Through-Hole Cutter for Automated Back Spotfacing

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Solution Overview

Problem

Existing back spotfacing systems for structures are costly, time-consuming, and pose ergonomic and safety issues due to the need for large tooling and manual monitoring, while also lacking precision in achieving required cut depths, especially in applications like aircraft manufacturing.

Innovation Solution

A back spotfacing system featuring a machining apparatus with a through-hole cutter tool that can extend through a hole in a workpiece, pivot to contact the inner surface, and extend radially to machine the backside, equipped with a measurement system to determine precise cut depths and profiles, allowing for automated operation and reduced labor requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If large tooling jigs and manual feed air motors are used for back spotfacing, then the back spotfacing operation can be performed, but the equipment becomes expensive to use and maintain, and time-consuming to set up

Engineering Contradiction:

Improveback spotfacing operation capabilityVSAvoidequipment cost and setup time

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the essential back spotfacing function from the complex assembly of large tooling jigs and manual feed air motors, isolating only the critical components needed for the operation. The through-hole cutter tool performs back spotfacing without requiring the bulky supporting equipment, thereby reducing device complexity and cost while maintaining operational capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system enables automated operation where the machining apparatus independently performs back spotfacing operations without requiring additional workers to monitor from inside the structure. The automated control system manages the entire process, eliminating labor costs and improving safety while maintaining reliable operation

Inventive Principle:

Principle #25Self-service

2Reliability

If additional workers are used to monitor the back spotfacing process from inside the structure, then the process can be supervised, but labor costs increase and ergonomic and safety issues arise

Engineering Contradiction:

Improveprocess supervisionVSAvoidlabor costs and worker safety

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The automated machining system performs self-monitoring and self-control of the back spotfacing process through integrated sensors and control mechanisms. The system automatically tracks cut depth, monitors tool position, and manages the machining parameters without human intervention, eliminating the need for workers to enter confined spaces while maintaining reliable process supervision

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces the mechanical system of human workers visually monitoring the process with an automated electronic control and sensing system. Sensors detect cut depth and tool position, while computer control manages the machining parameters, substituting human labor with automated mechanical and electronic systems that improve safety and reduce costs

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If visual determination is used to check cut depth, then the process can be monitored, but the determination is not precise enough to meet tight tolerances

Engineering Contradiction:

Improveprocess monitoring capabilityVSAvoidcut depth measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The invention replaces visual determination with electronic sensing and automated measurement systems. Sensors mounted on the machining apparatus precisely measure cut depth by detecting tool position relative to the workpiece, providing accurate numerical data that meets tight tolerance requirements. The system automatically records and reports measurements, eliminating the imprecision of human visual estimation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system implements continuous feedback through sensors that monitor cut depth in real-time during the back spotfacing operation. The measurement data is fed back to the control system, which automatically adjusts machining parameters to maintain precision within tight tolerances. This closed-loop feedback mechanism ensures accurate cut depth determination throughout the entire process

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9751136B2Back spotfacing system and method

Publication Date: 2017.09.05 THE BOEING CO

AI summary

A back spotfacing system having a machining apparatus with a through-hole cutter tool. The tool has an elongate member movable to coaxially extend through a hole in a workpiece from a first side of the workpiece, the workpiece coupled to the apparatus. The tool has a cutter element pivotal between a stowed position on the elongate member, a contact position with an inner surface of the hole, and an extended position extending radially from the elongate member. In the extended position, the cutter element extends to machine and back spotface a surface on a second side of the workpiece opposite the first side. The system has a power system for powering the apparatus and tool, and a measurement system coupled to the apparatus for measuring one or more hole exit positions of the cutter element and one or more surface contact positions of the cutter element on the surface.