Structured Casting Mold Surface for Thin-Wall Aluminum Flow

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current casting technologies face limitations in producing cast parts with wall thicknesses less than 5 mm due to surface tension and oxide skin formation during long flow paths of aluminum melts, leading to increased material usage and weight, particularly in lightweight construction applications.

Innovation Solution

A casting tool with a surface structure composed of unit cells featuring protruding and recessed structures that minimize contact area with the molten metal, promoting local turbulent flows and reducing surface tension, allowing for increased flow length or reduced wall thickness without negatively impacting the cast part's properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a smooth casting surface is used, then the contact area with molten metal is maximized, but this causes oxide skin formation and surface tension issues that limit flow path length

Engineering Contradiction:
Improveflow path lengthVSAvoidoxide skin formation
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The casting surface is equipped with a structured surface pattern consisting of protrusions and recesses that create localized air pockets. This local structural modification reduces the contact area between molten metal and mold surface, preventing oxide skin formation in critical flow path areas while maintaining overall casting integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The structured surface pattern acts as an intermediary layer between the molten metal and the mold cavity. The protrusions and recesses trap air to form a gas barrier that mediates the interaction between molten metal and mold surface, reducing direct contact and preventing harmful oxide formation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Weight of moving object

If wall thickness is reduced for lightweight construction, then material usage and weight decrease, but flow path length increases causing surface tension and oxide layer issues

Engineering Contradiction:
Improvecasting weightVSAvoidflow path length
Core Design Contradiction:
Weight of moving objectVSQuantity of substance

Solution Approach 1:

The structured surface pattern is specifically applied in regions where thin-walled sections require long flow paths. The localized modification of the casting surface in these critical areas prevents oxide skin formation and surface tension issues, enabling production of lightweight castings with wall thicknesses below 5 mm.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The casting surface is segmented into multiple protrusions and recesses that divide the continuous contact area into discrete zones. This segmentation creates multiple small air pockets throughout the flow path, collectively preventing oxide skin formation and enabling longer flow paths necessary for thin-walled lightweight castings.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a structured surface is applied across the entire casting surface, then oxide skin formation is prevented, but manufacturing complexity increases

Engineering Contradiction:
Improvecasting qualityVSAvoidsurface structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of applying the structured surface pattern across the entire casting surface, it is selectively applied only to critical flow path areas where thin-walled sections require extended metal flow. This partial application maintains casting quality in critical regions while minimizing manufacturing complexity and cost.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The structured surface is divided into repeating unit cells with standardized protrusion and recess patterns. This modular segmentation simplifies manufacturing by allowing the use of standardized patterns in critical areas rather than requiring complex custom surface treatments across the entire mold.

Inventive Principle:
Principle #1Segmentation

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 surface structuring enables the production of cast parts with wall thicknesses less than 5 mm by breaking up the oxide skin and reducing surface tension, optimizing lightweight construction by minimizing material usage and weight while maintaining the quality of the cast parts.

Implementation Method 1

promoting local turbulent flows

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

reducing surface tension

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 3

breaking up the oxide skin

Methodology Applied
Scientific EffectOxide layer formation: Oxidation

Data Source

PatentEP3212350B1Casting mold comprising at least one cavity for manufacturing at least one cast article
Publication Date: 2022.09.21 VOLKSWAGEN AG
  • EP3212350B1 patent drawingFigure 1~3
  • EP3212350B1 patent drawingFigure 4a~4e
  • EP3212350B1 patent drawingFigure 5a~5f

AI summary

The invention relates to a casting mold (2) which comprises at least one cavity (4) for manufacturing at least one cast article and in which at least some areas of a casting surface (3) of the casting mold (2) delimiting the cavity (4) have a surface structure (7). The surface structure (7) consists of a plurality of elementary cells, each of which has a structure that is raised and/or recessed in relation to the casting surface (3) and ends within the elementary cell. The invention further relates to a cast article manufactured using said casting mold (2).