Molding Insert Edge Sharpening to Prevent Two-Shot Plastic Overflow
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Solution Overview
Problem
Existing methods for manufacturing inserts for injection molding machines result in rounded edges due to mechanical material removal processes, leading to material overflow during the second plastic component injection, which affects the aesthetic quality and durability of two-component plastic parts.
Innovation Solution
Utilize ultra-short pulse lasers to ablate material from the transition area between the base surface and bordering wall of the insert, reducing the radius to less than 0.1 mm or creating a groove, thereby preventing material overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If material is removed from the metal block by eroding and/or milling, then the depression is formed for defining the mold cavity, but the material transition area has a large radius which causes material overflow during injection molding
Solution Approach 1:
The patent replaces mechanical material removal processes (eroding and milling) with laser ablation technology. The laser beam directly ablates material from the metal block to create the depression and bordering walls, eliminating the rounded edges that result from mechanical processes. This substitution enables achievement of essentially zero radius edges without the limitations of mechanical tooling.
Solution Approach 2:
The patent changes the physical parameter of the material transition area by using laser ablation instead of mechanical removal. The laser process achieves a fundamentally different surface geometry with minimal radius at the edges, transforming the material transition from a rounded profile to a sharp edge that prevents material overflow during injection molding.
2Object-generated harmful factors
If the insert is assembled from two parts to achieve sharp edges, then material overflow is reduced, but the device complexity increases
Solution Approach 1:
The patent eliminates the need for segmented insert construction by using laser ablation to create sharp edges on a single-piece insert. The laser process can achieve essentially zero radius edges on monolithic metal blocks, removing the requirement to assemble multiple parts to obtain sharp geometric features.
Solution Approach 2:
The patent replaces the mechanical assembly approach (joining multiple insert parts) with a laser-based monolithic manufacturing approach. The laser ablation process creates the necessary sharp edges directly on the single-piece insert, eliminating assembly complexity and potential leakage paths at joints.
3Manufacturing precision
If ultra-short pulse laser is used to ablate material from the material transition area, then the radius is reduced to prevent material overflow, but the manufacturing process becomes more complex
Solution Approach 1:
The patent uses ultra-short pulse laser ablation as a direct replacement for multi-step mechanical manufacturing processes. The laser process consolidates what would otherwise require multiple machining operations, grinding steps, and manual finishing into a single non-contact processing step that directly achieves the required edge sharpness.
Solution Approach 2:
The patent changes the manufacturing approach by introducing ultra-short pulse laser parameters (pulse duration in the picosecond or femtosecond range, specific energy density, scanning patterns) that enable direct ablation of metal to achieve essentially zero radius edges. This parameter change transforms the manufacturing process from mechanical removal to optical field-based material removal.
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 enhances the aesthetic quality and durability of two-component plastic parts by minimizing material overflow and preventing pocket formation, suitable for premium products like electric toothbrushes.
Implementation Method 1
removing material from the material transition area by applying laser light so that the resulting material transition area has a second radius smaller than the first radius
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The present disclosure is concerned with a method of making an insert for an injection molding machine comprising the steps of providing a metal block, removing material from the metal block by eroding and/or milling so that at least one depression is formed for at least partly defining a mold cavity for molding a first component of a two-component plastic part, the depression being defined by at least one bordering wall of the metal block, where between a base surface of the depression and at least a portion of the bordering wall a material transition area is present having a first radius, removing material from the material transition area by applying laser light so that the resulting material transition area has a second radius smaller than the first radius.