Winding Apparatus for Bottom-First Bag Rolls
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Solution Overview
Problem
The bag making industry has struggled for decades to wind premade bags with the seal off first (SOF) orientation, which is necessary for unwinding with the bottom first, while avoiding air trapping and the associated costs and inefficiencies of previous solutions.
Innovation Solution
A winding apparatus comprising a perforator unit and a winding shaft, designed to receive web tubular film with crosswise welds, create crosswise perforations to form interconnected individual bags, and wind them onto a core with the opening/top first, thereby creating a bottom-first bag roll without air trapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bags are wound with open end first to achieve bottom-first unwinding, then the correct position for automatic filling is achieved, but air enters and is trapped inside the bag
Solution Approach 1:
The perforator unit creates crosswise perforations in the web tubular film before winding, defining individual bags with top and opening at the downstream end. This preliminary action ensures that when bags are wound open-end first, the air can escape through the perforations rather than being trapped, while still achieving the correct bottom-first unwinding orientation for automatic filling
2Object-generated harmful factors
If extremely low speed is used to avoid air trapping, then air trapped inside bag is reduced, but production efficiency decreases
Solution Approach 1:
Instead of relying on slow winding speed to prevent air trapping, the invention performs preliminary perforation of the web tubular film before winding. The crosswise perforations create defined individual bags that allow air to escape during normal-speed winding, thereby maintaining both production efficiency and preventing air trapping
Solution Approach 2:
The invention changes the physical structure of the film by introducing crosswise perforations, transforming the continuous web into segmented individual bags. This parameter change allows air to escape through the perforations during winding at normal speeds, eliminating the need for extremely low operating speeds
3Ease of operation
If two-step winding process is used to achieve bottom-first bag rolls, then correct unwinding orientation is achieved, but cost and power consumption increase
Solution Approach 1:
The perforator unit performs preliminary crosswise perforation of the web tubular film, defining individual bags with specific top and opening orientation. This single-step preliminary action enables direct winding of bottom-first bag rolls without requiring a subsequent rewinding step, thereby reducing both cost and power consumption while achieving the correct unwinding orientation
Solution Approach 2:
The invention combines the perforation function and winding function into a single integrated process. The crosswise perforations create defined individual bags that can be directly wound onto the winding shaft in the correct orientation, merging what was previously two separate operations (conventional winding followed by rewinding) into one efficient step
Data Source
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AI summary
Disclosed herein is a winding apparatus for winding of bottom-first bag rolls, the winding apparatus comprising a perforator unit (105) and a winding shaft (107). Further disclosed is a bottom-first bag roll making machine for making bottom-first bag rolls and a process for making bottom-first bag rolls.