Polyoxymethylene (POM), also known as Acetal, is an advanced type of engineering plastic that is considered an industrial revolution owing to the broad scope of its utilization and commendable mechanical properties. It has been widely accepted within the industry as an optimal solution for cost-effective and precision applications ranging from automotive parts, consumer electronics, medical equipment, and industrial use. In this blog post, we will closely examine what POM plastic is, what characteristics distinguish it from the rest, and how it is utilized in various industries. This goes without saying that POM is a robust material that solves a wide range of design engineering problems and completely reinvents products. This article will show how POM plastic offers the most cost-effective solutions for today’s engineering.
What is POM Plastic, and Why is it Important in Engineering?
Polyoxymethylene (POM), commonly known as acetal, is a high-performance engineering thermoplastic with high strength, stiffness, and durability properties. It Is found in engineering applications owing to its superior dimensional stability, low friction, wear, and chemical resistance. POM is used in products that require precision and reliability, such as automotive parts, electrical equipment, and other components, making it a key material in today’s engineering development.
Understanding the Molecular Structure of Polyoxymethylene (POM)
Polyoxymethylene (POM) is a polymer of high-performance engineering plastics. It is sometimes geometrically twinned into a heteropolymer, often called polyacetal. This synthetic plastic has a complicated molecular structure, with chains of repeating formaldehyde units (CH2O). In addition to providing stability to the polymer, these tightly bound chains also give it high mechanical strength and wear resistance. A thermoplastic polymer exists in two forms: homopolymer, which is usually designated as POM-H and has a competitive edge on the POM-C, which is POM-C is a thermoplastic polymer but inferior in strength and stiffness because it is a combination of two or more forming units. A toy made from perfect plastic blankets may maintain these traits and mix naturally.
Key Properties That Make POM a Versatile Engineering Plastic
Mechanical Stability and Strength
Due to its outstanding tensile strength and stiffness, POM is perfect for use in applications requiring high structural durability. Depending on its grade and shape, its tensile strength typically falls between 60 and 70 MPa.
Anti Wear Characteristics
Because POM has a low friction coefficient (about 0.2 – 0.3), mechanical parts experience moderate wear, making it a perfect candidate for manufacturing gears, bushings, and conveyor belts.
Precision of POM
POM can be relied on in precision components because it has an average water absorption of around 0.2% -0.3 %, which avoids constant size change under diverse environmental circumstances.
Thermal Stability
For copolymers (POM-C), a service operating temperature of -40 up to 100 degrees Celsius can be set. In contrast, for the homo polymers (POM-H), this can be set up to 120 degrees Celsius. These temperatures indicate the appropriate boundaries in which POM can function stably.
Chemical Stability
POM can withstand fuels, oils, solvents, and most weak acids and bases, making it a good candidate for use in chemical-resistant conditions. However, it does not do well in strong acids and halogens.
Ease of Machining and Processing
Thanks to its amorphous character and toughness, POM is good at machinability and can easily undergo several processing techniques, such as injection molding and extrusion, increasing its possible applications.
Due to its wide range of characteristics, POM is widely used in automotive and consumer electronics industries, where reliability, durability, and accuracy are vital.
Comparing POM to Other High-Performance Thermoplastics
Polyoxymethylene (POM) possesses an unusual combination of strength, dimensional stability, and low friction. When investigating POM alongside other thermoplastics, it becomes evident that POM is unrivaled when making precision parts with tight tolerances as it outbids nylon, PA, and PET, even if nebulously. In addition, it is straightforward to comprehend as POM provides more excellent wear resistance and strength compared to Nylon. POM also surpasses PET in thermodynamic applications; however, as the temperatures rise, PET inicio makes up for it as it possesses excellent resistance to chemicals while sustaining those high temperatures alongside its stability.
Some POM Key Technical Parameters include:
Tensile Strength: POM around 60-70MPa. Nylon, on the contrary, compares to 50-70MPa.
Density: POM is around 1.41g/cm³, Nylon is around 1.15g/cm³, and PET is around 1.38g/cm³.
Friction Coefficient: Unlike other economically viable alternatives, POM has a friction coefficient of 0.1 to 0.3, lower than most alternatives. This provides a suitable engineer direction, allowing for more static and moving parts wear.
Max Continuous Use Temperature: POM’s maximum temperature is 100 °C, while Nylon can run up to 120°C and PET 150°C.
