Can Body Spray Coating Sensor Timing Control

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Solution Overview

Problem

Current spray coating machines for can bodies apply excessive lacquer due to large timing tolerances, leading to inefficiencies and wastage, as the spraying time is not accurately synchronized with the can body's rotation, resulting in unnecessary lacquer application and increased production costs.

Innovation Solution

A can body spraying machine equipped with a sensor coupled to the spinning device that determines the predefined number of rotations, triggering the spray gun to switch off only when the desired number of revolutions is achieved, eliminating the need for timing-based tolerances and ensuring precise lacquer application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If timing-based spray window control is used, then the spraying process is simple to implement, but excessive lacquer is applied due to large timing tolerances

Engineering Contradiction:
Improvelacquer wastageVSAvoidspray timing precision
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical timing-based spray window control with an optical sensing system. A sensor detects the position of a timing flag on the indexing box shaft, and this positional information is used to trigger the spray guns at the precise moment when the can body is in the correct position. This substitution of mechanical timing with optical detection eliminates the timing tolerances that caused excessive lacquer application.

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

2Productivity

If a fixed spray window duration is used, then the control system is simple, but production efficiency is reduced due to excessive lacquer application and longer spray times

Engineering Contradiction:
Improveproduction efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where a sensor continuously monitors the position of the indexing box shaft and provides this information to the control system. The control system uses this feedback to determine the precise moment to activate and deactivate the spray guns, ensuring that spraying occurs only during the exact time window when the can body is in the correct position. This feedback mechanism optimizes spray timing without requiring complex predetermined timing sequences.

Inventive Principle:
Principle #23Feedback

3Reliability

If timing tolerances are increased to ensure correct lacquer weight, then the spraying process is more reliable, but excessive lacquer is applied resulting in wastage

Engineering Contradiction:
Improvelacquer application reliabilityVSAvoidlacquer wastage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces the mechanical timing-based spray window control with an optical sensing system. A sensor detects the position of a timing flag on the indexing box shaft, and this positional information is used to trigger the spray guns at the precise moment when the can body is in the correct position. This substitution of mechanical timing with optical detection eliminates the timing tolerances that caused excessive lacquer application.

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

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 solution reduces lacquer wastage, increases production efficiency by shortening the spray window, and allows for more precise control over the coating thickness, thereby optimizing the use of lacquer and enhancing the overall output of the spraying machine.

Implementation Method 1

A sensor coupled to the can body spinning device determines when the can body spinning device has undergone a predefined rotation

Methodology Applied
Scientific EffectPosition detection:

Data Source

PatentEP3302821B1Spray coating of cans
Publication Date: 2020.07.01 CROWN PACKAGING TECH INC
  • EP3302821B1 patent drawingFigure 1
  • EP3302821B1 patent drawingFigure 2
  • EP3302821B1 patent drawingFigure 3

AI summary

A can body spraying machine comprises a can body spinning device, a spray gun for spraying a coating onto an interior of a can body mounted on the can body spinning device and a controller configured to cause the spray gun to switch when the can body spinning device is in a correct spraying position. A sensor coupled to the can body spinning device determines when the can body spinning device has undergone a predefined rotation following commencement of spraying and, in response to such determination, causes the spray gun to be switched off.