{"id":6924,"date":"2026-03-25T03:36:08","date_gmt":"2026-03-25T03:36:08","guid":{"rendered":"https:\/\/le-creator.com\/?p=6924"},"modified":"2026-03-25T05:51:27","modified_gmt":"2026-03-25T05:51:27","slug":"cnc-machining-parameters-for-pom","status":"publish","type":"post","link":"https:\/\/le-creator.com\/pt\/blog\/cnc-machining-parameters-for-pom\/","title":{"rendered":"Par\u00e2metros de usinagem CNC para POM: velocidades, feeds e configura\u00e7\u00e3o"},"content":{"rendered":"
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CNC Machining Parameters for POM \u2014 Speeds, Feeds, Tools and Tolerance Data<\/strong><\/p>\n

Polyoxymethylene (POM) is one of the most machinable engineering plastics you can expect to find on any shop floor. This POM machining guide<\/a> is compiled from actual cut parameters, tool selections and tolerance ranges that matter when you program a POM plastic part on a CNC plastic milling or turning center\u2014no theory, only numbers you can punch into the controller.<\/p>\n

<\/p>\n

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Quick Specs<\/h3>\n\n\n\n\n\n\n\n\n\n\n
Material<\/td>\nPOM (Polyoxymethylene \/ Acetal \/ Delrin)<\/td>\n<\/tr>\n
Typical Cutting Speed<\/td>\n150\u2013500 m\/min<\/td>\n<\/tr>\n
Feed Rate (Milling)<\/td>\n0.05\u20130.25 mm\/tooth<\/td>\n<\/tr>\n
Feed Rate (Turning)<\/td>\n0.05\u20130.30 mm\/rev<\/td>\n<\/tr>\n
Achievable Tolerance<\/td>\n\u00b10.02\u20130.10 mm<\/td>\n<\/tr>\n
Surface Finish (Ra)<\/td>\n0.4\u20131.6 \u03bcm (as-machined)<\/td>\n<\/tr>\n
Max Service Temp<\/td>\n90\u2013100 \u00b0C continuous \/ 140 \u00b0C short-term<\/td>\n<\/tr>\n
Preferred Tool Material<\/td>\nUncoated carbide \/ PCD<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/p>\n

What Is POM and Why Does It Machine Well?<\/h2>\n

\"What<\/p>\n

A full name for POM, polyoxymethylene can be purchased by many traders, such as Delrin (DuPont) and Ultraform (BASF)\u2014semi-crystalline engineering plastics, in which the crystallinity is as high as 75%. It is such a crystalline nature that brings this POM material its typical strength, noting that: the tensile strength = 60-70 MPa, the coefficient of friction coefficient= 0.20-0.35 and the dimensional stability is tightly as time goes on.<\/p>\n

Basically, there are two grades of POM: homopolymer POM (POM-H) and co-polymer POM (POM-C). Of the two, POM-H has a higher stiffness and tensile strength\u2014roughly 5-10% more than POM-C\u2014for the machining work of gear and structure components. POM-C is inferior to POM-H in these aspects, but throughly better for its chemical resistance, thermal conductivity during machining and reduced Centreline porosity susceptibility. For workpieces with tight tolerances, the latter is preferred.<\/p>\n

Apart from having a lower coefficient of moisture absorption (less than 0.2%, compared with 1-2% of nylon fibers), POM exhibits excellent dimensional stability for shop floors\u2014whether dry or humid. When coupled with its naturally good lubricity and notable resistance to solvents, alcohols, weak acids and fuels, the mechanical properties of POM material make it suitable for precision parts in automobile components, medical instruments and food processing machinery.<\/p>\n

<\/p>\n

Recommended Cutting Parameters for POM Turning, Milling and Drilling<\/h2>\n

\"Recommended<\/p>\n

Material is machined with process parameters to produce both a dimensionally stable and smooth part or a warped one from heat generated. The roughing and finishing tables are provided separately\u2014most guides just give the former, but the latter counts for machining a POM workpiece with tight tolerance.<\/p>\n

