Sheet Manufacturing Apparatus Jam Recovery Mechanism
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Solution Overview
Problem
Existing sheet manufacturing apparatuses face challenges in restarting after a jam occurs, as the presence of defibrated material or work-in-progress in the mechanisms can destabilize the sheet quality and require specialized maintenance.
Innovation Solution
The apparatus includes a sheet forming unit and a transport unit with an upstream and downstream transport roller group, along with an abnormality detection sensor that triggers an opening mechanism to facilitate the restart by consuming the remaining material and reducing labor required for recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the apparatus operation is immediately stopped when a jam is detected to prevent damage to mechanisms, then the mechanisms are protected from damage, but the restart time increases and sheet quality stability deteriorates due to presence of remaining defibrated material and work-in-progress
Solution Approach 1:
The system performs preliminary actions by detecting jams early through the abnormality detection sensor and automatically executing the opening mechanism before the jam causes damage. This preliminary detection and response allows the system to stop at optimal points where less material remains in the mechanisms, reducing restart time and maintaining sheet quality stability.
Solution Approach 2:
The abnormality detection sensor provides continuous feedback on the transport status to the control unit. When a jam is detected, the control unit receives this feedback and automatically triggers the opening mechanism. This feedback loop enables timely intervention that protects mechanisms while minimizing the amount of remaining material, thus reducing restart time and maintaining quality.
2Reliability
If the apparatus operation is immediately stopped when a jam is detected, then mechanism damage is prevented, but specialized maintenance worker intervention is required and labor increases
Solution Approach 1:
The system performs self-service by automatically detecting jams through the abnormality detection sensor and executing the opening mechanism via the control unit without requiring external intervention. The automated sequence opens the appropriate transport unit, allows remaining material to be consumed or removed, and prepares the system for restart, eliminating the need for specialized maintenance workers and reducing labor requirements.
3Loss of time
If the opening mechanism is activated to consume remaining material and facilitate restart, then restart time is reduced and sheet quality stability is maintained, but the device complexity increases
Solution Approach 1:
The transport unit is segmented into multiple independent transport units (first transport unit with first transport rollers, second transport unit with second transport rollers). The opening mechanism can selectively open only the specific transport unit where a jam is detected, rather than opening the entire transport system. This segmentation reduces the complexity impact by localizing the opening function to specific segments.
Solution Approach 2:
The opening mechanism serves multiple functions: it opens the transport unit to allow jam removal, enables consumption of remaining material, and prepares the system for restart. The abnormality detection sensor also serves dual purposes by detecting both jams and providing feedback for automated control. This multi-functionality justifies the added complexity by consolidating multiple operations into integrated components.
Data Source
AI summary
A sheet manufacturing apparatus includes a sheet forming unit that forms a strip-shaped sheet by accumulating a material containing fibers and then compressing the material and a transport unit including a plurality of transport rollers arranged in a transport direction of the sheet to transport the strip-shaped sheet, a cut sheet, and a sheet. The transport unit includes an upstream transport unit including a first transport roller group including some of the plurality of transport rollers, a downstream transport unit including a second transport roller group including, among the plurality of transport rollers, a plurality of transport rollers installed downstream of the first transport roller group in the transport direction, and a sheet sensor that detects an abnormality in transport of the sheet in the transport unit. The upstream transport unit includes an opening mechanism that performs an opening operation when the sheet sensor detects the abnormality.