Electrostatic Coater Twisted Shaping Air Flow

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Solution Overview

Problem

Conventional electrostatic coaters of a rotary atomization type face challenges in achieving high-level coating quality, particularly with metallic paints, as the spraying pattern control is inferior, leading to inefficiencies in paint deposition and resulting in dual patterns with large particles on the workpiece surface.

Innovation Solution

The electrostatic coater positions air ports behind the outer peripheral edge of the rotary atomizing head to direct shaping air in a twisted flow opposite to the rotation direction, creating an air curtain that collides with paint particles further away from the atomizing head, thereby extending the liquid thread, micronizing particles, and directing them forward with reduced momentum to improve coating efficiency and quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If shaping air is discharged from air ports positioned near the outer peripheral edge of the rotary atomizing head, then the paint atomization is facilitated, but the painting pattern control becomes inferior and dual patterns are formed

Engineering Contradiction:
Improvepaint atomization efficiencyVSAvoidpainting pattern uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent positions air ports on a plane different from the outer peripheral edge plane of the rotary atomizing head, specifically on a plane farther from the rotation axis. This spatial repositioning allows the shaping air to act on paint particles at a different location in the atomization field, enabling better control of the painting pattern while maintaining atomization efficiency by operating in a different spatial dimension.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The shaping air discharged from the repositioned air ports serves as an intermediary that modifies the trajectory and distribution of paint particles after atomization. By positioning the air ports farther from the rotation axis, the shaping air acts as a mediating force that corrects the painting pattern without directly interfering with the initial atomization process at the outer peripheral edge.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the collision speed of paint particles with the workpiece is slow, then the coating process is gentler, but the finished appearance becomes dark

Engineering Contradiction:
Improvecoating process gentlenessVSAvoidfinished appearance brightness
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent changes the spatial parameters of the air port positioning and the flow characteristics of the shaping air to optimize the collision speed of paint particles. By adjusting the position of air ports on a plane farther from the rotation axis and controlling the shaping air discharge, the system achieves an optimal collision speed that balances gentleness with appearance quality, preventing both excessive impact damage and dark appearance.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the diameter of paint particles is larger, then the paint deposition is faster, but the finished appearance becomes darker

Engineering Contradiction:
Improvepaint deposition speedVSAvoidfinished appearance brightness
Core Design Contradiction:
ProductivityVSIllumination intensity

Solution Approach 1:

The patent applies local quality control by positioning air ports at specific locations farther from the rotation axis, where the shaping air locally affects paint particles in specific regions of the atomization field. This localized action allows different regions of the paint spray to have optimized particle characteristics, achieving a balance between deposition speed and appearance quality by controlling particle size distribution in different zones.

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

This configuration enhances coating efficiency and quality by reducing the formation of dual patterns, ensuring more even deposition of metallic paint with smaller particles, thereby exposing a larger number of aluminum chips and improving the coating non-volatile value.

Implementation Method 1

a rotary atomizing head (10), and shaping air (SA) discharged from a plurality of air ports (12) arranged behind an outer peripheral edge (10b) of the rotary atomizing head (10) on a plane different from an outer peripheral edge plane of the rotary atomizing head (10)

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the shaping air (SA) is in a state of being twisted in a direction opposite to a rotation direction (R) of the rotary atomizing head (10) about a rotational axis (O) of the rotary atomizing head (10)

Methodology Applied
Scientific EffectTwisted flow: Vortex Ring

Implementation Method 3

creating an air curtain that collides with paint particles further away from the atomizing head, thereby extending the liquid thread, micronizing particles, and directing them forward with reduced momentum

Methodology Applied
Scientific EffectAir curtain: Jet

Implementation Method 4

Electrostatic coater

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Data Source

PatentEP3067120B1Electrostatic coater
Publication Date: 2020.05.06 RANSBURG IND FINISHING
  • EP3067120B1 patent drawingFigure 1
  • EP3067120B1 patent drawingFigure 2
  • EP3067120B1 patent drawingFigure 3~4

AI summary

An electrostatic coater capable of realizing high-level coating quality is provided. Shaping air SA, discharged from an air port 12, is directed radially outward. An elevation angle thereof preferably ranges from 10° to 20°. Further, the shaping air SA is a flow in a state of being twisted in a direction opposite to the rotation direction R of a bell cup 10. The twisting angle about the axis O of the bell cup 10 preferably ranges from 38° to 60°. A liquid thread 20 of paint extends radially outward from the outer peripheral edge 10b of the bell cup 10, and the paint separated from the tip end thereof becomes a particle 22. It is preferable that the shaping air SA collides with the paint particle at a point P where the momentum of the paint particle 22 is decreased.