Interpolation in Numerical Control Machining
Numerical control machining (NC) is a process used in the manufacturing of machinery and other components that involves the use of computer-controlled numerical codes to program machines to cut particular shapes from a material such as metal. In NC machining, the operator uses CAD/CAM software to generate an NC (numerical control) program from a 3-D model of the part being machined. This program contains a series of numerical codes that control the movements of the machines to cut the desired shape. Interpolation is an important part of NC machining and is used to create smooth and precise curves and shapes.
Interpolation is the process of locating a point that lies in between two other points, such as on a curve or a line. In NC machining, the NC program contains G-codes that tell the machine where to move on a three-dimensional coordinate plane. The machine must be able to interpret these codes in order to find its way back and forth between points on the plane. Linear interpolation is used when the machine is moving along a straight line between two points, while circular interpolation is used when the machine is moving in a circular or curved trajectory.
In linear interpolation, the machine calculates the exact angular difference between the two points, and the distance between them. It then uses this information to determine the rate of change of the coordinates along the straight line connecting the two points. This rate of change is the slope, or the amount of increase in the x or y coordinate value for each change in the z coordinate. Once the slope is known, the machine can move in a linear path along the line.
Using circular interpolation, the machine calculates the exact coordinates of three points on the circle: the starting point, the ending point, and the center point. Then, the machine calculates the distance between each of these points and the circles center. Using this information, the machine is able to calculate the exact location of a point on the circle at any given angle. It then uses a G-code to tell the machine the exact coordinates of the point that the operator wants to move to. As the machine moves in a circular path, the coordinates of each point on the circle is calculated and used as the control input to the machine.
By utilizing both linear and circular interpolation, NC machining can be used to create precisely curved and irregular shapes. Due to the high degree of accuracy, NC machining is often used in rapid prototyping and for the production of components for the aerospace, automotive, and medical industries. With the use of these interpolation techniques, machines can now produce parts with higher precision and accuracy than ever before.
