Roller Blind Fabric Tensioning for Extrusion Shrinkage
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Solution Overview
Problem
The existing devices for producing roller blind webs in motor vehicles face issues with fabric wrinkling due to the shrinkage of plastic material applied during the extrusion process, which affects the flatness and quality of the final product.
Innovation Solution
A device with a tensioner that pre-stretches the fabric along an extrusion track before applying plastic material, allowing for controlled tension release after solidification to prevent wrinkling, and a method involving sequential tensioning and extrusion in both transverse and longitudinal directions to ensure a wrinkle-free roller blind web.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic material is applied to fabric during extrusion process, then lateral guide strip is formed, but fabric wrinkles due to plastic shrinkage
Solution Approach 1:
The fabric is pre-stretched in the tensioning device before the extrusion process begins. This preliminary action creates initial tension that counteracts the subsequent shrinkage forces when plastic material is applied and cooled, preventing fabric wrinkling while maintaining the ability to form lateral guide strips.
Solution Approach 2:
The tensioning device applies a preliminary counteracting force to the fabric before the harmful shrinkage effect occurs. By stretching the fabric in advance, the system creates a pre-compression state that resists the dimensional changes caused by plastic material cooling and solidification.
2Manufacturing precision
If fabric is tensioned during extrusion, then wrinkling is prevented, but device complexity increases
Solution Approach 1:
The tensioning device is designed to perform multiple functions: it stretches the fabric in the extrusion direction, provides lateral guidance, and maintains tension throughout the process. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting overall device complexity.
Solution Approach 2:
The tensioning mechanism is integrated with the extrusion system rather than being a separate independent device. The tensioning device and extrusion track are combined into a unified system, reducing the number of separate components and simplifying the overall device architecture.
3Reliability
If plastic material shrinks during cooling, then material solidification occurs, but fabric quality deteriorates
Solution Approach 1:
The fabric is pre-stretched before plastic material application, creating a tension state that persists through the cooling and solidification process. This preliminary action ensures that when the plastic material shrinks during cooling, the fabric remains taut and wrinkle-free, maintaining quality while achieving reliable solidification.
Solution Approach 2:
The system controls the tension parameters of the fabric throughout the temperature changes during extrusion and cooling. By maintaining appropriate tension levels as the plastic material transitions from molten to solid state, the fabric quality is preserved despite the dimensional changes occurring during solidification.
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 effectively reduces fabric wrinkling and maintains flatness, enabling the production of high-quality roller blind webs with modular adjustments for various dimensions, ensuring smooth series production and efficient use of materials.
Implementation Method 1
During subsequent cooling and solidification, the plastic shrinks in a range between 0.5% and 4%. This causes the fabric to wrinkle.
Implementation Method 2
A tensioner tensions the fabric in the direction of the extrusion track and at least partially limits the fabric at its edges.
Implementation Method 3
an extruder, which is configured to apply a plastic material in flowable form to the fabric along an extrusion track from above
Data Source
AI summary
A device for producing a roller blind web of a motor vehicle, the device having an application table having a continuously flat support surface for a fabric; and an extruder configured to apply a plastic material to the fabric from above along at least one extrusion track. A tensioner tensions the fabric in the direction of the extrusion track. Moreover, a method for producing a roller blind web is provided.