HVAC Duct Section Perforation Layout for Easier Bending

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Solution Overview

Problem

Existing methods for forming features like notches, taps, and access doors in HVAC duct sections using plasma cutters compromise the structural integrity of the sheet material, making subsequent bending and rolling processes more difficult and reducing the material's structural soundness.

Innovation Solution

A method and apparatus that use a plasma cutter with a controller to form a series of perforations in the sheet material, which define the features without completely removing the material, maintaining structural integrity and allowing for easier downstream processing like bending into duct sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plasma cutter is used to remove quantities of material from the sheet material to form notches, taps, access doors and like features prior to bending, then these features can be formed in the sheet material, but the integrity of the sheet material is greatly reduced, rendering it less structurally sound and making subsequent rolling and bending processes much more difficult

Engineering Contradiction:
Improveease of forming featuresVSAvoidstructural integrity of sheet material
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The method forms a preliminary channel through the sheet material that defines the future location of notches, taps, and access doors before bending occurs. This preliminary action allows the features to be pre-positioned accurately while maintaining material integrity during the bending process, as the channel walls provide structural support until the final forming stage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The channel formed in the sheet material is segmented into discrete sections rather than being a continuous cut. This segmentation maintains material connectivity and structural integrity while still defining the necessary feature locations. The segmented channel allows material to remain attached at intervals, preserving strength while enabling subsequent feature formation.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If a plasma cutter is used to remove quantities of material from the sheet material to form notches, taps, access doors and like features prior to bending, then these features can be formed in the sheet material, but the subsequent rolling and bending processes become much more difficult

Engineering Contradiction:
Improveease of forming featuresVSAvoiddifficulty of rolling and bending processes
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The channel is formed in advance before bending operations, establishing precise feature locations while the material is still in its flat, manageable state. This preliminary positioning eliminates the need for complex adjustments during rolling and bending, as the channel structure guides the forming process and maintains feature accuracy throughout subsequent manufacturing steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The channel formation applies material modification only at specific locations where features are needed, rather than uniformly across the entire sheet. This localized approach maintains overall material integrity and flexibility in regions not affected by the channel, allowing standard rolling and bending processes to proceed without encountering widespread structural weaknesses.

Inventive Principle:
Principle #3Local quality

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

The method allows for efficient and cost-effective fabrication of HVAC duct sections by preserving the material's integrity, facilitating easier bending and rolling processes while maintaining the structural soundness of the sheet material.

Implementation Method 1

creating an electrical channel of superheated, electrically ionized gas ('plasma') from the plasma cutter, through the material to be cut

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

An electrical arc is then formed within the gas, between an electrode near or integrated into the gas nozzle and the work piece itself

Methodology Applied
Scientific EffectElectrical arc: Electric Arc

Implementation Method 3

The electrical arc ionizes some of the gas, thereby creating an electrically conductive channel of plasma

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 4

As electricity from the torch travels down this plasma, it delivers sufficient heat to melt through the workpiece

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 5

much of the high velocity plasma and compressed gas blow the hot molten metal away, thereby separating i.e. cutting through the work piece

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP3326744A1Method and apparatus for manipulating metal workpieces
Publication Date: 2018.05.30 MESTEK MACHINERY INC
  • EP3326744A1 patent drawingFigure 1
  • EP3326744A1 patent drawingFigure 2
  • EP3326744A1 patent drawingFigure 3

AI summary

A method of forming a duct section from a web of material includes the steps of forming a series of perforations (25) in a web of material, the series of perforations (25) defining an outline of one of a hole (21) or notch in a finished duct section, forming a male lock bend and a female lock seam in first opposed edges of the web of material, forming flanges in second opposed edges of the web of material, removing the portion of material interior to the series of perforations to form the hole or notch, and bending the web of material to form the finished duct section.