Water-Soluble Pouch Thermoforming Mold Roughness for Controlled Separation
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Solution Overview
Problem
Water soluble pouches made from soft, flexible, and tacky films are difficult to separate predictably and controllably from thermoforming molds, leading to processing irregularities such as damaged or torn pouches and misalignment during high-speed manufacturing.
Innovation Solution
A thermoforming mold with a forming surface featuring recesses and a continuous land area with an average roughness of 2.2 µm to 10 µm, facilitating the separation of water soluble pouches by supporting the film at peaks of the rough surface, reducing the force required for separation, and enhancing control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a smooth thermoforming mold surface is used, then the pouches can be easily formed, but the pouches stick to the mold and cannot be separated predictably and controllably
Solution Approach 1:
The mold surface is designed with non-uniform roughness, creating peaks and valleys. The peaks provide support points for the pouch film during formation, while the valleys create air gaps that reduce adhesion. This local variation in surface quality enables both easy formation and predictable separation.
Solution Approach 2:
The mold surface is pre-conditioned with a specific roughness profile (Ra 0.5-3.0 µm) before the pouching process. This preliminary surface preparation ensures that when the soft, flexible film is formed, it naturally contacts only the peaks, establishing support points that facilitate controlled separation without requiring additional actions during the process.
2Productivity
If high manufacturing line speeds are used, then productivity increases, but pouch separation becomes uncontrollable and pouches may be damaged or torn
Solution Approach 1:
The roughened peaks on the mold surface create localized support points that maintain their function even at high speeds. The distributed nature of these peaks ensures that pouch separation occurs predictably across the entire pouch array, enabling high-speed operation without loss of control or increased damage.
Solution Approach 2:
The invention replaces the need for complex mechanical separation systems with a passive surface topology approach. The roughness profile itself performs the separation function by reducing adhesion forces, eliminating the need for additional mechanical components that would complicate high-speed operation.
3Ease of operation
If excessive force is applied to separate pouches from the mold, then separation occurs, but pouches become damaged or torn
Solution Approach 1:
The valleys between peaks create localized regions of reduced contact and adhesion. When separation force is applied, the pouch naturally detaches from these low-adhesion valleys first, requiring minimal force and preventing damage to the pouch structure.
Solution Approach 2:
The roughness profile is pre-established on the mold surface to create inherent separation zones. This preliminary configuration means that separation occurs passively with minimal applied force, rather than requiring excessive force to overcome uniform adhesion across the entire mold surface.
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
The solution improves the predictability and controllability of pouch separation, allowing for higher manufacturing line speeds and reducing pouch damage, ensuring consistent production.
Implementation Method 1
applying vacuum to the water soluble film through the vacuum orifices to thermoform the water soluble film to the recesses
Implementation Method 2
heating the water soluble film; heating the water soluble film to a temperature from about 80°C to about 150°C
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An apparatus including a thermoforming mold having a forming surface; a plurality of spaced apart recesses in the forming surface, wherein each recess includes a vacuum orifice and each vacuum orifice is in fluid communication with a vacuum source; a continuous land area (250) surrounding the recesses, wherein portions of the land area between the recesses have an average roughness Ra from 2.2 µm to 10 µm.