Swaging Tool Low-Friction Coating for Fastening Reliability
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Solution Overview
Problem
Existing swaging tools experience increased friction and fastening failures when lubricants like cetyl alcohol wear off, leading to poor workability and frequent re-fastening requirements.
Innovation Solution
A swaging tool with a low-friction coating film, such as diamond-like carbon (DLC) coating, applied to the inner surface of the swaging die, which maintains low friction and wear resistance, even when lubricants are absent, and is formed by physical vapor deposition to prevent hydrogen infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lubricant such as cetyl alcohol is applied to the collar surface, then friction between the swaging tool and collar is reduced during initial operation, but the lubricant comes off with time and friction increases leading to fastening failure
Solution Approach 1:
A low-friction coating film is formed on the inner peripheral surface of the swaging hole before the swaging operation. This preliminary coating provides lasting low-friction properties that do not come off like liquid lubricants, ensuring reliable swaging throughout the tool's service life.
Solution Approach 2:
The friction characteristic is changed from temporary (liquid lubricant that comes off) to permanent (coating film that adheres to the surface). The coating film maintains low friction coefficient over extended periods, preventing the friction increase that leads to fastening failure.
2Productivity
If friction between the swaging tool and collar increases due to lubricant wear-off, then fastening failure occurs requiring removal and re-fastening, but this lowers workability and increases processing time
Solution Approach 1:
The low-friction coating film is applied in advance to the swaging hole surface, ensuring that friction remains low throughout the entire service life of the tool. This prevents fastening failures and eliminates the need for time-consuming removal and re-fastening operations.
3Reliability
If a low-friction coating film is formed on the inner peripheral surface of the swaging hole, then friction between the tool and collar is suppressed even without lubricant, but this requires additional coating process
Solution Approach 1:
The surface property of the swaging hole is permanently modified by forming a low-friction coating film. This changes the friction parameter from variable (depends on lubricant presence) to consistent (maintained by coating), ensuring reliable swaging performance throughout tool life.
Solution Approach 2:
The low-friction coating film provides self-lubrication, eliminating the need for external lubricant application and reducing dependency on additional lubrication processes. The coating itself serves the lubrication function continuously.
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 low-friction coating significantly reduces friction between the tool and collar, preventing fastening failures and extending tool life by maintaining effective swaging performance even without lubricants.
Implementation Method 1
As low-friction coating, there is diamond-like carbon coating (DLC coating), diamond coating, titanium light coating, titanium aluminum coating, or the like.
Implementation Method 2
the diamond-like carbon coating is performed by physical vapor deposition
Data Source
Figure 1~2
Figure 3
AI summary
A swaging tool (1) in which the pinhead (7a) of a fastening pin (7) is positioned on one plate (3a) of a pair of plates (3a, 3b) through which the fastening pin (7) is passed, the pintail (7c) of the fastening pin is positioned on the other plate (3b), a collar (8) mounted on the pintail (7c) side of the fastening pin (7) is moved to the pinhead (7a) side so as to be brought into contact with the plate (3b), the collar (8) is swaged to the fastening pin (7) in the state of contact with the plate (3b), and a tensile load is applied to the pintail (7c) to break and remove the pintail, whereby the pair of plates (3a, 3b) are fastened; wherein the tool is provided with a swage die (11) in which there is formed a swaging hole (19) that is brought into contact with the collar (8) to swage the collar (8), a low-friction coating film (21) being formed on the inner peripheral surface of the swaging hole (19).