Mold Sections with Frangible Seal for Thermal Expansion

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Solution Overview

Problem

The expansion and contraction of thermoplastic molds during the molding process of thermoset components can lead to issues such as parts being squeezed out or trapped, causing damage to the mold or the part, especially when the mold is not made of the same material as the part, resulting in costly solutions like constructing molds from the same material as the part.

Innovation Solution

A 3D printing process that produces molds with a frangible sealing material, allowing the mold to fracture or separate in a controlled manner, using multiple sections with a sealing material that maintains vacuum during heating and releases during cooling, or employing mechanical means like springs, hydraulic cylinders, or scissor mechanisms to manage contraction forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the mold is made of different material than the part, then manufacturing cost is reduced and manufacturing flexibility is improved, but the mold may expand or contract at different rates causing parts to be squeezed out or trapped

Engineering Contradiction:

Improvemold manufacturing flexibilityVSAvoidpart damage from mold expansion/contraction

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The mold is divided into multiple sections that can move independently relative to each other. This segmentation allows each section to accommodate expansion and contraction differently, preventing the harmful effects of uniform thermal stress while maintaining the ability to use different materials for the mold and part.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mold transitions from a static structure to a dynamic one where sections can move relative to each other in response to thermal expansion and contraction. This dynamic capability allows the mold to adapt to temperature changes without causing part damage, resolving the contradiction between material flexibility and thermal stability.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the mold sections are held together rigidly, then vacuum seal integrity is maintained, but thermal expansion and contraction forces cause damage to the mold or part

Engineering Contradiction:

Improvevacuum seal integrityVSAvoidmold and part structural integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

A flexible seal element is used between mold sections to maintain vacuum integrity while accommodating thermal movement. The flexible nature of the seal allows it to deform with expansion and contraction forces, maintaining the seal without transmitting damaging forces to the part or mold structure.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The connection between mold sections is designed to change its mechanical properties in response to temperature changes. The connection allows rigid positioning at operating temperature for seal integrity, but permits movement during thermal transitions to prevent damage.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If the mold allows free movement during thermal expansion, then part damage is prevented, but vacuum seal integrity is compromised

Engineering Contradiction:

Improvepart damage preventionVSAvoidvacuum seal integrity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The flexible seal element enables the mold sections to move relative to each other during thermal expansion while maintaining vacuum integrity. The flexibility of the seal allows accommodation of dimensional changes without compromising the seal or requiring rigid constraints that would cause part damage.

Inventive Principle:

Principle #30Flexible shells and thin films

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

Enables the production of thermoset components with molds made of different materials, preventing damage to the mold or part by allowing controlled separation and maintaining vacuum integrity during the curing process, thus addressing the issues of expansion and contraction without the need for expensive matching material molds.

Implementation Method 1

maintaining vacuum between mold sections

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

The expansion and contraction of thermoplastic molds during the molding process

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20240208114A1Systems and methods for producing parts at elevated temperatures

Publication Date: 2024.06.27 THERMWOOD CORP

AI summary

A mold assembly for producing a part includes a first section, a second section movably coupled to the first section, and a cavity defined by the first section and the second section, the cavity being shaped to receive a part while the first section and the second section are movably coupled to each other. The mold assembly includes a joint formed by adjacent surfaces of the first section and the second section and a seal extending along the joint.