Drawing Die Tool With Shrink-Fitted Carbide Insert

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Solution Overview

Problem

Existing drawing die tools face challenges in achieving high dimensional accuracy, low frictional forces, and mechanical resistance while maintaining a compact size, especially during the cold working process of drawing metals, where frictional forces and high temperatures pose significant design constraints.

Innovation Solution

A drawing die tool design featuring a wear-resistant cemented carbide forming insert with a tapering outer surface, a steel sleeve made of hot working steel for shrink-fitting, and a securing element, which provides compressive pre-stress and reduces friction through a CVD coating, allowing for precise machining and high-temperature coating processes without compromising mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a wear-resistant forming insert is used in a drawing die tool, then mechanical resistance is improved, but frictional forces increase due to contact with the material

Engineering Contradiction:
Improvemechanical resistanceVSAvoidfrictional forces
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The drawing die tool is segmented into multiple functional components: a steel sleeve providing structural support and compressive pre-stress, a separate wear-resistant forming insert for mechanical resistance, and a CVD coating layer for friction reduction. This segmentation allows each component to optimize its specific function without compromising the others.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A CVD coating layer is introduced as an intermediary between the wear-resistant forming insert and the material being drawn. This coating layer serves as a mediator that reduces frictional forces while allowing the underlying forming insert to maintain its wear-resistant properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the drawing die tool is made compact, then device complexity is reduced, but dimensional accuracy deteriorates

Engineering Contradiction:
ImprovesizeVSAvoiddimensional accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The steel sleeve is subjected to controlled thermal parameters (heating and cooling cycles) to induce compressive pre-stress in the forming insert. This parameter change allows the compact tool structure to maintain high dimensional accuracy through stress-controlled precision.

Inventive Principle:
Principle #35Parameter changes

3Strength

If compressive pre-stress is applied to the forming insert, then mechanical resistance is improved, but device complexity increases due to additional components

Engineering Contradiction:
Improvemechanical resistanceVSAvoidstructure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The steel sleeve and forming insert are merged into a integrated assembly where the sleeve serves multiple functions: providing structural support, applying compressive pre-stress through thermal contraction, and housing the forming insert. This merging reduces overall device complexity while maintaining mechanical resistance.

Inventive Principle:
Principle #5Merging (Combining)

4Object-generated harmful factors

If CVD coating is applied to reduce friction, then frictional forces are reduced, but manufacturing complexity increases due to additional coating process

Engineering Contradiction:
Improvefrictional forcesVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The CVD coating is applied as a preliminary action before the forming insert is installed in the drawing die tool. This preliminary coating ensures friction reduction is built into the component itself, eliminating the need for additional friction management mechanisms during operation.

Inventive Principle:
Principle #10Preliminary action

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 achieves improved dimensional accuracy, reduced frictional forces, and enhanced mechanical resistance, enabling efficient drawing of tougher materials with increased speed and reduced wear, while maintaining a compact size and allowing for easy recycling of the forming insert.

Implementation Method 1

a steel sleeve made of hot working steel into which the wear-resistant forming insert is fitted by shrink-fitting, the steel sleeve providing compressive pre-stress to the wear-resistant forming insert

Methodology Applied
Scientific EffectShrink-fitting: Thermal Contraction

Implementation Method 2

reduced friction through a CVD coating

Methodology Applied
Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 3

the steel sleeve having an internal surface tapering in the working direction which is adapted for cooperating with the outer surface of the wear-resistant forming insert

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2796218B1Drawing die tool and method of forming such a drawing die tool
Publication Date: 2016.03.16 CERATIZIT ITAL
  • EP2796218B1 patent drawingFigure 1~3
  • EP2796218B1 patent drawingFigure 4~6c

AI summary

A drawing die tool (1) is provided, which comprises: a wear-resistant forming insert (5) having an outer surface (50) tapering in a working direction (W); a steel sleeve (4) made of hot working steel into which the wear-resistant forming insert (5) is fitted by shrink-fitting, the steel sleeve (4) having an internal surface (41) tapering in the working direction which is adapted for cooperating with the outer surface (50) of the wear-resistant forming insert (5) and an external surface (40); an outer casing (2) having an internal surface (25) in which the steel sleeve (4) together with the wear-resistant forming insert (5) is mounted with the external surface (40) of the steel sleeve (4) contacting the internal surface (25) of the outer casing (2); and a securing element (6) for securing the steel sleeve (4) and the wear-resistant forming insert (5) in the outer casing (2).