Turning Parameters<\/h3>\n
\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nRoughing<\/th>\nFinishing<\/th>\n<\/tr>\n<\/thead>\n
Cutting Speed<\/td>\n200\u2013400 m\/min<\/td>\n300\u2013500 m\/min<\/td>\n<\/tr>\n
Feed Rate<\/td>\n0.15\u20130.30 mm\/rev<\/td>\n0.05\u20130.12 mm\/rev<\/td>\n<\/tr>\n
Depth of Cut<\/td>\n1.5\u20133.0 mm<\/td>\n0.3\u20130.8 mm<\/td>\n<\/tr>\n
Rake Angle<\/td>\n6\u00b0\u201310\u00b0 positive<\/td>\n6\u00b0\u201310\u00b0 positive<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

CNC Milling Parameters<\/h3>\n
\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nRoughing<\/th>\nFinishing<\/th>\n<\/tr>\n<\/thead>\n
Cutting Speed<\/td>\n150\u2013250 m\/min<\/td>\n250\u2013350 m\/min<\/td>\n<\/tr>\n
Feed per Tooth<\/td>\n0.10\u20130.25 mm\/tooth<\/td>\n0.05\u20130.10 mm\/tooth<\/td>\n<\/tr>\n
Axial DOC<\/td>\n2.0\u20134.0 mm<\/td>\n0.5\u20131.5 mm<\/td>\n<\/tr>\n
Spindle Speed<\/td>\n4,000\u20136,000 RPM<\/td>\n6,000\u20138,000 RPM<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Drilling Parameters<\/h3>\n
\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nRecommended Value<\/th>\n<\/tr>\n<\/thead>\n
Spindle Speed<\/td>\n1,000\u20132,500 RPM<\/td>\n<\/tr>\n
Feed Rate<\/td>\n0.05\u20130.15 mm\/rev<\/td>\n<\/tr>\n
Point Angle<\/td>\n118\u00b0 (standard twist drill)<\/td>\n<\/tr>\n
Peck Cycle<\/td>\nRequired for L\/D > 3:1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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\ud83d\udcd0 Engineering Note<\/strong><\/p>\n

A study printed by MDPI Metals in 2023<\/a> found that accurate parameters for POM-C turning over a PCD tool reduced total machining time by 44%. The work employed RSM and a face-centered CCD experimental design, with the goal to harmonize surface roughness with workpiece deflection and good chip formation.<\/p>\n<\/div>\n

In general, compressed air suffices to cool off POM machining. Since POM absorbs practically no humidity, it is also possible to use water-based coolant for mass production without alteration of workpiece dimensions\u2014an issue that cannot happen when using carbide-grit-filled thermoplastics like nylon where the sudden coolant flow may result in material swelling.<\/p>\n

<\/p>\n

Tool Selection and Tool Life When Machining POM<\/h2>\n

\"Tool<\/p>\n

To choose a tool and tool geometry for POM will firstly depend on the batch size and surface roughness that you expect. POM typically performs better than most reinforced plastics or metals with lower tool wear on the CNC machine, thanks to its softness, but it also is delicate to have burrs or melted parts if the wrong tool geometry is used.<\/p>\n

\n\n\n\n\n\n\n\n\n
Tool Material<\/th>\nBest For<\/th>\nTypical Tool Life<\/th>\nSurface Finish<\/th>\n<\/tr>\n<\/thead>\n
HSS (High-Speed Steel)<\/td>\nPrototypes, short runs<\/td>\n500\u20132,000 parts<\/td>\nRa 0.8\u20131.6 \u03bcm<\/td>\n<\/tr>\n
Uncoated Carbide<\/td>\nProduction volumes<\/td>\n5,000\u201315,000 parts<\/td>\nRa 0.4\u20130.8 \u03bcm<\/td>\n<\/tr>\n
PCD (Polycrystalline Diamond)<\/td>\nHigh-volume, tight tolerance<\/td>\n50,000+ parts<\/td>\nRa 0.2\u20130.4 \u03bcm<\/td>\n<\/tr>\n
DLC-Coated Carbide<\/td>\nReduced friction applications<\/td>\n10,000\u201320,000 parts<\/td>\nRa 0.4\u20130.6 \u03bcm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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\ud83d\udca1<\/span> Pro Tip<\/strong><\/div>\n

