CNC Plastic POM (Polyoxymethylene) Parts: Machining Guidelines and Applications

1. Introduction:

CNC plastic POM parts, or polyoxymethylene, boast widespread utilization in various industries, owing to their commendable mechanical attributes and dimensional reliability. Recognized for their thermoplastic nature, these parts are easily machined using CNC (Computer Numerical Control) techniques. POM exhibits several advantages, including superior strength, wear resistance, and low friction, making it a versatile choice for a multitude of applications.

2. Material Characteristics, Parameters, Pros, and Cons:

Material Features:

a. High Tensile Strength:

POM exhibits remarkable tensile strength, ensuring the structural integrity of machined components, making it suitable for applications demanding robustness.

b. Stiffness and Dimensional Stability:

With high stiffness and dimensional stability, POM parts maintain their shape and resist deformation, providing consistency in performance across various conditions.

c. Wear Resistance:

POM's exceptional resistance to wear is a standout feature, contributing to the longevity of components in applications subjected to friction and abrasion.

d. Low Friction Properties:

The inherent low friction of POM is advantageous for applications involving sliding or rotating parts, reducing frictional heat and enhancing overall efficiency.

e. Chemical Resistance:

POM demonstrates good chemical resistance, particularly against solvents and fuels, expanding its suitability for diverse industrial environments.

Parameters:

a. Density:

POM has a density ranging from 1.41 to 1.43 g/cm³, influencing the weight and overall performance of machined parts.

b. Melting Point:

With a melting point typically between 165 to 175°C (329 to 347°F), POM's thermal properties are critical considerations in applications with varying temperature conditions.

c. Water Absorption:

POM's low water absorption rate, typically less than 0.2%, ensures dimensional stability in humid environments.

Pros:

a. Enhanced Durability:

The combination of high tensile strength and wear resistance contributes to the overall durability of POM components, extending their service life.

b. Versatility:

POM's versatility enables its use in a broad spectrum of applications across different industries, showcasing its adaptability.

c. Low Frictional Coefficient:

The low friction properties of POM reduce the need for additional lubrication, making it suitable for applications requiring smooth movement.

Cons:

a. UV Sensitivity:

POM is susceptible to degradation when exposed to prolonged UV radiation, limiting its suitability for outdoor applications without proper UV stabilization.

b. Limited Acidic and Alkaline Resistance:

Compared to some engineering plastics, POM has relatively poor resistance to acidic and alkaline environments, necessitating careful consideration in specific applications.

c. Cost Considerations:

While POM provides excellent performance, its cost-effectiveness should be weighed against project budgets, especially in comparison to alternative materials.

3. Applications:

POM finds application across diverse sectors, including:

- Automotive: Used in fuel systems, interior components, door handles, and gears.

- Electrical and Electronics: Employed in connectors, switches, insulators, and housings.

- Consumer Goods: Utilized in zippers, fasteners, handles, and toys.

- Machinery and Equipment: Applied in gears, bearings, rollers, and sliding components.

4. Comparisons with Similar Materials:

Comparisons with other materials are vital for informed decision-making:

- POM vs. Nylon: POM offers higher stiffness and better dimensional stability, while nylon excels in impact resistance and vibration damping applications.

- POM vs. PEEK: POM is cost-effective with superior wear resistance, whereas PEEK provides heightened chemical resistance and high-temperature tolerance.

- POM vs. ABS: POM boasts better mechanical properties, while ABS is more cost-effective with superior impact resistance.

FAQ:

Q1. Can POM be used for food contact applications?

A1. Yes, POM is FDA-compliant for food contact applications. However, it is essential to confirm the specific grade's suitability and compliance with necessary regulations.

Q2. What is the maximum temperature POM can withstand?

A2. POM typically withstands continuous use temperatures up to approximately 100-120°C (212-248°F), depending on the specific grade.

Q3. Is POM recyclable?

A3. Yes, POM is recyclable, but proper handling and separation from other materials are crucial to maintain its properties.

Q4. Can POM be used in high-wear applications?

A4. Certainly, POM's excellent wear resistance makes it suitable for high-wear applications like gears, bearings, and sliding components.

Q5. What considerations are essential when designing parts with POM?

A5. Design considerations should encompass factors like dimensional stability, part geometry, wall thickness, and the incorporation of draft angles for seamless ejection from molds.