Metal Surface Roughening via Dual-Mold Undercut Formation
Solution Overview
Problem
Current surface roughening methods for metals, such as laser processing and shot blasting, are inefficient and costly, and methods like those in JP 2011-005549 A require excessive processing time to form undercuts, which are necessary for enhanced bonding strength.
Innovation Solution
A surface roughening apparatus and method using a first mold with angular protrusions to form recesses and a second mold with lower, sharper protrusions to deform these recesses into undercut shapes, allowing for simultaneous formation of multiple undercut portions efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser processing is used to roughen the metal surface, then bonding strength is improved, but processing time and equipment cost increase
Solution Approach 1:
The patent replaces conventional mechanical methods (shot blasting, etching) and expensive laser processing with a specialized mold pressing system. The mold with protrusions directly presses into the metal surface to form recesses with undercuts, achieving both roughening and undercut formation in a single mechanical operation, thus eliminating the need for time-consuming laser processing while maintaining bonding strength
Solution Approach 2:
The mold pressing operation performs preliminary action by simultaneously forming both the recesses and the undercut shapes in one step. The protrusions on the mold are designed with specific geometry (larger base area than tip area) to create the undercut profile directly during pressing, eliminating the need for subsequent processing steps that would otherwise be required to create the undercut structure
2Productivity
If conventional mechanical methods (etching, shot blasting) are used to roughen the metal surface, then processing time is reduced, but the depth of convex and concave portions is insufficient for adequate bonding strength
Solution Approach 1:
The patent replaces conventional mechanical methods (shot blasting, etching) with a specialized mold pressing system that uses controlled plastic deformation. The mold protrusions press into the metal surface to form deeper recesses with undercut profiles, achieving both efficient processing and sufficient depth for strong bonding
Solution Approach 2:
The patent changes the geometric parameters of the mold protrusions (base area larger than tip area) to control the depth and profile of the formed recesses. By adjusting the pressing force and mold geometry, the system achieves optimal recess depth and undercut shape that provide adequate bonding strength while maintaining high processing efficiency
3Strength
If ridges are plastically deformed continuously by roller rotation to form undercuts, then bonding strength is improved, but processing time increases due to sequential deformation at single locations
Solution Approach 1:
The patent segments the deformation function across multiple protrusions on the mold. Each protrusion is responsible for forming a recess with undercut at a specific location, allowing simultaneous formation of multiple undercuts across the entire surface in one pressing operation, rather than sequential deformation by a single roller
Solution Approach 2:
The patent transitions from one-dimensional sequential deformation (roller moving along the surface) to two-dimensional parallel deformation (multiple protrusions pressing simultaneously across the surface). This dimensional change allows all undercuts to be formed at the same time, dramatically increasing processing speed while maintaining the undercut structure needed for bonding strength
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 approach significantly reduces processing time and cost while ensuring uniform undercut shapes, thereby enhancing bonding strength between metal and resin.
Implementation Method 1
press the first mold in the metal stock in a state where the surface of the first mold faces a first surface of the metal stock such that recesses are formed by the plurality of first protrusions in the metal stock
Implementation Method 2
press the plurality of second protrusions into the recesses formed by the plurality of first protrusions such that each of the recesses formed by the plurality of first protrusions in the metal stock is deformed into an undercut shape
Data Source
Figure 1
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AI summary
A surface roughening apparatus (1) includes a first mold (10) and a second mold (20). The first mold (10) has a plurality of protrusions (12) each formed in an angular shape. The first mold 10 presses a metallic material (50) to form recesses (52) corresponding to the respective shapes of the protrusions (12) in a surface (50a) of the metallic material (50). The second mold (20) has a plurality of protrusions (22) each formed in an angular shape. After the first mold (10) presses the metallic material (50), the second mold (20) presses the metallic material (50), thereby deforming each recess (52) into an undercut shape. A height of each protrusion (12) is greater than that of each protrusion (22). A tip angle of each protrusion (12) is smaller than that of each protrusion (22).