Speeds and Feeds
Speeds (rpm) and Feeds (feed per tooth) are an important part of getting the most of your machine and your tools. Many factors have to be considered when selecting starting feeds and speeds. The following are general guidelines based on my experiences with the tools we sell.
Aluminum
Generally aluminum is a very forgiving material when it comes to feeds and speeds. Milling is by its very nature always an interrupted cut so chip control is not a concern. Turning can be very sensitive to small changes in feeds and speeds. Especially when performing boring operations.
Tri fly
Generally i reccomend starting rpm for the Tri Fly in aluminum to be 2500rpm Which is approximately 1300sfm (surface sped per min) And a chip load of .004-.006fpt.
Boring bar
When boring aluminum The most important factor is avoiding chip jamming in the bore. I normally bore aluminum at 600SFM and Feed .002-.0012ipt. this range is wide because boring bars come in many different sizes.
Solid endmill
Solid endmills are very versatile tools capable of excellent surface finishes in aluminum. Typically I Run 800-1200sfm And adjust feed based on specific manufacturer reccomendations.
Workholding
Workholding is a very important consideration when selecting feeds and speeds. If you are not confident in your workholding having a secure grip on the material you are machining approach with caution. Likewise if material is thin areas or has large areas of unsupported material reduction of SFM is usually a good idea. If you are having issues with chatter, try reducing the surface speed and take any actions you can to improve workpiece support and stability.
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You should also consider the rigidity and stability of your machine tool. Someone with a vmc such as a Haas Vf2 will be able to take much larger and faster cuts than someone with a tormach Pcnc 440. Additionally geared head knee mills such as a bridgeport series 1 will be able to take larger cuts than someone with a tormach pcnc 770.