Adaptive Welding Head Positioning for Profile Parts

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Solution Overview

Problem

Current welding devices for plastic profile parts, such as PVC window frames, face inefficiencies due to reliance on theoretical nominal dimensions, leading to increased welding times, material deviations, and risks of decomposition or combustion at higher temperatures, resulting in reduced fracture values and asymmetric welds.

Innovation Solution

A device and method that allow the welding head to be positioned within a specified tolerance range around the target welding position, compensating for dimensional deviations of the profile parts, ensuring equal melting and joining times for both ends, and reducing the risk of material changes by maintaining symmetry and consistent heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher welding temperatures are used to reduce adjustment and warm-up times, then productivity is improved, but the risk of material decomposition or combustion increases

Engineering Contradiction:
Improvewelding speedVSAvoidmaterial decomposition
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The welding head positioning system is made dynamically adjustable within a tolerance range rather than being fixed at a single theoretical position. This allows the system to adapt to actual profile dimensions while maintaining consistent welding parameters, enabling higher temperatures to be used safely without causing material decomposition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of welding head position from a fixed theoretical value to a variable value within a specified tolerance range. This parameter change allows the system to compensate for profile dimensional variations, ensuring that the welding process can be performed at higher temperatures with shorter times without risking material degradation.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If welding heads are positioned according to theoretical nominal dimensions, then device complexity is reduced, but manufacturing precision deteriorates due to profile dimensional deviations

Engineering Contradiction:
Improvepositioning systemVSAvoidwelding position accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention merges the theoretical nominal positioning system with actual profile measurement data. By combining these two approaches, the system achieves high welding precision without requiring complex additional positioning mechanisms, thus maintaining device simplicity while improving manufacturing accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs preliminary positioning within a tolerance range based on theoretical dimensions, then makes final adjustments during the welding process. This preliminary action allows the system to prepare for welding efficiently while retaining the ability to achieve precise positioning, thereby balancing device complexity with manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

3Strength

If longer melting and joining times are used to ensure complete welding, then weld strength is improved, but productivity decreases

Engineering Contradiction:
Improveweld strengthVSAvoidproduction speed
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The invention enables the welding process to rush through the melting and joining phases more quickly by positioning the welding head optimally within a tolerance range. This allows complete welding to be achieved in shorter times, improving productivity while maintaining adequate weld strength through precise positioning rather than extended duration.

Inventive Principle:
Principle #21Skipping (Rushing through)

4Ease of operation

If profile dimensional deviations are not compensated, then ease of operation is improved, but welding quality deteriorates due to asymmetric melting

Engineering Contradiction:
Improveoperation simplicityVSAvoidweld symmetry
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The welding head positioning system performs self-adjustment within a tolerance range to compensate for profile dimensional deviations. This self-service capability maintains ease of operation by requiring no additional manual intervention while automatically ensuring symmetric melting and high welding quality.

Inventive Principle:
Principle #25Self-service

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 significantly reduces welding times, minimizes material changes, and enhances the strength of the welds by allowing for shorter melting times at higher temperatures without decomposition, while also improving manufacturing efficiency and accuracy.

Implementation Method 1

The actual welding of the profile parts is done by melting and then joining the ends of the profile bar. When melting and joining the ends of the profile bar, part of the melted material is displaced

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The actual welding of the profile parts is done by melting and then joining the ends of the profile bar

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP2421692B1Device and method for welding profiled parts
Publication Date: 2015.02.25 ROTOX BESITZ UND VERW GMBH
  • EP2421692B1 patent drawingFigure 1
  • EP2421692B1 patent drawingFigure 2
  • EP2421692B1 patent drawingFigure 3

AI summary

The invention relates to a device for welding profiled parts (8), in particular plastics profiled parts, having at least one welding head (1) that can be positioned in a predetermined or predeterminable target welding position (6) relative to another welding head (1, 9) and/or relative to a holding device. According to the invention the welding head (1) and/or a part of the welding head (1) that comprises at least one heating element, such as a heating plate, for melting the profiled parts, can be positioned and/or is movable in accordance with at least one dimensional variation of at least one of the profiled parts (8) from a target dimension in a spatial tolerance range (5) around the target welding position (6).