Base Strip Center of Gravity Alignment for Shrinkage Control

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Solution Overview

Problem

Conventional plastic base strips for connecting to printed circuit boards often experience material shrinkage during cooling, leading to distortion and deformation, which can result in incorrect solder connections during automated assembly, especially in multi-pin configurations.

Innovation Solution

The center of gravity of the base strip is aligned with the geometric center of an imaginary enveloping cuboid, ensuring even material distribution and minimizing shrinkage, combined with a U-shaped design and transverse webs for increased rigidity, allowing for precise manufacturing and reliable attachment to printed circuit boards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the base strip is made from plastic and produced in a plastic mold at elevated temperature, then the base strip can be manufactured in one piece with complex geometry, but material shrinkage during cooling causes distortion and deformation

Engineering Contradiction:
Improveone-piece manufacturing capabilityVSAvoidshape accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameters of the plastic material by adding glass fiber reinforcement. This composite material has different shrinkage characteristics compared to conventional plastic, reducing the distortion and deformation during cooling while maintaining the one-piece manufacturing capability through injection molding

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The base strip uses a composite material consisting of plastic and glass fibers. This composite structure combines the ease of plastic molding with the dimensional stability of glass fiber reinforcement, eliminating the shrinkage-induced deformation problem while enabling complex one-piece geometry

Inventive Principle:
Principle #40Composite materials

2Productivity

If the base strip deviates from its desired shape due to shrinkage effects, then automated assembly and soldering processes cannot be performed accurately

Engineering Contradiction:
Improveautomated assembly capabilityVSAvoidsolder connection accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By changing the material parameters to include glass fiber reinforcement, the patent achieves dimensional stability that enables both automated assembly and precise soldering. The reduced shrinkage ensures that the base strip maintains its geometric accuracy throughout the manufacturing process, allowing automated placement machines to position components correctly and soldering processes to create accurate connections

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multi-pin base strips are used with more than twelve contacts, then connectivity requirements are met, but shrinkage effects become even more pronounced leading to greater deformation

Engineering Contradiction:
Improvemulti-pin connectivityVSAvoidgeometric distortion
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The glass fiber-reinforced plastic composite material provides the dimensional stability needed for multi-pin base strips. The glass fibers act as a rigid framework that resists the shrinkage forces during cooling, maintaining the precise geometric relationships between multiple contact points even in complex multi-pin configurations with more than twelve contacts

Inventive Principle:
Principle #40Composite materials

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 design reduces deformation during production and cooling, enabling secure and reliable electrical connections with reduced material requirements, facilitating precise attachment and soldering processes.

Implementation Method 1

After the workpiece has been removed from the mold, the workpiece cools down, which can be accompanied by material shrinkage on the workpiece

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP3224908B1Base strip for connection to a printed circuit board
Publication Date: 2019.01.02 PHOENIX CONTACT GMBH & CO KG
  • EP3224908B1 patent drawingFigure 1A~1C
  • EP3224908B1 patent drawingFigure 2A~4
  • EP3224908B1 patent drawingFigure 5~6

AI summary

A base strip (1) for connection to a printed circuit board (3) comprises a first side wall (11) which extends longitudinally along a longitudinal direction (L) and comprises a second side wall (12) which extends longitudinally along the longitudinal direction (L) and is at a distance from the first side wall (11) along a transverse direction (Q) which is directed transverse to the longitudinal direction (L), so that a receiving space (13) is formed between the side walls (11, 12), it being possible for one or more plug elements (2) to be inserted into said receiving space in an insertion direction (E). A base (10) connects the first side wall (11) and the second side wall (12) to one another and has a plurality of receiving openings (103) for receiving electrical contact elements (14). In this case, it is provided that the centre of gravity (M) of the base strip (1) corresponds to the geometric centre of gravity of an imaginary cuboid (B) which encloses the base strip. A base strip which can exhibit reduced shrinkage and, associated therewith, reduced deviation in shape from a desired shape is provided in this way.