CNC feed and speed for aluminum can make or break your machining results. If you use the wrong settings, you might end up with poor surface quality, excessive heat, tool wear, or even broken bits. In this article, you'll learn how to adjust your feed and speed for aluminum when using different cutting strategies and depths of cut.
Feed and speed are two of the most important parameters in CNC machining. Feed refers to how fast the tool moves along the workpiece, measured in inches per minute (IPM) or millimeters per minute (MM/M). Speed refers to how fast the tool rotates, measured in revolutions per minute (RPM) or surface feet per minute (SFM). Feed and speed affect the chip load, which is the amount of material removed by each cutting edge of the tool per revolution.
Aluminum is a soft and ductile metal that requires a different approach than harder materials like steel or titanium. Aluminum has a low melting point and high thermal conductivity, which means it can easily overheat and weld to the tool if the feed and speed are too low. On the other hand, if the feed and speed are too high, the tool can experience excessive wear and chatter, which can damage the workpiece and the machine. Therefore, finding the optimal feed and speed for aluminum is crucial for achieving a smooth and accurate cut.
Remember there are many different grades of aluminum. What works for one may not apply to another. Knowing your specific material grade will help determine best strategy,
There are various formulas and charts that can help you calculate the feed and speed for aluminum based on the tool diameter, number of flutes, material type, and desired chip load. However, these are only general guidelines that may not account for all the factors that affect your machining conditions, such as tool geometry, coolant, rigidity, and clamping. Therefore, it's always advisable to test your settings on a scrap piece of material and adjust them accordingly. A good rule of thumb is to start with a lower feed and speed and gradually increase them until you find the best compromise between performance and tool life.
Almost all cutting tool manufacturers provide guidance on how to not only select the right tool but best place to start your speeds and feeds.
During this process remember to evaluate your work holding, tool holder and the machines build, as these factors determine vibration dampening.
Different cutting strategies require different feed and speed settings to achieve the best results. For example, when roughing, you want to remove as much material as possible in the shortest time, so you need a higher feed and speed than when finishing, where you want to achieve a finer surface quality and accuracy. Similarly, when contouring, you need to reduce the feed and speed to account for the varying engagement angle of the tool, whereas when drilling, you need to increase the feed and speed to avoid clogging the flutes and breaking the tool.
Again always involve your tooling provider when you’re deciding strategy they can help point you in the right direction. You are not alone.
The depth of cut is another factor that affects the feed and speed for aluminum. The depth of cut is the distance that the tool penetrates into the workpiece per pass, measured in inches or millimeters. Generally, the deeper the cut, the lower the feed and speed should be, and vice versa. This is because a deeper cut increases the cutting force and friction, which can generate more heat and wear on the tool. A shallower cut reduces the cutting force and friction, but also increases the chip load and the risk of chatter. Therefore, you need to find the optimal depth of cut that balances these effects.
Usually refined through trial and error. If you prefer to get to the sweet spot quicker look at Blueswarf’s products they can help you identify the most effective speed, feed and cutting depths.
If you want to optimize your feed and speed for aluminum, you should use a sharp and coated tool that is designed for aluminum. A single-flute or two-flute end mill is preferable as it allows more space for chip evacuation and coolant flow. Climb milling is recommended, as it means the tool moves in the same direction as the workpiece feed, reducing the cutting force and heat. Additionally, you should use a constant chip load strategy and a mist coolant system to reduce the heat and lubricate the tool and workpiece. Doing so can improve tool life, performance, and the surface finish while reducing chatter.