Challenges Faced by the Client:

1. 0.2-Degree Demolding Angle: Common Drag Marks Issue in Injection Molding:

   - The product had a demolding angle of only 0.2 degrees, resulting in common drag marks during injection molding.

2. Nearly 0-Degree Demolding in PC Plastic Injection Molding:

   - The product exhibited a strong demolding force due to the nearly 0-degree demolding in PC plastic injection molding.

   - Wingtat implemented a combination of vacuum injection molding and the addition of lubricants to address the issue without compromising aesthetics and transparency.

Client Details:

- Client: Meidijia

- Product Specifications:

  - Dimensions: φ80X220

  - Material: PC

  - Mold Cavities: 1*1

  - Cycle Time: 40 seconds

  - Design Period: 4 working days

  - Manufacturing Period: 45 working days

  - Manufacturing Date: February 2022

Understanding PC Material Characteristics:

1. Physical Properties:

   - Non-crystalline, odorless, tasteless, transparent thermoplastic polymer.

   - Relative density: 1.18~1.20, glass transition temperature: 140~150°C, melting point: 220~230°C.

   - Excellent chemical corrosion resistance and oil resistance.

2. Mechanical Properties:

   - Excellent impact resistance and dimensional stability.

   - Maintains high mechanical strength across a wide temperature range.

3. Thermal Properties:

   - Decomposition temperature above 300°C.

   - Long-term working temperature up to 120°C.

   - Good resistance to cold, with a low brittle temperature of -100°C.

4. Electrical Properties:

   - Low molecular polarity, excellent electrical insulation properties.

5. Aging Resistance and Heat Resistance:

   - Good resistance to heat aging.

   - Combustible with an oxygen index of only 25%.

6. Optical Properties:

   - Non-crystalline substance, pure PC is colorless and transparent.

Design Considerations:

1. Gate Design:

   - Implemented a three-point direct fine water gate at the top to address size-related issues such as eccentricity and non-circular diameters.

2. Cooling System Design:

   - Maintained uniform mold temperature and cooling for consistent transparency.

   - Controlled water flow diameter, distance from the product, and spacing proportionately for effective cooling.

   - Avoided the use of well-type water flow and employed double-inclined water flow when necessary.

3. Demolding Design:

   - Adopted a peripheral ejector block demolding method to ensure no visible traces on non-assembled surfaces.

4. Steel Material Selection:

   - Selected NAK80 steel for its excellent pre-hardened state, high polishing performance, and good cutting and erosion resistance.

   - Considered elements like carbon, silicon, nickel, manganese, molybdenum, copper, aluminum, and chromium in the steel composition.

5. Machining and EDM Conditions:

   - Utilized high-speed steel (M2 or SKH9) or P40 tool materials for milling and drilling.

   - Followed specific conditions for EDM processing using copper electrodes.

Wingtat's comprehensive solutions addressed the client's molding challenges, resulting in successful lens production with optimal transparency and demolding performance. The collaboration has established a strong partnership between Wingtat and the Shenzhen-based client.