Permanent Mold Parting-Line Bulges for Burr-Controlled Helix Casting

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Solution Overview

Problem

Existing methods for producing helices by casting technology are inefficient and costly due to the need for additional cores or slides, which lead to high stresses in the mold, causing washouts, cracks, and raised burrs on the coil surface, requiring extensive finishing and shortening the mold's service life.

Innovation Solution

A method using a permanent mold with mold halves that can be joined together, featuring a cavity that defines a helix or bent-up helix with a flattened winding cross-section profile. The mold has protrusions along the mold parting line, creating indentations in the casting that house burrs, thereby preventing them from affecting the coil's quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional cores or slides are used in the mold for complex geometries, then the mold can produce complex helix shapes, but the production cost increases and the mold service life decreases due to high stresses

Engineering Contradiction:

Improveability to produce complex helix geometriesVSAvoidproduction process complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The mold is divided into multiple mold halves that can be assembled together to form the complete cavity. This segmentation allows the mold to produce complex helix geometries without requiring additional cores or slides, as each mold half can be independently designed and positioned to create the desired complex shape when joined together.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If additional cores or slides are used in the mold, then complex geometries can be produced, but the mold is subjected to high stresses leading to washouts and cracks

Engineering Contradiction:

Improveability to produce complex helix geometriesVSAvoidmold service life

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using additional cores or slides to create complex geometries (which would increase stress on the mold), the invention inverts the approach by designing the mold cavity itself to directly form the complex helix shape. The cavity is designed with varying cross-sections that match the desired helix geometry, eliminating the need for stress-inducing additional components.

Inventive Principle:

Principle #13The other way round (Inversion)

3Productivity

If the mold is subjected to high casting temperatures, then the casting process can proceed, but washouts and cracks occur in the mold leading to raised burrs on the coil surface

Engineering Contradiction:

Improvecasting process efficiencyVSAvoidcoil surface quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention converts the potential harm of high casting temperatures by designing a mold cavity that is optimized for thermal resistance. The segmented mold structure allows for better heat distribution and reduced thermal stress concentration, transforming the high temperature condition from a harmful factor into a manageable process parameter that does not compromise mold integrity or surface quality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Productivity

If raised burrs are formed on the coil surface, then the casting process can complete, but extensive finishing is required which increases production time and cost

Engineering Contradiction:

Improvecasting cycle completionVSAvoidfinishing time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12296375B2Method for producing a helix and permanent mold for casting a helix

Publication Date: 2025.05.13 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

A permanent mold can include mold halves which can be joined together on a mold separation plane. The mold halves of the permanent mold are joined together such that the permanent mold has a cavity, which defines the shape of the helix or the shape of a bent-up helix, when the permanent mold is joined together. The specified helix or the bent-up helix has a flattened profiled winding cross-section which has two opposite flat faces, an outer face and an inner face opposite the outer face. The mold separation plane runs at least partly along the flat faces from the inner face to the outer face, wherein the permanent mold has a bulge which extends along the mold separation plane and protrudes into the cavity at least in a region in which the mold separation plane runs along one of the flat faces such that the cast body is provided with recesses on the flat faces.