It’s worth mentioning that POM, like so many materials, has its strengths and weaknesses. However, due to its versatility, POM has excellent all-around performance, allowing it to be desired and even used in more harrowing situations.
What Are the Different Types of POM Grades Available?
Polyoxymethylene (POM) has several varieties that help meet specific application requirements. The different types are discussed below:
Homopolymer (POM-H): This type exhibits greater strength, stiffness, and hardness than the other copolymer grades. It is suitable for applications such as gears and bearings that require improved mechanical performance.
Copolymer (POM-C): This type delivers excellent chemical resistance, superior thermal stability, and deterioration capabilities in hot water, making it ideal for components immersed in water, chemical solutions, and high temperatures for prolonged periods.
Reinforced Grades: Using glass fibers or other minerals in reinforced grades dramatically improves strength, rigidity, and dimensional stability, making them suitable for harsh industrial applications.
Lubricated or Modified Grades: This type of polymer is infused with additives such as PTFE or silicone. The polymer is then designed to reduce friction and increase the wear resistance of the component. This is useful for moving parts that require low friction.
Food-Grade POM: These polymers can fulfill the requirements of FDA or EU certifications for food contact, so they are primarily used in food processing and packaging machinery components.
Each grade of these polymers has distinct advantages in formula and engineering, making them suitable for various industrial and commercial uses.
Homopolymer vs. Copolymer POM: Which One to Choose?
Considering whether to go with a homopolymer or a copolymer POM, I start by evaluating the factors of the intended purpose of the POM. High-performance needs would require a homopolymer POM as the latter usually tends to be stronger, stiffer, and have better thermal resistance. High moisture and acid-attacking environments would, however, require a copolymer POM as it allows for better chemical and dimensional stability. In cases where I want my application to be stronger and sturdier, I would prefer a homopolymer POM. In contrast, in cases where I want to ensure the longevity of my application and use it in moisture-rich places, I would use a copolymer POM.
Specialty POM Grades: Enhancing Performance with Additives
Unique graded POM with additives has been developed to meet specific requirements and enhance its performance properties. Let us summarize this into a few key points while keeping in mind all the information we have pulled together:
Wear Resistance Enhancement
Additive: PTFE or silicone-type additives.
Effect: Lowering the coefficient of friction allows for improved sliding and hence wear minimization.
Applications: Gears, bearings, and any structure that has sliding motion.
Technical Parameters: Friction coefficient ~ 0.1-0.2 and a wear rate decrease of around 50%.
Increased UV Stability
Additive: Light-absorbing chemicals such as HAL or UV stabilizers.
Effect: Light amines and stabilizers restrict the amount of UV light, which helps maintain the material’s color and prevent degradation and discoloration.
Applications: Parts such as car trims and gardening tools best suit outdoor conditions.
Technical Parameters: When used under harsh outdoor conditions, the material’s life is predicted to be around 5+ years.
Conductive grades
Additive: Carbon fibres or carbon powder.
Effect: The build-up of electrostatic charges is avoided, and static conductivity and dissipation are achieved.
Applications: Housing of electronics and tools designed for ESD protection.
Technical Parameters: Surface resistivity ranges from 10^3 to 10^6 ohm/sq.
Flame Retardant Improvement
Additive: Compounds such as phosphorus and halogen-free flame retardants.
Effect: Using these compounds leads to less smoke emission and compliance with fire safety measures.
Applications: Used to make components such as HVAC or parts used in automotive interiors.
Technical Parameters: Achieving a UL94 V-0 rating while maintaining a thickness of 1.5 mm.
Reinforced Mechanic Strength
Additive: Fibers of glass or minerals.
Effect: Induces strength, rigidity, and the ability to endure more impact.
Applications: Structural parts working under high tension.
Technical Specifications: Maximum tensile strength of 100 MPa and maximum flexural strength of 150 MPa.
These specialty grades illustrate how additives can modify the POM properties to make them reliable and perform well in the targeted context.
How Does POM Plastic Benefit Various Industries?
When it comes to applications for plastics, POM plastic is definitely at the top of the list as it provides low friction properties, high strength, and excellent dimensional stability. Its characteristics of resistance and endurance make it well-suited for various automotive applications such as door lock systems, fuel system components, and even automotive gears. The electronics sector prefers POM over other materials for connectors and switches because it is a good electrical insulating material. On the other hand, POM is in high demand in the medical industry because it is biocompatible and chemically resistant, making it ideal for components of medical devices and surgical instruments. The customized grades of Pom enable it to fulfill specific needs in various fields of operation.
