Angular Profile Welding with Tolerance-Compensating Milling

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Solution Overview

Problem

The existing methods for connecting plastic profile pieces at an angle to form frames, such as window or door frames, face challenges with dimensional and angular tolerances, leading to excessive weld bead formation and increased material removal, which affects the stability and visual appearance of the frames.

Innovation Solution

A method involving the use of a processing tool with symmetrical milling disks to clamp and precisely adjust profile pieces before welding, compensating for length and angular tolerances in a single machining step, minimizing the formation of weld beads by ensuring accurate dimensional alignment and reducing material excess.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If profile pieces are welded directly after sawing and mitring without additional machining, then the manufacturing process is simple and quick, but dimensional tolerances accumulate leading to excessive weld bead formation and poor visual appearance

Engineering Contradiction:
Improvedimensional accuracy of connecting surfacesVSAvoidcomplexity of machining equipment
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the machining function (milling tool with two milling disks) and welding function (heating element) into a single integrated welding machine. The machining unit with spacers and milling disks is integrated into the welding device, allowing both operations to be performed in one setup without requiring separate machining and welding equipment. This reduces device complexity while improving dimensional accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs machining of the connecting surfaces immediately before welding within the same device setup. The milling disks machine the profile surfaces to precise dimensions, and then the heating element immediately welds the machined surfaces. This preliminary machining action eliminates tolerance accumulation and ensures accurate dimensions before welding occurs.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If profile material is removed excessively to compensate for tolerances, then weld bead formation is reduced, but material waste increases and frame dimensions become inaccurate

Engineering Contradiction:
Improveaccuracy of frame dimensionsVSAvoidmaterial waste from profile pieces
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent uses adjustable spacers with precise thicknesses to control the machining depth and dimensions. By changing the spacer parameters (thickness and positioning), the machining process can be precisely controlled to remove only the necessary amount of material to compensate for tolerances, rather than excessive material removal. This ensures accurate frame dimensions while minimizing material waste.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces manual tolerance compensation methods with an automated machining system using milling disks and adjustable spacers. The mechanical positioning system with spacers and the controlled milling process automatically compensate for tolerances, eliminating the need for manual material removal and ensuring consistent, accurate dimensions without excessive material waste.

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

3Productivity

If a single milling cutter is used to machine connecting surfaces, then the device is simpler, but machining time increases and productivity decreases

Engineering Contradiction:
Improvemachining speed of profile piecesVSAvoidcomplexity of milling tool
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the milling operation into two simultaneous operations using two milling disks mounted on the same spindle. Each milling disk machines one of the two profile pieces at the same time, effectively doubling the machining productivity. The segmented tool design with two disks allows parallel processing of both profile surfaces without increasing overall device complexity significantly.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If profile pieces are re-clamped after machining to perform welding, then positioning accuracy is maintained, but production time increases

Engineering Contradiction:
Improvepositioning accuracy for weldingVSAvoidtime for re-clamping operations
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent combines the machining and welding operations into a single continuous process within the same clamping setup. The profile pieces are clamped once, machined by the milling disks, and then immediately welded by the heating element without release or re-clamping. This integrated approach maintains positioning accuracy while eliminating the time-consuming re-clamping step.

Inventive Principle:
Principle #5Merging (Combining)

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 ensures high dimensional accuracy, reduces the need for re-clamping, and minimizes the formation of weld beads, resulting in a more stable and visually appealing frame with optimized dimensions.

Implementation Method 1

separating profile material in the region of the connecting surfaces with at least one machining tool

Methodology Applied
Scientific EffectMechanical cutting: Abrasion

Implementation Method 2

melting the connecting surfaces and contacting the melted connecting surfaces to form a welded joint

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3072668B2Method and device for connecting profile sections
Publication Date: 2024.12.11 URBAN GMBH & CO MASCHINENBAU KG
  • EP3072668B2 patent drawingFigure 1
  • EP3072668B2 patent drawingFigure 2
  • EP3072668B2 patent drawingFigure 3a

AI summary

A method for connecting profile pieces (1, 1a, 1b) that meet at an angle comprises the following steps: (i) clamping the profile pieces, (ii) compensating for at least one tolerance in at least one connecting surface of the profile pieces extending perpendicularly to a frame plane a cutting removal of profile material in the area of ​​the connecting surfaces with at least one machining tool (2a, 2b) producing chips, (iii) melting the connecting surfaces (10a', 10b') and contacting the melted connecting surfaces to form a welded joint.