Optimization of a Ceramic Circuit Board Clamp

Abstract

This paper documents the design optimization of a board-mounting system for securing a ceramic or other heavy circuit board to the electronics chassis in a wireline logging tool. A clamp fixes the extreme lower end of the circuit board to the chassis while allowing the board and chassis to undergo differential thermal expansion above that fixed point, through the use of sliding board mounts. After developing equations that describe the stress, deflection, and thermal expansion of the clamp/board assembly, they are used to select the geometry and material options available in the design. Results of a parametric study are presented that demonstrate how material selection determines whether the clamping pressure on the circuit board improves or degrades at elevated temperature, and how the geometries of the clamp components affect the magnitudes of the forces, deflections, and setting torque of the clamp.