Expandable Casing Pin for Casting Model Feeder Residue Separation

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Solution Overview

Problem

In foundry technology, the separation of feeder residue from the cast part after casting is laborious due to the feeder not coming into contact with the model surface during molding, resulting in a large distance between the feeder and the casting surface, which complicates the removal of the feeder residue.

Innovation Solution

A forming mandrel with an elastically expandable cover that bridges the distance between the model surface and the feeder, forming a predetermined breaking point on the cast part surface, eliminating the need for additional components like crusher cores and simplifying the separation of the feeder residue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rigid forming mandrel is used to fix the feeder during molding, then the feeder remains at a distance from the model surface, but this results in laborious removal of feeder residue after casting

Engineering Contradiction:
ImproveFeeder positioning stabilityVSAvoidFeeder residue removal
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The forming mandrel incorporates an elastically expandable casing that can dynamically change its state. During molding, the casing is in a compressed state to allow feeder placement, and during demolding, it expands to bridge the gap between the feeder and model surface, enabling easy residue removal. This dynamic adaptation resolves the contradiction between maintaining feeder distance during molding and enabling close contact for residue removal.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic casing changes its physical parameters (volume, shape, position) in response to pressure changes. Under molding pressure, the casing compresses to accommodate the feeder; after molding, it expands back to its original form, bringing the feeder into contact with the model surface. This parameter change allows the system to satisfy different requirements at different stages of the process.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If molding pressure is applied to fix the feeder, then the feeder is securely positioned, but the feeder does not contact the model surface creating a large distance

Engineering Contradiction:
ImproveFeeder fixationVSAvoidDistance from model surface
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The forming mandrel is segmented into a rigid core structure and an elastically expandable casing. The rigid core provides stable fixation during molding, while the expandable casing acts as a separate element that can independently expand after molding to bridge the gap. This segmentation allows the system to simultaneously achieve secure fixation and close contact with the model surface.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If an additional crusher core is used to create a breaking point, then feeder residue can be separated, but the device complexity increases

Engineering Contradiction:
ImproveFeeder residue separationVSAvoidNumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the functions of the forming mandrel and the breaker core into a single integrated structure. The elastically expandable casing of the forming mandrel simultaneously serves as both the fixation mechanism during molding and the breaker core that creates the predetermined breaking point. This merging eliminates the need for separate crusher core components, reducing device complexity while maintaining residue separation capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The elastically expandable casing performs multiple functions: it provides a receiving area for the feeder during molding, maintains feeder positioning, and after expansion, creates the predetermined breaking point for residue removal. This multi-functionality replaces what would traditionally require separate components (forming mandrel + crusher core), thereby reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 elastically expandable cover ensures a stable breaking point on the cast part surface, significantly reducing the effort required to remove the feeder residue, as it maintains contact with the model surface and absorbs molding pressure, allowing for easy detachment of the feeder residue after casting.

Implementation Method 1

at least one foot and/or a partial area of its receiving area for the feeder (16) is elastically expandable

Methodology Applied
Scientific EffectElastic expansion: Elasticity

Data Source

PatentEP3368234B1Pin having an expandable casing, and casting model having a pin, and method for casting metals
Publication Date: 2020.08.26 GTP SCHAFER GIESSTECHN PROD
  • EP3368234B1 patent drawingFigure 1
  • EP3368234B1 patent drawingFigure 2
  • EP3368234B1 patent drawingFigure 3

AI summary

The invention relates to a pin (12) to be placed on a casting model (10) molded into a casting mold used when casting metals during the production of said mold, comprising a foot (13) standing on the model surface (11) of the casting model (10) and a holding area (14) arranged on the foot (13) for receiving a riser (16) to be molded therein during the production of the casting mold, wherein the riser (16) is plugged onto the pin (12) by means of a riser opening (20) formed in the bottom surface (17) of the riser facing the casting model (10) before the molding in, characterized in that a casing (21) that is elastically expandable and is connected to the foot (13) of the pin (12), immediately adjacent to the model surface (11), enclosing at least the foot (13) of said pin and/or a sub-region of the holding region (14) thereof for the riser (16), connected immediately adjacent to the model surface (11), is fitted to the pin (12) in such a way that, the casing (21), which is widened before the start of the molding, bridges a distance to the model surface (11) that still exists following the molding of the riser (16), such that after casting the model (10) having the pin (12) placed thereon has been de-molded from the casting mold, an intended fracture point (27a) formed by the contour (26) of the expanded casing (26) is formed for a riser residue (28) that remains after the casting operation has been completed.