Negative entity modeling method

Abstract

The invention discloses a negative entity modeling method, and belongs to the technical field of machining modeling. According to the negative entity method, a modeling sequence of negative entities is determined according to the processing sequence, parts which are cut in one step by cutters of the same specification in the processing process are simulated via negative entities, and the negative entities represents parts that needs to be removed from a processing entity. The method comprises the following steps that 1) a design reference is collected, and a constraint sketch of a part to be established is drawn; 2) a blank entity of the part to be established is established according to the constraint sketch; 3) a contour entity of the part to be established is established; 4) a negative entity packet is established according to the processing sequence; 5) a geometric parameter feature of the part to be established is processed according to the negative entity packet; and 6) the established contour entity is inspected. According to the invention, the modeling process is standard, the design quality and working efficiency are improved, manufacture related work is considered in the design stage, and the consistency between a design digital model and a technical digital model is improved.

Description

technical field [0001] The invention belongs to the technical field of machining modeling, and in particular relates to a negative solid method modeling method. Background technique [0002] Most of the metal machined parts on the aircraft are processed by CNC, and these parts have complex shapes and high processing precision requirements, especially very important large parts, such as frames, beams and other load-bearing components, which are difficult to process. Most of the frame and beam parts are curved surfaces with lug joints. In order to meet a series of requirements such as strength, structural layout, and weight, multiple cavities will be designed inside the machined parts (generally, the removal of the "cavity" inside the part is called a cavity), which also includes partial closed angles. Processing, which in turn increases the difficulty of CNC machining. The traditional CATIA modeling conforms to the design intent with the final geometric features, but cannot...

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Problems solved by technology

[0003] 1) The modeling process of designing digital models has poor readability, which is not conducive to digital model maintenance, and the client operation efficiency is low when the design digital model modeling process is complicated;

[0004] 2) It is difficult to classify the same kind of tools for parts, which leads to frequent tool changes during processing;

[0005] 2) The utilization rate of the process digital model in the programming process to the design digital model is extremely low, and even the process digital model of most parts has to be rebuilt;

[0006] 3) There are a large number of phenomena that the rounding and chamfering of the design digital model cannot be processed by CNC;

[0007] 4) The closed-angle processing part cannot construct geometric features in the design digital model, resulting in a theoretical error between the design digital model and the actual part, causing certain difficulties to the inspection work

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