Heated Tool Cutting Thermoplastic Bristles

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Solution Overview

Problem

Existing brush manufacturing methods face challenges with high blade wear and precise front trimming processes, which are time-consuming and inefficient, especially when dealing with thermoplastic bristles.

Innovation Solution

A method and device utilizing a heated tool, such as a flat wire, to cut bristles before or after attachment to the base part, leveraging heat and cutting geometry to minimize wear and facilitate high-speed cutting, with the option to use the hot knife in conjunction with a second unheated tool for fine trimming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a sharp knife is used to cut bristles on the back of the guide part, then the bristles can be trimmed, but the blade experiences high wear

Engineering Contradiction:
Improvecutting capabilityVSAvoidblade wear
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces the mechanical cutting system (sharp knife) with a thermal cutting system (heated tool). The heated tool cuts bristles through thermal melting rather than mechanical shearing, eliminating blade wear while maintaining high cutting speed capability. This substitution of cutting mechanism directly resolves the contradiction between productivity and blade reliability.

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

Solution Approach 2:

The patent changes the cutting parameter from mechanical force to thermal energy. By heating the tool to sufficient temperature, the bristles are melted and separated rather than cut mechanically. This parameter change allows continuous operation without blade degradation, resolving the wear issue while maintaining productivity.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If front trimming is performed in several stages from coarse to fine, then precise brush surface profiling is achieved, but the process becomes time-consuming

Engineering Contradiction:
Improvebrush surface profiling precisionVSAvoidtrimming process time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces multi-stage mechanical trimming with a single-stage thermal cutting process. The heated tool can directly achieve precise profiles without requiring progressive stages, as thermal melting provides clean, controlled cuts in one operation. This substitution eliminates the time-consuming multi-stage process while maintaining or improving precision.

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

Solution Approach 2:

The patent performs preliminary heating of the tool to enable it to perform both coarse and fine trimming in a single pass. The pre-heated tool can be moved at controlled speeds to achieve different levels of precision without requiring multiple tool changes or stages, thus reducing total process time while maintaining manufacturing precision.

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

The solution results in a wear-free cutting process with reduced stress on bristles, enabling efficient profiling and attachment, while the heated tool's softening effect allows for bristle welding, improving positioning and fixing during processing.

Implementation Method 1

The heated tool comprises an electrical resistance heater in the cutting area or forms an electrical resistance heater itself

Methodology Applied
Scientific EffectElectrical resistance heating: Joule Heating

Implementation Method 2

The bristles are made of thermoplastic. The trimmed ends become soft when cut and stick together

Methodology Applied
Scientific EffectThermal softening and welding of thermoplastic: Melting

Data Source

PatentEP2377425B1Device and method for manufacturing brushes
Publication Date: 2013.10.23 GB BOUCHERIE NV
  • EP2377425B1 patent drawingFigure 1a~1d
  • EP2377425B1 patent drawingFigure 1e~1h
  • EP2377425B1 patent drawingFigure 2~3

AI summary

The method involves attaching bristles at a base part (12) in a clumpful manner. The bristles are cut by a heated tool (70), which stays in contact with the bristles to be cut. The bristles are plugged into openings of the base part and are cut by the heated tool. Tool geometry and temperature of the tool are adjusted to brush geometry in such a manner that a bunch (16) of bristles or an adjacent bunch of bristles is welded together by cutting. The tool is arranged at distance from the base part and is displaced transverse to the bristles without a support body during cutting. An independent claim is also included for a device for manufacturing brushes.