Anodic Oxidation Mold Manufacturing with Mixed Acid Electrolyte
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Solution Overview
Problem
Existing methods for manufacturing molds with fine uneven structures using anodic oxidation face challenges in controlling current density at high voltages and achieving uniform oxidized coating film thickness without special equipment, leading to macro size irregularities and poor appearance in molded articles.
Innovation Solution
The method involves using an electrolytic solution with a mixture of two or more acids, such as oxalic acid and phosphoric acid, to control current density and oxidized coating film thickness, allowing for the formation of a mold with a homogeneous micropore diameter and regular arrangement, even at high applied voltages, by adjusting the acid ratio and concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If anodic oxidation is performed at high applied voltage to increase micropore depth, then the micropore depth is improved, but the current density significantly increases making it difficult to control the oxidized coating film thickness
Solution Approach 1:
The patent applies parameter changes by modifying the electrolytic solution composition (adding phosphoric acid to oxalic acid) to alter the anodic oxidation characteristics. This enables control of current density and oxidized coating film thickness even at high applied voltages (60-120 V), allowing micropore depth to be increased while maintaining manufacturability and control.
2Ease of manufacture
If the initially formed oxidized coating film is too thin to remove mechanical processing remnants, then the appearance is improved, but the macro size irregularities remain visible after removal
Solution Approach 1:
The patent modifies the electrolytic solution parameters by combining oxalic acid and phosphoric acid in specific ratios. This produces an oxidized coating film with controlled thickness (0.5-10 μm) that is sufficient to cover mechanical processing remnants while maintaining uniformity and preventing visible macro size irregularities after removal.
3Manufacturing precision
If the initially formed oxidized coating film is too thick to ensure complete coverage of irregularities, then the uniformity is improved, but the macro size irregularities become visually recognizable after removal
Solution Approach 1:
The patent uses parameter changes in the electrolytic solution composition to achieve optimal oxidized coating film thickness. The mixed acid solution produces a film thick enough to cover irregularities uniformly but not so thick that grain boundary steps become visually recognizable after removal, balancing coverage and visibility concerns.
4Ease of manufacture
If a single acid electrolytic solution is used for anodic oxidation, then the process is simple, but the current density cannot be controlled at high voltages and uniform micropore diameter is difficult to achieve
Solution Approach 1:
The patent applies composite materials by combining oxalic acid and phosphoric acid in the electrolytic solution. This composite electrolytic solution provides both simplicity of use and precise control over current density and micropore uniformity at high voltages, achieving manufacturing precision while maintaining ease of manufacture.
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 enables the production of molds with controlled oxidized coating film thickness and uniform micropore diameter, reducing macro size irregularities and improving the appearance of molded articles, while allowing for efficient and cost-effective manufacturing without the need for special equipment.
Implementation Method 1
anodic oxidation of an aluminum substrate has drawn attention
Implementation Method 2
The surface of an aluminum substrate is subjected to anodic oxidation
Implementation Method 3
anodic oxidation is performed in two divided steps
Implementation Method 4
controlling time or current density for anodic oxidation
Data Source
Figure 1(a)~1
Figure 2~3
AI summary
The present invention relates to a method for manufacturing a mold has: a step (a) for anodizing an aluminum substrate at a voltage of 60 V to 120 V in an electrolytic solution in which two or more species of acid are mixed, and forming an oxide film having a plurality of minute holes on a surface of the aluminum substrate; and a step (b) for removing at least a portion of the oxide film; the electrolytic solution used in step (a) satisfying the relation (D1)/2 < D2, where D1 is the current density when the aluminum substrate is anodized under the same conditions as in step (a) in an electrolytic solution of only the acid (A) having the highest acid dissociation constant (Ka) of the two or more species of acid, and D2 is the current density when the aluminum substrate is anodized under the same conditions as in step (a) in the same electrolytic solution as that of step (a).