Automotive Applications: Why POM is a Go-To Material
Polyoxyethylene, or POM, ranks first for its strength, durability properties, and versatility features among various materials used for automotive applications. I depend on this material for products like gears, fuel systems, and door locks as it has low friction and surpasses wear resistance. POM is a game-changer in challenging conditions because it can withstand extreme temperatures and chemicals, ensuring that it will be helpful in the long term. It is also lightweight, which increases the efficiency of the vehicle and lowers its overall weight, which is essential for fuel economy. All these properties contribute to POM being a low-cost solution that is very dependable within the automotive industry.
Medical Devices: POM’s Role in Healthcare Innovation
Thanks to its outstanding mechanical and chemical properties, Pom (Polyoxymethylene) has been applied in medical devices for various purposes. It is ideal for devices such as surgical instruments, insulin pens, and inhalers, as it has high dimensional stability. Due to its wear and fatigue resistance, it can tolerate repeated use, which is essential in the medical industry. Furthermore, its resistance to sterilization techniques, such as autoclaves and chemical disinfection, helps to guarantee hygiene and patient protection.
POM Parameters in Medicine Applications:
Tensile Strength: 60-70 Mpa (means flexural strength).
Thermal Resistance: Cannot exceed 100 -120 grade during sterilization (essential for sterilization to occur).
Low Friction Coefficient: ~0.2-0.3 (corresponding to syringes and inhalers with sliding components).
Chemical Resistance: Resistant to solvents, alcohol, and dilute acids (beneficial in disinfection cleaning to maintain a normal state of the material).
Because of the above, POM has become the preferred material in medical services, as it is dependable, efficient, and meets precise medical requirements.
Aerospace and Electronics: Leveraging POM’s Unique Properties
POM’s exceptional mechanical strength, low friction slit, along with outstanding dimensional stability makes it significantly crucial for use in aerospace and electronics. Its low weight, high wear, and creep resistance make it a precision component in aviation systems and electrical devices. For instance, POM is widely employed in gears, connectors, and case structures as they require reliability across the temperature spectrum and mechanical stress.
The Technical Parameters Considered Are:
Tensile Strength: ~60-70 MPa (assures resistance during structural use).
Thermal Stability: Suitable for use in the temperature range between -40°C to 100°C (very important for aerospace applications, particularly at high altitudes).
Dielectric Strength: ~25-35 kV/mm (superb electrical insulation proper for electronics).
These properties improve the life and functionality of sophisticated aerospace and electronics equipment, making POM a material of choice for these industries because of their stringent requirements.
What Are the Key Advantages of Using POM in Manufacturing?
Polyoxymethylene (POM) has its share of advantages that make it highly suitable for use in the industry:
High Strength and Stiffness: The mechanical characteristics of POM guarantee structure integrity in tough-use environments.
Excellent Dimensional Stability: Its capacity for low moisture uptake reduces swelling, thus maintaining accuracy.
Superior Wear and Friction Resistance: The low friction and wear rate coefficients enable POM to be used in moving parts, reducing the need for maintenance.
Chemical Resistance: Able to withstand fuels, solvents, and other chemicals, strengthening the integrity of the material in extreme conditions.
Ease of Processing: POM is moldable and machinable, thus facilitating effective mass production.
The above qualities are used in design and application in many industries, including the automotive and aerospace sectors and electronic gadgets, whose performance and reliability are critical.
Excellent Mechanical Properties: Strength, Toughness, and Dimensional Stability
Undeniably, POM contains remarkable mechanical properties, allowing for the versatility of applications. It has high strength, allowing it to withstand stress and increased toughness, whereby it can withstand high stress without cracking or breaking. Moreover, POM demonstrates excellent dimensional stability whereby its shape and size remain constant and steady when exposed to mechanical load or temperature changes. Considering all of the statements above, it’s evident that POM is reliable in its performance and has a consistent response, making it ideal for the industry that needs high resilience and precision as a contribution to the production process of the product.
