Abrasive Stream Perforation of Composite Parts
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Solution Overview
Problem
Current methods for perforating composite parts, such as aircraft nacelles, are costly, time-consuming, and prone to defects, with existing techniques like pin mat molding, laser drilling, mechanical drilling, and grit blasting either being inefficient or damaging to the material.
Innovation Solution
An abrasive stream perforation system that uses compressed air and particulate to create holes directly in composite parts without a maskant, utilizing a flexible diaphragm valve and support frame to position nozzles accurately and efficiently form perforations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pin mat molding is used to perforate composite parts, then perforations can be formed during cure, but the process is costly and time-consuming with multiple manual steps
Solution Approach 1:
The patent replaces the mechanical pin mat molding system with a pneumatic abrasive stream system. Compressed air drives abrasive particles through nozzles to erode holes in the composite part, eliminating the need for mechanical pin mats, rollers, and manual contouring operations. This substitution dramatically reduces process complexity and time requirements.
Solution Approach 2:
The invention uses pneumatic pressure to deliver abrasive particles to the composite part surface. A compressed air source forces abrasive material through a valve and nozzles, creating a high-velocity abrasive stream that erodes the part. This pneumatic mechanism simplifies the system compared to mechanical pin mat systems while maintaining efficient perforation capability.
2Manufacturing precision
If pin mat molding is used, then holes are formed in composite parts, but defects are created due to pin mat flaws and surface waviness
Solution Approach 1:
The patent eliminates mechanical contact tools (pin mats) that cause defects by substituting them with a pneumatic abrasive stream. The abrasive particles erode material without mechanical contact, preventing pin mat flaws, bent pins, resin richness, and surface waviness. This non-contact approach ensures clean, defect-free perforations.
Solution Approach 2:
The invention changes the delivery mechanism from mechanical compression to pneumatic pressure-driven abrasive erosion. By controlling abrasive particle size, air pressure, and nozzle positioning, the system achieves precise hole formation without the defects inherent in mechanical pin mat systems.
3Productivity
If laser drilling is used to perforate composite parts, then holes are formed quickly, but heat-affected zones weaken structural integrity
Solution Approach 1:
The patent replaces the thermal laser drilling process with a mechanical abrasive erosion process. Compressed air drives abrasive particles to physically erode holes through the composite part without generating heat. This eliminates heat-affected zones while maintaining high productivity, as the abrasive stream can rapidly remove material through controlled erosion.
4Manufacturing precision
If mechanical drilling is used after cure, then holes are formed in composite parts, but setup and drilling time are long with costly equipment
Solution Approach 1:
The invention uses a pneumatic abrasive stream system that eliminates the need for complex mechanical drilling equipment and lengthy setup procedures. The compressed air-driven abrasive particles can be directed at the part surface and immediately begin eroding holes, significantly reducing setup time and equipment costs compared to traditional mechanical drilling.
Solution Approach 2:
The patent changes the material removal mechanism from mechanical drilling to abrasive erosion. By controlling abrasive particle size, air pressure, and exposure time, the system achieves precise hole formation rapidly without requiring costly drill bits or extensive setup, thereby reducing both time and equipment costs.
5Manufacturing precision
If grit blasting with maskant is used, then perforations are formed in composite parts, but maskant production, application, and removal are expensive and time-consuming
Solution Approach 1:
The patent removes the maskant component entirely from the perforation process. Instead of applying, positioning, and removing maskant stencils, the system uses a pneumatic abrasive stream that can directly erode holes at predetermined locations without any protective masking. This extraction of the maskant step eliminates associated costs and time requirements.
Solution Approach 2:
The invention replaces the mechanical maskant system with a pneumatic abrasive delivery system. Compressed air drives abrasive particles through nozzles positioned at predetermined locations, eliminating the need for maskant stencils. This substitution maintains perforation precision while dramatically simplifying the process by removing maskant production, application, and removal operations.
6Productivity
If grit blasting is used, then holes are formed in composite parts, but a large percentage of abrasive particles are wasted and rebound particles interfere with the stream
Solution Approach 1:
The patent uses a pneumatic system to deliver abrasive particles in a controlled stream. Compressed air maintains particle flow and direction, preventing rebound and interference. The pneumatic pressure ensures abrasive particles continue toward the target surface rather than scattering or rebounding, improving particle utilization efficiency and maintaining high perforation rates.
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 costs and defects by eliminating the need for maskants and expensive equipment, while maintaining the structural integrity of the composite parts through precise and efficient perforation.
Implementation Method 1
a flow from the air or gas pressure source forces the particulate through the plurality of nozzles directed at a surface of the composite part
Implementation Method 2
The particulate forced against the surface of the composite part forms the holes or perforations therethrough
Data Source
AI summary
An abrasive stream perforation (ASP) system and method for forming a plurality of perforations through a composite part. The ASP system may include a compressed air source, a particulate source, a valve, nozzles, and a positioning device. The valve is actuatable between an open state and a closed state. The compressed air and particulate are simultaneously forced through the valve in its open state and then forced through the nozzles and against the surface of the composite part, forming the perforations through the composite part. The support frame maintains the nozzles in a spaced relationship to each other and a selected distance away from the composite part. The positioning device is fixed to the support frame and actuates the support frame relative to the surface of the composite part for proper positioning of the nozzles and the resulting perforations.