MX Series Speeds and Feeds Chart – 4 & 6 Flute End Mills
MX Series tooling data should be read as a controlled machining reference, not as a casual setup suggestion. For shops cutting stainless steel, titanium, alloy steel, die steel, cast iron, and high-temperature alloys, the MX series end mill speeds and feeds chart gives programmers a measured starting point for cutter speed, feed rate, flute count, and material response. Each value still requires shop-floor verification. Holder rigidity, coolant access, machine condition, tool projection, radial engagement, and material hardness decide whether a chart value becomes a safe production parameter or only a first trial setting.
About the MX Series End Mills
CGS MX Series end mills are built for difficult milling conditions where strength, chip control, and repeatable edge behavior matter. Their 4 flute and 6 flute formats give programmers different operating choices depending on part geometry, finish expectations, toolpath style, and machine stability.
A 4 flute cutter often gives better chip space in heavier cuts, especially where evacuation and heat control are active concerns. In that context, 4 flute end mill speeds feeds must be set with attention to chip thickness rather than speed alone. A feed rate that appears conservative can still create rubbing when the chip load falls below the cutter’s working range.
A 6 flute cutter changes the pressure profile. More cutting edges can support higher feed rates during controlled radial engagement, yet flute crowding may create risk during slotting or poor evacuation. For that reason, a 6 flute carbide end mill chart should be applied with close review of radial width, axial depth, coolant method, and programmed entry motion.
MX Series Speeds and Feeds by Material
Material grouping is the first control point. Alloy steel, stainless steel, titanium, and die steel do not respond to the same cutter speed or feed pressure, even when tool diameter remains unchanged.
For 4140, 4340, and similar steels, alloy steel milling feeds should be separated by hardness condition. Softer stock may allow a higher operating window, while hardened material increases cutting force, edge pressure, and tool wear. Shops running mixed heat lots should record hardness before approving repeat parameters.
Stainless steel creates a different liability. Work hardening and heat concentration can punish both excessive speed and timid feed. A valid stainless steel end mill SFM selection should support cutting action without polishing the material. Once rubbing begins, tool life can fall quickly.
Titanium requires tighter heat discipline. Since titanium holds heat near the cutting zone, titanium end mill speeds feeds must be paired with controlled engagement, proper coolant or air strategy, and conservative startup review. Cutter extension matters here. Long reach can turn an acceptable chart value into chatter, deflection, or edge fracture.
Die steel demands a cautious record trail. Published die steel milling parameters may serve as a baseline, yet cavity depth, finish requirement, hardness, tool reach, and interrupted contact can force reduction before production release.
High vs Low SFM Values Explained
High and low SFM values are not quality labels. They are operating bands tied to machine condition, setup rigidity, cutter engagement, material behavior, and risk tolerance.
High SFM values may be suitable when the machine is rigid, the holder is accurate, coolant delivery is stable, the toolpath avoids overload, and the material condition has been confirmed. A clean side-milling pass on a stable setup can often operate closer to the upper reference range.
Low SFM values belong where uncertainty exists. Long projection, hard material, poor evacuation, interrupted cuts, deep cavities, thin walls, or limited coolant access can justify a lower starting speed. Conservative speed control is not inefficiency. It is evidence-based process protection.
We verify speed selection against tool diameter, flute count, radial engagement, programmed feed, and first-article results before using a chart value for repeat production.
Slotting vs Profile Milling Adjustments
Profile milling and slotting create different load conditions. A profile pass usually allows chip escape away from the cutter, especially when radial engagement stays controlled. Slotting places the cutter in a full-width condition, increasing torque demand, chip packing risk, heat retention, and deflection.
Because of that, slotting parameters should not be copied directly from profile milling values. Feed reduction, speed adjustment, pecking strategy, coolant access, and chip evacuation must be reviewed before approval.
Controlled parameter records should include these items:
- Cutter diameter and flute count confirmation before setup release
- Material grade and hardness record attached to the work order
- Radial width and axial depth documented for each toolpath family
- Slotting reduction recorded when full-width cutting is present
- Coolant or air method noted with pressure and access limitations
- RPM and IPM calculation retained with program revision
- First-article inspection feedback tied to final production values
- Tool wear review after the first qualified run
No chart can correct an overloaded toolpath. Program review remains part of risk control.
RPM & IPM Conversion Formulas
RPM and IPM should be calculated through a closed chain, not guessed from old setup sheets. Surface speed, cutter diameter, chip load, flute count, and feed rate are linked values.
The standard RPM formula is:
RPM = SFM × 3.82 ÷ cutter diameter
The standard feed formula is:
IPM = RPM × flute count × chip load per tooth
A small diameter change can shift spindle speed sharply. A flute count change can move feed rate just as quickly. When a 4 flute program is converted to a 6 flute cutter, the feed calculation must be reviewed rather than copied.
We execute direct calculation checks where tolerance sensitivity, high material cost, or contractual inspection risk is present. Documentation protects the process.
Download the MX Series PDF
The MX Series PDF should be kept with setup documentation, programming notes, and controlled machining records. For repeat jobs, the PDF value, trial adjustment, approved production setting, material lot, holder assembly, coolant method, and inspection result should remain connected.
CGS MX Series speeds and feeds provide the operating baseline. Verified shop data turns that baseline into a reliable production record.
Frequently Asked Questions
What is the recommended SFM for milling titanium alloys with MX series end mills?
For titanium alloys, the MX chart lists 250 SFM under HIGH and 212 SFM under LOW. Start at the lower value when rigidity, coolant, tool reach, or material condition is uncertain.
How much should I reduce feed for slotting operations?
For slotting, reduce the charted speed and feed values by 20 percent. Slotting loads the cutter across its full width, so chip evacuation, torque, heat, and deflection need tighter control than profile milling.
What is the difference between HIGH and LOW SFM values in the MX chart?
HIGH values are intended for optimum working conditions, including solid fixturing, stable coolant, rigid holders, and controlled engagement. LOW values give a safer starting point when the setup has uncertainty or the cut may run hotter.
Are MX series end mills suitable for high temp alloys like Inconel?
Yes. The MX chart includes a high temperature alloys category for difficult heat resistant materials such as Inconel applications. Use the listed range carefully, since these alloys punish poor coolant access, long reach, and aggressive engagement.
How do I convert SFM to RPM for my machine?
Use the formula RPM equals 3.82 multiplied by SFM, then divided by cutter diameter. For example, a smaller cutter needs more RPM at the same SFM, so always recalculate after diameter changes.