Injection Mold Cavity Deformation for Part Shape Compensation

Solution Overview

Problem

Existing injection molding methods often result in deformation of parts relative to their nominal shape due to residual stresses, requiring complex and costly compensation molds, which are typically determined through iterative testing.

Innovation Solution

An injection molding device and method that uses deformation elements, such as actuators or bladders, to modify the mold cavity shape from a circular to an oval section, allowing for precise compensation of deformation without the need for intermediate molds, utilizing a servo-control system to verify and control the deformation elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a compensation mold is made through iterative testing to counter deformation, then the part achieves its nominal shape after extraction, but the process becomes expensive and time-consuming

Engineering Contradiction:

Improvepart shape accuracyVSAvoidmold development time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and pre-applying the compensation deformation to the mold cavity shape before production begins. Instead of iterative testing, the compensation mold is designed using theoretical calculations of residual stress distribution and deformation patterns, allowing the mold to be prepared in advance with the correct compensating geometry.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical/empirical iterative testing process with a theoretical calculation-based approach. By using mathematical models to predict deformation and calculate compensation parameters, the system substitutes physical trial-and-error with computational analysis, significantly reducing development time and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If a compensation mold is made through iterative testing to counter deformation, then the part achieves its nominal shape after extraction, but the cost increases

Engineering Contradiction:

Improvepart shape accuracyVSAvoidmold manufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical/empirical iterative testing process with a theoretical calculation-based approach. By using mathematical models to predict deformation and calculate compensation parameters, the system substitutes physical trial-and-error with computational analysis, significantly reducing development time and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a theoretical model or digital representation of the deformation behavior and uses this copy to determine the compensation parameters. Instead of physically testing multiple mold iterations, the system uses computational models to replicate and analyze deformation patterns, allowing virtual optimization before actual manufacturing.

Inventive Principle:

Principle #26Copying

3Manufacturing precision

If multiple intermediate molds are made to determine proper compensation shape, then the optimal compensation is found empirically, but productivity decreases

Engineering Contradiction:

Improvecompensation accuracyVSAvoidpart production rate

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and pre-applying the compensation deformation to the mold cavity shape before production begins. Instead of iterative testing, the compensation mold is designed using theoretical calculations of residual stress distribution and deformation patterns, allowing the mold to be prepared in advance with the correct compensating geometry.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical/empirical iterative testing process with a theoretical calculation-based approach. By using mathematical models to predict deformation and calculate compensation parameters, the system substitutes physical trial-and-error with computational analysis, significantly reducing development time and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10737422B2Device and a method for fabricating a part by injection molding

Publication Date: 2020.08.11 SAFRAN AIRCRAFT ENGINES SAS

AI summary

An injection molding device for fabricating a part, the device including an injection mold, the mold being formed of a support and a countermold that are distinct and that define between them a mold cavity presenting a first shape; and at least one injection device for injecting a fluid material into the mold cavity; the device including deformation elements configured to modify the shape of the mold cavity into a second shape distinct from the first shape.