Multilayer Plastic Sheet Calendering and Coupling
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Solution Overview
Problem
The existing processes for producing sheet products with two layers of plastic material, such as those used for synthetic floors, are inefficient due to the slow nature of extrusion-based methods and the unsuitability of calendering processes, which result in warping and high energy consumption.
Innovation Solution
A calendering process where two plastic compound sheets, obtained from counter-rotating cylinders, are directly coupled using adjacent coupling cylinders, minimizing temperature drop and avoiding external heating or deformation, allowing for the production of multilayer sheets with high productivity and economic advantages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If extrusion process is used to produce sheet products, then manufacturing capability is achieved, but productivity is low due to slow process speed
Solution Approach 1:
The patent combines multiple operations (calendering of two sheets and their coupling) into a single continuous process. The calendering cylinders both form the sheets and couple them together, eliminating the need for separate extrusion and assembly operations, thereby dramatically increasing productivity while maintaining manufacturing feasibility
2Productivity
If calendering process is used to increase productivity, then production speed improves, but sheets warp and lose flatness due to cooling
Solution Approach 1:
The coupling operation is performed immediately while the sheets are still warm and pliable from calendering, before cooling can cause warping. The timing of the coupling action is critical - it must occur while the material is in a state that allows easy bonding without subsequent deformation
Solution Approach 2:
The calendering and coupling operations are merged into a single continuous process where sheets are formed and joined without interruption or cooling in between, preventing warping by eliminating the cooling step that would otherwise occur between separate operations
3Shape
If sheets are heated to maintain temperature during calendering, then flatness is preserved, but energy consumption increases significantly
Solution Approach 1:
The sheets maintain their own temperature through the residual heat generated during the calendering process itself, eliminating the need for external heating systems. The mechanical energy of the calendering operation is converted to thermal energy that is retained and utilized by the material
Solution Approach 2:
The heating function is merged into the calendering operation itself, where the friction and compression during calendering generate the necessary heat. This eliminates the need for separate heating equipment and the associated energy consumption
4Adaptability or versatility
If path between calendering and coupling is lengthened, then equipment layout flexibility improves, but temperature drop and deformation increase
Solution Approach 1:
The calendering and coupling stations are merged into a tightly integrated unit where the output of one is immediately the input of the other. This minimal separation distance prevents temperature drop and deformation while the entire assembly can be positioned as a single module to provide layout flexibility
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 enables the high-productivity and cost-effective production of multilayer sheets suitable for synthetic floors, maintaining sheet temperature and preventing deformation, thus overcoming the limitations of traditional extrusion and calendering methods.
Implementation Method 1
The sheets are obtained by calendering in two respective groups (calenders) each comprising at least two counter-rotating cylinders
Implementation Method 2
the sheets thus obtained, after detachment from the respective calendering group, are led directly to a further pair of cylinders operating as coupling cylinders and sandwiching directly the two plastic compound sheets
Data Source
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AI summary
Calendering process, and calender thereof, in which two sheets (14, 15) of a plastic compound, of the type comprising a thermoplastic polymer, a filler material and additives, are obtained by calendering and directly coupled with each other or with an intermediate reinforcement layer (16), by passing through two coupling cylinders (10, 11) immediately adjacent the calendering cylinders, thus forming a sheet product (18) suitable for constituting the underlayer of synthetic flooring, in particular of the LVT or SPC type.