Chemical Resistance and Low Moisture Absorption: Ensuring Longevity
As already mentioned, POM has an excellent grade of being resistant to an ample number of chemicals. As a result, it is fantastic for use in environments exposed to solvents, fuels, and various chemicals. Above all, it resists degradation due to oils, grease, weak acids, and alkalis; thus, POM’s mechanical properties remain intact for extended periods. In addition, POM is characterized by low moisture absorption, generally in the range of 0.2% to 0.5% at 23C and 50 relative humidity(Jianlin, 2012). This property helps reduce POM’s excessive swelling and warping, thus keeping the structure intact even in humid or wet environments. These traits make POM an optimal choice for components such as gears, bearings, and valves in industries ranging from automotive to medical and consumer goods.
Low Friction and High Wear Resistance: Ideal for Moving Parts
The POM is ideal for its low-friction variable capacity ranging approximately from 0.02 to 0.03, making it a first-rate ally for the moving joints. Its elevated operations, plain wear, and even excessive repeating ensure the moving components with no surface destruction, which further vastly increases the lifetime of said components. These characteristics combined render the POM excellent in producing precise parts such as bearings, gears, and moving slides, which require durable and efficient performance. Furthermore, some systems are relieved from using external lubricants due to POM’s self-lubricating abilities, which maintains POM’s usefulness even more.
How is POM Plastic Processed and Fabricated?
POM plastic’s primary processing and fabrication methods include extrusion and injection molding. In injection molding, high-precision molds are employed, and the plastic material in the form of POM pellets is melted and injected into the mold, which produces very complex components in terms of shape and dimension, which makes this method very useful for the manufacture of small and detailed parts such as gears and fasteners. In extrusion, composite materials are heated and then pushed or drawn through a die to create a sun continuous profile, sheet, or rod so that the rod can be shaped like required parts. POM retains its thermal stability, and hence, both processes can benefit from POM’s thermal stability in the final products.
Injection Molding: Precision Parts with POM
Regarding injection molding, POM is easily machined because of its low friction and exceptional stiffness while remaining dimensionally stable, which maximizes and optimizes efficiency and accuracy. Based on the research, POM is best used for constructing components like handles, gears, and fasteners, provided the components must be wear-resistant and strong. The practice entails heating POM pellets loaded in the injector until they turn into liquid. The liquid POM is then injected into the specialized molds, after which the fluid is cooled, allowing the liquid POM to form slight variations of the same. The method minimizes and optimizes costs for mass production and enhances accuracy and performance.
Machining POM: Tips for Optimal Results
Machining POM needs careful techniques and parameters to be observed to achieve decent results without compromising the thickness of the material. Given this, here are a few pointers and relevant considerations.
Cutting Speeds and Feeds
Proposed cutting speed: 200 to 500m/min.
Feed rate: 0.1 to 0.5mm/tooth, depending on the tool and the part in question.
With these parameters, heat generated is cut short, thus preventing distortion of the material.
Tool Selection
Apply SHARP tools, HIGH-HSS, or Carbide tools for cuts needing cleaning.
Positive rake angles of around 5 – 15 degrees are recommended for proper chip tooling, as they ease chip flow and reduce tool wear.
Coolant Usage
Although POM has low heat sensitivity, a coolant such as water-soluble oil reduces friction and improves surface quality during extended machining operations. However, using the coolant itself is not mandatory.
Clamping and Support
Overuse of pressure needs to be avoided since POM is prone to deformation if too much force is applied. However, moderate clamping pressure is required in order to prevent vibration.
Soft jaws or fixtures should keep the material’s surface safe.
Drilling Considerations
Using an excessive feed rate risks overheating and cracking the material, so start with a low feed rate and gradually increase it.
Ensure somewhere around the ratio of 5:1 is maintained while drilling and ensure appropriate chip removal when drilling is performed to keep material buildup away.
Polishing, sanding, or altering the tool edge can dramatically improve the function and look of a POM. However, several conditions must be ensured for a POM to match properly with the desired set of parameters. It is claimed that a POM can even reach a Ra of 0.4µm in roughness.
Lastly, a component can perform well if all the parameters are modified accordingly, which maximizes the surface finishing potential while ensuring high quality.
What Challenges Might You Face When Working with POM?
When dealing with POM, numerous issues may occur due to its distinct characteristics. One critical aspect to consider in POM is its thermal expansion properties, as poor management could cause a loss of dimensional stability in the plastic during machining. Furthermore, the low surface energy of POM creates bonding problems with adhesives, restricting assembly possibilities. The potential for overheating during machining processes increases the probability of either deformation or surface problems, underscoring the importance of temperature control. Chipping or cracking of POM can occur during the machining process if appropriate tooling and cutting specs are not met; this is especially true for complex geometries. Despite the challenges, implementing proactive measures and understanding the complexities of these problems may prevent or reduce associated issues.
