Internal Pipe Welding Head Control for Cantilever Deflection

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Solution Overview

Problem

Internal welding machines face issues with cantilever arm deflection and twisting due to magnetic fields and temperature differences, affecting the positioning of the welding head and weld seam quality.

Innovation Solution

A control device with lasers and cameras on the suspension and welding head, which detects deviations in laser beam positions and generates signals to adjust the welding head's position, creating a closed control loop to compensate for cantilever arm deflections and torsions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the cantilever arm is inserted deeper into the pipe to reach the welding area, then the welding head can access the welding position, but the magnetic field and heat effects cause greater deflection and twisting of the cantilever arm

Engineering Contradiction:
Improveinsertion depth of cantilever armVSAvoidpositioning accuracy of welding head
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent implements a feedback control system where sensors detect the actual position of the welding head, and the control unit calculates compensation values based on the relationship between insertion depth and deflection/torsion. The system continuously adjusts the welding head position to counteract the effects of magnetic fields and heat, maintaining positioning accuracy despite deep insertion into the pipe.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the control parameters dynamically based on insertion depth. The control unit uses pre-determined relationships (from calibration measurements) to adjust positioning parameters in real-time, compensating for the increasing deflection and torsion that occur with greater insertion depth.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the cantilever arm length is increased to reach welding areas in large diameter pipes, then the welding head can access larger pipes, but the deflection and twisting due to magnetism and heat effects are amplified

Engineering Contradiction:
Improveapplicability to large diameter pipesVSAvoidwelding head position stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The feedback control system continuously monitors the welding head position and applies real-time corrections based on the insertion depth and environmental conditions. This ensures reliable positioning even when using long cantilever arms for large diameter pipes, where magnetic field and heat effects are most pronounced.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces purely mechanical positioning with a controlled system that uses sensors, signal processing, and active compensation. Instead of relying solely on mechanical rigidity, the system uses electronic control to counteract deflection and torsion, enabling reliable operation with longer cantilever arms.

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

3Ease of manufacture

If welding media (powder, cables) are transported through the cantilever arm, then the welding process can be performed, but temperature differences cause additional deflection and twisting

Engineering Contradiction:
Improvewelding process capabilityVSAvoidwelding head positioning accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The control system compensates for thermal effects by detecting position deviations and applying corrective adjustments. The feedback mechanism accounts for temperature-induced deflection and torsion, maintaining positioning accuracy despite the presence of hot welding media being transported through the cantilever arm.

Inventive Principle:
Principle #23Feedback

4Ease of operation

If the welding head is positioned at the end of the cantilever arm for internal welding, then the welding process can be performed from inside the pipe, but the welding head position is affected by cantilever deflection and twisting

Engineering Contradiction:
Improveinternal welding capabilityVSAvoidweld seam geometry
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent uses a feedback control system that continuously monitors the welding head position and applies real-time compensation for cantilever deflection and torsion. This enables internal welding operations to be performed with maintained precision, ensuring proper weld seam geometry despite the inherent instability of the cantilever configuration.

Inventive Principle:
Principle #23Feedback

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 solution reduces welding errors and improves weld seam quality by maintaining accurate welding head positioning, enhancing reproducibility and geometry of the weld seams.

Implementation Method 1

one or more lasers are attached to the suspension, one or more cameras are attached to the welding head, one or more laser beams respectively the one or more cameras are directed

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

During the welding process, a magnetic field is created which deflects and/or twists the cantilever arm

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

the welding process itself and the transport of the welding media to the welding head - especially when welding 'under powder'; the welding flux is typically at 120°C and the welding cables can reach 100°C - high temperatures that cause additional change in deflection and twisting of the cantilever

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4028206B1Internal welding of pipes and profiles
Publication Date: 2023.08.16 SMS GROUP GMBH
  • EP4028206B1 patent drawingFigure 1

AI summary

The invention relates to a device (1) for the internal welding of pipes and profiles, comprising a cantilever arm (2, 2a), which is secured to a suspension (3), which cantilever arm can be inserted into the pipe or profile to be welded and on which a welding head (4) is displaceably attached, the cantilever arm (2, 2a) further comprising at least one laser (5) and at least one camera (6). To avoid the disadvantageous effects of magnetism and heat on the position of the welding head (4), the invention proposes that a laser (5) is attached on the suspension (3), and a camera (6) for observing the laser beam (5a) is attached on the end of the cantilever arm (3) or on the welding head (4). A correction signal is calculated from the change in position of the laser beam (5a) observed with the camera (6) and forwarded to a control unit for adjusting the welding head (4) by means of displacement devices (8, 9).