End mills have to undergo a lot of stressful forces, especially when working at high speeds. Like all rotating tools, end mills have a tendency to wobble at high speeds. While this effect might not be visible to the naked eye, it can have a big impact on the performance of your tools. One of the most noticeable side effects of high speed milling is tool chatter. Variable end mills have made big steps in alleviating this problem.

What is Tool Chatter?
Tool chatter is a loud, screeching like sound produced by high speed machining. Because tools are naturally prone to oscillating, they end up applying different amounts of force against the surface of a workpiece. If you viewed a straight cut at slow motion, the tool would be wobbling and striking the surface harder or softer at different points in the cutting process. These tiny impacts create the sound known as chatter and the effects can range from irritating to deafening.

Is Chatter Dangerous?
When it comes to tool chatter, most of the issues are auditory. The sound can be extremely loud, just another reason why ear protection is so important around any milling machine. On top of producing an irritating sound, the effects of tool chatter can also have an impact on the finish of your cuts. The force of those tiny impacts can lead to machined surfaces that have an almost scale like pattern on the cut portions of your workpiece. This is especially obvious on soft materials like aluminum, though chatter can also impact the finish of harder materials like stainless steel. The effects of chatter tend to increase at high speeds and feeds.

Variable End Mills
The name of the game when it comes to preventing tool chatter is minimizing the vibrations that impact forces. One way to do that is to minimize how tools oscillate. Part of the reasons why tools oscillate is because they are subjected to regular impact forces of the cutting edges contacting your workpiece at perfectly even intervals. Variable tools are designed to be slightly asymmetrical, which helps to break up the internal vibrations caused by even impact forces. This asymmetry can be achieved using variable helix angle and variable flute end mills The end result is a significant reduction in vibration, which can help to cut down chatter without sacrificing your material removal rates.

If you are interested in finding some high performance variable end mills for your shop, you need to check out the cutting tools available at Online Carbide. Their variable helix end mills can help reduce chatter so you can get a clean finish on your workpieces. All of their tools are also constructed from solid carbide tool stock, a material that provides superior edge retention, tool life, and heat resistance compared to tool steels. You can see all of the tools available from Online Carbide by visiting their store at www.onlinecarbide.com.