Two-flute end mills work much better than four-flute sets when working with POM. The unitary larger cutter GFI elements and deflects chips far quicker, resulting in fewer accumulations of re-cut melted Plastics. Using a positive rake angle of around 6-10 degrees boosts the machine’s ability to preplan the shear rather than forces the material\u2014hence your tool\u2014pushing\u2014thus improving process quality and extending tool life.<\/p>\n<\/div>\n

For precision machined POM parts<\/a>, carbide tools are the cheapest and most effective option. Save PCD for jobs requiring sub-micron surface finishes, or where the tooling investment can be amortized across medium-high batch quantities.<\/p>\n

<\/p>\n

Surface Finish and Tolerance Ranges for CNC-Machined POM Parts<\/h2>\n

POM tends to yield one of the best as machined surface finishes of any engineering plastics. With sharp carbide tooling and a conservative feed rate, 0.4-0.8 Ra is possible directly from the CNC without polishing.<\/p>\n

\n\n\n\n\n\n\n\n\n
Feature Type<\/th>\nStandard Tolerance<\/th>\nTight Tolerance<\/th>\nNotes<\/th>\n<\/tr>\n<\/thead>\n
Linear Dimensions<\/td>\n\u00b10.10 mm<\/td>\n\u00b10.02 mm<\/td>\nRequires annealing + climate control<\/td>\n<\/tr>\n
Bore Diameter<\/td>\n\u00b10.05 mm<\/td>\n\u00b10.02 mm<\/td>\nReam after drilling<\/td>\n<\/tr>\n
Flatness<\/td>\n0.10 mm\/100 mm<\/td>\n0.05 mm\/100 mm<\/td>\nSymmetric material removal critical<\/td>\n<\/tr>\n
Surface Roughness<\/td>\nRa 0.8\u20131.6 \u03bcm<\/td>\nRa 0.2\u20130.4 \u03bcm<\/td>\nPCD tooling for best finish<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Coupled with zero tolerance-machined fixturing and stress-relief annealing, tolerances between 0.02 mm can be held. Researchers Pinisetty and Redner<\/a> demonstrated that for POM, feed rate and nose radius dominate surface roughness, with depth of cut holding a secondary influence.<\/p>\n

<\/p>\n

Common POM Machining Problems and How to Fix Them<\/h2>\n

\"Common<\/p>\n

A reputation for easy machining means it is always a surprise when any of three problems catch operators off guard, especially metal machinists new to plastics. Each stems from a specific trait of the POM machining process and has an appropriate solution.<\/p>\n

\n\n\n\n\n\n\n\n
Problem<\/th>\nRoot Cause<\/th>\nSolution<\/th>\n<\/tr>\n<\/thead>\n
Warping after machining<\/td>\nResidual stress from extrusion\/molding released by material removal<\/td>\nAnneal between rough and finish passes; remove material symmetrically<\/td>\n<\/tr>\n
Burr formation on edges<\/td>\nDull tool edge or excessive dwell at exit points<\/td>\nMaintain sharp tools; use climb milling; program exit paths to avoid dwell<\/td>\n<\/tr>\n
Cracking (especially POM-H)<\/td>\nStress concentration at sharp internal corners; centerline porosity in homopolymer POM<\/td>\nAdd fillet radii \u22650.5 mm; switch to POM-C for thick-wall parts; anneal before final machining<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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\ud83d\udcd0 Engineering Note \u2014 Annealing Protocol for POM<\/strong><\/p>\n

Anneal at 140-150 C (10-20 C below heat distortion temperature) to minimize residual stresses. In an oil bath, hold for 40-60 minutes per 5 mm wall. In a room temperature air bath, hold 20-30 minutes per 5 mm wall. Allow to cool to room temperature fully before machining or reintroducing stress. Avoid forced cooling at the annealing step; reintroduced residual stresses would offset the dimensional benefits. Schedule after rough machining or during intermediate finishing stages. This step matters most for POM features requiring tolerances finer than 0.05 mm.<\/p>\n<\/div>\n

