Vacuum Solderability Testing Apparatus for MicroNewton Force Measurement
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Solution Overview
Problem
Current solderability testing methods for small surface mount components face challenges in accurately measuring the wetting forces due to inadequate sensitivity and non-uniform heating, particularly with the smaller pin sizes and reduced solder amounts, leading to unreliable results from thermal currents and non-uniform heating.
Innovation Solution
A vacuum chamber-based apparatus with a load sensor and precise control module that measures wetting forces over time, utilizing a load sensor with microNewton measurement accuracy and controlled heating elements to minimize thermal currents and ensure uniform heating, allowing for accurate assessment of solderability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If analytical balances are used to measure wetting forces with smaller solder globules, then the testing can be performed on smaller pin sizes, but the measurement sensitivity becomes inadequate for microNewton-level forces
Solution Approach 1:
The patent replaces the mechanical analytical balance system with an optical measurement system that detects wetting forces through optical lever methods or capacitive sensing, enabling measurement of microNewton-level forces with sufficient precision for small pin sizes while maintaining the ability to test various component sizes
2Temperature
If components are suspended over molten solder for heating prior to immersion, then pre-heating can be achieved, but the heating becomes non-uniform across the component sample
Solution Approach 1:
The patent divides the heating function into multiple independent heating zones with separate control, allowing each zone to be optimized for uniform heat distribution across different areas of the component sample, thereby achieving both pre-heating capability and heating uniformity
3Device complexity
If standard atmospheric pressure is maintained during testing, then the testing environment is simple, but thermal currents in air create high interference relative to small wetting forces
Solution Approach 1:
The patent replaces the atmospheric air environment with a vacuum or inert gas atmosphere during testing, eliminating thermal currents and convection effects that interfere with microNewton-level force measurements, while maintaining a controlled and reproducible testing environment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides precise and reliable measurements of solderability by minimizing thermal interference and ensuring uniform heating, enabling accurate determination of wetting forces for small components, thus improving the reliability of solderability testing.
Implementation Method 1
the load sensor measures force arising from wetting of the solder to the contact surface
Implementation Method 2
thermal currents in air at standard pressure may be high enough relative to the small wetting forces that unreliable results would be recorded
Data Source
AI summary
The described embodiments relate generally to methods and apparatus for use in determining solderability of an electrical component. One particular aspect relates to apparatus comprising a vacuum chamber, a load sensor, a platform and a control module. The load sensor has a contact portion disposed within the vacuum chamber and the platform is disposed in relation to the contact portion and has a component mounting surface and a mounting member for mounting an electrical component to the component mounting surface. The control module causes relative movement between the platform and the load sensor so that a contact surface of the electrical component is brought into close proximity with the contact portion. When the contact portion has solder thereon and the solder is brought into contact with the contact surface, the load sensor measures force arising from wetting of the solder to the contact surface. The force generated under contact changes over time, depending on the degree of solderability of the electrical component. Thus, measurement of the wetting forces over time provides an indication of the solderability of the electrical component.