POM cnc machining
We can achieve an accuracy of 0.005mm in POM CNC machining. If you would like to learn more about POM machining case studies and pricing, please feel free to contact us.
What is POM cnc machining ?
Polyoxymethylene (POM), an engineering thermoplastic, also known as acetal, Delrin, or polyacetal, possesses excellent rigidity, a low coefficient of friction, good dimensional stability, chemical resistance, and wear resistance. Precision machining operations such as turning, milling, and drilling of POM workpieces are performed using program-controlled cutting tools. POM precision parts are widely used in the automotive, electronics, and consumer goods industries for manufacturing gears, bearings, sliders, bushings, and other components requiring low wear and high strength.
Types of material for POM cnc machining
In CNC machining, POM (polyoxymethylene) materials are mainly divided into two categories: homopolymer POM-H and copolymer POM-K.
Homopolymer POM-H
Composition: Polymerized from pure formaldehyde.
Properties: High crystallinity and high melting point (around 175℃); High strength and excellent fatigue resistance; High mechanical strength, good rigidity, and strong wear resistance.
Applications: Suitable for manufacturing high-load mechanical parts, such as gears, bushings, washers, and automotive interior and exterior trim.
Copolymer POM-K
Composition: Modified by copolymerizing formaldehyde with other monomers.
Properties: Melting point is slightly lower than homopolymer POM-H, generally around 165℃.
It has better thermal and chemical stability.
Easy to process and has excellent molding properties.
Applications: Suitable for precision mechanical parts and electronic equipment, such as gear parts requiring low friction characteristics.
Surface finish for cnc machining POM parts
Based on over 15 years of CNC machining experience, we have compiled the following list of surface finish processes used for various precision-machined parts made from POM material.
Machined finish
The prototype processed by the machine tool retains traces of tool machining.
Polish
Polishing enhances surface finish and aesthetic appeal, suitable for materials such as metals, ceramics, plastics, and PMMA.
Sand blasting
Sandblasting involves propelling abrasive material at high pressure or mechanically onto a workpiece to achieve a clean, roughened, and matte finish.
Brushed finish
Brushed finish creates a textured pattern on metal surfaces, enhancing aesthetic appeal. Suitable for aluminum, copper, stainless steel, and other materials.
Powder coating
Powder coating is applied to the workpiece surface via electrostatic adhesion, then cured at high temperatures to form a dense coating, enhancing the corrosion resistance of metal and plastic surfaces.
Black oxidize
A black oxide coating is formed on metal surfaces through chemical oxidation, offering low cost, a simple process, and reduced light reflection.
Advantage of precision POM parts
Excellent Precision and Rigidity:CNC machining, utilizing precise computer control of machine tools, allows POM parts to maintain tolerances within ±0.01 mm, achieving high-precision forming. Furthermore, POM material boasts high strength and rigidity, capable of withstanding significant external forces without deformation.
Wear-Resistant and Low-Friction:POM material exhibits strong wear resistance, ensuring stable shape and dimensions of parts over extended use. Its low coefficient of dynamic friction and self-lubricating properties make it excellent in applications requiring reduced friction.
Stable Performance:POM has low moisture absorption, resulting in minimal dimensional changes under varying environmental conditions. Its uniform texture and lack of directionality lead to low cutting resistance, high processing efficiency, and minimal tool wear. It also demonstrates good resistance to various solvents, oils, and chemicals.
Applications of precision POM parts
Automotive Industry:Used in the manufacture of gears, bearings, universal joints, fuel system parts, etc., capable of handling high pressure, heavy loads, and frequent friction.
Electronics and Electrical: Used in the manufacture of connectors, switching components, precision gears, guide rails, etc., meeting high precision, high rigidity, and wear resistance requirements.
Mechanical Manufacturing: Used to manufacture transmission components, sliders, gaskets, fixtures, etc., adapting to frequent friction and wear scenarios due to their wear resistance and self-lubricating properties.
Medical Devices: Due to their non-toxicity and resistance to sterilization, they are used to manufacture precision instrument parts, conveying device components, etc., meeting the high requirements of medical devices.
POM CNC machining capabilities
Maximum machining size: 3000mm × 1200mm × 850mm
Minimum machining size: 10mm*10mm*10mm
Minimum machining radius: 0.05mm
Tolerance: ±0.008mm to ±0.2mm
Maximum accuracy: ±0.005mm
Minimum wall thickness: 0.5mm
Guideline of POM CNC machining
Spindle speed: 600 – 3000 rpm, adjustable according to tool diameter and operating requirements.
Feed rate: 10 – 20mm/min, balancing machining efficiency and surface quality.
Coolant: Use POM-compatible coolant to prevent chemical degradation of the material.
Thermal stability: Machining temperature controlled between 180 – 230℃, avoiding temperatures exceeding 240℃ to prevent severe decomposition, and dwell time should not be too long.
Solidification rate: Solidification temperature approximately 160℃, rapid cooling rate, prone to surface defects (such as wrinkles, blemishes), requiring optimized cooling strategy.
Wear resistance: POM has good wear resistance and is suitable for high-load parts, but tool wear needs to be controlled during processing to ensure accuracy.
FAQ of POM CNC machining
What are some typical problems that occur when machining POM materials using CNC machining? How can they be prevented?
Common problems include thermal decomposition (overheating), internal stress deformation (uneven cooling), and rapid tool wear (high hardness). Prevention requires controlling machining temperature, optimizing cooling paths, using coated tools, and reducing the depth of cut.
How to optimize cutting parameters for POM CNC machining to improve surface quality?
Roughing should use low speeds (800-1500 rpm) and high feed rates (15-20 mm/min). Finishing should use high speeds (1500-2500 rpm) and low feed rates (5-10 mm/min), with a depth of cut ≤0.3 mm, and should be performed with high-pressure coolant.
Why is a special coolant needed for POM machining? How to choose one?
POM is prone to decomposition at high temperatures, producing formaldehyde. A special coolant can quickly cool it down and prevent degradation. Choose water-soluble or oil-based coolants, avoiding those containing chlorine/sulfur. Thin-walled parts can be cooled using low-pressure spray cooling.
What are some common surface defects after POM CNC machining?
How to solve them? Defects include wrinkling (uneven cooling), burrs (tool wear), and deformation (excessive fixture pressure). Solutions require optimized cooling, regular tool changes, controlled feed rate, and the use of flexible fixtures to hold thin-walled parts.
What are the advantages of POM parts compared to materials like ABS/PA66?
POM has superior wear resistance compared to ABS, stronger dimensional stability than PA66 (low water absorption), and excellent chemical resistance, making it suitable for precision machinery, non-toxic medical components, and other applications where it can operate long-term without lubrication.
