Convergent Nozzle Masking for Uniform Metal Coating
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Solution Overview
Problem
The existing powder coating methods for metal automotive parts, particularly for columnar or tubular parts, face challenges in preventing paint penetration into uncoated areas, leading to uneven coating thickness and compromised corrosion resistance due to high air flow velocities used to prevent paint from entering gaps between masking jigs and the parts.
Innovation Solution
A method utilizing a convergent nozzle-shaped covering jig with a sectionally skirt-shaped configuration, discharging compressed air to create a controlled gas flow that prevents paint from penetrating into uncoated areas, ensuring uniform coating thickness and adhesion on rotating metal automotive parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressed gas is flowed into the gap between the masking jig and the work at high flow rate to prevent powder penetration, then powder coating paint penetration is prevented, but the flow velocity of air becomes high at the boundary between coated and uncoated portions causing decreased coating thickness and deteriorated corrosion resistance
Solution Approach 1:
The invention changes the parameters of gas flow by using a convergent nozzle-shaped covering jig that controls gas flow velocity and distribution. The nozzle shape creates a controlled flow pattern where gas is discharged from the tip onto the work surface, preventing powder penetration into uncoated areas while maintaining lower velocity at the boundary between coated and uncoated portions, thus ensuring uniform coating thickness and corrosion resistance
Solution Approach 2:
The convergent nozzle-shaped covering jig acts as an intermediary device between the gas source and the workpiece. It mediates the gas flow by shaping and directing it in a controlled manner, converting high-pressure gas into a distributed flow pattern that protects the boundary area from excessive velocity while still preventing powder penetration into uncoated areas
2Extent of automation
If a masking jig is disposed in the vicinity of the work to automate masking operation, then manual masking is automated, but powder coating paint penetrates into the gap between the masking jig and the work surface causing unnecessary deposition on uncoated portions
Solution Approach 1:
The invention applies pneumatic principles by using compressed gas discharged through the convergent nozzle-shaped covering jig. The gas flow creates a protective barrier that prevents powder coating paint from penetrating into the gap between the masking jig and the work surface, eliminating unnecessary deposition on uncoated portions while maintaining automated masking operation
Solution Approach 2:
The invention changes the gas flow parameters by using a convergent nozzle shape that controls velocity and distribution. This creates an optimal flow pattern that prevents powder penetration without causing excessive velocity at boundaries, thereby maintaining coating precision while achieving automation
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 achieves uniform film formation on the circumferential portions of metal automotive parts, preventing unnecessary deposition and spillage, and maintaining high corrosion resistance by adjusting gas flow velocity and flow rate within the covering jig, resulting in improved mechanical accuracy and chipping resistance.
Implementation Method 1
A method utilizing a convergent nozzle-shaped covering jig with a sectionally skirt-shaped configuration, discharging compressed air to create a controlled gas flow that prevents paint from penetrating into uncoated areas
Implementation Method 2
In a case of powder coating and in particular in the case of electrostatic powder coating
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
It is an object of the present invention to provide a method for uniformly forming a film on an outer circumferential portion of a metal automotive part by preventing penetration of a coating substance into a portion thereof unnecessary to be coated with paint. The method for producing a columnar or cylindrical metal automotive part whose outer circumferential surface includes a portion to be coated with paint and a portion to be uncoated therewith includes the following processes: (1) a process of providing a convergent nozzle-shaped covering jig which covers an outer circumferential surface of the columnar or cylindrical part at an axial end thereof and covers the portion to be uncoated with the paint, with a gap formed between the covering jig and the outer circumferential surface of the part; (2) a process of discharging a gas from the gap toward an end of a nozzle of the covering jig with the columnar or cylindrical part being rotated; (3) a process of sticking a film-forming substance to the columnar or cylindrical part from an axial side surface thereof.