PCB Test Fixture Translator Mechanism for High-Density Probe Contact
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Solution Overview
Problem
Existing test fixtures for loaded printed circuit boards struggle to achieve reliable electrical contact with high-density test points due to insufficient spring force from traditional spring probes, which limits their ability to test fine pitch test point arrangements effectively.
Innovation Solution
A test fixture with a removable translator fixture that translates a wide-spacing probe pattern to a fine pitch test pattern using high-force spring probes and tilt pins, optimized by software algorithms to ensure precise contact and minimize manual wiring, allowing for the use of heavy-duty spring probes and flexible pin arrangements to accommodate various circuit board configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spring probes are used to contact test points, then the fixture structure is simple, but the spring force is insufficient for high-density test points
Solution Approach 1:
The patent introduces tilt pins as intermediary elements between the spring probes and the test points. The spring probes contact the tilt pins, which then contact the test points on the circuit board. This intermediary mechanism allows the spring force to be effectively transmitted to high-density test points while maintaining a relatively simple overall fixture structure.
Solution Approach 2:
The fixture is divided into distinct functional components: spring probes for applying force, tilt pins for contact and signal transmission, and a modular translator fixture. This segmentation allows each component to be optimized independently, with spring probes providing force and tilt pins providing precise contact with test points.
2Reliability
If a customized wired test fixture is used, then the test signal transmission is reliable, but the manufacturing complexity and cost increase
Solution Approach 1:
The translator fixture with tilt pins serves multiple functions: it provides mechanical support, transmits test signals, and accommodates various circuit board configurations. The standardized tilt pin design can be used across different test fixtures, reducing manufacturing complexity while maintaining reliable signal transmission.
Solution Approach 2:
Instead of creating completely customized wired fixtures for each circuit board, the patent uses a standardized translator fixture design that can be adapted to different boards. The tilt pin array is configured to match the test point pattern, copying the necessary connections without requiring complex custom wiring for each application.
3Measurement precision
If the test fixture is customized for each circuit board configuration, then the testing accuracy is high, but the productivity decreases due to reconfiguration time
Solution Approach 1:
The translator fixture is designed to be dynamically reconfigurable. The tilt pins can be quickly repositioned or replaced to match different test point patterns on various circuit boards. This dynamic adaptability allows the fixture to maintain high contact accuracy for different boards without requiring complete reconfiguration, thereby improving productivity.
Solution Approach 2:
The fixture allows for changes in the arrangement and configuration of tilt pins to match different test point densities and patterns. By changing the parameters of the tilt pin array configuration rather than the entire fixture structure, the system maintains measurement precision across different applications while reducing reconfiguration time.
4Force
If high-force spring probes are used directly on test points, then the contact force is sufficient, but the probe spacing must be wide reducing test point density capability
Solution Approach 1:
The tilt pins serve as intermediaries that allow high-force spring probes to contact high-density test points. The spring probes apply force to the tilt pins with sufficient magnitude, and the tilt pins transmit this force to the closely spaced test points, effectively decoupling the probe spacing from the test point density.
Solution Approach 2:
The contact mechanism is segmented into force application (spring probes) and signal contact (tilt pins). This segmentation allows the spring probes to be spaced widely for adequate force while the tilt pins are densely arranged to match high-density test point patterns, resolving the contradiction between force requirements and density capability.
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 enables reliable electrical contact with high-density test points, supports testing of loaded circuit boards with diverse configurations, and reduces manufacturing time and costs by optimizing pin placement and force distribution, while minimizing the need for manual wiring and reconfiguration of test fixtures.
Implementation Method 1
spring loaded test probes arranged to make electrical contact under spring pressure with designated test points
Implementation Method 2
a vacuum may be applied to the interior of the test fixture housing during testing to compress the circuit board into contact with the test probes
Data Source
AI summary
A test fixture for testing loaded printed circuit boards having a plurality of test points having a probe plate including an array of widely spaced high force spring test probes in compliant contact with solid translator pins located in a translator fixture removably positioned over the probe plate. The test fixture includes optimization software wherein translation of the test signals are optimized by providing the shortest interconnect distance in the x-y plane between the test points on the printed circuit board and the test probes in the probe plate. The fixture further includes an unpowered opens device for testing components on the loaded printed circuit board.