Metal Bonding Surface Topology for Stronger Resin Anchoring
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Solution Overview
Problem
Existing methods for joining metal and resin materials, such as those described in JP 5 774246 A and JP 5 701414 A, often fail to achieve sufficient anchor effects due to insufficient convex shape formation on the metal surface, leading to inadequate joining strength between the metal and resin components.
Innovation Solution
A metal member for joining is designed with a surface featuring a smooth part and an uneven part, where the uneven part includes concavities and protrusions, with the protrusions having a maximum width greater than the concavities at the same height, enhancing the anchor effect and joining strength when joined with a resin member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the metal formed body is roughened by continuously irradiating the surface with laser light at high speed, then the processing speed is increased, but the convex shape is hardly formed at positions higher than the reference surface, resulting in insufficient anchor effect
Solution Approach 1:
The patent applies periodic action by using pulse laser irradiation instead of continuous wave laser. The pulse laser irradiates the metal surface at specific intervals, allowing heat accumulation during the pulse duration and cooling between pulses. This periodic heating and cooling cycle enables the formation of protrusions that extend higher than the reference surface, creating sufficient anchor effect while maintaining efficient processing speed.
Solution Approach 2:
The patent changes the laser irradiation parameters from continuous wave to pulse mode, adjusting the pulse width, frequency, and duty cycle to optimize the surface morphology. By controlling the pulse duration and interval, the process achieves both high processing speed and the formation of adequate protrusions for strong anchoring of the resin material.
2Ease of manufacture
If conventional laser roughening is used, then the surface is roughened with convex shapes, but the convex shapes are insufficient in height, leading to inadequate anchor effect
Solution Approach 1:
The pulse laser irradiation creates periodic thermal cycles that allow molten metal to accumulate and form higher protrusions during each pulse, while the interval between pulses allows partial cooling and solidification. This repeated melting and solidification process builds up protrusions that extend significantly higher than the reference surface, providing adequate anchor effect while maintaining manufacturing efficiency.
Solution Approach 2:
The patent utilizes phase transitions of metal between solid and liquid states through controlled pulse laser heating. The rapid heating melts the metal surface, and the subsequent cooling causes solidification, forming protrusions with heights sufficient for strong anchoring. This phase transition mechanism enables the creation of adequate anchor structures without requiring excessively long processing times.
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 metal member with a specific surface topology achieves excellent joining strength with resin members by increasing the surface area for contact and providing a sufficient anchor effect, surpassing the limitations of methods without specific protrusions or tapering protrusions.
Implementation Method 1
a method of roughening a surface of a metal formed body and a method of manufacturing a composite formed body have been proposed in which the surface of the metal formed body is roughened by continuously irradiating the surface of the metal formed body with laser light
Implementation Method 2
the surface of the metal formed body is roughened by continuously irradiating the surface of the metal formed body with laser light
Data Source
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AI summary
A metal member for joining, comprises a surface that comprises a smooth part and an uneven part, the uneven part including a plurality of concavities and a plurality of protrusions, wherein, when a surface of the smooth part is defined as a reference surface, a given number of the concavities and a given number of the protrusions satisfy the following formula (1). X<Y In formula (1), X represents a maximum width of the concavities at the same height as the reference surface, and Y represents a maximum width of the protrusions, adjacent to the concavities, at an outer side of the reference surface and in a direction parallel to the reference surface.