How To Process POM Plastic?

Polyoxymethylene (POM), also known as polyacetal, polyacetaldehyde, and polyformaldehyde, is one of the plastic materials that offers many advantages when it comes to CNC machined parts. This plastic is popular in several industries due to its outstanding properties, advantages and various uses. It is a reliable material for engineering applications due to its chemical resistance, dimensional stability, mechanical strength and low friction.

So, what is POM material and is CNC machining POM material suitable for manufacturing parts? Read on as we provide more information on machining POM.

What is POM material?

POM is an engineering thermoplastic with a variety of beneficial properties. Some of its properties include excellent hardness, strength, and stiffness. Although it can be made in a variety of colours, its high crystallinity gives it a natural opaque white appearance.POM has a density between 1.410 and 1.420 g/cm3.

POM plastics are often used to make precision parts that require dimensional stability, high stiffness and low friction. This low friction makes POM ideal for rotating or sliding parts such as sleeves, bearings and gears.

Like many other synthetic POM polymers, POM is manufactured by a number of chemical companies using slightly different formulations and is sold under a number of brand names, such as Celcon, Tenac, and Duracon.

Properties of POM Plastics

The high-performance engineering plastic polyoxymethylene (POM) is used in a wide range of applications in many fields. It is suitable for a variety of applications due to its unique properties.

Low friction and wear resistance: POM plastic stands out for its low coefficient of friction, which helps explain why it has such excellent self-lubricating properties. Fluid sliding or rotary motion is achieved due to reduced frictional resistance, lower wear, and overall higher efficiency.

Chemical Resistance: POM is ideally suited for products that come into contact with substances such as chemical solvents, such as pump parts, seals and fuel system components. This is largely due to POM plastic's excellent resistance to a wide range of chemicals, solvents and fuels. It can resist contact with many organic chemicals, alcohols, oils and greases without significant deterioration.

Low Water Absorption and Dimensional Stability: POM plastics have excellent dimensional stability, maintaining their size and shape even under conditions of humidity and temperature change. Because it absorbs very little water, it is less susceptible to moisture-related problems such as humidity, warping and other dimensional changes. Applications requiring precise tolerances and consistent performance also rely heavily on POM's dimensional stability.

Ease of machining: The ease of machining of POM plastics makes possible a precise and efficient manufacturing process. It is easy to mould, machine, turn and drill, making it easy to manufacture complex parts and intricate designs. Because of this property, POM resins are often used in applications that require complex geometries and high precision.

Excellent Creep/Impact Resistance: POM plastics exhibit excellent creep resistance, which means it can withstand constant mechanical stress without deforming. Due to this property, POM parts continue to function properly even when subjected to constant loading or strain.

How to CNC machine POM plastics?

There are usually two methods that can be used to machine POM parts. The first is by using standard machining methods. The second method is by annealing a POM part that has been pre-machined.

To machine POM, you first need to generate a CAD file of the part, which is then converted to CAM for further conversion to G-code that can be handled by a CNC machine. The next step is to cut the POM workpiece to a specific size for placement on the machine. After cutting the POM workpiece to the right size, it is placed on the machine tool and secured using fixtures to ensure that it does not move during the machining process.

It is important to ensure that the POM workpiece is held firmly in position as the CNC cutting tool moves using pre-set co-ordinates and any change in the position or alignment of the workpiece can have a negative impact on the quality of the part.

After ensuring the POM workpiece is stable, the material is removed from the workpiece using a specialised cutting tool fixed to the CNC machine. The recommended cutting tool is a general-purpose flat-end milling cutter, as it is more efficient when machining plastics.

Finally, vacuum the CNC machine frequently when machining POM to ensure that material debris does not clog the milling cutter.