Segmented Pressing Tool Die for Radial Stress Relief
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Solution Overview
Problem
The existing press tooling methods for manufacturing mechanical parts by pressing powders face issues such as radial stress-induced damage and dimensional defects during demolding, with current solutions either being ineffective, costly, or complex to implement, particularly due to non-uniform compression and subsequent shrinkage issues.
Innovation Solution
A press tool with a die composed of integrally joined sectors and a unitary part, featuring conical surfaces for sliding movement and inserts made of harder materials for improved durability and adaptability, along with a controlled mechanism using a pinion and crown system to manage the movement and force distribution, allowing for controlled stress release and reclosure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single punch or pair of punches is used for compression, then high-speed production is achieved, but non-uniform compression causes radial stress and dimensional defects in the pressed parts
Solution Approach 1:
The die is divided into multiple sectors that can move independently relative to each other. During compression, the sectors remain closed together to ensure uniform compression. During demolding, the sectors separate to release radial stresses progressively, preventing cracking while maintaining high production speed
Solution Approach 2:
The die sectors are made movable rather than fixed, allowing them to dynamically adjust their position. The sectors can close tightly during pressing to ensure uniform compression, then separate during demolding to control stress release, adapting the die structure to different phases of the pressing cycle
2Strength
If lubricant or binder additives are added to the powder, then cohesion of the material is improved, but sintering quality deteriorates due to volatility and pollution
Solution Approach 1:
The die is segmented into movable sectors that separate during demolding, creating a gradual stress release that prevents part cracking without requiring harmful additives. This mechanical solution replaces the need for lubricant or binder additives
Solution Approach 2:
The invention converts the potentially harmful sudden stress release (which causes cracking) into a beneficial gradual stress release by using movable sectors. The harm of radial stress is transformed from a cracking cause into a controlled demolding process
3Ease of operation
If the die housing orifice is provided with a chamfer or connecting radius, then part removal is facilitated, but the solution is only effective for specific orifice profiles and is difficult to implement
Solution Approach 1:
Instead of modifying the orifice geometry with complex chamfers or radii, the invention segments the die into movable sectors. This provides a universal demolding solution that works for various orifice profiles without requiring complex geometric modifications
4Ease of operation
If tubes of rubber or flexible materials are added to the matrix, then demolding is facilitated, but the cost increases significantly
Solution Approach 1:
The die is segmented into movable sectors that separate during demolding, providing a cost-effective alternative to expensive rubber tubes. The segmentation mechanism itself enables easy demolding without requiring additional sacrificial materials
5Extent of automation
If sector actuators are used to control sector movements, then automation is achieved, but the device complexity increases and sector positioning reliability is not guaranteed
Solution Approach 1:
The movable sectors are designed to open and close automatically based on the pressing cycle without requiring complex actuators. The sectors self-adjust their position in response to the punch movements and internal pressure, achieving automation through the inherent mechanics of the system rather than external control mechanisms
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 design enables reliable and automated high-speed compression with reduced risk of part damage and defects, ensuring consistent part quality by utilizing the elasticity of the matrix for stress management and allowing for precise adjustments and adaptations without complex sector actuators.
Implementation Method 1
a frame surrounding the die, which rests on the frame in a sliding manner by conical surfaces
Implementation Method 2
The construction of the die in sectors joined integrally to a unitary part makes it possible to take advantage of the elasticity of the material of the matrix to allow the separation of the sectors under the internal pressure of the parts
Data Source
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AI summary
The invention is characterised by the use of a tool in a pressing machine, including one or two punches (2 or 3) and a die (5) including circle sectors (23) that can move apart but are connected to a main common portion (21), a ring (25) surrounding and retaining the sectors, against which it is adjusted via conical surfaces, and having a variable altitude due to the rotation of a wheel (15) with a raised surface. When the compression is complete, the stripping is preceded by a slight spacing of the sectors in order to relieve stresses in the compressed part and to avoid numerous risks of damage to the part. The sectors are made resistant by inserts (46) which are made of a hard material, generally removable, and which can be wrought into the exact profile of the parts to be formed.