CN114713771A

CN114713771A - Manufacturing method of sand core with built-in complex oil way pipeline

Info

Publication number: CN114713771A
Application number: CN202011523234.6A
Authority: CN
Inventors: 孟祥林; 张凯强; 苑延华; 徐衍峰; 李景贺; 于广滨; 赵灿
Original assignee: Heilongjiang University of Science and Technology
Current assignee: Heilongjiang University of Science and Technology
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-07-08

Abstract

The invention discloses a rapid manufacturing method of a die insert with a built-in complex oil way. For a specific die insert, a three-dimensional CAD modeling software (such as Pro/Engineer or Unigraphics) is used for intercepting the outline of the die insert, and a three-dimensional graph with a certain thickness outline is formed and exported in an STL format file, and is input into a computer of a laser sintering additive manufacturing system. According to the requirements of users, resin coated sand is used as forming raw material powder, forming is carried out on a laser sintering system, then a copper pipe is adopted to bend an oil way pipeline and is assembled into a profile blank of a die insert, then a casting method is adopted to cast metal liquid into the profile blank, a complete die insert is formed after cooling, and the insert is used for production after necessary surface treatment.

Description

Manufacturing method of sand core with built-in complex oil way pipeline

Technical Field

The invention belongs to the field of intersection of laser rapid manufacturing and die technology, and particularly relates to a rapid manufacturing method of a sand core with a built-in oil way pipeline.

Background

The manufacturing of the aeroengine is the centralized reflection of the national industrial manufacturing level, and the service life and the production efficiency of the sand core casting mould manufactured by the additive manufacturing technology have important influence. The traditional casting method needs to prepare a mould according to a part and then cast by using the mould. The above method is difficult to add oil path and other structures into the complex parts, therefore, the mold manufactured by the traditional method is generally composed of a group of straight open pore systems, and in order to form a closed oil path, the open pores except the inlet and the outlet need to be sealed by plugs. This technique has the following problems: the manufacturing efficiency is low and the precision is poor. Because the mold cavity is generally very complicated and the processing technology is complicated, the system composed of straight holes can not ensure the uniformity of all parts of the mold cavity, and the deformation is easy to cause. The design and manufacture of complex oil circuits is still limited to relatively simple circuits, and there is a need for cost-effective manufacturing methods.

The sand core additive manufacturing technology of laser sintering forming selects resin coated sand as a forming material, generates a CAD model of an entity on a computer, generates an STL file through slicing processing, controls laser layer by layer forming by utilizing the computer, and finally forms a required prototype or part after layer by layer superposition. The technology has the characteristics of wide molding materials, high manufacturing efficiency and low cost, and the manufacturing process is not influenced by the complexity of parts, and is particularly suitable for manufacturing the die with the cooling conformal cooling flow channel.

In order to overcome the defects of the traditional machining technology and the traditional die manufacturing technology, the selective laser forming technology and the casting technology are combined, an energy-saving and efficient sand core manufacturing method with a built-in oil way pipeline is researched, and the sand core manufacturing method can be flexibly and conveniently used for manufacturing parts of an aero-engine.

Disclosure of Invention

The invention aims to provide a method for manufacturing engine parts with complex oil paths, which mainly comprises a laser rapid manufacturing technology and a casting technology, can directly form a die with a built-in complex oil path through a three-dimensional model of a die computer, has the characteristics of simple and rapid process, material saving and energy saving, and can solve the technical problem that the traditional method cannot manufacture according to the adjustment of the surface performance of the die.

The invention provides a method for manufacturing engine parts with complex oil passages, which comprises the following steps:

(1) fully stirring the resin coated sand to uniformly distribute the components of the resin coated sand;

(2) according to the characteristics of the formed powder material, designing an outer contour three-dimensional model with a certain thickness of the die by adopting computer three-dimensional structure design software;

(3) forming the mixed powder by adopting an SLM (selective laser melting) technology to manufacture the outline of the die;

(4) adopting a pipe material with a melting point close to that of a mould material to mechanically bend and form an oil way pipeline required by the mould, wherein the route of the pipeline has the characteristic of following the structure of a mould cavity;

(5) and (3) assembling the oil pipeline into the hollow structure of the die insert, then casting metal liquid by adopting a casting method, and cooling and solidifying the metal liquid to be integrated with the outer contour of the die insert.

(6) The surface of the die insert is subjected to necessary treatment by adopting an electrolytic polishing or mechanical polishing method, so that the surface smoothness of the die insert meets the requirement of a cast part.

Detailed Description

Firstly, on the basis of a three-dimensional computer model file of a mold, designing an outer contour three-dimensional computer model of the mold by adopting design software such as ProE, UG and the like according to the structure of the mold, thickening the mold at a proper place according to the requirement of the strength of a cavity of the mold, designing an oil path inlet and outlet in the model, inputting the oil path inlet and outlet into an additive manufacturing forming system, and preparing for forming. At the same time, the precoated sand is subjected to necessary treatment and then charged into the molding cavity.

Then, powder forming is carried out by utilizing laser sintering, and proper forming technological parameters are selected according to different thermophysical properties such as melting points of materials in the forming process, so that the density of the outer contour of the formed die reaches more than 98 percent, and the die has good surface smoothness. Taking off the formed outer contour blank of the die, designing an arrangement scheme of an oil way according to the structural condition of the inner contour, and processing a steel pipe or a copper pipe into a frame of the oil way, wherein an inlet and an outlet are matched with the actual condition, so that an oil way pipeline is positioned.

And casting alloy liquid after arrangement, wherein the melting point of the cast alloy is matched with the melting point of the structural material of the mould and the melting point of the cooling water channel material. The casting is carried out in a low-temperature casting mode, so that the high structure performance of the cast die insert can be guaranteed. And finally, polishing the surface of the die to meet the forming requirement, thereby finishing the final manufacture of the die insert with the built-in complex oil path.

Example 1

Selecting resin coated sand powder to carry out die outline thickness determination to be 3mm, and laser forming parameters are as follows: the laser power is 150-.

After the outer contour of the die is formed, a right pipeline is manufactured by adopting a pure copper pipe, the diameter of the pipe is determined according to the design requirement, and the pipe is installed in a contour cavity of the die.

And casting the mold contour cavity by adopting aluminum alloy and magnesium alloy, and enabling the liquid brass to become metallurgical bonding with the surfaces of the mold steel and the pure copper cooling water channel.

The substantially manufactured mold is subjected to necessary machining, such as grinding, etc., to finally complete the manufacturing.

Claims

1. A laser rapid manufacturing method of a sand core mold with a built-in complex oil path comprises the following manufacturing steps:

(1) forming the outer contour of the die by a laser sintering method;

(2) designing the structure of an oil pipeline according to the cooling requirement of the mould, bending the oil pipeline by adopting a copper pipe, and assembling the bent oil pipeline into the outline of the mould;

(3) casting the mold contour by adopting materials such as copper and the like to finish the forming of the mold insert entity;

(4) and (3) polishing the surface of the die insert to enable the die insert to meet the injection requirement of parts.

2. The laser rapid manufacturing method with the built-in complex oil way sand core mold as claimed in claim 1, is characterized in that: the forming powder material used in the step (1) is resin-coated sand.