Electrostatic Coating Machine Shield Member Design

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Solution Overview

Problem

In electrostatic coating machines, paint particles often adhere to the rotary atomizing head and shaping air spurting member due to insufficient axial kinetic vector component and uneven air pressure from shaping air, leading to reduced productivity and frequent washing requirements, especially in narrow spaces.

Innovation Solution

The electrostatic coating machine incorporates a shield member to shield electric flux lines, an insulating member to manage electric fields, and a discharge buffering member to mitigate electrical stress, ensuring paint particles are effectively directed towards the coating object and preventing adhesion on the machine components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If shaping air is spurted from limited holes arranged in circular pattern, then spray pattern can be controlled, but axial kinetic vector component becomes insufficient and air pressure becomes uneven

Engineering Contradiction:
Improvespray patternVSAvoidcoating efficiency
Core Design Contradiction:
ShapeVSProductivity

Solution Approach 1:

The shaping air spurting member is divided into multiple independent air holes arranged in circular pattern, allowing separate control of air flow in different directions to simultaneously achieve spray pattern control and sufficient axial kinetic component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Air holes are strategically positioned and oriented to create localized air flow characteristics - some holes provide radial shaping while others provide axial propulsion, ensuring both spray pattern control and adequate axial kinetic vector component for preventing paint adhesion

Inventive Principle:
Principle #3Local quality

2Productivity

If paint particles are electrified to negative polarity, then coating efficiency is enhanced, but paint particles adhere to machine parts with ground potential

Engineering Contradiction:
Improvecoating efficiencyVSAvoidpaint adhesion
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

A shield member made of conductive material is introduced as an intermediary between the electrified paint particles and the ground-potential machine parts. The shield member is connected to ground potential and creates an electric field barrier that redirects electrostatic field lines, preventing direct attraction between negative paint particles and ground-potential surfaces while allowing coating to proceed efficiently

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If shield member is added to prevent paint adhesion, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvecoating efficiencyVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The shield member serves multiple functions simultaneously: it acts as an electric field barrier to prevent paint adhesion, provides structural support for the shaping air spurting member, and can be integrated with existing machine components. This multi-functionality minimizes the increase in device complexity while achieving the productivity improvement

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration enhances coating efficiency by reducing paint adhesion on the machine parts, minimizing washing frequency, and improving productivity, especially in confined areas.

Implementation Method 1

the electrostatic coating machine can fly the electrified paint particles along an electrostatic field formed between each of the electrodes and the coating object

Methodology Applied
Scientific EffectElectrostatic field: Electric Field

Implementation Method 2

the paint particles sprayed from the rotary atomizing head are indirectly electrified to be in the negative polarity. Accordingly, the electrostatic coating machine can fly the electrified paint particles along an electrostatic field

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 3

the paint supplied to the rotary atomizing head is atomized by centrifugal forces generated when the rotary atomizing head rotates and is sprayed as paint particles from the releasing edge

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 4

the shaping air spurting member sprays the shaping air spurted from each of the air spurting holes to the paint particles. As a result, the shaping air spurting member controls a kinetic vector component of the paint particle in a coating object direction

Methodology Applied
Scientific EffectFluid spray: Fluid Spray

Data Source

PatentEP3593906B1Electrostatic coating machine
Publication Date: 2024.03.20 ABB (SCHWEIZ) AG
  • EP3593906B1 patent drawingFigure 1
  • EP3593906B1 patent drawingFigure 2
  • EP3593906B1 patent drawingFigure 3

AI summary

A shield member (14) is provided on an outer peripheral side of a front surface section (9D) of a shaping air spurting member (9) and is formed of an annular body radially extending to shield electric flux lines traveling toward rotary atomizing head (4) from each of electrodes (6C) in an external electrode member (6). A tubular insulating member (15) formed of an insulating material covering an outer peripheral surface (9B) of the shaping air spurting member (9) is provided on an outer peripheral side of the shaping air spurting member (9). Further, a discharge buffering member (16) formed of an annular self-returning insulator or semi-conductive material is provided in a position where the shield member (14) is separated from the insulating member (15) between the shield member (14) and the insulating member (15).