To differentiate between PC (Polycarbonate) and Acrylic (PMMA or Plexiglas) in precision parts processing, here are some key points to consider:
Material Properties:
Acrylic is known for its high light transmission and stiffness, making it an ideal alternative to glass . It has excellent optical clarity, with a light transmittance above 90%, and is lightweight with a density of only 1.17 to 1.20 g/cm³. Acrylic is also strong and durable, with impact resistance sixteen times that of ordinary glass .
PC, on the other hand, is a high-strength engineering thermoplastic that is often used where transparency and toughness are required. It has a light transmittance of up to 90% and is highly resistant to shock loads without shattering .
Visual Identification:
When holding the parts under light, Acrylic will have a slight yellow tint, and it is harder compared to PC. PC, when viewed under light, will have a slight purple tint and is more flexible .
Applications:
Acrylic is used in applications requiring maximum optical clarity and smoothness, such as lenses, covers, and high-end decorative pieces . It is also suitable for medical applications due to its non-toxicity and easy sterilization .
PC is used in applications that require high toughness and flame resistance, such as eyeglass lenses, diagnostic lab equipment, and bulletproof windows .
Processing Techniques:
Acrylic can be processed through various methods, including CNC machining, flame polishing, buffing and polishing, sanding, vapor polishing, chemical polishing, bead blasting, painting and coating, and laser engraving .
PC is also CNC machined, but it requires different considerations due to its higher toughness and different physical properties .
Durability and Resistance:
Acrylic is not exceptionally tough or impact-resistant. It is also not resistant to scratches and is easily damaged .
PC is flame resistant and will not ignite when exposed to an open flame. It has a flammability rating of B1, indicating "low" flammability . However, it is not resistant to UV radiation and can yellow over time .
Chemical Considerations:
Some grades of PC contain BPA (Bisphenol A), which is linked with adverse health effects, but BPA-free variants are available .
In summary, while both materials are transparent and used in precision parts processing, they differ in their physical properties, processing requirements, and applications. Acrylic is lighter and offers better optical clarity, whereas PC is tougher and more resistant to impacts and flames. Understanding these differences is crucial for selecting the appropriate material for specific precision parts processing needs.
