Polycarbonate vs. Polyoxymethylene for Gear - What is The Difference?

Polycarbonate offers high impact resistance and transparency, making it suitable for gears requiring toughness and visual inspection. Polyoxymethylene provides superior stiffness, low friction, and excellent dimensional stability, ideal for precision gears with high wear resistance.

Table of Comparison

Introduction to Engineering Plastics in Gear Manufacturing

Polycarbonate and Polyoxymethylene are prominent engineering plastics widely used in gear manufacturing due to their mechanical strength and dimensional stability. Polycarbonate offers excellent impact resistance and heat distortion temperature around 147degC, making it ideal for gears subjected to dynamic loads and moderate thermal stress. Polyoxymethylene provides superior stiffness, low friction coefficient, and high wear resistance with a melting point near 175degC, suitable for precision gears requiring minimal maintenance and high durability.

What is Polycarbonate? Properties and Uses

Polycarbonate is a durable thermoplastic known for its high impact resistance, optical clarity, and excellent dimensional stability, making it suitable for precision gears requiring toughness and transparency. Its properties include a high tensile strength of approximately 60 MPa, good electrical insulation, and resistance to heat up to 135degC, which ensures reliability in mechanical and electronic applications. Common uses of polycarbonate gears include automotive components, consumer electronics, and industrial machinery where strength and wear resistance are critical.

What is Polyoxymethylene (POM)? Properties and Applications

Polyoxymethylene (POM), also known as acetal, is a high-performance engineering thermoplastic characterized by its excellent mechanical strength, stiffness, and low friction properties. This material offers outstanding dimensional stability, wear resistance, and chemical resistance, making it ideal for precision gears in automotive, consumer electronics, and industrial machinery. Compared to polycarbonate, POM provides superior load-bearing capacity and durability in gear applications where high stiffness and low friction are critical for long-term performance.

Mechanical Strength: Polycarbonate vs Polyoxymethylene

Polyoxymethylene (POM) exhibits superior mechanical strength and stiffness compared to Polycarbonate (PC), making it ideal for high-load gear applications requiring durability and resistance to wear. Polycarbonate offers excellent impact resistance and toughness but has lower tensile strength and modulus than POM, limiting its use in demanding mechanical environments. Gears made from Polyoxymethylene benefit from high dimensional stability and low friction, enhancing performance and longevity under continuous operational stress.

Wear Resistance and Durability Comparison

Polyoxymethylene (POM) exhibits superior wear resistance compared to polycarbonate (PC), making it ideal for high-friction gear applications. POM's low coefficient of friction and excellent dimensional stability under load contribute to enhanced durability and reduced wear rates. In contrast, while polycarbonate offers good impact resistance and toughness, it generally experiences higher wear and faster degradation in gear mechanisms over time.

Impact Resistance: PC vs POM Gears

Polycarbonate (PC) gears exhibit superior impact resistance compared to Polyoxymethylene (POM) gears, making PC ideal for applications requiring high shock absorption and durability under sudden loads. POM gears, while offering excellent stiffness and low friction, tend to be more brittle and less resistant to impact forces, which can lead to premature failure in high-impact environments. Engineers often choose PC gears for heavy-duty machinery where resilience against impact is critical, whereas POM gears are preferred for precision and low-wear scenarios.

Machinability and Manufacturing Considerations

Polycarbonate offers excellent machinability with its high thermal stability and impact resistance, making it ideal for precision gear manufacturing where dimensional tolerance is critical. Polyoxymethylene (POM), also known as acetal, provides superior low-friction properties and excellent wear resistance, enabling efficient machining with minimal tool wear and consistent gear performance. Manufacturing gears from POM requires careful control of moisture absorption and temperature to maintain dimensional stability, whereas polycarbonate machining demands attention to potential thermal deformation during high-speed cutting.

Chemical Resistance in Gear Environments

Polycarbonate offers moderate chemical resistance but is prone to stress cracking when exposed to solvents and alkalis, limiting its use in harsh gear environments. Polyoxymethylene (POM), also known as acetal, exhibits superior chemical resistance against oils, fuels, and many solvents, making it more suitable for gears exposed to aggressive chemicals. The enhanced chemical stability of POM ensures longer gear life and consistent performance in demanding industrial applications.

Cost Analysis: Polycarbonate vs POM for Gears

Polyoxymethylene (POM) gears generally offer lower overall cost in high-volume production due to superior wear resistance and dimensional stability, reducing maintenance and replacement expenses. Polycarbonate gears, while often cheaper per unit in small batches, tend to have higher long-term costs caused by increased wear and lower mechanical strength. Considering lifecycle cost, POM is typically more cost-effective for gears subjected to continuous load and friction.

Best Applications: Choosing the Right Material for Gear Performance

Polycarbonate offers excellent impact resistance and transparency, making it ideal for gears requiring toughness and visual inspection in applications like consumer electronics and automotive components. Polyoxymethylene (POM), also known as acetal, provides superior stiffness, low friction, and wear resistance, which suits high-precision, high-load gear systems found in industrial machinery and robotics. Selecting between polycarbonate and polyoxymethylene depends on performance priorities such as durability under stress versus precision and low friction for optimal gear functionality.