Welcome to our simple guide on the G114.2 CNC code. Whether you are new to CNC programming or an experienced machinist, understanding the G114.2 code is essential.
This guide will explain everything you need to know about this unit mode command—what it is, when to use it, and why it matters.
(Step-by-step.)
Key Takeaways
- G114.2 is a CNC code that defines a canned cycle for milling a circular pocket with a subprogram for user-defined pocket geometries.
- The code requires specifying the coordinate system, including the X, Y, and Z axes, for precise control over the machining process.
- G114.2 consists of a series of movements that the tool follows to create the circular pocket, with the feed rate determining the tool’s movement speed.
- The code allows for complex pocket milling operations with a single block of code, making it ideal for advanced milling operations.
- G114.2 is used in conjunction with other G-codes, such as G01 and G02, to create complex geometries and precise movements in CNC machining.
Understanding G114.2 CNC Code
You’re likely familiar with G-code, the programming language used to control CNC machines.
G114.2 is a specific type of G-code that defines a canned cycle for milling a circular pocket. When writing G114.2 code, you’ll need to specify the coordinate system, including the X, Y, and Z axes.
You’ll also need to set the feed rate, which determines how quickly the tool moves along the specified path. The canned cycle consists of a series of movements that the tool follows to create the circular pocket.
The code will specify the end point of each movement, ensuring precise control over the machining process. By carefully crafting your G114.2 code, you can achieve accurate and efficient results in your CNC machining operations.
Gear Cutting Processes Explained
Five primary methods are used in gear cutting processes: hobbing, broaching, milling or grinding, shaping, and skiving.
Each method has its own strengths and weaknesses, depending on the specific gear cutting task at hand.
- Hobbing is ideal for medium to high production runs, using a hob to cut teeth into a blank.
- Broaching is perfect for very large gears or splines and high production runs, using a vertical broach with a single tooth cutter.
- Milling or grinding is suitable for spur gears, using a numbered gear cutter on a milling machine or jig grinder.
- Shaping works well for low and high production runs, mounting a gear blank in a shaper and using a tool shaped in the profile of the tooth to be cut.
- Skiving is another gear-cutting process, although less common than other methods.
Mill G-Codes and Circular Interpolation
Mill G-codes and circular interpolation are essential components of CNC machining, allowing you to create complex curves and arcs with precision.
When using circular interpolation, you’ll employ G02 and G03 G-codes, which define clockwise and counterclockwise motion, respectively.
To specify the arc or circle, you’ll need to include optional address codes. These include I, J, and/or K to define the center of the arc relative to the starting point, and X, Y, and/or Z to define the end point of the arc within the current coordinate system.
The I J K values represent relative X Y Z distances from the starting point to the center of the circle, while the X Y Z values represent absolute distances to the end point of the arc.
Cutter Compensation and Feed Adjustments
When working with circular interpolation, you’ve likely encountered situations where the cutter’s path needs adjustment to maintain precise dimensions.
This is where cutter compensation and feed adjustments come in.
- Cutter compensation (G41 and G42) shifts the cutter by an exact amount for exact print dimensions, turning on during G01 X,Y moves ≥ cutter radius and turning off using the same rules.
- Feed adjustments are made when the cut is on the inside of circular motion, but no speed-up adjustments are made when the cut is on the outside of circular motion.
- The rules for cutter compensation include turning on during G01 X,Y moves ≥ cutter radius, turning off using the same rules, and not being able to turn on/off in G02/G03 circular moves.
- Setting 44 limits feed adjustment percentage (1%-100%) when using cutter compensation in circular moves.
- G02 and G03 are used for circular interpolation (clockwise and counterclockwise), with G41 and G42 cutter compensation used to shift the cutter by an exact amount for exact print dimensions.
Special G-Codes for Advanced Milling
Most CNC milling operations rely on a set of standard G-codes to control machine movements and perform various tasks. However, for advanced milling operations, special G-codes like G114.2 are used. This G-code is specifically designed for circular pocket milling with a subprogram to machine user-defined pocket geometries.
| G-Code | Function | Description |
|---|---|---|
| G114.2 | Circular Pocket Milling | Mills circular pockets with a subprogram |
| G01 | Linear Interpolation | Moves the machine in a straight line |
| G02 | Circular Interpolation | Moves the machine in a circular motion |
When using G114.2, you must guarantee the subprogram geometry is a fully closed shape, and the X-Y starting point is within the boundary of the shape. This code allows for complex pocket milling operations with a single block of code, making it a useful tool for efficient and precise machining. You must also verify the subprogram geometry is a fully closed shape, and the X-Y starting point is within the boundary of the shape.
CNC Codes Similar to G114.2
|
Code
|
Mode
|
|---|---|
| G114.3 | Gear hobbing |
| G113 | Polar coordinate interpolation cancel mode |
| G112 | Transforms lathe into virtual milling machine |
| G111 | G code macro CALL type |
| G110 | Constant speed cutting on turret A |
| G115 | Start point queuing (Type 1) or Queuing during an axis movement (Type 1) |
| G116 | Tool change macro |
| G117 | Execution of CNC codes during an axis movement |
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