Manufacturers commonly use computer numerical control (CNC) milling machines for cutting, tapping, countersinking and cutting complex features. CNC milling machines help save time and money, allowing fabricators economic ways to transform objects into products. Here are key points to know about CNC machines and why they are widely used across many industries.
How CNC Machines Have Revolutionized Milling
Prior to the rise of CNC machines in the sixties, milling – or the cutting and drilling process to make tools – was done with manual tools. These days CNC milling machines with 2 to 5 axes are favored due to accuracy from computer programming. Axes are labeled letters such as X and Y, which associate with horizontal movement, whereas Z is used to reflect vertical movement.
Jobs can be completed much quicker without sacrificing quality. The machines are used for making parts in various industries such as aerospace and medicine. They are also commonly used for machine components, offroad components and prototypes. A milling machine has the capability of milling a wide variety of precision shapes on wood, plastic and metal that cannot be created manually.
Although CNC machines are capable of cutting through any type of object, it’s mainly used for cutting metal. There are multiple types of CNC machines that must be considered for any given assignment. Some machines are more appropriate than others for cutting thick metal.
Why CNC Machines Are Favored for Prototyping
A common use of CNC machines is to create a prototype of a new product. The machine can be programmed to make complex cuts quickly, making it useful when adjustments need to be made on prototypes. It’s the ideal choice for high volume repeatability. The machine relies on digital instructions from a CAM or CAD file.
The tools on a CNC machine are capable of doing the jobs of classic workshop machines such as grinders, drills and lathes. These machines come in different types, such as laser cutters, plasma cutters and water-jet cutters. CNC machines with laser cutters are becoming more widely adopted over traditional cutting tools for prototyping because they provide greater efficiency. Key benefits include easy testing, accurate replication and environmental sustainability. Using CNC machines reduces waste and costs of raw materials.
Cutting shapes, tapping, countersinking and drilling holes to make machine parts does not have to be a long drawn out process, which is why manufacturers are increasingly using CNC milling machines for prototypes and products. Contact us at Serra Laser for more information about how to meet deadlines on prototypes quickly using CNC technology.
A computer numerical control (CNC) milling machine is programmed with electronic tools including a dial and keypad to control mechanical devices such as drills, saws and lathes. A CNC machine is commonly used to manufacture industrial parts, such as engines. Computer-aided design (CAD) software is used to manipulate mechanical processes.
What CNC Milling Machines Manufacture
- Products made of metal, plastic, glass and wood
- Customized machine parts
- Precision cuts, curves and a wide range of shapes
Key Parts and Machining Process
The CNC milling process starts with a designing a CAD model. This model must then be converted into a CNC program. The operator then prepares the machine and executes the program. The primary components of a CNC milling machine are:
- Drill bits
- Limit switches
- A spindle
- Vise to clamp the stock in place
Parallels are strips of metal with a series of holes and are used to help mount stock in a vise. The vise should be cleaned with a brush since you need a flat surface for mounting a part. The stock is placed in the device and tightened with a handle.
The machine contains a door that opens and closes so that you can insert the stock. An edge finder tool is used to identify the stock’s location. The operator shuts the door and selects the manual data input (MDI) button from a menu viewed on the digital monitor. This menu allows you to select tool changes. You then type in the appropriate tool number and press the automatic tool change (ATC) button. The red emergency stop button is used when a part gets disconnected from the vise. The green start button resumes where the program left off.
Codes and Functions
A CNC milling machine translates programs identified by letters and numbers. G codes program moving parts while M codes turn devices on or off. Programming involves pressing buttons on a keypad starting with the program button. All programs start with the letter “O” and are numbered. These codes write instructions for the machine to perform specific functions using 16 building block tools. These tools control location, speed and other factors.
Designs can be cut seamlessly in various shapes from straight to circular patterns. At high speed, you can create complex designs in a matter of minutes. Location is determined by an X, Y and Z axis. The X, Y and Z buttons are controls for moving the parts, as X moves the table left and right, Y moves the table forward and backward and Z moves the spindle up and down.
You then set the edge finder, which works most efficiently at 1,000 rpm, with the door closed. If you want better visibility with the door open, it must be set at 750 rpm or lower. Modern CNC milling machines can get as fast as 12,000 rpm.
Here at Serra Laser, we can use CNC milling either to reverse engineer your part, or to draw specifications from scratch. Contact us to learn more about our capabilities.