Web Material Rod Shaping with Sub-4°C Cooling
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Solution Overview
Problem
The processing of continuous web materials, such as cellulose or plastic webs, into aerosol-generating article components is challenging due to materials like polylactic acid web being prone to overheating from friction, leading to irregular folding and reduced reproducibility of products.
Innovation Solution
A method and apparatus for shaping continuous web materials into rods involve providing a continuous web material with a glass transition temperature below 150°C, using a shaping device to gather the web into a rod shape, and employing a cooling means to maintain a material contact surface and the gathered web at temperatures below 4°C, effectively preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If continuous web material is gathered into rod shape by shaping device, then rod-shaped product is formed, but local overheating occurs due to friction between web material and stationary shaping device
Solution Approach 1:
The web material is cooled below its glass transition temperature before entering the shaping device and maintained at this temperature throughout the gathering process. This preliminary cooling prevents friction-induced overheating that would otherwise cause irregular folding and shape defects during rod formation.
Solution Approach 2:
The temperature of the web material is changed from ambient conditions to below its glass transition temperature through active cooling. This parameter change fundamentally alters the material's friction characteristics and thermal behavior during the shaping process, preventing local overheating while maintaining rod shape formation.
2Reliability
If web material is cooled to below glass transition temperature, then irregular folding and sticking are prevented, but additional cooling equipment and process complexity are required
Solution Approach 1:
The cooling system is segmented into distinct functional zones: a pre-cooling section before the shaping device and a cooling section within the shaping device. This segmentation allows targeted cooling where needed most (at the material contact surface) while avoiding unnecessary cooling elsewhere, reducing overall system complexity.
Solution Approach 2:
A cooling medium is introduced as an intermediary between the shaping device and the web material. This cooling medium absorbs friction-generated heat at the material contact surface, effectively preventing overheating and irregular folding without requiring direct complex thermal management of the entire shaping device.
3Ease of manufacture
If friction heating is allowed to occur during gathering, then material becomes tacky or partially molten, but this causes individual folds to stick together and fuse, reducing product quality
Solution Approach 1:
The web material is pre-cooled below its glass transition temperature before entering the gathering process. This preliminary anti-action counteracts the tendency of friction heat to make the material tacky or molten, preventing folds from sticking together or fusing while still allowing the gathering process to proceed.
4Temperature
If cooling fluid is used to cool the shaping device, then efficient cooling is achieved, but handling and controlling the cooling fluid becomes more complex
Solution Approach 1:
The invention uses inexpensive cooling fluids (such as water or water-glycol mixtures) that can be easily handled and discarded or recycled. These simple, short-living cooling media provide efficient cooling without requiring complex handling systems, making the operation straightforward while maintaining low material contact surface temperatures.
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 approach prevents local overheating of the web material, maintains material properties, reduces the risk of sticking or fusion during gathering, and enhances the reproducibility of the final product by keeping the web material significantly below its glass transition temperature.
Implementation Method 1
cooling a material contact surface of the shaping device to a surface temperature below four degree Celsius and cooling the continuous gathered web material by the cooled material contact surface in contact with the continuous gathered web material
Implementation Method 2
The cooling means may be a Peltier element or a cooling fluid. Using a cooling fluid is very efficient in cooling.
Implementation Method 3
The cooling means may be a Peltier element or a cooling fluid
Implementation Method 4
Friction between the web material and in particular a stationary shaping device is highest in a final rod forming section of the gathering process (garniture). With an undercooling of the web material a local overheating of the web material due to friction upon gathering in the shaping device may basically be prevented.
Implementation Method 5
local overheating of the web material due to friction upon gathering
Data Source
AI summary
The method for shaping a continuous web material (1) into a rod comprises providing a continuous web material (1) having a glass transition temperature below 150 degree Celsius and gathering the continuous web material (1) from a flat shape into a rod-shape by means of a shaping device (2). The method further comprises providing a cooling means (34) providing a temperature below four degree Celsius, cooling a material contact surface of the shaping device (2) to a surface temperature below four degree Celsius, and cooling the continuous gathered web material by the cooled material contact surface in contact with the continuous gathered web material. Also provided is an apparatus for shaping a continuous web material (1).