Foldable Bag Inward Crease and Spot Welding for Bag-in-Box
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Solution Overview
Problem
In existing foldable bag manufacturing methods for bag-in-box assemblies, incomplete unfolding during filling occurs due to uneven liquid flow between compartments above and below inwardly creased bag portions, leading to difficulty in filling the lower compartment and potential leakage issues from stress concentrations in welded seams.
Innovation Solution
A method involving a flexible bag made of front and back sheets joined circumferentially, where the sheets are displaced to form double-walled flaps perpendicular to the side edge, creating inwardly creased compartments with free closed ends, allowing for improved flow capacity and stress-free unfolding by preventing sheet sticking through spot welds and vacuum engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bag is manufactured with inwardly creased bag portions using conventional welding methods, then the bag structure is formed with compartments, but incomplete unfolding occurs during filling due to uneven liquid flow between compartments
Solution Approach 1:
The bag is divided into multiple compartments by inwardly creased portions, with each compartment able to fill independently. The segmentation allows liquid to distribute evenly across compartments through communication openings, preventing the uneven filling that causes incomplete unfolding.
Solution Approach 2:
Communication openings are introduced as intermediary elements between compartments. These openings allow liquid to flow between compartments, equalizing pressure and enabling simultaneous filling, which resolves the unfolding problem caused by pressure imbalances.
2Adaptability or versatility
If compartments are formed above and below inwardly creased bag portions, then the bag structure provides multiple storage sections, but liquid pressure in upper compartments makes filling lower compartments difficult
Solution Approach 1:
The communication openings create a pressure equilibrium between upper and lower compartments during filling. Liquid can flow freely between compartments, equalizing the pressure potential and allowing simultaneous filling without the upper compartment pressurizing the lower one.
3Reliability
If sheets are welded to create inwardly creased bag portions, then the bag structure is formed, but stress concentrations in welded seams cause leakage risks
Solution Approach 1:
The welding is segmented into discrete spot welds rather than continuous seams. This segmentation reduces stress concentration points and provides multiple independent connection points, lowering the risk of leakage at any single location.
Solution Approach 2:
Spot welds are strategically positioned at specific locations to create the inwardly creased portions without requiring extensive welding. This local approach minimizes the total welded area and reduces overall stress concentrations in the seams.
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
Ensures complete unfolding during filling and prevents stress concentrations in welded seams, enhancing the filling process and reducing leakage risks by maintaining high flow capacity between compartments.
Implementation Method 1
The sheets can be engaged by applying a suction force thereon, which can be applied by a vacuum tool, for example.
Data Source
AI summary
A method of manufacturing a foldable bag for use in a bag-in-box assembly is described. The foldable bag being manufactured according to this method has a folded condition in which it includes at least an inwardly creased bag portion in a longitudinal direction thereof. Furthermore, the bag includes a bottom edge and a top edge opposite to each other in a longitudinal direction of the bag. The inwardly creased bag portion has a first closed end and a second closed end opposite to each other in the longitudinal direction of it. The first and/or second closed end of the inwardly creased bag portion is a free end. The bag according to the invention has an improved unfolding process during filling it, and has such a configuration that it does not cause material stress in certain welded seams such as in known bags.