Inspection Group for Elongated Elements Using Single Light Stripe

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Solution Overview

Problem

Current inspection methods for elongated elements in the tobacco industry, such as continuous rods, are costly and imprecise due to the need for multiple optical assemblies and high processing times, leading to inaccuracies in diameter measurement and shape analysis, especially at high production speeds.

Innovation Solution

An inspection system using a single optical scanning assembly with two projectors projecting stripes of light from opposite sides to acquire three-dimensional light traces, which are then processed to reconstruct the shape and diameter of the rod, allowing for precise detection of defects like ovalness and reducing the overall dimensions and cost of the inspection setup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple optical assemblies are used for inspection, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvediameter measurement precisionVSAvoidinspection group complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple optical assemblies into a single integrated optical assembly that performs both diameter measurement and shape analysis functions. The single assembly includes a light source, optical axis aligned with the rod axis, and detection means positioned to receive light after interaction with the rod, integrating capabilities that previously required separate devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single optical assembly is designed to perform multiple inspection functions simultaneously: diameter measurement through light intensity detection and shape analysis through position detection of light traces. This multi-functional design eliminates the need for separate specialized devices while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple optical assemblies are used for inspection, then measurement precision is improved, but processing time increases

Engineering Contradiction:
Improveshape analysis precisionVSAvoidinspection processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The optical assembly continuously emits light along the rod axis and detects light traces in real-time as the rod passes through, enabling continuous measurement without interruption. This allows simultaneous diameter measurement and shape analysis during rod production, eliminating sequential processing delays.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs preliminary light tracing and position detection during the rod's passage, capturing shape information in advance. The detection means records light trace positions continuously, allowing rapid processing and reconstruction of rod geometry without time-consuming post-processing.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a single optical scanning assembly is used, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improveinspection setup dimensionsVSAvoiddiameter measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from two-dimensional light intensity measurements to three-dimensional light trace position detection. By detecting the positional coordinates of light traces in space and reconstructing the rod's cross-sectional shape from these 3D position data, the system achieves high measurement precision with a single optical assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system replaces complex mechanical measurement systems with optical field-based measurement. Light traces serve as measurement probes, and their position detection through optical means substitutes for physical contact or multiple mechanical sensors, maintaining precision while reducing device complexity.

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

4Productivity

If high-speed production is maintained, then productivity is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveproduction speedVSAvoidshape detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The optical system uses periodic light emission and detection cycles synchronized with rod production speed. The light source emits light in periodic intervals, and the detection means captures light traces at regular intervals, ensuring consistent measurement precision even at high production speeds through rhythmic, controlled measurement cycles.

Inventive Principle:
Principle #19Periodic action

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

The system achieves high precision and accuracy in shape analysis and diameter measurement with reduced space and cost, enabling efficient quality control of elongated elements during high-speed production.

Implementation Method 1

a projecting device to project from a first half-space a first stripe of light onto an external face of the elongated element to obtain a first three-dimensional light trace on said external face

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

an electronic sensor is arranged, for example an alignment or array of photosensitive elements of linear or two-dimensional matrix type... and appropriate optical receiving means that is fixed to the body, for example an objective consisting of one or more lenses, by means of which the sensor is suitable for receiving the light diffused from the object to be acquired

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP3377850B1Inspection group of an elongated element
Publication Date: 2023.04.19 GD SPA
  • EP3377850B1 patent drawingFigure 1~2
  • EP3377850B1 patent drawingFigure 3~4
  • EP3377850B1 patent drawingFigure 5~6

AI summary

An inspection group (1) is proposed tor inspecting cylinder-shaped elongated elements for smoking articles, in which a working plane (P) is selected passing through a longitudinal axis (S) of a first elongated element (2) and there are considered a first half space (3) and a second half space (4) arranged on opposite parts with respect to the working plane (P). The inspecting group (1 ) comprises: a projecting device adapted to project a first stripe of light (5) from the first half space (3) onto an inspection portion (6) of an external surface (8) of the first elongated element (2) and to obtain a first three-dimensional light trace (7), and also adapted to project a second stripe of light (9) from the second half space (4) onto the inspection portion (6) to obtain a second three-dimensional light trace (10); an optical assembly adapted to frame the first elongated element (2) and to process a first view and a second view; a processing device (1 1) adapted to reconstruct a first closed curved section profile (12) of the first elongated element (2) processing an identified first curved light line (7') in the first view and a second identified curved light line (10') in the second view and comparing the first reconstructed closed curved profile (12) with an ideal section profile to identify possible deformations of the reconstructed first closed curved profile (12) with respect to the ideal section profile. The projecting device comprises a single projector (28) of a single stripe of light (29); a shield (30), arranged between the single projector (28) and the first elongated element (2), adapted to split the single stripe of light (29) into a first part of a stripe of light (29a) and into a second part of a stripe of light (29b); first deflectors (31) of the first part of a stripe of light (29a) arranged in the first half space (3) and second deflectors (32) of the second part of the stripe of light (29b) arranged in the second half space (4) to obtain respectively the first stripe of light (5) projected from the first half space (3) and the second stripe of light (9) projected from the second half space (4) by a single stripe of light (29).