Resilient Contact Members for Insert Molding Dimensional Variations

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Solution Overview

Problem

Conventional mold assemblies for insert-molding heterogeneous objects face issues with dimensional variations, leading to clearance or interference, which result in polymer elastomer overflow or damage to the insert object due to the lack of resilience and deformation capability in the mold materials.

Innovation Solution

A mold assembly incorporating resilient contact members on both the upper and lower molds to absorb dimensional variations of the insert object, preventing direct contact between the insert object and the rigid mold parts, thereby avoiding overflow or damage during the molding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a rigid mold assembly is used for insert-molding, then the mold structure is simple and easy to manufacture, but clearance or interference occurs between the part and mold due to dimensional variation, leading to polymer elastomer overflow or damage to the insert object

Engineering Contradiction:

Improvedimensional accuracy of insert objectVSAvoidmold assembly structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

A resilient member is introduced as an intermediary between the rigid mold assembly and the insert object. This resilient member deforms elastically to accommodate dimensional variations in the insert object, preventing both clearance (which causes overflow) and interference (which causes damage), while the rigid mold structure remains simple and easy to manufacture.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the size of the non-elastic part is too small, then the part can be easily positioned, but gap occurs between the part and lower mold, leading to overflow of injected polymer elastomer

Engineering Contradiction:

Improvepositioning of insert objectVSAvoidgap control between part and mold

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The resilient member changes its physical state from a pre-loaded compressed condition to a relaxed condition during molding. This parameter change allows the resilient member to expand and fill small gaps around small insert objects, preventing polymer elastomer overflow while maintaining ease of positioning.

Inventive Principle:

Principle #35Parameter changes

3Strength

If the size of the non-elastic part is too big, then the part provides sufficient structural support, but interference occurs between the part and lower mold, damaging the appearance of the insert object

Engineering Contradiction:

Improvestructural support of insert objectVSAvoidappearance quality of insert object

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The resilient member is pre-compressed between the upper and lower molds before the insert object is placed. This beforehand cushioning creates a protective buffer that absorbs the dimensional variations of large insert objects, preventing interference damage to the appearance while maintaining sufficient structural support.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If thermal expansion occurs during the insert-molding process, then the molding process can be completed, but interference occurs between the part and rigid mold assembly, damaging the appearance of the part

Engineering Contradiction:

Improvemolding process completionVSAvoidappearance quality of part

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The resilient member utilizes elastic phase transition - it is compressed to a deformed state during mold closing, then relaxes to its original state during molding, accommodating thermal expansion of the insert object. This allows the molding process to complete successfully while preventing appearance damage from thermal expansion interference.

Inventive Principle:

Principle #36Phase transitions

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 use of resilient contact members ensures accurate dimensional formation of the heterogeneous object without damaging the structure or appearance, improving processing yield and durability by absorbing dimensional variations and allowing for high-temperature resistance and easy replacement of mold components.

Implementation Method 1

a resilient contact member... such that the resilient contact member absorbs a dimensional variation of the insert object

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9004894B2Mold assembly

Publication Date: 2015.04.14 PIONEER MATERIAL PRECISION TECH CO LTD

AI summary

A mold assembly for insert-molding a heterogeneous object includes an upper mold and a lower mold. The upper mold includes a cavity for accommodating an insert object. The lower mold includes a rigid body and a resilient contact member for resting the insert object. The resilient contact member absorbs dimensional variations of the insert object during the insert molding process.