Knowledge and Applications of Special Engineering Plastics

2:Main Types and Properties of Special Engineering Plastics

2.1 Polyarylether Ketones (PAEK: PEEK / PEKK)

• PEEK: Continuous use temperature up to 260 °C, tensile strength 90–100 MPa, water absorption only 0.1–0.2%, and excellent chemical stability.

• PEKK: Similar performance to PEEK but with a higher glass transition temperature, used in high-temperature filters and aerospace structural components.

2.2 Polyphenylene Sulfide (PPS)

• PPS: Maximum use temperature 200 °C, tensile strength 60–70 MPa, water absorption <0.05%, outstanding chemical resistance and dimensional stability.

2.3 Polyimide (PI)

• PI: Both thermosetting and thermoplastic types, continuous use up to 300 °C, tensile strength 80–90 MPa, excellent radiation resistance; used in aerospace insulation and electronic packaging.

2.4 Polysulfone (PSU / PESU)

• PSU / PESU: Heat resistance around 180 °C, high transparency, good toughness; suited for medical devices and food-grade components.

2.5 Polytetrafluoroethylene (PTFE)

• PTFE: Service range −200 °C to +260 °C, extremely low friction coefficient, outstanding chemical inertness; used in valve seals, bearings, and chemical equipment.
  

  plastic mold design: Material Types & Mold Essentials

  Different families of special engineering plastics demand tailored plastic mold design strategies to handle their unique flow and shrink characteristics:

  • PAEK (PEEK/PEKK): High melt viscosity and processing temperatures call for hot-runner systems, generous cooling channels, and gate designs in plastic mold design that mitigate shear and thermal stress.

  • PPS: Optimized gate location and hot-runner layouts in plastic mold design prevent short shots and voids.

  • PI and PSU/PESU: Balanced runner systems and controlled cooling circuits in plastic mold design avoid internal stress buildup.

  • PTFE: Due to difficult demolding, plastic mold design incorporates larger draft angles and sometimes flexible mold inserts.

  Processing temperature ranges to consider in plastic mold design: PEEK 380–420 °C; PPS 280–320 °C; PI 350–400 °C; PSU/PESU ~180 °C; PTFE –200 °C to +260 °C.
  
  

  high precision plastic injection molding: Applications & Benefits

  Employing high precision plastic injection molding achieves tolerances down to ±0.01 mm, with key uses including:

  • Aerospace components: PAEKs molded via high precision plastic injection molding withstand extreme heat and mechanical load.

  • Automotive parts: PPS fuel-system connectors produced by high precision plastic injection molding ensure leak-free performance.

  • Electronic insulators: PI and PSU parts made through high precision plastic injection molding maintain dielectric strength under high temperatures.

  • Wear parts: PTFE’s near-zero friction surfaces benefit from high precision plastic injection molding in sliding applications.

  Critical controls in high precision plastic injection molding include melt-temperature regulation, mold-temperature profiling, injection speed optimization, and full-dimensional inspection.
  

  medical device molding: Medical-Grade Forming Essentials

  In medical device molding, products must meet biocompatibility, sterilization, and cleanliness requirements:

  • PEEK implants: medical device molding ensures repeated autoclave resistance without deformation.

  • PSU housings: Transparent diagnostic equipment casings via medical device molding allow visual inspection and chemical cleaning.

  • Insert & overmolding: medical device molding integrates multi-material assemblies into single-cycle tools.

  • Certification: medical device molding processes comply with ISO 13485, FDA, and RoHS, accompanied by full-dimensional inspection reports.

  Mold Design & Molding Considerations

  1. Gate & Runner Layout

     • Choose gate types (needle-valve, valve-gate, tunnel) and balanced runners in plastic mold design for uniform cavity filling.

  2. Shrinkage Compensation

     • Factor material shrink rates (PEEK ~0.3 %, PPS ~0.2 %, PI ~0.5 %) into cavity dimensions and include locating ribs in plastic mold design.

  3. Thermal & Pressure Control

     • high precision plastic injection molding parameters: PEEK melt 380–420 °C, mold 150–200 °C; PPS melt 280–320 °C, mold 80–120 °C; PI melt 350–400 °C.

     • Employ conformal cooling channels and precise pressure profiling.

  4. Clean-Room & Certification

     • Conduct medical device molding in ISO 14644-1 clean-rooms; validate biocompatibility and sterilization cycles.
       
       If you need professional plastic mold design, high precision plastic injection molding or compliant medical device molding services, please contact Vanmodel immediately for free quotes and one-stop technical support!