Roughing End Mills
Roughing End Mills have scallops on the cutting edges, which cause the chips to break into smaller segments. This results in lower cutting pressures at a given radial depth of cut. They are designed to remove large amounts of material quickly and more efficiently than standard end mills.
The distance between scallops is referred to as pitch. Haas roughing end mills come in fine- and coarse-pitch versions. Fine-pitch scallops are smaller and better for lighter cuts in hard materials. The fine-pitch end mills leave a better finish, and don’t require as much stock to be left to clean up with a finish pass using standard end mill. Deep slotting or deep profile applications with a lot of metal removal in softer steel are perfect for coarse-pitch roughing end mills. The coarse pitch also works great on nonferrous materials, like aluminum.
Available Coating:
Titanium Aluminum Nitride (TiAlN) is an outstanding coating that provides excellent wear resistance, especially in high-temperature applications. It is good for hard materials like pre-hardened alloy steels up to HRc45.
Aluminum Chromium Nitride (AlCrN) has remarkable wear resistance at lower speeds and feeds, as well as tremendous heat resistance at high speed. It is the coating of choice for titanium and high-temperature alloys.
Titanium Carbon Nitride (TiCN) provides excellent abrasive resistance, and hardness to the cutting edge. It does not perform well at very high temperatures, so properly applied coolant is a must. This coating is perfect for aluminum and abrasive high-silicon aluminum alloys.
Roughing end mills create a LOT of chips, and there is no faster way to prematurely wear out an end mill than recutting chips. A strong stream of coolant or compressed air should always be used to clear chips from the cutting zone.
Control Your Chips! Chip Splitters and Roughing End Mills
When you're machining pockets with an end mill it's not uncommon to get a stack of chips in the pocket that's hard to get out. Mark takes a look at several styles of end mills that cut your chips into smaller pieces, making them a lot easier to get out of the pocket before your end mill gets damaged re-cutting those same chips.
Haas End Mill Series
Coarse-Pitch Roughing (CPR)
CPR series milling cutters are coarse-pitch HSSCo8 (High-Speed Steel with 8% cobalt) roughing end mills. These general-purpose roughers are designed for high-production metal removal in a wide range of workpiece materials. Most are Titanium Aluminum Nitride (TiAlN) coated, but the larger 2-inch roughers are uncoated. They are recommended for cutting steel grades, and many non-ferrous materials. The ends of these tools have center holes, allowing them to be held between centers for accurate resharpening multiple times.
Fine-Pitch Roughing (FPR)
FPR series milling cutters are fine-pitch HSSCo8 (High-Speed Steel with 8% cobalt) roughing end mills with Titanium Aluminum Nitride (TiAlN) coating. These general-purpose roughers are designed for high-production metal removal in a wide range of workpiece materials. They are suitable for a very broad range of materials having up to high tensile strengths. In many cases, the milled surfaces are of acceptable quality, without a finishing pass.
Coarse-Pitch Roughing Aluminum (CPRA)
CPRA series milling cutters are coarse-pitch HSSCo8 (High-Speed Steel with 8% cobalt) 3-flute, 37° helix roughing end mills. These tools are designed specifically for aluminum, although they are suitable for a very broad range of materials having up to high tensile strengths. In many cases, the milled surfaces are of acceptable quality, without a finishing pass. The Titanium Carbon Nitride (TiCN) coating provides excellent abrasive resistance, and hardness to the cutting edge, making it the perfect coating for aluminum and abrasive high-silicon aluminum alloys. It does not perform well at very high temperatures, so properly applied coolant is a must.
Sinusoidal High-Temperature Roughing (SHTR)
SHTR series milling cutters are HSSCo8 (High-Speed Steel with 8% cobalt) end mills specifically designed to rough titanium alloys used in the aerospace and power-generation industries. The sinusoidal geometry outperforms standard roughing end mills, by allowing higher metal-removal rates with increased feeds, and producing better surface finishes.
The engineered flute geometry provides optimal chip formation and evacuation, while reducing friction and heat generation. The variable flute profile and sinusoidal cutting edges reduce vibrations and chatter, while allowing large cut depths in slotting and profile-milling applications. A standard chamfer on the corners protects the edges from premature wear. The smaller cutters are coated with a Hybrid Aluminum Chromium Nitride (AlCrN) coating, providing remarkable wear resistance at lower speeds and feeds, as well as tremendous heat resistance at high speed. The larger diameter cutters are uncoated.
Fine-Pitch Carbide High-Helix (FPCHH)
FPCHH series milling cutters are fine-pitch carbide roughing end mills that come in two styles: a 30° helix, and a 45° helix version. Both are designed to cut exotic materials, such as stainless steels, nickel alloys, and titanium.
The Titanium Aluminum Nitride (TiAlN) coating makes them the perfect choice for rough milling applications on all steels up to HRc45, as well as the exotic materials listed above.
The lower helix-angle version has a larger core, to enhance the strength of the cutter to better resist deflection. The higher helix-angle version produces smaller chips, due to less engagement length, and therefore can evacuate the chips more efficiently, especially given the lower RPM necessary on the nickel and titanium alloys. The corners also have a reinforced cutting edge, and all sizes are center-cutting.
Fine-Pitch Carbide Low-Helix (FPCLH)
FPCLH series milling cutters are fine-pitch carbide roughing end mills featuring a 20° helix, and a modified Aluminum Chromium Nitride (AlCrN) coating that make them the perfect choice for rough milling applications on pre-hardened steels up to HRc55, mold-and-die steels, and cast iron.
The low helix angle enhances the strength of the cutter, because the core is larger, to better resist deflection. The corners have a 45° angle to reinforce the cutting edge, and all sizes are center-cutting.
Recent upgrades include higher-quality raw material, the use of a proprietary advanced honing technology, and a modified Aluminum Chromium Nitride (AlCrN) coating. All together, these upgrades improved wear resistance an average of 67% in testing on HRc35 mold steel.
The aluminum chromium-based coating has very high thermal shock stability and great wear resistance. It remains thermally stable up to 1100 degrees Celsius, so it’s good for wet or dry machining, and excellent in high-speed machining applications.