CNC Machine Types

Benchtop CNC Mill

Benchtop CNC Mill

Many questions could be asked about the various types of machines available, and which kind is best suited for your needs. It is true that CNC controls nearly every kind of equipment imaginable, but we will focus on just a few of the most common types that relate to manufacturing. Selecting the right machine for the right task is crucial to the success of your project and goals. Bob Warfield, on his website www.cnccookbook.com, lists 3 of the most common types of CNC machines.

First, is the mill. Mills typically are associated with primarily metal cutting, and Warfield defines a mill as machine that moves the work piece about a stationary cutter head (“CNC Machine Overview and Computer Numerical Control History”, par 19). While this is not completely agreed upon as far as terminology goes, it is very typical that this arrangement is refereed to as a mill, and it will probably not lead to any confusion when talking with other machinists. Mills are usually upright, freestanding, and have a relatively small cutting travel area. Typically the spindles run very slow, such as 400-4000 RPM. Again, these setups are generally very heavy, very slow, but extremely accurate and rigid.

CNC Router

CNC Router

Next is the router. Routers are usually used for cutting wood and plastics, but many would define a router as a machine where the work piece stays stationary,  and the cutter head moves about the work area via a gantry (par 21). Routers are typically relatively light weight compared to a mill, have very fast rapid speeds, and cut at a very high RPM, such as the 13-20K range. Routers often perform very repetitive tasks, such as cutting parts out of large sheets. Accuracy and rigidity are considerably less then their mill counter-parts, but still are extremely effective when it comes to quickly cutting a product where tolerances are more fogiving.

CNC Lathe

CNC Lathe

The final CNC we will talk about is the lathe. Lathes turn a workpiece around a center axis, and use cutter to remove material from a workpiece as it turns (par 16). Typically lathes are used for creating round or cylindrical parts, although a clever machinist can use them for much more. Lathes often get over looked, but as you begin to look around in the machine world around you, you can see how they become almost a necessity for certain parts manufacturing.

CONCLUSION
There is no such thing as a “one tool for everything.” Thankfully, you probably already have a good idea of what your needs are, and from this summary can determine which type of machine (or machines) are suited for your needs. Also keep in mind, milling and routing can certainly over lap in some areas. Be careful- I would not try to mill hardened steel with a router- but there are certainly many times and projects where either machine would fit the bill. Choose the one that you will use the most.