Knowledge & Community You are here

You’ll want to go with a long-length end mill designed for aluminum and choose polished flutes to help with chip evacuation. A 2- or 3-flute tool works best for this. For chatter, using a variable helix end mill will help. It disrupts the vibration of standing waves. Also, consider roughing the cavity with a larger tool, leaving a small stock for a finishing pass.

For aluminum 6061, keep the surface speed around 400-600 m/min, depending on your tool. Use a moderate feed per tooth—0.05 mm/tooth is a good starting point. Coolant is crucial. Flood cooling works well, but if chip evacuation is still an issue, consider air blasting or a high-pressure coolant system. A pecking or trochoidal milling strategy can also improve chip clearance while reducing heat buildup.

[Lyn Stewart]

Hi all, I’m machining 60 mm deep, 20 mm diameter cavities in Aluminum 6061 with ±0.05 mm tolerances. Issues like chatter, tool deflection, and poor chip evacuation make it tricky, and I’m concerned about overheating and tool wear. Do you have any advice on tool selection, speeds/feeds, cooling, or strategies to balance precision and efficiency?

0

[J Kalberg]

That’s a challenging need – 60 mm depth at ±0.05 mm tolerance is pushing it, especially allowing for chatter and tool deflection. First, the depth-to-diameter ratio is 3:1, which is on the edge of manageable, beyond ideal. With higher aspect ratio cavities, precision is harder, and machining time and tooling costs rise. Can you split the machining into multiple stages to reduce the effective depth per pass?

0

[Lyn Stewart]

That’s a good approach. What tools would you recommend for moderating deflection and chatter at that depth? How about speeds, feeds, and cooling?

0

[J Kalberg]

You’ll want to go with a long-length end mill designed for aluminum and choose polished flutes to help with chip evacuation. A 2- or 3-flute tool works best for this. For chatter, using a variable helix end mill will help. It disrupts the vibration of standing waves. Also, consider roughing the cavity with a larger tool, leaving a small stock for a finishing pass.

For aluminum 6061, keep the surface speed around 400-600 m/min, depending on your tool. Use a moderate feed per tooth—0.05 mm/tooth is a good starting point. Coolant is crucial. Flood cooling works well, but if chip evacuation is still an issue, consider air blasting or a high-pressure coolant system. A pecking or trochoidal milling strategy can also improve chip clearance while reducing heat buildup.

0