Rotating Template Hot-Melt Adhesive Dispensing
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Solution Overview
Problem
Existing apparatuses for applying hot-melt adhesives to substrates, such as disposable hygiene products, face challenges in achieving precise and reliable application patterns while optimizing adhesive usage, often resulting in smearing issues and high production costs.
Innovation Solution
An apparatus featuring a template with cavities for hot-melt adhesive, an adhesive-transfer infeed, and a transporting-fluid-supply opening, where the template is displaced to separate and discharge adhesive using compressed air, ensuring precise application without continuous adhesive pressure, allowing for complex patterns and efficient adhesive use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If volumetric gear pumps are used to provide precise metering of molten adhesive, then adhesive metering precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the adhesive metering function from the complex volumetric gear pump system and relocates it to simple cavities in a template. The template with cavities serves as both the metering device and the application surface, eliminating the need for separate complex pumping and application mechanisms.
Solution Approach 2:
The invention uses cavities in a template to replicate the metering function. Each cavity acts as a discrete metering unit that transfers adhesive to the substrate, replacing the continuous complex mechanical metering of gear pumps with discrete cavity-based transfer.
2Reliability
If continuous adhesive pressure is applied through volumetric pumps, then adhesive delivery is maintained, but smearing occurs in the application pattern
Solution Approach 1:
The invention uses periodic action by rotating the template to bring cavities into contact with the substrate only at specific moments. This intermittent contact allows adhesive to be deposited precisely without continuous pressure that would cause smearing, while still maintaining reliable delivery through the rotational cycle.
Solution Approach 2:
The invention extracts the adhesive from continuous pressure contact with the substrate by using discrete cavities that transfer adhesive only when positioned correctly. This separates the adhesive supply function from the application function, preventing smearing while maintaining delivery reliability.
3Adaptability or versatility
If rotary screen systems are used to apply adhesive patterns, then complex patterns can be achieved, but adhesive pressure causes smearing
Solution Approach 1:
The invention uses cavities in a template as an intermediary between the adhesive supply and the substrate. These cavities hold and transfer adhesive without direct pressure contact with the substrate, enabling complex patterns to be applied precisely without smearing.
Solution Approach 2:
The template rotation creates periodic contact between cavities and the substrate, allowing complex patterns to be applied at precise moments without continuous adhesive pressure that would cause smearing.
4Ease of operation
If application rollers with hollows or protuberances are used, then adhesive application is achieved, but the apparatus becomes complex and costly to produce
Solution Approach 1:
The template serves multiple functions simultaneously: it acts as the adhesive carrier, the application surface, and the pattern-defining element. This multi-functionality eliminates the need for separate application rollers and complex mechanisms, simplifying the overall apparatus.
Solution Approach 2:
The template with cavities replicates the adhesive transfer function that would otherwise require complex application rollers. The cavities serve as discrete transfer points, replacing the need for continuously contoured rollers with a simpler planar template.
5Ease of operation
If application rollers are used for adhesive dispensing, then adhesive can be applied to substrate, but application speeds are insufficient for hygiene articles
Solution Approach 1:
The invention uses a jet of gas (pneumatics) to transfer adhesive from the cavities to the substrate. This gas jet mechanism enables rapid adhesive transfer at high speeds, meeting the productivity requirements for hygiene article manufacturing while maintaining application capability.
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
Enables precise, reliable, and optimized application of hot-melt adhesives with minimal adhesive waste, reducing the need for costly volumetric gear pumps and achieving desired application speeds for hygiene products.
Implementation Method 1
the adhesive, in the second position, can be discharged from the cavity by a transporting fluid flowing through the transporting-fluid-supply opening
Data Source
AI summary
The invention relates to applying a liquid to pasty hot-melt adhesive to a substrate (44), comprising a template (29), having at least one cavity (38) for the hot-melt adhesive, and also comprising an adhesive-transfer infeed (33), which is assigned to the template (29) and through which the adhesive can be introduced into the cavity (38). The special feature consists in that the apparatus (10) further comprises a transporting-fluid-supply opening (35), assigned to the template (29), and a device for displacing (13, 15), in particular pivoting, the template (29) between a first position, in which the cavity (38) is assigned to the adhesive-transfer infeed (33), and a second position, in which the cavity (38) is assigned to the transporting-fluid-supply opening (35), and therefore the adhesive, in the second position, can be discharged from the cavity (38) by a transporting fluid flowing through the transporting-fluid-supply opening (35).