\n
\u26a0\ufe0f<\/span> Important<\/strong><\/div>\n

From a chemical standpoint, POM begins degrading above 230 C and simultaneously emits formaldehyde. If machining during hot chip removal, proper ventilation should be maintained at the operator station. Cases of excessive heat generation at the work zone due to unbaffled chips and concentrated cutting zone friction heat is well documented.<\/p>\n<\/div>\n

<\/p>\n

POM vs Nylon vs PEEK \u2014 Machining Parameter Comparison<\/h2>\n

\"POM<\/p>\n

Optimum application selection between POM and other engineering plastics depends on what operating conditions are most important to the application and the process. Below, a table compares the actual property values (values for “good” are also listed to illustrate that there is no take-for-granted correlation) of each.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Property<\/th>\nPOM (Acetal)<\/th>\nNylon (PA6\/66)<\/th>\nPEEK<\/th>\n<\/tr>\n<\/thead>\n
Tensile Strength<\/td>\n60\u201370 MPa<\/td>\n70\u201385 MPa<\/td>\n90\u2013100 MPa<\/td>\n<\/tr>\n
Friction Coefficient<\/td>\n0.20\u20130.35<\/td>\n0.35\u20130.45<\/td>\n0.35\u20130.40<\/td>\n<\/tr>\n
Max Continuous Temp<\/td>\n90\u2013100 \u00b0C<\/td>\n80\u2013100 \u00b0C<\/td>\n250 \u00b0C<\/td>\n<\/tr>\n
Moisture Absorption<\/td>\n<0.2%<\/td>\n1.0\u20132.5%<\/td>\n<0.1%<\/td>\n<\/tr>\n
Machinability<\/td>\nExcellent \u2014 clean chips<\/td>\nGood \u2014 tends to smear<\/td>\nGood \u2014 higher cutting forces<\/td>\n<\/tr>\n
Relative Material Cost<\/td>\n1.0\u00d7<\/td>\n0.7\u20130.9\u00d7<\/td>\n15\u201320\u00d7<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

For applications where dimensional stability and friction coefficient are most critical, POM is the best. POM does not absorb water and change dimensions, like Nylon will, by 0.5-1.0% in an otherwise humid environment. POM also loads easier and equilibrates quicker than PEEK under high-temperature \/ chemically harsh environments, but costs 15-20 \/kg. For CNC machined parts<\/a> and the applications they are most suitable for, POM will outperform composites or other plastics below 100 C in cost, machinability, and performance.<\/p>\n

<\/p>\n

Industry Applications of Precision-Machined POM Components<\/h2>\n

\"Industry<\/p>\n

POM’s combination of low friction and the mechanical properties of this plastic material make it ideal for self lubricating applications where excess weight or excess material would be a hindrance to a product. The following industries make up the majority of the machined POM market:<\/p>\n

Automotive: Fuel system clips, seat belt guide bushings, window regulator gears, and interior mechanism components. POM is used here because it resists lots of cycles, and being exposed to room temperatures, and long-term exposure to automotive fluids, even repeatedly over many cycles without decomposition.<\/p>\n

Medical Devices: Inhaler bodies, surgical instruments handles, medicament delivery pump parts. Because POM homopolymer conforms to FDA 21 CFR 177.2480<\/a>, use in contact with food, extractives are limited to 0.5mg\/in and formaldehyde content is below 0.0050percent by weight. POM copolymer is separately regulated under 21 CFR 177.2470<\/a>.<\/p>\n

Food Processing: Conveyer guides, packing machine wear strips, and valve seats. POM’s proven endurance in the wet environment of food processing, coupled with FDA-compliant grades, makes POM an excellent choice for food contact machinery.<\/p>\n

Industrial Equipment: Plain bearings, gear mechanisms, valve bodies, and pump impellers. POM’s low coefficient of friction (0.20-0.35) enables some bearing applications to be run without lubrication – cutting down on maintenance frequency and preventing contamination of clean environments.<\/p>\n

For all of these end markets, POM machined to custom specifications by CNC<\/a> not only provides great tolerances and amazing repeatability, but outperforms injection molding in the 5,000 pieces-per-order range.<\/p>\n

