Web Cutter Loop Control for High-Speed Mail Inserter Throughput
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Solution Overview
Problem
High-speed inserter systems face limitations in throughput due to web breakage caused by high acceleration forces and aerodynamic forces, leading to lower cycle rates and reduced productivity.
Innovation Solution
A web loop is introduced between the web handler axis and the primary axis feeding the cutter, with a motion control module using a web control algorithm to regulate the web handler velocity based on constant acceleration, minimizing forces by adjusting velocity according to the web loop size, and incorporating an anti-hunting algorithm to stabilize web flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high acceleration is used to increase throughput, then cycle rate is improved, but web breakage increases due to acceleration forces and aerodynamic effects
Solution Approach 1:
The system pre-positions a loop of web material between the web handler axis and primary axis before cutting operations begin. This preliminary configuration allows the web to be drawn into the cutter without sudden acceleration forces that would cause breakage at perforations or sprocket holes.
Solution Approach 2:
The web loop acts as an intermediary buffer between the web handler axis and the primary cutting axis. It absorbs and dampens acceleration and deceleration forces, preventing direct transmission of harmful forces to the web material during high-speed operation.
2Productivity
If high acceleration is used to increase cycle rate, then productivity is improved, but forces on the web increase causing web breakage
Solution Approach 1:
The web loop is established in advance before high-speed cutting cycles begin. This pre-positioned loop allows the system to immediately operate at high cycle rates without subjecting the web to damaging acceleration forces during the transition to high-speed operation.
Solution Approach 2:
The web loop serves as a mechanical intermediary that decouples the high-speed primary axis from the web handler axis. It absorbs acceleration and deceleration forces, preventing direct force transmission to the web material during high-cycle-rate operation.
3Reliability
If aerodynamic forces are reduced by lowering speed, then web breakage is reduced, but throughput decreases
Solution Approach 1:
The web loop acts as a buffer that isolates the web material from aerodynamic forces generated by high-speed operation. It absorbs wind resistance forces before they can act directly on the web, allowing high throughput to be maintained without increasing web breakage from aerodynamic effects.
Solution Approach 2:
The web loop is pre-configured to provide a cushion of material that absorbs aerodynamic forces before they reach vulnerable points in the web. This allows the system to operate at high speeds that generate aerodynamic forces without causing web breakage.
Data Source
AI summary
A mail inserter has a first web driver to move a web from a web supply and a second web driver to feed the web to a cutter for cutting the web into sheets, wherein the first and second web drivers have different velocity profiles to allow a web loop to form between the web drivers. The loop is variable between a maximum size and a minimum size. When the loop reaches the minimum size, the first web driver is running at its maximum speed. At this point the first web driver is decelerated at a rate such that when the first web driver stops, the web loop is at its maximum size. The acceleration of the first web driver is at a constant rate which is inversely proportional to the difference between the maximum loop size and the minimum loop size.