Metallic Pin Mat Perforation for Uncured Composite Sheets
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Solution Overview
Problem
Current methods for perforating composite sheets, such as abrasive perforation and mechanical drilling, face issues like high cycle times, complex tooling, fiber cutting, and difficulties in removing plastic pin mats, which complicate the process and result in inefficient production of acoustic panels.
Innovation Solution
A method involving a metallic pin mat with tapered pins that perforate an uncured composite sheet while being heated, allowing the pins to penetrate through the entire thickness and partially cure the perimeter areas to maintain hole shape, while keeping the rest of the sheet flexible, using a pressure backer and electrical heating to facilitate efficient perforation and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic pin mats are used to perforate composite sheets, then hole formation is achieved, but separation difficulty and process complexity increase
Solution Approach 1:
The patent replaces the mechanical plastic pin mat system with a metallic pin mat system that uses resistive heating. The metallic pins are heated electrically during perforation, transforming the process from purely mechanical to electro-thermal-mechanical, enabling both hole formation and facilitation of separation through controlled curing of surrounding material.
Solution Approach 2:
The patent changes the physical state and properties of the composite material during perforation by applying heat. The resistive heating of metallic pins raises the temperature of surrounding composite material, causing partial curing that maintains hole shape while allowing easy separation of the pin mat from the perforated sheet.
2Ease of manufacture
If mechanical drilling is used to perforate composite sheets, then holes are formed, but cycle time and production efficiency decrease
Solution Approach 1:
The patent merges multiple functions into a single perforation step: hole formation, heating, and partial curing occur simultaneously during one pass of the metallic pin mat through the composite sheet. This eliminates separate operations and reduces cycle time while maintaining production efficiency.
Solution Approach 2:
The resistive heating of metallic pins occurs during the perforation process itself, preparing the surrounding composite material for separation before the pin mat is removed. This preliminary thermal treatment prevents material adhesion and facilitates immediate separation without additional processing steps.
3Ease of manufacture
If abrasive perforation is used on composite sheets, then holes are created, but tooling complexity and cleanup requirements increase
Solution Approach 1:
The patent replaces abrasive mechanical perforation with a metallic pin mat system that uses resistive heating. This substitution eliminates the need for complex abrasive tooling and reduces cleanup requirements, as the heated metallic pins create clean holes without generating abrasive waste or requiring extensive post-processing.
4Manufacturing precision
If pins are heated to cure surrounding resin, then hole shape is maintained, but heat isolation from remaining uncured portions becomes necessary
Solution Approach 1:
The patent applies heating locally only to the immediate surroundings of each metallic pin during perforation. This localized resistive heating cures the resin immediately surrounding the holes to maintain their shape, while the rest of the composite sheet remains uncured and flexible. The heating is confined to specific zones around each pin rather than affecting the entire sheet.
Solution Approach 2:
The patent segments the curing process into localized zones around each pin rather than curing the entire composite sheet. This segmentation allows individual hole perimeters to be cured for shape maintenance while leaving the bulk material uncured, preserving overall flexibility and eliminating the need for extensive heat isolation mechanisms.
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
This method reduces cycle time, minimizes fiber damage, and allows for easy separation of the pin mat from the composite sheet, maintaining hole shape and flexibility, thus improving the efficiency and quality of perforated composite structures.
Implementation Method 1
The step of heating the plurality of pins preferably includes resistively heating the plurality of pins by an electrical energy source
Implementation Method 2
The step of heating the plurality of pins preferably includes heating the plurality of pins prior to the perforation of the uncured composite sheet, during the perforation of the uncured composite sheet, or both prior to and during the perforation of the uncured composite sheet to reduce a viscosity of a resin of the uncured composite sheet
Implementation Method 3
The step of heating the plurality of pins preferably includes partially curing perimeter portions of the uncured composite sheet surrounding each pin
Data Source
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AI summary
A method for forming holes within an uncured composite sheet (130) includes perforating the uncured composite sheet (130) with a plurality of pins (112) of a metallic pin mat (110) and heating the plurality of pins (112) to heat portions of the uncured composite sheet surrounding each pin.