Polyolefin Seat Element Moulding With Template-Controlled Shrinkage
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Solution Overview
Problem
Expandable and reticulable polyolefin materials used for seat elements face challenges in controlling expansion and shrinking processes, leading to dimensional issues and complex assembly with support frames, resulting in high reject rates and increased production costs.
Innovation Solution
A manufacturing method involving a first expansion phase followed by a thermoretraction phase during cooling, using a template to control final dimensions and provide a stiffening system, with the template acting as a stable fixing means to anchor the seat element to a frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If expandable and reticulable polyolefin material is used for seat elements, then lightness and resistance to wear and water are improved, but dimensional control and assembly simplicity deteriorate due to uncontrolled expansion and shrinking
Solution Approach 1:
The patent applies preliminary action by inserting a rigid template into the mould before injection, positioned to define the final dimensions of the seat element. The template is placed in advance to guide the expansion and reticulation process, ensuring the material conforms to precise dimensional specifications during the phase changes.
Solution Approach 2:
The rigid template serves as an intermediary element between the expandable polyolefin material and the final dimensional requirements. It mediates the uncontrolled expansion and shrinking processes by providing a physical constraint that guides the material to achieve precise dimensions without direct human intervention during the phase changes.
2Weight of moving object
If expandable and reticulable polyolefin material is used for seat elements, then lightness is improved, but assembly simplicity with support frame deteriorates due to dimensional changes after moulding
Solution Approach 1:
The rigid template is inserted into the mould before injection and remains in place during the expansion and reticulation process. This preliminary positioning ensures that the fixing means (holes or protrusions) are created at precise locations that will align with the support frame, enabling simple assembly after the material completes its phase changes.
Solution Approach 2:
The rigid template acts as an intermediary that establishes the precise geometry of fixing means during the manufacturing process. By constraining the material during expansion and reticulation, it ensures that holes or protrusions are formed at exact positions, eliminating the need for complex adjustments during assembly with the support frame.
3Ease of manufacture
If traditional injection moulding process is used without template, then production cost is reduced, but reject rate increases due to high dimensional variability
Solution Approach 1:
The rigid template is a simple, inexpensive component that can be easily replaced if needed. It is a basic structural element rather than a complex tooling system, making it cost-effective to incorporate into the moulding process. The template ensures high dimensional precision without requiring expensive advanced moulding equipment or complex process controls.
Solution Approach 2:
The rigid template serves as a simple intermediary element that dramatically reduces dimensional variability and reject rates. By providing a physical constraint during expansion and reticulation, it ensures consistent dimensional accuracy without requiring complex process controls or expensive equipment modifications.
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
Ensures precise control of seat element dimensions, simplifies assembly, and reduces production costs by stabilizing the seat element and providing a secure anchoring system, eliminating the need for additional stiffening ribs or inserts.
Implementation Method 1
these items are manufactured by injecting into the mould plastic material that expands and reticulates inside it
Implementation Method 2
the reticulation of the material and decomposition of expanding loads are performed
Implementation Method 3
When the mould is opened, the product is spontaneously released from the mould because of its violent expansion, continues on expanding and then starts shrinking during cooling
Implementation Method 4
starts shrinking during cooling
Implementation Method 5
The template (3) is inserted in the seat (1) before assembly, in order to stabilise it during the thermoretraction phase
Data Source
Figure 1~3
Figure 4~6
AI summary
A manufacturing method of a seat element (1; 101) is disclosed, comprising a body (2) obtained from moulding polyolefin plastic materials of expandable and reticulable type, and a template (3; 103) made of rigid material, which is coupled with the body (2) when it is still hot, in such a way to control the shrinking of the material of the body during cooling.