Multi-Step Drilling Sequence Control Using Air Flow Sensing

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Solution Overview

Problem

In multi-step drilling processes for composite/metal stacks, ensuring the proper sequence of machining operations among multiple drilling units is challenging, leading to potential damage or wastefulness due to incorrect sequencing, as existing methods lack effective control mechanisms to determine if a hole has already been drilled.

Innovation Solution

The use of air flow sensing through absolute pressure sensors in a vacuum exhaust system to control the sequence of drilling operations, preventing units from starting if a hole has already been drilled or if no hole exists, thereby ensuring each drilling unit performs its operation in the correct order.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple drilling units are used to perform multi-step drilling process, then productivity is improved, but control of machining sequence becomes difficult leading to potential damage or wastefulness

Engineering Contradiction:
Improvedrilling speedVSAvoidmachining sequence control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system uses air flow sensors to detect whether a hole has been previously drilled by measuring air flow resistance through the hole. This feedback mechanism allows drilling units to automatically determine the current state of each hole and adjust their operation accordingly, preventing duplicate drilling and ensuring proper sequencing without requiring complex inter-unit communication or manual control

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Each drilling unit is equipped with its own air flow sensing capability, allowing it to independently determine whether it should perform drilling operations on a given hole. The drilling units self-regulate their operation based on local sensor feedback, eliminating the need for external sequence control systems and enabling autonomous coordination among multiple units

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If air flow sensing control is implemented, then machining sequence accuracy is improved, but device complexity increases due to additional sensors and control systems

Engineering Contradiction:
Improvehole qualityVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system employs simple air flow sensors that measure air flow resistance through drilled holes to detect hole presence and status. This pneumatic sensing approach provides reliable detection of machining sequence status using straightforward pressure differential measurements, avoiding the need for complex electronic sensors or sophisticated control algorithms while maintaining high sequencing accuracy

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

Air flow acts as an intermediary medium between the physical state of the workpiece (drilled holes) and the control system. The air flow sensors translate the physical condition of holes into measurable signals that trigger appropriate drilling unit responses, providing a simple and reliable interface between the workpiece state and control logic without requiring direct mechanical or complex electronic coupling

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution ensures accurate and efficient multi-step machining by preventing damage from drilling the same hole twice and optimizing hole quality by maintaining the proper sequence of operations among drilling units, thereby improving the overall efficiency and accuracy of the drilling process.

Implementation Method 1

at least one absolute pressure sensor positioned to indicate air flow through the vacuum exhaust system by measuring air pressure at its position

Methodology Applied
Scientific EffectPressure sensing:

Data Source

PatentEP3167987B1Multi-step drilling apparatus and methods utilizing air flow sensing control
Publication Date: 2021.04.21 THE BOEING CO
  • EP3167987B1 patent drawingFigure 1
  • EP3167987B1 patent drawingFigure 2A~2B
  • EP3167987B1 patent drawingFigure 3A~3B

AI summary

Apparatus and methods for performing and controlling the sequence of steps in a multi-step machining process utilizing a plurality of drilling units, where each drilling unit is configured to perform at least one step of the multi-step machining process. Air pressure sensors in each drilling unit measure air pressures at the surface of a workpiece where the cutting tool of the drilling unit is engaged, which measured air pressures indicate air flow at the surface. These air flows in turn indicate the state of the machining at the surface of the workpiece, and based on the state of the machining, a machine control system will determine whether a drilling unit can perform its particular machining operation in the proper sequence on the workpiece.