Delta-Robot Laser Welding for Shadow-Free Plastic Joint Access

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Solution Overview

Problem

Existing methods for quasi-simultaneous laser transmission welding of plastics face limitations, including beam shadowing due to component geometry and low speeds, which are not adequately addressed by conventional galvo scanners or articulated robots.

Innovation Solution

A method and device utilizing a delta robot with laser optics on a platform, combined with a movement device that includes pivotable mirrors or a gimbal suspension, allowing for flexible guidance of the laser beam to overcome spatial limitations and achieve high speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a galvo scanner with movable mirrors is used to guide the laser beam, then high welding speeds can be achieved, but beam shadowing occurs due to component geometry and the laser beam cannot reach certain welding locations

Engineering Contradiction:
Improvewelding speedVSAvoidability to access welding locations
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a 2D mirror-based deflection system to a 3D spatial positioning system using a delta robot. The laser source is moved in three-dimensional space along with the platform, enabling the laser beam to approach welding locations from multiple angles and dimensions, thereby overcoming beam shadowing caused by component geometry.

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

Solution Approach 2:

The patent introduces a transparent platform as an intermediary carrier that holds the laser source. This platform is manipulated by the delta robot to position the laser at precise three-dimensional coordinates, serving as a mediator between the robot's motion capabilities and the laser beam delivery system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If an articulated robot with laser optics on its arm is used, then flexibility in positioning is improved, but the robot cannot achieve high speeds required for quasi-simultaneous welding

Engineering Contradiction:
Improvepositioning flexibilityVSAvoidwelding speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent replaces the traditional articulated robot's mechanical arm structure with a delta robot's parallel kinematic mechanism. This substitution maintains positioning flexibility while dramatically increasing speed capability, as the delta robot's parallel structure allows for faster acceleration and movement without the mechanical limitations of serial articulated arms.

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

3Ease of operation

If the laser beam is directed by a last mirror in the beam path, then the system is simple to operate, but unfavorable angles of incidence occur with convex components and existing connections

Engineering Contradiction:
Improvesystem operation simplicityVSAvoidangle of incidence control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent makes the laser source position dynamic by mounting it on a movable platform controlled by the delta robot. This allows the laser to approach each welding location with optimally adjusted angles of incidence, adapting to convex component surfaces and existing connections, thereby improving manufacturing precision while maintaining operational simplicity through automated control.

Inventive Principle:
Principle #15Dynamics

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 approach enables efficient and high-speed quasi-simultaneous welding by allowing precise control of the laser beam's spatial orientation, reducing beam shadowing and achieving optimal angles of incidence, thereby improving welding efficiency and quality.

Implementation Method 1

The laser beam passing through one joining partner thus ensures local heating at the joint located between the two components

Methodology Applied
Scientific EffectOptical energy to thermal energy conversion: Absorption (EM radiation)

Implementation Method 2

a movement device which causes a further movement of the laser beam in order to guide the laser beam

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3630461B1Quasi-simultaneous laser welding process
Publication Date: 2021.07.07 CONSULTENGINEERIP AG
  • EP3630461B1 patent drawingFigure 1a~2d
  • EP3630461B1 patent drawingFigure 3~4
  • EP3630461B1 patent drawingFigure 5~6

AI summary

The invention relates to the quasi-simultaneous welding of at least two welding locations by means of a laser beam, characterized in that the laser beam is emitted by laser optics that are associated with a platform of a delta robot and is guided by a movement of said platform.