Milling is a process that uses rotary cutters to systematically shear, bore, and shape a variety of materials, especially metals. On a CNC milling machine, computer software controls the rotary drill to move along multiple axes, allowing the machine to manufacture pieces that would be hard to produce manually. Most CNC milling machines operate their tooling on 3 to 5 geometrical axes. For example, vertical milling machines will have the common X, Y, and Z axes. The X and Y axes control horizontal movements of the tool, while the Z-axis controls the vertical movement. In a vertical machine, the spindle is fixed and has a bed that moves horizontally and vertically.

 Typical 3-Axis vertical machine

Meanwhile, horizontal milling machines will have additional axes, usually a W and B-axis. The W-axis allows for a cross-slide or diagonal movement of the Z-axis, while the B-axis allows for a rotation of the Y-axis. Horizontal milling machines usually have rotating beds, allowing for cutting pieces at multiple angles.

Multi-Axis hortizontal machine. The numerous axes allow for cutting at multiple angles on a single piece.

While there are machines with additional axes, most have 3 to 5. The specific milling machine you choose will vary according to your business needs.

What to look for in a Milling Machine: CNC milling machines can be used on several types of work materials, but they are usually employed to shape metals. Whether buying a new or used machine, the type of materials you work with should be factored in before committing to buying. For example, when working with heavier metals, like cast iron, that need to be moved while cutting, a horizontal machining center may be a better choice than a vertical, whose spindle is static. Similarly, if you need to cut a piece at multiple angles, an HMC may be a better choice than a VMC because of their rotating beds. If you are working with smaller and lighter metals, such as aluminum, a vertical machine will work fine. If you choose to purchase a used milling machine, know what qualities to look for before committing to buying. 

Parapass SL -80 Hortizonal Milling Machine

When shopping for a CNC milling machine, ensure that the cutters and other tooling used will able to handle that type of material you will be working on. For example, if you are working with a heavier metal, you will need tooling that withstands heat well, as cutting causes friction, which will heat up the tooling.

 If you have questions about choosing the right used milling machine, contact an MMI sale representative.