Basics of lathe

. Metric (Metric) and Imperial Programming

There are two types of length unit sizes used on CNC lathes, metric (metric) and imperial, and the length unit sizes are set by special instruction codes, such as the FANUC-0TC system with G20 to indicate the use of imperial unit sizes and G21 to indicate the use of metric (metric) unit sizes. When the system is powered on, the machine is automatically in the metric sizing state.

2. Diameter Programming and Radius Programming

(1) Diameter Programming: When using diameter programming, the coordinate value of the X-axis in the CNC program is the diameter value on the part drawing.

(2)Radius Programming: With radius programming, the X-axis coordinate value in the CNC program is the radius value on the part drawing. Considering the convenience of use, generally use the diameter programming. the default programming method of CNC system is diameter programming.

a) A:(30.0,80.0), B:(40.0,60.0) b) A:(15.0,80.0), B:(20.0,60.0)

3. The front tool holder and rear tool holder of the lathe

There are two forms of tool holder arrangement of the CNC lathe:

(1) Front tool holder. The front tool holder is located in front of the Z-axis, the same as the traditional horizontal lathe tool holder arrangement, the tool holder guideway for the horizontal guideway, the use of four-station electric tool holder;

(2) rear tool holder. Rear tool holder is located at the back of the Z-axis, the position of the guide rail of the tool holder is tilted with the positive plane, this structural form is easy to observe the cutting process of the tool, chips are easy to exclude, the rear of the space is large, can be designed for more stations of the tool holder, general multi-functional CNC lathes are designed for rear tool holder.

4. Tip radius compensation

In the CNC turning programming for programming convenience, the tip of the tool as a point, the CNC program tool trajectory that is the hypothetical tip of the trajectory.

The CNC system introduces tip radius compensation: after the CNC program is written, the known tip radius value is entered into the tool compensation table, and the CNC system automatically compensates for the actual trajectory of the tool according to the corresponding tip radius value when the program is running.

CNC machining generally use indexable inserts, each insert tip radius is certain, the selected insert type, the corresponding insert tip radius value can be determined.

Tip radius compensation instruction:

Instruction format G41 (G42, G43) G01 (G00) X (U)_Z (W)

Instruction function G41 is the tip radius left compensation;

G42 is the tip radius right compensation;

G40 is to cancel the tip radius compensation.

Instruction Description Viewed in the direction of tool movement, the tool on the left side of the workpiece is tip radius left compensation; the tool on the right side of the workpiece is tip radius right compensation. The tip radius compensation can be established and canceled only by the linear movement of the tool.

5. Initial state of the CNC machine

Initial state: refers to the state of the CNC machine after power on, also known as the default state of the CNC system, generally set the absolute coordinates of the way to program, the use of metric length units of the outline, cancel the tool compensation, the main spindle and the cutting fluid pump to stop the work of the state as the initial state of the CNC machine.