Expandable King Core for Riser Inner Cavity Demolding

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Solution Overview

Problem

The existing methods for producing feeders for casting molds are complex and require the use of multiple core geometries, making it difficult to produce a one-piece feeder body with intricate inner cavity shapes, such as barrel-like or spherical designs, due to the challenges of demolding from core shooters.

Innovation Solution

A method using an expandable king with a flexible membrane or spring element within a core box allows for the reversible expansion of the outer contour, enabling the formation of a one-piece feeder body with a simplified process, where the king's expanded shape forms the inner cavity, and it returns to its original shape for easy demolding, allowing the feeder body to be removed without additional core insertion or removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If complex inner cavity shapes (barrel-like or spherical) are used to improve feeder module and solidification control, then casting quality improves, but manufacturing complexity increases requiring multiple core geometries and assembly steps

Engineering Contradiction:
Improveinner cavity shape precisionVSAvoidcore geometry complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The core (king) is designed with expandable geometry, transforming from a compact transport state to an expanded forming state. This dynamic transformation allows a single core to create complex inner cavity shapes without requiring multiple static core geometries, resolving the contradiction between shape precision and device complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The king is inserted into the core box cavity in a compact nested state, then expanded to form the desired inner cavity shape. This nesting principle allows the core to be transported and positioned easily while still achieving complex geometries during the shooting process, eliminating the need for multiple core components

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If undercut inner cavity designs are used to optimize feeder performance, then solidification control improves, but demolding difficulty increases requiring additional core removal steps

Engineering Contradiction:
Improvesolidification controlVSAvoiddemolding ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The expandable king maintains undercut inner cavity designs for optimal solidification control while enabling easy demolding through geometric transformation. After shooting, the king is contracted to a compact form that can be easily removed through the feeder opening, eliminating the demolding difficulties associated with undercut geometries

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The manufacturing process is segmented into distinct phases: the king remains stationary during shooting to form the complex inner cavity, then is contracted and removed in a separate demolding phase. This temporal segmentation allows complex geometries to be formed without compromising demolding ease

Inventive Principle:
Principle #1Segmentation

3Device complexity

If a one-piece feeder body is produced to simplify assembly, then manufacturing steps are reduced, but demolding from core shooter becomes more difficult due to undercut geometries

Engineering Contradiction:
Improvefeeder assembly structureVSAvoiddemolding process
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The expandable king enables one-piece feeder body production by forming complex inner cavities during shooting, then contracts to allow easy removal of the completed feeder from the core box. This dynamic geometry change resolves the contradiction between producing integrated structures and maintaining demolding ease

Inventive Principle:
Principle #15Dynamics

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

This approach simplifies the production of feeders with complex inner cavity shapes by allowing the feeder body to be removed intact, eliminating the need for additional core handling and enabling the production of feeders with undercut designs, such as spherical shapes, in a single piece.

Implementation Method 1

a spring element (18) surrounding said mandrel (17), by the tension of which the outer contour of the king (15) can be enlarged

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

the membrane (19) surrounding said spring element (18) on the outside, which follows its movements in each case

Methodology Applied
Scientific EffectElastic recovery: Elastic Recovery

Data Source

PatentEP3349923B1Method for producing a riser in a core shooter, and core box suitable for performing the method
Publication Date: 2019.08.21 GTP SCHAFER GIESSTECHN PROD
  • EP3349923B1 patent drawingFigure 1
  • EP3349923B1 patent drawingFigure 2
  • EP3349923B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a riser for inserting into a casting mold used for casting metals, which riser consists of a riser body (31), which surrounds an inner cavity (36) as a riser volume and is composed of an exothermic and/or insulating riser material (30), wherein a riser opening (35) is formed in the base region (34) and the inner cavity (36) has, in at least a partial region, a diameter that is larger than the diameter of the riser opening (35), and wherein the riser body (31) is produced by shooting in a core shooter, characterized in that, in order to produce a single-piece riser body (31) having the specified shape in a two-part core box (10) having a bottom box (11) and a top box (12), a cavity (14) reproducing the outer contour of the riser body (31) is formed and, in order to produce the inner cavity (36), a king (15), the outer contour of which can be reversibly expanded, is set in the cavity (14) in such a way that, in the shooting of the riser body (31), the wall region (32), the cap region (33), and the base region (34) of the riser body are formed by the riser material (30) introduced into the intermediate space (41) between the expanded king (15) and the inner wall (40) of the cavity (14), wherein the riser opening (35) arranged in the base region (34) of the riser body (31) is formed by a foot segment (37) of the king (15), which foot segment specifies a first diameter, and the king (15) does not protrude beyond the diameter of the foot segment (37) in the non-expanded position of the king such that the completely shot riser body (31) can be removed from the king (15) by means of the riser opening (35) of the riser body during the unmolding from the core box (10).