<\/p>\n

Frequently Asked Questions<\/h2>\n

\"CNC<\/p>\n

\n

Q: What is the difference between Delrin and POM?<\/h3>\n
\nView Answer<\/summary>\n
To clarify, Delrin is DuPont’s trade name for POM homopolymer. The generic name is polyoxymethylene. The abbreviation homopolymer is POM-H; copolymer is POM-C. POM-H is the stiffer of the two, while POM-C better resists cracking while milling.<\/div>\n<\/details>\n<\/div>\n
\n

Q: What is the tightest tolerance POM CNC machining can achieve?<\/h3>\n
\nView Answer<\/summary>\n
Achievable tolerances for critical dimensions are approximately 0.02 mm. Accurate CNC POM machining of tight tolerances requires stress-relief annealing at 140-150 C between roughing and finishing operations, an environment for temperature-stabilized machining (2 C), fixturing which applies smooth and even force to the part, and designing work-holding which minimizes torque on critical features.<\/div>\n<\/details>\n<\/div>\n
\n

Q: How to prevent warping during POM machining?<\/h3>\n
\nView Answer<\/summary>\n
Preventing warping occurs in three stages: 1. Remove metal equally in all directions by removing material from all sides, rather than trying to “face off” a single, critical edge; 2. Use many light passes in the roughing stage (0.5-1.5mm DOC) rather than few heavy. 3. Anneal at 140-150 C for approximately 40-60 minutes for every 5 mm thickness of wall, in a heated oil bath, after roughing and before finishing. Allow the part to cool without forced airflow to prevent reintroducing the internal stress that causes post-machining deformation. Occasionally, POM-H can require two stress-relief anneals, one in the middle of roughing and one after semi-finishing, when users desire inside\/outside measurement differences within 0.05 mm and the walls are above 25 mm thick. For heavy-walled parts, a second anneal prevents warping.<\/div>\n<\/details>\n<\/div>\n
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Q: What surface finishes are available for POM machined parts?<\/h3>\n
\nView Answer<\/summary>\n
As-machined, POM polishes to Ra 0.4-1.6 m depending on tool type and machining conditions. POM that is laser vapor-polished can reach Ra 0.2 m. Vapor polishing can provide POM of near-optical clarity. In most cases for common functional requirements, the as-machined surface quality is adequate.<\/div>\n<\/details>\n<\/div>\n
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Q: Can POM be used for food contact applications?<\/h3>\n
\nView Answer<\/summary>\n
Yes. POM-H is FDA 21 CFR 177.2480-compliant; POM-C is FDA 21 CFR 177.2470-compliant. Parts need to be clean prior to first contact with food.<\/div>\n<\/details>\n<\/div>\n
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Q: Is POM suitable for machining complex 3D shapes?<\/h3>\n
\nView Answer<\/summary>\n
Absolutely. Both 3 and 5 axis machining work well with POM, due to its rigidity and accordingly stiff deflections during multi-axis machining, and its low tool wear when on long machining runs. Undercuts and internal contours may have to be accomplished via EDM or precise fixturing. Willhold’s dimensional stable POM makes complex geometries stay true during machining with the classic twisted-part index while eliminating the common spring-back tendency of softer plastics.<\/div>\n<\/details>\n<\/div>\n
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Q: What is the maximum temperature POM can withstand?<\/h3>\n
\nView Answer<\/summary>\n
\n

Long-term service 90-100 C. Short-term exposure 140 C. Above 230 C POM decomposes and releases formaldehyde – adequate through ventilation is necessary during high-speed machining to prevent local overheating.<\/p>\n

Consider PEEK over 120 C, though at 15-20 the material cost.<\/p>\n<\/div>\n<\/details>\n<\/div>\n

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Need precision POM parts machined to your specifications?<\/p>\n


\nGet a POM Machining Quote \u2192
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About This Technical Reference<\/h3>\n

This guide has been compiled by the engineering department at Le-creator, a Shenzhen-based CNC machining company with 17 years of production experience working with POM, PEEK, nylon, and over 40 other engineering plastics. The milling ranges listed in this article have been cross-checked against existing research published by MDPI and Springer, as well as the data we obtain from operating over 80 CNC machines each day on polymer stock.<\/p>\n<\/div>\n

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