US 2020/0026809 A1Published application

Sand mold digital flexible extrusion near-net forming optimization method based on search algorithm

AssigneeBeijing National Innovation Institute of Lightweight Ltd.

InventorsZhongde SHAN, Feng LIU, Shuai ZHANG

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Abstract

Provided is a sand mold digital flexible extrusion near-net forming optimization method based on a search algorithm. The method includes: dividing a sand mold Computer Aided Design (CAD) 3D model near-net forming region; acquiring a curved surface function of a near-net forming sand mold CAD 3D model cavity; constructing a flexible extrusion array envelope volume optimization objective function; determining a valid optimization interval R; translating the position of a sand mold CAD 3D model cavity to a search initial position; performing a global search in the valid optimization interval R, comparing flexible extrusion array envelope volume values, and saving the larger value as V(x,y)max and the corresponding position as (x,y)max; and completing the search, translating the position of the near-net forming sand mold CAD 3D model cavity to (x,y)max, and executing a flexible extrusion array shape adjusting procedure.

A sand mold digital flexible extrusion near-net forming optimization method based on a search algorithm, the method comprising the following steps:

(1) dividing a sand mold Computer Aided Design (CAD) 3D model near-net forming region into m×n sub-regions, each having a size of a×b, according to arrangement of m×n flexible extrusion arrays, each having a size of a×b, on a sand mold digital flexible extrusion working platform;
(2) directly acquiring a curved surface function
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of a near-net forming sand mold CAD 3D model cavity under driving of a sand mold CAD 3D model, where i,j∈Z, and 1≤i≤m, 1≤j≤n.
(3) constructing a flexible extrusion array envelope volume optimization objective function V(x,y)=a×b×Σi=1nΣi=1m[fi,j(x,y)min] in the near-net forming sand mold CAD 3D model cavity;
(4) determining a valid optimization interval
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of a position of the near-net forming sand mold CAD 3D model cavity;
(5) translating the position of the near-net forming sand mold CAD 3D model cavity to a search initial position A1,1, which is equal to
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(6) determining a search direction as an x increment direction and a y increment direction;
(7) determining search step length parameters Δx and Δy in x and y directions according to error requirements of the x and y directions respectively;
(8) performing search in the valid optimization interval R, comparing flexible extrusion array envelope volume values V(x,y)p,q calculated in a search process, saving a larger value as V(x,y)max, saving the corresponding position as (x,y)max, and recording the corresponding value of fi,j(x,y)min;
and
(9) completing the search, translating the position of the near-net forming sand mold CAD 3D model cavity to (x,y)max, and executing a flexible extrusion array shape adjusting procedure.

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Abstract

Claims16