Sanding Tool Variable Compliance for Non-Flat Surface Control

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Solution Overview

Problem

Robotic sanding systems struggle to adaptively control pressure during sanding operations over non-flat part features, leading to inefficiencies in cut rate and abrasive selection, as they rely on compliant abrasive products that compromise performance.

Innovation Solution

Implementing variable compliance damping systems within the sanding tool, which can adjust compliance in real-time based on feedback and pre-programmed cycles, using mechanisms like magnetorheological fluids and ball bearings to manage force application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If compliant abrasive products are used to adapt to non-flat surfaces, then adaptability is improved, but cut rate and sanding efficiency deteriorate

Engineering Contradiction:
Improveadaptability to non-flat surfacesVSAvoidcut rate
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The sanding system is divided into separate functional components: a rigid abrasive product for maintaining cut rate, and a separate compliance mechanism (damping feature) that independently provides adaptability to non-flat surfaces. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A damping feature acts as an intermediary element between the sanding tool and the workpiece. This intermediary absorbs vibrations and provides compliance, enabling the rigid abrasive product to maintain optimal contact pressure and cut rate while still adapting to surface variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If rigid abrasive products are used to maintain cut rate, then productivity is improved, but adaptability to non-flat surfaces deteriorates

Engineering Contradiction:
Improvecut rateVSAvoidadaptability to non-flat surfaces
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The system separates the functions of material removal (performed by rigid abrasive product) and surface adaptation (performed by compliance mechanism). This allows the abrasive product to remain rigid for efficient cutting while the compliance mechanism handles surface conformity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The damping feature serves as a mediator that enables the rigid abrasive product to adapt to non-flat surfaces without compromising its rigidity. It transmits only the necessary contact forces while absorbing vibrations and accommodating surface variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If separate force control units are added to enable real-time force adjustment, then force control precision is improved, but device complexity increases

Engineering Contradiction:
Improveforce control precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sanding tool is equipped with intrinsic damping features and vibration absorption capabilities that automatically regulate force application. The system self-adjusts to maintain optimal contact pressure through the compliance of the damping feature, eliminating the need for external force control units.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex electronic force control systems with a mechanically inherent compliance solution. The damping feature provides passive force regulation through its physical properties, substituting active electronic control with passive mechanical behavior.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables real-time adjustability of force control, allowing for optimized cut rates and efficient sanding operations on complex surfaces without the need for separate force control units, enhancing robotic sanding capabilities.

Implementation Method 1

using mechanisms like magnetorheological fluids and ball bearings to manage force application

Methodology Applied
Scientific EffectMagnetorheological fluid: Magnetorheological Fluid

Implementation Method 2

Operation of sanding tools often causes vibrations

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP4263129B1Sanding system with damping feature
Publication Date: 2025.08.20 3M INNOVATIVE PROPERTIES CO
  • EP4263129B1 patent drawingFigure 1A
  • EP4263129B1 patent drawingFigure 1B
  • EP4263129B1 patent drawingFigure 2A~2B

AI summary

A sanding system is presented that includes a tool with a motor which, when actuated, drives movement of a drive shaft. The system also includes a backup pad coupled to the drive shaft. The backup pad is configured to receive an abrasive article. Movement of the drive shaft causes movement of the abrasive article. The system also includes a compliant damping unit configured to provide variable compliance for the tool when the abrasive article contacting a worksurface. The system also includes an electronic controller that receives a system operating condition and sends a signal to the compliant damping unit based on the system operating condition.