Smoothed Working Jig Surface to Prevent Linear Flaws in Metal Forming
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Solution Overview
Problem
Metal plastic working processes often result in linear flaws on the surface of molded products due to protrusions on the working jig, leading to rough surfaces and reduced tool life, especially when using sintered bodies like cemented carbide with inherent voids.
Innovation Solution
A jig with a working surface smoothed to an arithmetic mean surface roughness of not more than 0.12 μm and no protrusions wider than 200 μm or taller than 10 μm, coated with a polycrystalline diamond carbon film, is used to prevent linear flaws during metal plastic working.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a hard film is provided on the working surface to ensure abrasion resistance and seizure resistance, then the tool life is extended, but linear flaws are formed on the product surface due to protrusions on the hard film
Solution Approach 1:
The invention changes the surface parameter specifications by defining maximum protrusion dimensions (width ≤200 μm, height ≤10 μm) and arithmetic mean roughness (Ra ≤0.12 μm) to eliminate linear flaws while maintaining the hard film for abrasion and seizure resistance
Solution Approach 2:
The invention applies local quality control by specifically addressing protrusion characteristics on the hard film surface, ensuring that local irregularities do not exceed defined thresholds that would cause linear flaws, while maintaining the overall hard film structure for protection
2Manufacturing precision
If the working surface is smoothed to meet roughness requirements, then linear flaws are prevented, but the surface may still have protrusions that cause harmful effects
Solution Approach 1:
The invention uses multiple surface parameters (arithmetic mean roughness Ra ≤0.12 μm, maximum protrusion width ≤200 μm, maximum protrusion height ≤10 μm) to comprehensively control surface quality, preventing both linear flaws and harmful seizure/adhesion effects
3Reliability
If a lubricating film is used to avoid direct contact, then seizure is prevented, but under high surface pressure the lubricating film cannot be locally maintained, resulting in direct contact and seizure
Solution Approach 1:
The invention provides beforehand cushioning by creating a controlled surface topology with limited protrusions that prevents direct contact under high pressure, cushioning the interaction between workpiece and jig to maintain reliability even when lubricating film breaks down
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 solution effectively prevents the formation of linear flaws on the product surface, ensuring a smoother finish and extending the tool life by maintaining the surface integrity and slidability during high-pressure operations like ironing.
Implementation Method 1
a lubricant agent such as oil is usually used to avoid direct contact between the workpiece and the working jig
Implementation Method 2
maintaining the surface integrity and slidability during high-pressure operations
Implementation Method 3
The working surface of the jig is smoothed so that an arithmetic mean surface roughness Ra is not more than 0.12 μm, and so that no protrusion is observed that has a width of not less than 200 μm and a height of not less than 10 μm
Implementation Method 4
provide the working surface of the jig for use in plastic working of metals with a hard film mainly for the purpose or ensuring abrasion resistance
Implementation Method 5
abrasion powder of the soft metal is disadvantageously adhered and deposited (build-up) on the working surface
Data Source
AI summary
A jig for metal plastic working for use in plastic working of a metal or alloy workpiece, in which a working surface is moved relative to the workpiece in contact with the workpiece. The working surface of the jig is smoothed so that an arithmetic mean surface roughness Ra is not more than 0.12 μm, and so that no protrusion is observed that has a width of not less than 200 μm and a height of not less than 10 μm, which are calculated on a basis of a projection thereof along a working direction.