Pressware Forming Control for Curl and Jam Reduction
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Solution Overview
Problem
Current methods for producing pressware from materials like paper are prone to jams due to intrinsic curling, require manual adjustment, and limit production rate to a single row of products per machine stroke, leading to inefficiencies and high labor costs.
Innovation Solution
A system comprising a positive mold assembly, negative mold assembly, heating element, forming station actuator, and control system that adjusts forming force and depth to form pressware products from a web of material, allowing for multiple products per stroke and reducing labor costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual adjustment of decurling rollers is used to counteract intrinsic curl, then curl compensation is achieved, but labor costs increase and human error causes jams
Solution Approach 1:
The system uses force sensors to automatically detect web tension and control the decurling roller position without manual intervention. The roller self-adjusts based on real-time feedback from the sensor, eliminating the need for experienced operators to manually adjust the system while maintaining reliable curl compensation.
Solution Approach 2:
A force sensor provides real-time feedback on web tension during the decurling process. The control system uses this feedback to automatically adjust the decurling roller position, creating a closed-loop system that maintains optimal curl compensation without manual intervention and reduces jams caused by human error.
2Productivity
If a single row of products is produced per machine stroke, then the forming process is simple, but production rate is limited to four or five parts per stroke
Solution Approach 1:
The forming process is segmented into multiple independent forming zones within the same press stroke. The web is divided into multiple product sections that are simultaneously formed in separate mold cavities, allowing multiple products to be produced in parallel during a single machine stroke, thereby increasing productivity without proportionally increasing device complexity.
3Adaptability or versatility
If paper is unwound from a roll to manufacture pressware, then sustainable material usage is achieved, but intrinsic curl increases especially as roll diameter decreases
Solution Approach 1:
The decurling roller applies a counteracting force to the intrinsic curl of the paper web before the forming process begins. By pre-treating the web to eliminate curl, the system prevents curl-related problems during subsequent handling and forming operations, allowing the use of sustainable paper materials from rolls of any diameter without suffering from excessive curl.
4Manufacturing precision
If forming force is not dynamically adjusted, then the forming process is simple, but product uniformity decreases leading to jams
Solution Approach 1:
The forming force is dynamically adjusted during the forming process based on real-time feedback from force sensors. The system transitions from a static forming process to a dynamic one where the applied force is continuously optimized to account for variations in material properties, ensuring uniform product formation and reducing jams.
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
The system increases production rates, decreases jam frequency, and ensures uniform product formation by dynamically adjusting forming forces and depths, enabling efficient production of pressware.
Implementation Method 1
holding, via the forming station actuator, the positive mold and the negative mold pressed against the pressware product so that the pressware product is heated via a heating element coupled to at least one of the positive punch or the negative mold
Data Source
AI summary
A system for forming a pressware product from a web of a roll of material includes a positive mold, a negative mold, a heating element, an actuator, a force sensor, and a control system. The positive mold forms a top surface of the pressware product. The negative mold forms a bottom surface of the pressware product. The heating element is coupled to the positive mold or the negative mold. The actuator shifts the positive mold or the negative mold to cut and form the pressware product in a single stroke. The force sensor detects the forming force applied by the actuator, and the control system directs the actuator to adjust the forming force.