Addressing POM’s Sensitivity to UV and High Temperatures
By design, POM (Polyacetal) is susceptible to degradation when exposed to UV light and high-temperature conditions for prolonged periods. Medium to high UV exposure can cause surface deterioration and a color change, decreasing mechanical strength. UV stabilizers or coatings can be applied to the material to prevent this from happening when it is used outdoors or in a high-UV-exposed region.
Regarding elevated temperatures, POM has an almost -40 C to 100 C – and sometimes higher than 110 C – unlimited service temperature range. However, surpassing this boundary can cause POM to degrade, warp, or structurally fail thermally. To mitigate this, consider using heat-resistant grades of POM that contain additives that increase thermal stability. Also, proper ventilation or thermal barriers in high-heat applications can safeguard the material.
If you follow these recommendations and do not exceed the desired technical parameters, you can maintain POM’s performance even in extreme environmental conditions.
Overcoming Potential Issues in POM Plastic Processing
To avoid the potential problems posed by processing POM plastic, I aim to regulate the processing parameters and material handling closely. An important aspect to note is that even after waiting for the desired amount of time for the component to be molded if the material still possesses a certain amount of moisture, it leads to porosity or surface defects. Regarding POM, the recommended drying temperature is 80 to 100 degrees Celsius, and considering the time, it is from 2 to 4 hours.
Similarly, specific temperature ranges ought to be adhered to to avoid thermal breakdown of the material. The melt temperature can be reliably set for injection molding between 190 and 230 degrees Celsius while keeping the mold temperature between 80 and 120 degrees Celsius. The correctness of these parameters and ranges allows shear stress and degradation to be minimal, ensuring the quality of the product.
Moreover, I also set specific appropriate parameters regarding pressure and speed of injection to avoid defects such as voids or warping. A steady cooling process and the uniform design of the mold reduce shrinkage and the internal stresses involved. After processing POM, the machines must be cleaned appropriately to avoid contamination of the materials and degradation residues.
More importantly, following such technical parameters precisely allows me to solve the Problems arising during POM processing while allowing the material to remain at its peak mechanical performance.
References
Frequently Asked Questions (FAQ)
Q: What are the key properties of POM material?
A: POM material, also known as acetal plastic, is characterized by its excellent mechanical properties, including high impact resistance, low coefficient of friction, and good lubricity. It also boasts good electrical insulation properties, making it suitable for various engineering applications.
Q: What are the benefits of using POM plastic in engineering applications?
A: The benefits of POM plastic include its high impact strength, excellent dimensional stability, and good wear resistance. These properties make POM suitable for producing durable plastic parts in machinery and other engineering applications, where the performance of POM is critical.
Q: How does the impact resistance of POM make it suitable for different applications?
A: POM’s high impact resistance makes it ideal for applications where the material will be subjected to sudden or repeated impacts. This property ensures that POM plastic parts can withstand mechanical stress and remain functional.
Q: What are the different POM grades available, and how do they affect its uses?
A: Different POM grades offer variations in properties such as impact strength, lubricity, and chemical resistance. These modifications of POM allow it to be tailored for specific applications, enhancing its versatility as an engineering thermoplastic.
Q: In what ways is POM used in plastic engineering applications?
A: POM plastic is extensively used in plastic engineering applications to manufacture gears, bearings, and other moving parts due to its low coefficient of friction and excellent wear resistance.
Q: How do the electrical properties of POM contribute to its applications?
A: POM’s electrical insulation properties make it suitable for applications requiring protection against electrical interference, such as electronic components and connectors.
Q: What makes POM an ideal choice for applications requiring lubricity?
A: POM’s inherent low coefficient of friction and good lubricity makes it an ideal choice for applications involving moving parts, reducing the need for additional lubrication and extending the lifespan of components.
Q: How is POM metal different from traditional metals in engineering applications?
A: POM metal is a versatile material that combines the benefits of POM plastic with the strength of metals, offering improved mechanical properties and better impact resistance while being lighter and more corrosion-resistant than traditional metals.
Q: What are the typical applications of POM in the plastic industry?
A: Common applications of POM in the plastic industry include producing precision parts like gears, bushings, and fittings, where the material’s high mechanical strength, stability, and resistance to wear and tear are essential.
