Manual machinists know that if you want a fine finish, you’ve got to use a fly cutter. While CNC machinists may rely on face mills, the savvy know that you just can’t beat the finish you get from a CNC fly cutter.
CNC Face Mill versus CNC Fly Cutter
In a previous blog post on Fly Cutters for Precision we mentioned that “the finest aluminum finishing is a fly cutter with a diamond insert”. If it’s true for a manual machinist, its true for a CNC machinist. A face mill may run at a higher speed, but you want a slower speed for a beautiful, brushed finish. Also, the only way to really get a face mill to give you that finish with no run out is to remove all the cutters except one. In effect, you are turning your CNC face mill into a CNC fly cutter. The face mill set up won’t remove material as quickly, but it will leave a nicer surface finish.
A fly cutter can get into places your face mill can’t. For example, check out this link to see an application where a fly cutter was used to resurface the table for a table saw. Only the use of a fly cutter allowed him the travel he needed to get the job done.
So why are you using a face mill when a CNC fly cutter is the better tool for the job?
Tips for Machining with CNC Fly Cutters
If you follow these tips, you can handle even the toughest to machine materials like titanium or stainless steel and get a flawless finish.
Feeds and Speeds – Use the right feed and speed and you can machine almost anything. Difficult materials are only difficult because of the small range in which they can be machined. Make sure the calculator you use can account for all the variables.
Coolant – Some materials machine better with coolant and some material require coolant. Use some form of coolant, even if it is a mist. It will help stainless reduce hardening, it will prevent aluminum chips from welding to the cutter, and prevent heat build-up in titanium.
Keep Chips Clear – Whether you are using a liquid coolant or an air mist, make sure you keep chips clear. Recutting chips that aren’t cleared just makes the job harder for your tool. No matter the method, clear chips as fast as they are made.
Use the Right Cutter
No matter your machine or material, make sure you use the right cutter. Sierra American has fly cutters in 1½”, 2”, and 2 ½” diameters. They are manufactured with alloy screws to reduce chatter. If your feed and speed calculations require high RPMs, its not a problem for the Sierra American fly cutter as they are balanced for higher RPM usage.
Sierra American fly cutters are manufactured in the USA and come with a 5 year warranty. If your local tool supply does not carry Sierra American, let them know you demand quality and you demand Sierra American fly cutters. You can call (800) 576-5331 to find a dealer near you or use the Contact Us form.