A Novel Hole System Dimension Analysis Tool Based on the Combination of the Process Path and Design Path

Abstract

In the calculation of process dimensions in the machining of porous parts, the traditional method is complicated in the establishment of the dimensional chain, it is easy to make mistakes in the judgment of increasing and decreasing loops, and there is difficulty in the calculation process; thus, this paper puts forward a method that combines the process path with the design path to analyze the hole system dimensions in response to these problems. First of all, the combination of the process path and design path is used to establish a system of vector equations and, according to the system of vector equations, to establish a matrix model to calculate the process dimensions based on the system of vector equations to construct the process dimensional chain and the dimensional chain function; then, the principle of differentiation is used to carry out a tolerance analysis of the process dimensions, which avoids the drawing of dimensional chain diagrams and the judgement of the incremental/decremental loops. Finally, the development of a process dimension analysis tool for hole system dimensions is completed based on CATIA CAA. In order to verify the effectiveness of the proposed method, the analysis tool was used to solve the three labeling methods of the hole system dimensions of porous parts and compared with the results calculated using the traditional method, and it was found that some of the tolerance results obtained by the proposed method were enlarged by about 50%, which is more in line with the actual production situation. Finally, in order to verify the accuracy of the tool’s calculation results, three porous parts were machined according to the process dimensions and tolerances calculated by the tool, and the center distance of each hole was measured by a coordinate meter. These measurements were compared and analyzed with the design dimensions specified in the engineering drawings, and it was found that the center distances of the holes were in full compliance with the design requirements.

Keywords

• process dimension
• CATIA CAA
• differential method
• tolerance design