CFRP Stack Machining with Real-Time Sensor Feedback

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Solution Overview

Problem

Current machining systems for carbon fiber reinforced plastic (CFRP) stacks face challenges in maintaining quality due to delamination issues during lamination processes, particularly with small diameter spindles, leading to tool damage and increased costs, and lack effective monitoring for heterogeneous composite materials.

Innovation Solution

A carbon fiber reinforced plastic machining method using a monitoring sensor that electrically connects a spindle and sensor via CNC, determines start and finish positions, and controls movement and rotational speeds in real-time, employing load cells, torque sensors, and impedance sensors to optimize machining conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If small diameter spindles are used for machining CFRP stacks, then productivity and precision are improved, but tool wear increases and delamination occurs

Engineering Contradiction:

Improvemachining precisionVSAvoidtool durability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by detecting machining state changes (such as delamination or tool wear) before they lead to complete tool failure or product defect. The monitoring system detects impedance changes, current variations, or vibration patterns that indicate impending problems, allowing intervention before the tool is completely worn or the workpiece is damaged.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring machining parameters (current, impedance, vibration, acoustic emission) and using this information to adjust machining conditions in real-time. The system provides feedback loops that allow dynamic adjustment of cutting parameters or tool replacement timing based on actual machining state, resolving the contradiction between using small spindles for precision and preventing tool wear.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If conservative tool wear management is applied, then product quality is maintained, but tool costs increase

Engineering Contradiction:

Improveproduct qualityVSAvoidtool cost

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The monitoring system provides real-time feedback on actual tool condition and machining quality, replacing tools based on actual wear state rather than conservative predetermined intervals. This allows extending tool life beyond traditional conservative limits while maintaining quality standards, reducing tool waste and cost.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system enables self-service by automatically detecting tool wear and machining quality degradation, allowing the machining system to self-regulate and make decisions about tool replacement based on actual conditions rather than requiring external inspection or conservative predetermined schedules.

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If real-time monitoring is implemented, then machining quality is improved, but device complexity increases

Engineering Contradiction:

Improvemachining qualityVSAvoidsystem complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies universality by using multi-functional monitoring sensors that can detect multiple machining parameters (vibration, impedance, current, acoustic emission) simultaneously with a single integrated system. This reduces the overall complexity compared to using separate dedicated sensors for each parameter, while still achieving comprehensive real-time quality monitoring.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The monitoring functions are merged into the existing spindle and machine tool structure rather than being added as separate external systems. Sensors are integrated into the spindle assembly or machine tool components, combining monitoring functions with existing structural elements to minimize additional complexity.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If automated machining is used, then productivity increases, but tool damage risk increases

Engineering Contradiction:

Improvemachining efficiencyVSAvoidtool safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The automated monitoring system provides continuous feedback on tool condition and machining state, enabling the automated system to detect and respond to abnormal conditions that could lead to tool damage. This allows maintaining high automated productivity while reducing tool damage risk through real-time detection and intervention.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system takes preliminary action by detecting early signs of tool wear, delamination, or abnormal machining conditions before they progress to complete tool failure. This allows the automated system to intervene proactively, maintaining productivity while preventing tool damage.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10265779B2Carbon fiber reinforced plastic stack machining method using a monitoring sensor

Publication Date: 2019.04.23 KOREA INSTITUTE OF INDUSTRIAL TECHNOLOGY

AI summary

Provided is a carbon fiber reinforced plastic machining method using a monitoring sensor which includes the step (S10) of electrically connecting a spindle and the monitoring sensor by a computer numerical control (CNC) device, the step (S20) of determining a start position in relation to machining of the spindle and a machining finish position, and the step (S30) of controlling the movement speed and rotation speed of the spindle in accordance with the determination result.