommodate different part sizes, materials, thermodes, and joining requirements.

The Role of the Bonding Head in Hot Bar Reflow Soldering

A successful hot bar reflow soldering process depends on the coordinated control of temperature, time, and force, along with proper contact and alignment.

During the process, the bonding head brings the thermode into contact with the parts and applies force across the joint area. Electrical current supplied to the thermode generates resistance heat, which is transferred from the thermode to the parts under pressure.

The bonding head maintains force as the solder heats, melts, and flows, and continues to hold the parts in position as the joint cools and solidifies.

Proper bonding head setup helps provide:

• Controlled force across the joint
• Consistent thermode-to-part contact
• Even heat transfer
• Accurate thermode positioning and alignment
• Stable part positioning during heating and cooling
• Repeatable joining conditions from cycle to cycle

Why Force and Alignment Matter

Adequate force is required for effective heat transfer between the thermode and the parts. The thermode must also be coplanar with the contacts being heated.

Uneven contact can produce uneven heat transfer across the joint, potentially resulting in areas that do not reach the temperature required for proper solder wetting and flow.

The appropriate bonding head, force range, thermode, tooling, and process settings therefore need to be selected together according to the parts and joining application.

Bonding Head Configurations

AMADA WELD TECH offers bonding heads for different force and production requirements, including:

• Pneumatic bonding heads for controlled force application and integration into production equipment
• Manual bonding heads for applications requiring operator-controlled actuation
• Motorized bonding heads for programmable force and motion control

Available configurations range from light-force heads for delicate parts and fine-pitch connections to higher-force bonding heads for larger thermodes and applications requiring greater bonding pressure.

Hot Bar Bonding Head Applications

AMADA WELD TECH bonding heads can be configured for processes including:

• Hot bar reflow soldering
• ACF bonding and laminating
• Heat seal bonding
• Heatstaking
• Thermocompression bonding

Typical hot bar reflow soldering applications include flex circuits, ribbon cables, wires, flex-to-PCB connections, flex-to-LCD connections, and gold ribbon thermocompression bonding.

Bonding head selection depends on the required force, thermode size and geometry, part construction, joining process, and level of automation.