The machining quality of titanium alloy includes machining accuracy and surface quality: Machining precision refers to the actual size, shape and position of the parts after machining, which are in accordance with the ideal geometric parameters required by the drawing.The deviation value between the actual geometric parameters and the ideal geometric parameters is called machining tolerance.

Machining accuracy and machining tolerance are terms used to evaluate geometric parameters of machining surface.Machining accuracy is measured by tolerance grade,the smaller the grade value, the higher the accuracy;The machining tolerance is expressed by numerical value,the larger the value, the greater the tolerance.The accuracy is high, the tolerance is small, and vice versa;The actual parameters obtained by any machining method are not absolutely accurate,from the point of view of the function of the parts, as long as the tolerance is within the range required by the parts drawing, the machining accuracy is considered to be guaranteed.

The quality of the machine depends on the machining quality of the parts and the assembly quality of the machine.Parts processing quality includes parts processing accuracy and surface quality.Machining precision refers to the degree of conformity between the actual geometric parameters and the ideal geometric parameters after machining, and the difference between them is called machining tolerance.The tolerance reflects the machining accuracy,the greater the tolerance, the lower the machining accuracy,the smaller the tolerance, the higher the machining precision;Main aspects affecting machining accuracy: dimension accuracy;the actual dimensions of the machined parts are in accordance with the tolerance zone center of the dimensions of the parts.

Position accuracy: refers to the actual position accuracy difference between the parts' relevant surfaces after machining.The items of position accuracy are parallelism, perpendicularity, inclination, coaxiality, symmetry, position, circular jump and full jump.Position accuracy is controlled by position tolerance,the position tolerance of each item is also divided into 12 accuracy grades.

The relationship between dimensional accuracy, shape accuracy and position accuracy of mold parts:Usually when designing machine parts and specifying the machining accuracy of the parts,we should pay attention to control the shape tolerance within the position tolerance, and the position tolerance should be less than the size tolerance.A precision part or an important surface of a part,the accuracy of its shape should be higher than that of its position, and the accuracy of its position should be higher than that of its dimension.