For parts with complex shapes and high precision requirements, CNC machine tools are typically used for machining. CNC machining is automatically completed by a CNC system under program control. The key to program development is calculating the tool's motion trajectory, i.e., calculating the coordinates of the base points and nodes of the machining contour. CNC systems generally only provide linear interpolation and circular interpolation functions. For non-circular planar curves y=f(x), the contour curve is approximated by a straight line or circular arc according to the programmed allowable error. The coordinates of the intersection or tangent points of the approximating straight line or circular arc with the contour curve are calculated. When using circular arcs as interpolation segments, the coordinates of the center of each segment must also be calculated. Manual and Automatic Programming for Machining an Adjustment Device Disc As shown in Figure I, the adjustment device disc has six Archimedean spiral grooves evenly distributed on its surface, with a starting point of φ40 and an ending point of φ100, rotating 300 degrees. The lifting distance is 30. The key to CNC machining of this adjustment device disc is the CNC program development for the Archimedean spiral grooves on its surface. Therefore, this paper focuses on discussing the design method of its machining program. The polar equation of the Archimedean spiral is given as: p = p0 + α × θ, where p0 is the base circle radius, equal to 20, and θ is the spiral angle. From the given conditions in the drawing, α = 0.1 can be calculated. Substituting this into the polar equation, we get p = 20 + 0.1 × θ. For manual programming, the equal-distance method is used to calculate the nodes by approximating the curve with a straight line. The spiral angle is divided into equal intervals Δθ, θi+1 = θi + Aθ. According to the polar equation, PI is obtained from Δθ, which represents the node. Since the normal distance between the curve and the line connecting two adjacent nodes is required to be less than the allowable programming error δ, the method for setting the Δθ value is to first take a certain value for trial calculation, then perform error verification. If the error exceeds the tolerance, the Δθ value is reduced until the requirement is met. Due to the large number of nodes—even with a dimensional tolerance of IT15, there are still 30 nodes—it is necessary to program and calculate the nodes, and then write the CNC machining program. Obviously, the workload for node calculation, program input, and debugging is very large and prone to errors. The Archimedes flute parameter equations are automatically programmed using Mastercam 7.1 software. You can access the editing menu via `create—next menu—fplot—edit eqn`: Set to 0. II. Parametric Programming Using parametric programming provided by the CNC system can solve the above problems and improve the efficiency of CNC programming and the utilization rate of machine tools. The Siemens SINUMERIK 8IOD system has parametric programming capabilities, providing 250 parameter variables R00-R249. R100-R249 are used as transfer parameters for machining cycles, while R0-R99, which are not assigned values ​​by the system, can be programmed by the user. The system can also perform function calculations, such as SIN, COS, SQR, ABS, POT, TRUND, EXP, etc., as well as data judgment and transfer, such as IF, GOTOWF, GOTOWB, etc. Using the parametric programming function, programs similar to BASIC can be compiled, reducing manual programming workload and improving the reliability of automatic programming. III. Parametric Programming for Machining of the Adjustment Device Disc The parameter program flowchart (as shown in Figure 2) and machining program for the Archimedes spiral groove of the adjustment device disc are as follows: The above program has a machining start angle of 0 [sup]. For the helical groove [/sup], simply assigning values ​​like l5[sup]. [/sup] and 30[sup]. [/sup] to R1 allows for the machining of several other helical grooves. This program is versatile and extensible, and can be stored as a user subroutine in the system. When machining Archimedean spirals of other sizes, it can be directly called and the value of the parameter variable R can be specified. The above program was tested on an MV610 machining center equipped with a SINUMERIK 81OD system, and parts were machined with satisfactory results. IV. Conclusion Parameter programming has the following characteristics: ☆ Simple program, good versatility, strong adaptability, and high reliability. If the product model can be constructed using the mathematical functions given by the system, parameter variable programming can be used. ☆ Interpolation accuracy can be modified at any time according to machining requirements. The same program is suitable for different situations of roughing and finishing. For example, the interpolation spacing R4 value can be set larger during roughing to improve efficiency; a smaller value for R4 can be used during finishing to ensure machining quality.