What is Thread Milling? Thread milling is a CNC machining process used to produce internal or external threads by using a rotating multi-point cutting tool (thread mill) . Unlike tapping, which cuts threads in a single linear motion, thread miling involves a helical interpolation movement, allowing for greater flexibility and precision.
How Does Thread Milling Work? Tool Selection – A thread mill (with multiple cutting edges) is chosen based on thread size, pitch, and material.CNC Programming – The machine follows a helical toolpath (circular interpolation with axial movement) to cut threads.Cutting Process – The thread mill rotates at high speed while moving in a circular and downward/upward motion to create the thread profile.Finishing – The process can produce threads in a single pass or multiple passes for better surface finish and accuracy.Thread Milling Tools Single-Form Thread Mills – For one specific thread size and pitch.Multi-Form Thread Mills – Can cut multiple thread sizes with the same tool.Solid Carbide Thread Mills – High precision, used for small threads.Indexable Thread Mills – Cost-effective for larger threads.Advantages of Thread Milling Versatility – One tool can produce multiple thread sizes (with multi-form cutters).Precision – Better thread quality and tighter tolerances than tapping.No Chip Evacuation Issues – Unlike tapping, thread millng generates smaller chips, reducing breakage risk.Works in Tough Materials – Effective for hardened steels, titanium, and other difficult-to-machine metals.Left- & Right-Hand Threads – Same tool can cut both types.Disadvantages of Thread Milling Slower than Tapping – For small, simple threads, tapping may be faster.Requires CNC Capability – Needs 3-axis CNC machines with helical interpolation.Higher Initial Cost – Thread mills are more expensive than taps.Thread Milling Vs. Tapping Feature Thread Milling Tapping Tool Flexibility One tool can cut multiple thread sizes Each tap is size-specific Chip Control Better chip evacuation Risk of chip clogging in blind holes Thread Quality Higher precision & surface finish Faster but less precise Material Suitability Works well in tough materials Prone to breakage in hard metals Machine Requirement Needs CNC with helical interpolation Can be done on manual or CNC machines
Practical Tips for CNC Thread Milling Use Correct Feeds & Speeds – Optimize RPM and feed rate based on material.Climb Milling Preferred – Produces better surface finish.Use Coolant – Prevents overheating and prolongs tool life.Check Tool Runout – Misalignment can cause poor thread quality.Consider Thread Depth – Deeper threads may require multiple passes.Need an Expert Partner for Your CNC Thread Millng Projects? If you require high-precision threads in complex or tough materials, partnering with an experienced CNC machining service ensures optimal results. Contact us for expert thread millng solutions tailored to your needs!
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