Insert Molding Circuit Board Resin Pressure Deformation
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Solution Overview
Problem
Existing electronic circuit devices face issues with deformation of the circuit board and damage to electronic parts during the molding process due to resin pressure and hardening temperature differences, which also result in a compromised appearance due to the need for a holding pin in the molding die.
Innovation Solution
The circuit board is held in the molding die such that its opposite face closely contacts the die, eliminating the need for a holding pin and allowing resin pressure to act uniformly, preventing deformation and damage while improving the appearance by exposing the opposite face of the board as part of the casing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a holding pin is used in the molding die to hold the circuit board, then the circuit board can be held during molding, but the structure of the molding die becomes complicated and a hole remains in the case deteriorating appearance
Solution Approach 1:
The invention removes the holding pin from the molding die structure. Instead of using a separate holding component, the circuit board is directly held by the cavity wall through close contact, eliminating the need for the holding pin and its associated complexity while maintaining holding stability during molding
Solution Approach 2:
The holding function is segmented from the holding pin and integrated into the cavity wall structure itself. The cavity wall is designed with a specific configuration that enables direct contact and holding of the circuit board, distributing the holding function across the molding die structure rather than concentrating it in a single pin component
2Manufacturing precision
If resin pressure acts on the circuit board during molding, then the case is properly formed, but the circuit board deforms and electronic parts are damaged
Solution Approach 1:
The invention applies different local qualities to different regions of the circuit board during molding. The mounting face side receives resin pressure for proper case formation, while the opposite face is supported by close contact with the cavity wall to prevent deformation. This localized differentiation of pressure application and support ensures both case formation quality and circuit board integrity
Solution Approach 2:
The close contact between the circuit board opposite face and the cavity wall acts as a counterbalancing support that offsets the deforming effect of resin pressure on the mounting face. This counter-support mechanism prevents circuit board deformation while allowing the resin pressure to properly form the case
3Reliability
If the circuit board is entirely covered by resin material, then the circuit board is fully sealed, but the appearance is compromised due to holding pin holes
Solution Approach 1:
The invention removes the holding pin that creates the appearance-defacing hole in the case. By eliminating the holding pin and using direct cavity wall contact instead, the case surface remains intact and free of holes, improving appearance while maintaining the sealing function through the molded structure
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
This method effectively prevents circuit board deformation and electronic part damage, enhances the appearance of the molded casing by eliminating the hole from the holding pin, and reduces the complexity and cost of the molding die.
Implementation Method 1
a hardening step of hardening the resin material in the cavity
Implementation Method 2
When the casing is molded by the resin molding process, both of resin pressure caused when the resin is filled and resin pressure caused when the resin hardens act on one face of the circuit board
Data Source
AI summary
A casing of an electronic key transmitting and receiving apparatus is formed to seal entire bodies of circuit parts, a mounting face of a printed board, on which the circuit parts are mounted, and parts of terminals while the other parts of the terminals are exposed. A rear face of the printed board opposite from the mounting face provides a part of an outer surface of the casing. When the printed board is provided in the casing through an insert molding process, the printed board is held in a cavity of a molding die such that the rear face of the printed board closely contacts an inner face of the cavity. Accordingly, deformation of the printed board due to pressure caused when the resin is poured or when the resin hardens is inhibited.