Maximizing Milling Operations With the Right Cutter

When it comes to increasing the productivity of milling operations, several factors are in play, including toolpaths, feeds and speeds, and cutting tool selection. Whether the application requires roughing, facing, slotting, holemaking, finishing or all of the above, choosing the right cutting tool can boost metal removal rates without sacrificing precision.

In this article, we’ll cover three popular milling cutters — 90-degree, 45-degree and high-feed mills — and how they increase milling efficiency, if they’re deployed for the right application.

High-Feed Mills: The Roughing Powerhouse

High-feed mills ensure shops don’t leave money on the table during roughing operations. These tools, including Kyocera’s MFH Raptor, are designed to chew through material, making quick work of even the toughest parts. But it’s not just about speed — it’s about precision under pressure. Here are three benefits of high-feed mills:

1. Speed: High-feed mills use the chip thinning principle, enabling users to feed at higher speeds without overloading the machine. “Each insert has a lead angle that can be fed extremely fast into the workpiece, thinning out the chip and allowing for a much higher feed rate,” explains Justin Wilkes, regional sales manager at Kyocera. Getting chips out of the way enables clean feeds and faster cuts.

2. Longer Reach: The angled inserts that thin chips also direct cutting forces back into the tool, minimizing chatter and deflection, even on long, tricky reaches.

3. Precision: From plunging to pocketing, 3D surfacing to helical interpolation, tools like the MFH Raptor balance high material removal rates and precision .

But high-feed mills require high feed rates. If a machine tool can’t keep up , users won’t see the tool’s full potential. In these cases, a 90-degree or 45-degree cutter would be a better fit.

90-Degree Cutters: The Multitasker

Parts with complex geometries and tight tolerance requirements already pose a challenge, but this scenario often occurs with little space to maneuver around the fixturing. A 90-degree cutter, such as Kyocera’s MA90, provides versatility and can navigate tricky setups while delivering accurate cuts. Here are four advantages of 90-degree cutters:

1. Multitasking: A 90-degree cutter can perform a range of operations, from facing and slotting to enlarging holes. They’re also flexible in terms of machines. “90-degree cutters can be applied in many different types of machine tools, from heavy-duty to light-duty, manual to CNC,” Wilkes notes. “They’re extremely versatile.”

2. Space-Saving: Unlike 45-degree or high-feed mills, 90-degree cutters excel at cutting close to fixtures, making them perfect for setups where access is restricted .

3. Strength: 90-degree mills such as the MA90 are equipped with tangential inserts, offering four cutting edges for more cuts and less cost per edge. These cutters are built for strength , delivering clean sidewalls and face finishes even in tough materials.

4. Ramping: While most 90-degree cutters are not designed for ramping, the MA90 can ramp straight into a workpiece. This feature enables users to pocket or slot without a pre-drilled entry hole, saving time and reducing tool changes.

45-Degree Face Mills: The Speed and Finish Specialist

A 45-degree face mill like Kyocera’s MB45 is designed to balance power and economy, providing faster feeds, smoother finishes and lower cost per part. Here are three perks of 45-degree face mills:

1. Economic: With multiple cutting edges per insert, 45-degree face mills have more tool life. They remove more metal for every edge used, which means more cash in the user’s pocket. “Each insert has multiple cutting edges,” Wilkes says, “so you can increase economy while still getting a smooth workpiece finish.”

2. Speed: A 45-degree cutter can handle higher feed rates than a 90-degree option, making it a go-to for general facing when speed matters .

3. Surface Finishing: The MB45 45-degree tool doesn’t just remove metal; it leaves a smooth surface finish thanks to the wiper flats on each insert. “45-degree face mills strike an ideal balance between metal removal rate and economy, while still providing a great surface finish,” Wilkes points out.

But for applications that require getting close to fixtures or reaching around awkward geometries, the 45-degree mill may not cut it (literally). A 90-degree cutter or possibly a high-feed mill are better suited to handle these tasks.