Example of process analysis of typical parts in CNC turning

Write the processing technology of the part shown in the figure.

(1) Part drawing analysis

The part shown in the figure is composed of an arc surface, an outer conical surface, and a spherical surface. The outer cylindrical surface diameter of Φ50 is not processed, while the outer cylindrical surface diameter of Φ40 has a higher processing accuracy.

Part material: 45 steel

Blank size: Φ50×110

(2) Part clamping and fixture selection

The machine tool three-jaw automatic centering chuck is used. The part extends about 75mm outside the three-jaw chuck and is positioned and clamped with the outer circle.

(3) Determination of processing plan and processing sequence

The workpiece coordinate system is established with the right end face and the center axis of the part as the coordinate origin.

According to the part size accuracy and technical requirements, the part is processed from right to left, and the rough and fine processing are considered separately.

The processing sequence is: turning the right end face → compound turning fixed cycle roughing and finishing all the contours that need to be processed on the right end (roughing Φ44, Φ40.5, Φ34.5, Φ28.5, Φ22.5, Φ16.5 outer cylindrical surfaces → roughing arc surface R14.25 → finishing outer cylindrical surface Φ40.5 → roughing outer conical surface → roughing outer arc surface R4.75 → finishing arc surface R14 → finishing outer conical surface → finishing outer cylindrical surface Φ40 → finishing outer arc surface R5).

(4) Select tool

Select tool No. 1 as a 90° carbide machine clamp offset tool for roughing and finishing.

(5) Cutting parameters selection

The spindle speed for rough turning is n=630r/min, the spindle speed for fine turning is V=110m/min, the feed speed for rough turning is f=0.2mm/r, and the feed speed for fine turning is f=0.07mm/r.