Railcar Body Assembly With Tool-Free Laser Weld Positioning

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Solution Overview

Problem

Existing methods for manufacturing railcar bodies, such as welding and using through fasteners, incur high production costs due to the need for tooling and can result in heat distortion or added weight, while alternative methods like riveting and laser welding face challenges with precise positioning and component shape compatibility.

Innovation Solution

A method involving robotically laser-cut metal sheet and plate components with alignment holes and matching assembly features, secured with fasteners along orthogonal axes, allowing for assembly without tooling and low-heat laser welding to create butt and melt-through welds, eliminating the need for external tooling and minimizing distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding operations are used to join railcar body components, then strong joints are achieved, but heat distortion occurs and expensive tooling is required to hold components in place

Engineering Contradiction:
Improvejoint strengthVSAvoidheat distortion
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent introduces self-aligning fasteners as an intermediary joining mechanism that eliminates the need for expensive welding tooling. These fasteners feature alignment elements that automatically position themselves during assembly, providing strong joints without the heat distortion associated with welding operations

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces the thermal welding process with a mechanical fastening system. Instead of using heat to join metal components, the patent employs mechanically activated fasteners with alignment features that physically secure components together, eliminating heat-induced distortion while maintaining joint strength

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

2Object-generated harmful factors

If through fasteners are used to join railcar body components, then no heat distortion occurs, but substantial weight is added to the assembly

Engineering Contradiction:
Improveheat distortionVSAvoidassembly weight
Core Design Contradiction:
Object-generated harmful factorsVSWeight of moving object

Solution Approach 1:

The patent applies local quality by using sheet metal components of varying thicknesses strategically positioned in the assembly. Thinner sheets are used where full structural support is not needed, reducing overall weight while maintaining joint integrity through the fastening system. This localized variation in material properties optimizes the weight-strength ratio

Inventive Principle:
Principle #3Local quality

3Strength

If riveting and laser welding are used to assemble railcar body components, then strong joints are achieved, but precise positioning and component shape compatibility remain problematic

Engineering Contradiction:
Improvejoint strengthVSAvoidpositioning precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent implements preliminary action through pre-formed alignment elements integrated into the fastener design. These alignment features are prepared in advance and guide component positioning during assembly, eliminating the need for complex jigs or fixtures. The alignment elements ensure precise positioning and compatibility across various component shapes before the actual fastening occurs

Inventive Principle:
Principle #10Preliminary 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

This method reduces production costs by eliminating the need for tooling, avoids heat distortion, and provides a lightweight assembly with precise positioning, enabling efficient and cost-effective manufacturing of railcar bodies.

Implementation Method 1

providing a plurality of robotically laser cut metal sheet components where each one of the plurality of sheet components have a laser cut alignment hole

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

robotically laser welding the pairs of overlapping sheet components in the first lap joints

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3812233B1Method for manufacturing a railcar body
Publication Date: 2022.01.05 BOMBARDIER TRANSPORTATION GMBH
  • EP3812233B1 patent drawingFigure 1~2
  • EP3812233B1 patent drawingFigure 3~4
  • EP3812233B1 patent drawingFigure 5

AI summary

A method for manufacturing a railcar body comprises assembling an underframe assembly, side walls, a roof and end walls made from laser cut sheet and plate components where the assemblies made from sheet components are robotically laser welded by solely using melt-through welds and where the assemblies made from plate components are robotically laser welded using solely butt welds.