Plastic optical molds are categorized based on product application scenarios, molding process characteristics, cavity structure, and precision grade, which are the core classification criteria in the optical mold industry. The detailed English classification is as follows:
This classification is based on the specific optical components the molds produce, which directly determines the mold’s design standards and precision requirements.
- Lens Molds
Specialized for manufacturing various optical lenses, such as camera lenses, eyeglass lenses, microscope objective lenses, and automotive headlight lenses. These molds require ultra-high surface finish (Ra ≤ 0.001 μm) and strict dimensional tolerance control to ensure light transmittance and imaging quality.
- Prism Molds
Used for molding optical prisms applied in binoculars, spectrometers, and laser devices. The molds need precise angle machining (tolerance ±5″) to achieve light refraction, reflection, or dispersion functions.
- Optical Film Molds
Designed for producing thin optical films, including polarizing films, anti-reflective (AR) films, and light guide plates (LGP) for LCD screens. The mold cavity surface has micro-nano structures to realize light diffusion and uniform transmission.
- Optical Sensor Molds
Tailored for molding optical sensor components (e.g., infrared sensor lenses, barcode scanner lenses) widely used in smart devices and industrial detection systems. These molds focus on matching the sensor’s spectral response characteristics.
Classified according to the plastic molding technology adopted, different processes correspond to distinct mold structures and production efficiency.
- Injection Molding Molds for Optical Plastics
The most common type, suitable for mass production of optical components. It uses high-precision injection molding machines to inject molten optical-grade plastics (e.g., PMMA, PC, COP) into the mold cavity. The molds are equipped with hot runner systems to reduce material waste and ensure uniform melt filling.
- Compression Molding Molds for Optical Plastics
Mainly used for molding large-size or thick-wall optical components (e.g., large-diameter lenses, optical windows for aerospace). The process involves preheating the plastic blank and then compressing it into the mold cavity, which can reduce internal stress of the product and improve optical uniformity.
- Micro-injection Molding Molds for Optical Components
Designed for micro-optical parts (e.g., micro-lens arrays, optical fibers, miniature sensor lenses) with dimensions ranging from micrometers to millimeters. The molds require micro-precision machining technologies (e.g., micro-EDM, ultra-precision grinding) to fabricate tiny cavity structures.
Classified based on the number of cavities and the arrangement of the mold, which affects production efficiency and product consistency.
- Single-Cavity Optical Molds
Each mold has only one cavity, mainly used for high-precision optical components (e.g., professional camera lenses, laser lenses) where strict consistency is required. It ensures stable molding conditions and easy quality control.
- Multi-Cavity Optical Molds
Equipped with multiple identical cavities (e.g., 4-cavity, 8-cavity, 16-cavity) for mass production of medium-to-low precision optical parts (e.g., eyeglass lenses, LED optical covers). The key design point is to achieve balanced filling of each cavity to ensure uniform product quality.
- Family Molds for Optical Components
A single mold integrates multiple different cavities to produce a set of matching optical components (e.g., lens sets for a single optical module) at one time, which can reduce production costs and improve assembly efficiency.
Classified according to the precision level of the mold, which is the key indicator to distinguish the grade of optical molds.
- Ultra-Precision Optical Molds
Precision grade: ≤ ±1 μm, surface roughness Ra ≤ 0.001 μm. Used for manufacturing high-end optical components (e.g., aerospace optical lenses, semiconductor lithography lenses). The molds are made of high-hardness mold steel (e.g., SUS440C, SKD11) and undergo precision grinding and polishing.
- High-Precision Optical Molds
Precision grade: ±1~5 μm, surface roughness Ra 0.001~0.01 μm. Suitable for consumer electronic optical components (e.g., smartphone camera lenses, tablet computer lenses). It balances precision and production cost.
- Standard-Precision Optical Molds
Precision grade: ±5~10 μm, surface roughness Ra 0.01~0.1 μm. Used for low-end optical products (e.g., toy magnifying glasses, ordinary LED light covers) with relatively loose optical performance requirements.
