CNC Mill Operation - Produced by Glacern Machine Tools - A Crash Course - Chapter 3

A Vertical Machining Center (VMC) is an automated CNC milling machine. Various tools can be held in the cartridge spindle. A pull stud is threaded into the back of each tool holder. An electronically actuated drawbar interfaces with the pull stud to quickly release the tool from the spindle, or to firmly secure the tool in the tapered spindle socket. This method of tool retention offers high reliability making it ideal for use with automatic tool changers.

The electrical cabinet mounted to the back of the machine contains most of the electronic components. The control panel provides a user interface for various operations. When set to automatic mode, the machine reads programs stored in memory. Programs typically contain many lines or blocks of code, and each block contains instructions for various machining operations.

With the machine in MDI (Manual Data Input) mode, blocks of code are written one by one on the keypad, often for setup and diagnostic purposes. S100 M03 rotates the spindle in the forward direction at 100 RPM. S5000 speeds up the spindle to 5000 RPM. M05 stops the spindle. Replacing M03 with M04 rotates the spindle in the reverse direction. Electronic hand wheels called Manual Pulse Generators (MPG) are used to manually position the machine table or spindle to exact locations.

An MPG mounted to a Control Pendant allows the operator to get closer to the machine for a better view. Jog and Rapid buttons are used for quick rough positioning of the table and spindle.

Coolant pumps can be activated with the keypad or with an M08 code. Water-soluble coolant is used to remove heat and clear chips - as well as periodic machine washdowns. Chips are removed by conveyors; auger type, flat-belt type or both.