Segmented Mold Inserts for Cast Electrotechnical Coils

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Solution Overview

Problem

Existing methods for casting electrotechnical coils are inefficient, requiring extensive material usage and time, and often necessitate complex and costly production processes due to the need for multiple mold parts and cores.

Innovation Solution

A permanent mold casting tool designed for aluminum or aluminum alloys, featuring segmented mold inserts that can be manufactured efficiently using a single sinker electrode, allowing for precise geometry and reduced material usage, with a sprue system ensuring uniform filling and solidification of the mold cavities, enabling rapid and cost-effective production of coils with a filigree structure without the need for slides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional casting methods are used with multiple mold parts and cores, then complex coil geometries can be produced, but the production process becomes time-consuming and costly

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidproduction speed
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The mold insert is divided into multiple mold segments that can be manufactured separately and assembled together. Each segment corresponds to a specific coil turn, allowing for simplified individual manufacturing while achieving complex overall coil geometries through assembly. This segmentation enables parallel production of mold segments, improving overall productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mold segments are pre-manufactured with precise geometries using die-sinking EDM before assembly. The segmentation allows each mold segment to be prepared in advance, and the assembly of pre-fabricated segments into the complete mold insert significantly reduces the overall manufacturing time compared to creating the entire mold as a single complex piece.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If a single die-sinking electrode is used for manufacturing mold inserts, then manufacturing cost and time are reduced, but the precision and geometry of complex coil structures become difficult to achieve

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmold cavity geometry precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The complex mold insert geometry is segmented into multiple simpler mold segments that can each be manufactured using a single die-sinking electrode. This segmentation allows the use of simpler, more efficient manufacturing processes for each segment while the precise assembly of these segments achieves the overall complex coil geometry with high precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each mold segment is designed with specific local geometries optimized for its particular coil turn requirements. This allows die-sinking electrodes to be tailored for each specific segment's needs, achieving high precision for each local region while maintaining overall manufacturing efficiency through the segmented approach.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If mold segments are spaced apart during manufacturing, then the delicate mold cavity structure can be produced more easily, but the final coil geometry precision may be compromised

Engineering Contradiction:
Improvemold cavity production easeVSAvoidcoil geometry precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The mold insert is segmented into multiple independent mold segments that can be manufactured separately with easier, more accessible geometries. The spacing between segments during manufacturing allows for simpler die-sinking operations on each individual segment while maintaining the ability to achieve precise final coil geometry through careful assembly and positioning of the segmented components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Spacer elements or positioning features act as intermediaries between the mold segments during assembly. These intermediaries ensure precise relative positioning of the segmented mold pieces, maintaining the delicate mold cavity structure and achieving accurate final coil geometry despite the segments being manufactured separately with spacing.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If multiple mold cavities are arranged in a multi-cavity tool, then material usage and production time are reduced, but the complexity of the sprue system and uniform filling becomes more difficult to control

Engineering Contradiction:
Improvecasting cycle speedVSAvoidsprue system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The multi-cavity mold tool is segmented into multiple independent or semi-independent mold cavities, each capable of being filled and solidified relatively independently. This segmentation allows for a distributed sprue system design where molten metal can be delivered to multiple cavities through a branched sprue network, reducing the total material volume required compared to a single large cavity while maintaining controllable filling patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sprue system is designed to provide equipotential flow distribution to multiple mold cavities, ensuring uniform filling and solidification across all cavities. By carefully designing the sprue branch dimensions and routing, the system maintains balanced metal flow to each cavity, controlling the complexity of the multi-cavity system and ensuring consistent part quality across all cavities.

Inventive Principle:
Principle #12Equipotentiality

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 solution enables rapid, cost-effective, and precise production of electrotechnical coils with reduced material usage, allowing for efficient casting of coils with complex geometries while minimizing mechanical stress and optimizing space requirements, thus improving the efficiency and quality of the casting process.

Implementation Method 1

The spacing of the mold cavity allows it to be produced preferably by die-sinking EDM, particularly preferably using a single die-sinking electrode.

Methodology Applied
Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Implementation Method 2

Starting from this central casting center point, several, in particular at least two, preferably a maximum of six, and most preferably four, mold cavities are arranged one behind the other to form a common casting cavity.

Methodology Applied
Scientific EffectGravity-driven flow: Gravitation

Data Source

PatentEP3785821A1Casting tool for cast electrotechnical coils
Publication Date: 2021.03.03 VOLKSWAGEN AG
  • EP3785821A1 patent drawingFigure 1
  • EP3785821A1 patent drawingFigure 1
  • EP3785821A1 patent drawingFigure 2

AI summary

Casting tool (1) for producing cast electrotechnical coils (30), wherein the cast coil (30) has several spaced-apart windings (31) around a hollow core area (32) extending along a coil axis (33), wherein the casting tool (1) comprises at least two mold inserts (2, 3) movable relative to each other in a demolding direction (4) for forming at least one mold cavity (5) which is form-giving for exactly one coil.