Bundle Packaging Film Smoothing via Air Knife
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Solution Overview
Problem
Existing bundle-packaging methods using heat-shrinkable film for product batches result in non-uniform air stream expulsion, leading to wrinkles and folds on the film, which affects the aesthetic appearance and ease of opening the packaged batch.
Innovation Solution
The method involves shaping a second air stream as an air knife during the heating process in the second section of the oven, ensuring a controlled and uniform expulsion of heated air to smooth the film and prevent wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heated air stream is expelled through orifices in manifolds, then the film contracts and molds to the batch, but the air stream becomes non-uniform causing wrinkles and folds on the film
Solution Approach 1:
A laminar flow element is introduced as an intermediary component between the heated air stream source and the film. This element transforms the turbulent, non-uniform air flow into a laminar, uniform flow pattern that evenly contacts the film surface during heating, preventing wrinkles and folds while maintaining the contraction effect
Solution Approach 2:
The flow regime parameter of the air stream is changed from turbulent to laminar by introducing the laminar flow element. This parameter change ensures uniform distribution of heated air across the film surface, eliminating the non-uniformity that causes surface defects while preserving the heating and contraction function
2Shape
If hot air circulation is used for heating and shrinkage, then the film contracts around the batch, but wrinkles and folds appear on the film surface
Solution Approach 1:
The laminar flow element serves as a mediator that modifies the characteristics of hot air circulation. It maintains the heating and shrinkage function while transforming the air flow pattern to eliminate surface defects, achieving both film contraction and surface quality
3Ease of manufacture
If conventional oven heating is used, then the batch is heated and film shrinks, but the aesthetic appearance is degraded due to wrinkles
Solution Approach 1:
The oven heating process is segmented into two distinct sections: a first section for heating and shrinkage, and a second section with laminar flow for surface smoothing. This segmentation allows each section to perform its specific function optimally while maintaining overall process simplicity
Solution Approach 2:
The laminar flow element acts as an intermediary device within the existing oven system, enhancing the aesthetic appearance without requiring complete process redesign. It integrates seamlessly into the conventional heating setup while delivering improved surface quality
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 results in a perfectly smooth film surface with reduced risks of folds and wrinkles, enhancing the aesthetic appearance and making it easier to open the packaged batch.
Implementation Method 1
a wrapped batch is heated so as to form a contraction of each sheet around said batch
Implementation Method 2
each heating means comprises a heating block whose function is to heat the air which passes through it. A heating means also comprises a means for circulating air heated by said heating block, in the form of a heated air stream
Data Source
AI summary
The present invention relates to a method for bundle-packaging batches of products, wherein products are moved in a longitudinal running direction, grouped into batches and wrapped with a film of heat-shrinkable film. Each wrapped batch is heated to form a contraction of each sheet around said batch. Heating of a batch is performed by the circulation of at least one heated air stream and by the expulsion of said stream toward the interior of the enclosure of an oven provided, successively, with first and second sections; the sheet is cooled; during heating, along at least a part of the first section, a first air stream is shaped discontinuously and expelled toward the interior of said enclosure. The method consists, during heating, along said second section, in shaping a second stream as an air knife and expelling said air knife toward said sheet to be smoothed.