Pipe Section Separation Using Pre-Slotted Wedge Cutting

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Solution Overview

Problem

Existing methods for cutting pipe sections to length, particularly in high-strength steels and tight tolerances, face issues with burr formation, deformation, and tool wear due to introduced torque and lack of counter support, making them unsuitable for precision and mass production.

Innovation Solution

A method involving a pipe blank with a cutting slot and a punching knife with a smaller initial wedge angle that widens transversely, featuring centering tabs for stable cutting, ensuring the cutting slot is centered and reducing material removal in one step, allowing for precise and stable cutting with reduced tool load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a punching knife moves transversely into the pipe to cut it, then the cutting process can be completed, but torque is introduced into the pipe causing deformation and burr formation

Engineering Contradiction:
Improvecutting speedVSAvoidcut quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

A cutting slot is pre-formed in the pipe blank before the punching knife makes its transverse move. This preliminary action creates a controlled opening that guides the punching knife's path and reduces the torque introduced during cutting, thereby preventing deformation and burr formation while maintaining cutting speed

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the punching knife has a larger wedge angle for faster cutting, then productivity increases, but the load on the tool increases and manufacturing precision decreases

Engineering Contradiction:
Improvecutting speedVSAvoidtool life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The punching knife is designed with a specific wedge angle optimized for the pre-formed cutting slot geometry. This parameter optimization allows the knife to efficiently cut through the slot while distributing loads evenly, maintaining both high cutting speed and extended tool life without excessive wear

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the pipe blank is held stable during cutting, then manufacturing precision improves, but the complexity of the cutting device increases

Engineering Contradiction:
Improvedimensional accuracyVSAvoidclamping system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cutting slot is pre-formed in the pipe blank before the actual cutting operation. This preliminary action inherently stabilizes the pipe blank by creating a controlled geometry that guides the punching knife, thereby achieving high dimensional accuracy without requiring complex clamping or positioning systems

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 enables precise, burr-free cutting with reduced tool wear, allowing for efficient production of pipe sections with high accuracy and stability, suitable for mass production and continuous processes.

Implementation Method 1

Insertion of a punching knife, which becomes wider in the longitudinal direction of the cutting slit, transversely to the longitudinal extension of the pipe blank into the cutting slit, the punching knife having a wedge angle

Methodology Applied
Scientific EffectWedge: Wedge

Data Source

PatentEP3875197B1Method for separating pipe sections
Publication Date: 2022.07.27 WELSER PROFILE AUSTRIA GMBH
  • EP3875197B1 patent drawingFigure 1
  • EP3875197B1 patent drawingFigure 2
  • EP3875197B1 patent drawingFigure 3

AI summary

A method for cutting off pipe sections (2) comprising the following steps: providing a pipe blank (2) with at least one cutting slot (11) arranged in a predetermined cutting position and extending in the circumferential direction of the pipe blank (2), wherein the cutting slot (11) has an opening angle of β1 < 180°; inserting a cutting blade (3) widening in the longitudinal direction of the cutting slot (11) transversely to the longitudinal extent of the pipe blank (2) into the cutting slot (11), wherein the cutting blade (3) has a wedge angle (α1) which, at least in the region of the initial widening of the cutting slot (11) by the cutting blade (3), is smaller than the opening angle (β1) of the cutting slot (11); and cutting the remaining material in the extension of the cutting slot (11) by means of the cutting blade (3) extending further transversely to the longitudinal extent of the pipe blank. (2) incoming punching blade (3).The transverse edges of the cutting slot each have a projecting centering lug (15) which creates an expanding contact that intensifies as the cutting die (3) is inserted. The invention also relates to the use of a tube blank (2) and a cutting die (3) in such a method.