Thin-Resin Duct Structure for Stronger Parting-Line Welding
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Solution Overview
Problem
Thin ducts molded from thermoplastic resin face challenges in maintaining welding strength at parting lines, leading to potential cracking and peeling due to low cooling rates and small welding areas, which complicates attachment and increases the risk of deformation.
Innovation Solution
A resin duct design with projections on the inner surface and crashed sections on the outer surface at parting lines, featuring trumpet-shaped openings and connecting sections to enhance welding strength and facilitate attachment, while maintaining a thickness of 1mm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the duct thickness is reduced to 1mm or less to lower cost and weight, then the weight and cost are reduced, but the welding strength of the parting line is lowered due to quick cooling and small welding area
Solution Approach 1:
The invention applies local quality by forming projections and crashed sections specifically at the parting line regions where welding is required, while keeping the overall duct thickness at 1mm or less. The projections extend from the inner surface and crashed sections from the outer surface, creating localized thickening only where needed for welding strength, rather than increasing the thickness of the entire duct.
Solution Approach 2:
The invention addresses the thinness issue by adding dimensional features in the radial direction (inner and outer surfaces) at the parting line. By creating projections inward and crashed sections outward, the welding area is expanded in multiple dimensions, transforming a two-dimensional welding problem into a three-dimensional solution that increases welding strength without increasing overall duct thickness.
2Weight of stationary object
If the duct thickness is reduced to 1mm or less, then the cost and weight are lowered, but cracks easily occur at the parting line due to reduced welding strength
Solution Approach 1:
The projections and crashed sections create localized reinforcement specifically at the parting line where cracks are most likely to occur. This local quality enhancement provides crack resistance precisely where needed, without compromising the overall lightweight design of the thin-walled duct.
Solution Approach 2:
The projections and crashed sections act as beforehand cushioning by pre-reinforcing the parting line area before welding occurs. This localized thickening compensates for the inherently weak welding area in thin-walled ducts, preventing crack formation during and after the welding process.
3Strength
If a long rib is formed along the overall length of the crashed section to increase strength, then the welding strength is improved, but the rib interferes with other members and complicates the attaching job
Solution Approach 1:
The invention segments the reinforcement feature into separate components: projections at the inner surface and crashed sections at the outer surface, rather than forming a single long rib extending through the entire duct length. This segmentation provides the necessary welding strength at the parting line while avoiding interference with other members that would occur with a continuous long rib.
Solution Approach 2:
By localizing the reinforcement to specific regions (projections at inner surface, crashed sections at outer surface) rather than forming a long continuous rib, the invention maintains ease of operation for attaching other members while still providing sufficient welding strength at the critical parting line area.
Data Source
Figure 1(a)~1(b)
Figure 2(a)~3
Figure 4
AI summary
A duct in which the welding strength of the parting lines is enhanced and which facilitates the attaching job is provided. The duct of the present embodying mode has a mean thickness of the entire duct of 1mm or less, and includes projections (300) on inner surface sides of the duct on the parting lines PL.