Stretching Unit Air Bearing Decoupling for Film Processing
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Solution Overview
Problem
Existing transverse stretching systems for plastic films experience high friction and wear due to tilting moments, leading to increased energy consumption and reduced system speed, as well as oil contamination and overheating.
Innovation Solution
The system decouples weight forces from stretching and centrifugal forces, with a balanced design where the center of gravity is aligned with the guide rail, minimizing tilting moments and using lightweight carbon fiber materials, and incorporating air bearings for low-friction operation, and integrated cooling channels for efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the transport chain is supported on the guide rail with sliding elements, then the transverse forces and stretching forces can be supported, but high friction and wear occur due to tilting moments
Solution Approach 1:
The support function is segmented into two independent systems: guide rails for transverse force support and air bearings for weight support. This separation eliminates the tilting moments that caused high friction and wear in the unified sliding element system.
Solution Approach 2:
Air bearings are introduced to support the weight of the transport chain and clips, replacing the mechanical sliding contact. This pneumatic support system eliminates friction and wear associated with traditional sliding elements while maintaining force support capability.
2Device complexity
If the center of gravity is outside the guide rail, then the arrangement can be simplified, but tilting moments cause one-sided loads on the plain bearings
Solution Approach 1:
The weight support function is extracted from the guide rail system and transferred to the air bearing system. This allows the center of gravity to be positioned optimally without creating tilting moments on the guide rail plain bearings, as the air bearings independently support the weight.
3Productivity
If the system operates at higher speeds, then productivity increases, but friction and heat generation increase leading to overheating
Solution Approach 1:
Air bearings provide frictionless support that eliminates the heat generation associated with mechanical friction. This enables the system to operate at higher speeds without the overheating problem that limited previous designs.
4Device complexity
If traditional sliding elements are used, then the structure is simple, but oil lubrication is required leading to contamination risk
Solution Approach 1:
The air bearing system replaces oil-lubricated sliding elements with a pneumatic cushion. This eliminates the need for oil lubrication and the associated contamination risk to the plastic film, while maintaining smooth operation.
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 design significantly reduces friction, allowing for higher operating speeds, extended system lifespan, minimized energy consumption, and reduced maintenance costs while preventing oil contamination and overheating.
Implementation Method 1
incorporating air bearings for low-friction operation
Implementation Method 2
integrated cooling channels for efficient heat dissipation
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
The invention relates to an improved stretching unit characterised, amongst other things by the following: the clip-chain unit (KK) is designed such that the forces which are exerted are decoupled and applied in a tilting-free and torque-free manner to the clip-chain unit (KK) in order to prevent an increase of the surface pressure between the clip-chain unit (KK) and the supporting rail (17).