Injection Mold Surface Patterning with Laser Milling and Nickel Plating
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Solution Overview
Problem
Existing methods for manufacturing molds with patterned surfaces for injection molding of optical components, such as those used in automotive lighting devices, suffer from defects like incomplete removal of bath electrolyte, stitching errors, and high production costs due to complex and time-consuming galvanic processes, especially when precise surface patterns on the order of micrometers are required.
Innovation Solution
A method combining laser milling with ultrashort pulses and electroless nickel plating to create precise surface patterns on mold bodies, followed by heat treatment to enhance durability, achieving a spatial resolution of 1-10 μm and a coating thickness of 2-20 μm, suitable for various materials including tool steel, aluminum alloys, and copper-beryllium alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional galvanic manufacturing method is used to create patterned surfaces on mold insets, then the surface patterns can be formed, but the process is time-consuming and costly
Solution Approach 1:
The patent replaces the traditional mechanical galvanic manufacturing process with a laser-based manufacturing approach. The laser directly patterns the mold surface through ablation, eliminating the need for complex galvanic steps including electrolyte removal. This substitution of mechanical/chemical processes with optical energy delivery achieves high-precision surface patterns while dramatically reducing manufacturing time and cost.
Solution Approach 2:
The patent utilizes controllable laser parameters (pulse duration, energy density, scanning speed) to directly create the desired surface patterns. By adjusting these parameters, the laser can produce various pattern geometries and resolutions without changing the fundamental manufacturing process, thereby achieving both high precision and fast production.
2Manufacturing precision
If traditional galvanic manufacturing method is used for patterned surfaces, then the surface patterns can be formed, but defects occur due to incomplete removal of bath electrolyte
Solution Approach 1:
The patent replaces the wet chemical galvanic process with a dry laser ablation process. This eliminates the source of electrolyte contamination entirely, as no liquid bath is involved. The laser directly vaporizes material to create the pattern, ensuring clean surfaces free from electrolyte residue defects.
Solution Approach 2:
The patent converts the potential harm of material removal into a benefit by using controlled laser ablation. Instead of adding material through galvanic plating (which risks electrolyte contamination), the laser precisely removes material to create the desired pattern, transforming the challenge of surface preparation into a clean, direct patterning process.
3Manufacturing precision
If traditional galvanic manufacturing method is used for bended or complex three-dimensional insets, then the manufacturing process becomes even more complex, but the surface patterning remains difficult
Solution Approach 1:
The patent applies a universal laser patterning approach that works on any mold surface geometry, including flat, bent, and complex three-dimensional surfaces. The laser system can be programmed to follow complex toolpaths and adapt to various surface orientations, providing a single versatile manufacturing method that replaces multiple specialized processes.
Solution Approach 2:
The patent adds the dimension of temporal control through pulsed laser delivery, allowing precise energy deposition on complex geometries. By controlling pulse timing and duration, the laser can maintain consistent patterning quality on surfaces with varying orientations and curvatures, effectively handling three-dimensional complexity that would challenge traditional methods.
4Manufacturing precision
If traditional galvanic manufacturing method is used for insets, then the surface patterns can be created, but stitching errors occur when multiple subunits are assembled
Solution Approach 1:
The patent merges the patterning operation into a single continuous process that can treat the entire mold surface as one integrated component. By using laser direct writing or projection, the system can create seamless patterns across large areas without requiring assembly of multiple separately patterned subunits, thereby eliminating stitching errors.
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 method produces molds with high-precision, durable, and corrosion-resistant surfaces, ensuring high-quality optical components by preserving the surface roughness and extending tool life, suitable for mass production of optical parts with diffusing or diffracting properties.
Implementation Method 1
Laser milling is based on the physical process of laser ablation, i.e. sublimation of an irradiated material volume
Implementation Method 2
Laser milling is based on the physical process of laser ablation, i.e. sublimation of an irradiated material volume
Implementation Method 3
The subsequent coating of the patterned mold surface is performed by electroless nickel plating. Electroless nickel plating is an autocatalytic process, in which the reduction of nickel ions in a solution and the nickel coating deposition are carried out through the oxidation of a chemical compound present in the solution itself
Implementation Method 4
the method is followed by a heat treatment of the mold at a temperature in the range of 200° C. to 400° C. for a period in the range of 1 hour to 10 hours, which yields a significant hardening of the electroless nickel and thus improves its resistance against mechanical wear
Data Source
AI summary
A method is provided for manufacturing a mold for injection molding, especially for injection molding of optical components of automotive lighting devices. The method includes at least the following steps: providing a mold body, laser milling a pattern into a surface of the mold body, and coating the surface of the mold body by electroless nickel plating.