Hem Flange Adhesive Bonding Bubble Prevention
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Solution Overview
Problem
Hem flange adhesive bonds in industrial manufacturing face challenges such as the formation of bubbles and cracks, leading to corrosion issues due to incomplete filling and elastic panel rebound, which existing methods like heat treatment and sealant application have not adequately addressed.
Innovation Solution
The use of high-viscosity adhesives, particularly heat-curing epoxy resin adhesives with specific impact modifiers, and the incorporation of spacers to optimize adhesive layer thickness, allowing for simultaneous curing of the adhesive and sealant, thereby reducing bubble and crack formation and enhancing the bond's impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional low-viscosity adhesive is used in hem flange bonding, then the adhesive can be easily applied and spread, but bubbles and cracks form when pressure is released due to elastic panel rebound
Solution Approach 1:
The patent changes the viscosity parameter of the adhesive from conventional low-viscosity to high-viscosity (specifically 500-2000 Pa·s at 25°C). This parameter change allows the adhesive to maintain its position and fill the hem flange cavity effectively without being displaced by elastic rebound, thereby preventing bubble and crack formation while remaining easy to apply.
Solution Approach 2:
The patent uses composite adhesive formulations combining high-viscosity base materials with specific additives (such as silane-modified polymers, epoxy resins, or polyurethanes) to achieve both the desired viscosity characteristics and bonding performance. This composite approach maintains ease of application while providing the structural integrity needed to prevent defects.
2Reliability
If heat treatment is applied to cure sealant material first, then the adhesive can be gelated in the flange seam, but incorporated air creates cavities that lead to corrosion
Solution Approach 1:
The patent applies preliminary action by using high-viscosity adhesive that maintains its position and fills the cavity before curing occurs. The adhesive is applied in a state that prevents air incorporation, and the high viscosity ensures it remains in place during the subsequent curing process, eliminating the need for sequential heat treatment that would trap air.
Solution Approach 2:
The patent changes the viscosity parameter of the adhesive to a high range (500-2000 Pa·s), which allows the adhesive to be applied and positioned without incorporating air bubbles. This parameter change enables complete cavity filling before curing, preventing the formation of corrosion-causing cavities while simplifying the curing process.
3Reliability
If the entire component is heated to gelation temperature, then the adhesive can be cured, but the component becomes significantly distorted and cracks may occur
Solution Approach 1:
The patent applies partial action by using high-viscosity adhesive that achieves effective cavity filling and bonding with reduced heating requirements. The high viscosity allows the adhesive to maintain its position and cure effectively with localized or lower-intensity heat treatment, avoiding the need to heat the entire component to high temperatures, thereby preventing distortion and cracking.
Solution Approach 2:
The patent changes the viscosity parameter of the adhesive to a high range (500-2000 Pa·s), which fundamentally alters the curing behavior. The high-viscosity adhesive maintains its position and fills cavities effectively at lower temperatures and for shorter durations, enabling curing without significant component heating, thus avoiding thermal distortion and cracking.
4Loss of time
If local heating is applied immediately before sealant application, then heating time is reduced, but bubbles in adhesive and cracks in sealing material are not prevented
Solution Approach 1:
The patent changes the viscosity parameter of the adhesive to a high range (500-2000 Pa·s), which fundamentally prevents bubble and crack formation at the source. This parameter change eliminates the need for extensive heating to prevent defects, as the high-viscosity adhesive maintains its position and fills cavities effectively without incorporating air bubbles, even with minimal or localized heating.
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 process effectively prevents or minimizes bubble and crack formation, ensuring a more complete fill of the hem flange, reducing corrosion risks, and simplifies the manufacturing process by reducing steps and improving the quality and durability of the adhesive bond.
Implementation Method 1
application of a sealant material which is first gelated or cured in a first heat treatment from the side of the sealant material, and only then is the adhesive gelated in the flange seam by means of a second heat treatment by inductive heating
Implementation Method 2
the adhesive gelated in the flange seam by means of a second heat treatment by inductive heating
Data Source
AI summary
The present invention relates to a method of producing an edging-fold bond. For this purpose use is made more particularly of high-viscosity adhesives. The method features reduced bubble formation within the edging fold and also within the sealant (where present) that seals the edging-fold seam. More particularly the adhesive comprises spacers which further reinforce this effect.