In modern SMT manufacturing, available solder volume is increasingly limited by fine-pitch designs, reduced stencil thickness, and higher component density. At the same time, reliability requirements continue to increase, especially in applications exposed to mechanical shock, vibration, or thermal cycling.
SolderBonds solder preforms provide a controlled and repeatable method to increase solder volume without modifying the existing reflow profile or printing parameters.
What Are SolderBonds Solder Preforms?
SolderBonds solder preforms are precisely manufactured pieces of alloyed solder, available in rectangular or disc shapes. They do not contain additional flux.
The preforms are placed directly onto the printed solder paste deposit using standard pick-and-place equipment. Because the preform alloy matches the solder paste alloy, both materials melt simultaneously during reflow. The flux contained in the solder paste activates the metal surfaces, enabling proper wetting and metallurgical bonding.
As a result, the overall reflow process remains unchanged. No additional heating steps or profile adjustments are required.
Why Increasing Solder Volume Matters
Stencil thickness defines the printed solder paste volume. However, in many advanced assemblies, this volume is not sufficient to achieve optimal solder joint geometry.
This is particularly relevant for:
- Bottom Termination Components (BTCs)
- QFN and DFN packages
- Power components with thermal pads
- Fine-pitch designs ≤ 0.3 mm
Limited solder volume often leads to reduced standoff height. Consequently, the solder joint experiences higher mechanical strain during thermal cycling or mechanical shock.
By integrating SolderBonds solder preforms, manufacturers increase:
- Effective solder volume
- Standoff height
- Solder joint cross-sectional area
Therefore, mechanical stress caused by CTE mismatch is distributed more evenly across the joint.
Impact on Thermomechanical Reliability
Higher standoff height reduces shear strain during temperature cycling. Additionally, increased solder cross-section improves the joint’s ability to absorb mechanical energy during drop events.
This typically results in:
- Improved drop-test performance
- Enhanced thermal cycling resistance
- Reduced crack initiation within the solder joint
- More consistent IPC-compliant solder geometries
For automotive, industrial, and mobile electronics applications, this controlled volume increase can significantly extend service life.
Process Integration in SMT Lines
SolderBonds solder preforms are supplied in tape-and-reel packaging and are compatible with standard SMT placement systems.
The process flow remains straightforward:
- Solder paste printing
- Preform placement
- Component placement
- Reflow soldering
Because no additional flux source is introduced, flux residue levels remain stable. Moreover, the need for alternative volume-increasing methods such as step stencils, wave soldering, or selective soldering can be reduced or eliminated.
Compared to thicker stencils, localized solder volume increase using preforms offers better control at specific pads without negatively affecting adjacent components.
Available Alloys and Thermal Compatibility
SolderBonds solder preforms are available in common alloys such as:
- SAC305
- SAC387
- Sn63
- Sn62
- BiSn
Since the preform alloy matches the solder paste, melting behavior, intermetallic formation, and wetting characteristics remain consistent with the standard SMT process window.
Technical Conclusion
SolderBonds solder preforms offer a process-stable solution for controlled solder volume increase in SMT manufacturing. They improve standoff height, enhance thermomechanical reliability, and strengthen mechanical robustness — without increasing process complexity.
For assemblies with fine pitch, high reliability demands, or significant mechanical loading, SolderBonds solder preforms provide a precise and scalable method to optimize solder joint performance.
