A METHOD FOR INCREASING THE MECHANICAL STRENGTH OF SAND CORE PRODUCTS MANUFACTURED USING 3D ADDITIVE MANUFACTURING.

Abstract

The invention is an impregnation and heat treatment method for increasing the strength of sand cores (10) produced by additive manufacturing. The method consists of filling the gaps (13) between the sand grains (11) by spraying phenolic resin (20) onto the surface of the sand core (10) and then creating strong bonds (30) between the sand grains (11) by applying a burning process. With this method, the fracture strength of the sand cores is doubled, preventing damage during assembly and casting.

Description

1 TARIFF SAND CORE PILES PRODUCED USING 3D ADDITIVE MANUFACTURING METHODS A METHOD TO INCREASE MECHANICAL STRENGTH TECHNICAL FIELD The invention relates to the production of sand cores using 3D additive manufacturing methods. a method to increase its strength and sand cores obtained by this method It is related to. 10 The invention specifically applies phenolic compounds to sand cores produced by the binder spraying method. The fracture strength is increased by applying resin and then subjecting it to heat treatment. It is related to a method that enables its increase and the sand cores obtained by this method. STATE OF THE ART In current technology, 3D additive manufacturing systems use furan resin on sand grains. It produces the product layer by layer by spraying binders such as [types of adhesive]. However, in this method... The sprayed binder is unable to penetrate evenly and sufficiently at every point. 20 Ultimately, the bonds between sand grains can be broken by traditional mechanical compaction methods. It remains weaker compared to the manufactured parts and voids form within the structure. These sand cores, produced using additive manufacturing, generally have a fracture strength of 300 N / cm2. It is at this level, and this value is insufficient for many casting operations. In the current technology, the cores are not subjected to any additional strengthening process after production. It is used without being held. Especially thin-section sand cores under 5 mm, low Due to its strength, it carries a risk of fracture during assembly and casting, which... This leads to high rejection rates and dimensional errors. Ultimately, the problems mentioned above, which cannot be solved with current technology, are related. This has made it necessary to make an innovation in the technical field. 2 A BRIEF DESCRIPTION OF THE INVENTION The present invention eliminates the aforementioned disadvantages and the related technical High-performance sand cores produced through additive manufacturing to bring new advantages to the field. It relates to a method developed to increase strength. 5 The main purpose of the invention is to increase the fracture strength of sand cores produced by additive manufacturing. The aim is to increase [the effectiveness of the technique]. To this end, the sand core produced is impregnated by spraying it with phenolic resin. The process is carried out, followed by the incineration process. Another purpose of the invention is to improve the assembly and casting of sand cores, especially those with thin profiles. The aim is to prevent it from breaking. Accordingly, the core's tensile strength is 300 N / cm2 or higher. It has been increased to 600 N / cm2. Another aim of the invention is to prevent dimensional problems that may occur in the casting. The goal is to improve the flow of metal during casting by increasing the rigidity of the cores. The movements caused by this have been prevented. The best way to utilize the advantages of the existing invention, together with its structure and additional elements. For it to be understood, it should be evaluated together with the figures explained below. 20 is necessary. BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a representative view of a sand core produced using current technology. Figure 2 shows the process steps of the invented method and the sand obtained in these steps. It includes representative images of the spade. REFERENCE NUMBERS Sand spades 11 grains of sand 30 12 Weak bonds 13 Spaces Phenolic resin Strong bond 3 DETAILED DESCRIPTION OF THE INVENTION This detailed explanation aims to provide a better understanding of the innovation in the invention. This is explained with examples that will not create any limiting effect. Figure 1 shows additive manufacturing with a 3D printer where the method described in the invention was applied. A sand spade (10) produced using the method is shown. As can be seen voids (13) in the sand core (10) and weak bonds between sand grains (11) (12) is located. In Figure 2, the subject of the invention is on the sand spade (10) mentioned. The steps involved in the method are shown step by step. Figure 2a shows the first 10. The step is represented, and at this stage, sand is mixed with a spraying device. Phenolic resin (20) is applied to (10). As seen in Figure 2b. sprayed phenolic resin (20) penetrates into the voids (13) within the sand core (10) structure. by filling the spaces between the grains of sand (11). Sand cores (10) impregnated with resin are then heated by a heat source or flame. It is subjected to a burning process. A representation of this process is shown in Figure 2c. This heat treatment results in a phenolic resin, as represented in Figure 2d. (20) curing and completely eliminating the gaps between the sand grains (11) It forms strong bonds. At the end of the process, the bonds between the grains of sand (11) are 20 By strengthening it in this way, the initial fracture strength of the sand core (10) is increased. Its value reaches approximately twice that amount. A preferred option within the scope of the invention. In practice, phenolic resin (20) is prepared in solvent at a concentration of 50-70%. Sand is sprayed onto the surface of the core (10) at a pressure of 0.2-0.5 bar; then the core is pressed 150-200 It is cured in an oven or over an open flame for 5-15 minutes at a temperature range of °C. This 25 The fracture strength obtained with the parameters was measured in the range of 500-650 N / cm².

Claims

4 REQUESTS 1. Mechanical of sand cores (10) produced by 3D additive manufacturing method It is a method aimed at increasing its strength, and its characteristic feature is; - Thermoset resin or phenolic resin (20) 5 on the surface of the produced sand core (10). implementation, - the resin in question (20) penetrates into the spaces (13) between the grains of sand (11). ensuring that it does so, - and steps of heat treatment of the resin-impregnated sand core (10) It includes. 10 2. The method according to claim 1 is characterized by the resin (20) on the surface of the sand core (10). by one of the following methods: spraying, dipping or vacuum impregnation It is the implementation.

3. Method according to claim 1 or 2, and its characteristic is that the applied resin (20) is phenolic. It is resin. 15 4. Method according to any of claims 1 to 3, characterized by; heat treatment of resin. curing of the impregnated sand core (10) with external flame, oven or UV source It includes.

5. A method according to any of claims 1 to 4, characterized by the application of the method. The minimum cross-section of the sand core (10) must be less than 5 mm. 20 6. A method according to any of claims 1 to 5, and its characteristic is that the method... As a result of its application, the breaking strength of the sand core (10) is at least 500 It is the attainment of a value of N / cm².

7. A sand spade obtained by method according to any of claims 1 to 6 (10).

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