Wheel Disk Ironing with Non-Constant Thickness to Prevent Cracks
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Solution Overview
Problem
Conventional methods of manufacturing large- or medium-sized wheel disks often result in cracks during the diametric enlargement of the first-stage product, as the ironing process reduces the length of the ironed portion significantly, leading to material stress and potential cracking.
Innovation Solution
A method involving a first step of ironing a flat plate blank to a first-stage product with an axially non-constant thickness, where only the thickness-reduced portion is ironed, followed by a second step of diametrically enlarging the rising portion to form a conical shape, and a third step of forming the tip portion into a disk flange configuration, using a punch and die in each step to minimize material stress and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the entire rising portion is ironed to reduce thickness uniformly, then the thickness is reduced effectively, but cracks are generated during subsequent diametric enlargement
Solution Approach 1:
The ironing process is applied selectively to specific regions of the blank rather than uniformly across the entire rising portion. The first ironing step targets the base region to create a thickness-reduced portion, while the tip region is preserved with greater thickness to prevent cracks during subsequent diametric enlargement.
Solution Approach 2:
The rising portion is divided into distinct regions with different thickness characteristics: a thickness-reduced portion at the base and a thick portion at the tip. This segmentation allows each region to be optimized for its specific function - the thinned base for weight reduction and the thick tip for structural integrity during forming.
2Manufacturing precision
If multi-step ironing is performed to achieve precise thickness distribution, then the thickness control is improved, but the manufacturing process becomes more complex
Solution Approach 1:
Instead of performing multiple ironing steps to achieve complete thickness reduction across the entire rising portion, the process applies ironing partially to only the base region. This partial action achieves the necessary thickness distribution with fewer steps, avoiding unnecessary process complexity while maintaining precision where needed.
3Productivity
If the rising portion is diametrically enlarged immediately after ironing, then the forming efficiency is high, but cracks occur due to insufficient material length
Solution Approach 1:
The ironing step is performed as a preliminary action before diametric enlargement, but with a modified approach that preserves material length in the tip region. This preliminary thickness reduction at the base prepares the material for subsequent forming operations while the preserved thick portion provides sufficient material length to prevent cracks during enlargement.
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 reduces the occurrence of cracks in the wheel disk, allows for more stable formation of the product, and decreases the load on the ironing apparatus, resulting in a product with improved structural integrity and reduced manufacturing costs.
Implementation Method 1
a first step of ironing a blank of a flat plate as a material to a first-stage product having a cylindrical rising portion of an axially non-constant thickness using a punch and a die
Implementation Method 2
a second step conducted after the first step, of diametrically enlarging the rising portion of the first-stage product to form a conical rising portion
Data Source
AI summary
A method of manufacturing a large- or medium-sized wheel disk including using a punch or die in a first step of ironing a blank of a flat plate to a first-stage product. The first-stage product having a cylindrical rising portion with an axially non-constant thickness. The rising portion includes a thick portion located at a tip portion of the rising portion and a thickness-reduced portion which is a remaining portion of the rising portion excluding the thick portion. During the first step, only a portion of the blank corresponding to the thickness-reduced portion is ironed.