Fuel regulator shell metal mold casting method based on 3DP sand core

Abstract

The invention discloses a 3DP (three-dimensional printing) sand core-based fuel regulator shell metal mold casting method, which comprises the following steps of: integrally forming a complex sand core required by aero-engine fuel regulator shell metal mold casting by adopting a 3DP technology; the core problems that in a traditional casting method, a sand core is difficult to manufacture, prone to breakage, low in assembly precision and the like due to a slender, cantilever and hollowed-out structure are effectively solved, the strength and precision of the sand core are remarkably improved by combining optimized 3DP technological parameters with size compensation in sand core structure design, and it is ensured that an inner cavity runner as thin as 3 mm is completely formed.

Description

Technical Field

[0001] This invention relates to the field of metal mold casting, and more specifically to a method for casting a fuel regulator housing using a 3DP sand core. Background Technology

[0002] With the continuous advancement of aero-engine technology, the requirements for fuel control systems are becoming increasingly stringent. As the foundation for the assembly and functionality of the entire fuel control system, the fuel regulator housing is primarily made of aluminum alloy. It is characterized by its highly hollowed-out exterior, complex internal oil passage structure, high pressure resistance, high dimensional accuracy, and thin walls. In actual production, it is often manufactured using a combination of metal mold casting and sand core assembly. Due to the complex structural characteristics of this type of casting, conventional sand core manufacturing methods require the assembly of multiple sand cores, significantly increasing the number of core boxes. Furthermore, the assembly of sand cores inevitably leads to a reduction in the overall forming accuracy of the casting.

[0003] Additive manufacturing technology, which originated in the 1980s, is based on the "discrete / stacking" principle. It uses a forming machine to process and stack materials layer by layer to form the entire part. In the casting field, it is widely used in the manufacture of molds, cores, and patterns. Among these, spray bonding forming (3DP) technology is widely used in the sand mold (core) manufacturing process due to its high forming efficiency and low cost. Shaanxi Diesel Engine Heavy Industry Co., Ltd. successfully trial-produced a large diesel engine cast iron cylinder head casting composed of planes and hole systems using 3DP technology to produce sand cores. The Beijing Institute of Aeronautical Materials of China Aero Engine Corporation used a combination of 3DP sand mold (core) and metal mold casting to trial-produce complex aluminum alloy shells for aero engines, producing complex shell castings that met technical requirements, greatly shortening the product development cycle. Chongqing Jiangzeng Shipbuilding Heavy Industry Co., Ltd., targeting the characteristics of turbocharger shell castings such as thin walls, complex structures, and small batches with multiple varieties, applied 3DP forming sand mold (core) technology to the production of castings, increasing the product qualification rate by 15% compared to traditional casting, resulting in significant benefits. This series of successful application cases demonstrates the enormous application potential of 3DP forming sand mold (core) technology in the trial production and manufacturing of complex castings.

[0004] The casting process for the complex and intricate internal flow channels of aero-engine fuel regulator housings still presents challenges for 3DP-printed sand cores. Due to the small size of the internal channels, some with diameters as small as ϕ3mm, and their three-dimensional distribution, the 3DP sand cores exhibit complex structures, multiple cantilever structures, low room temperature sand mold strength, and a tendency to crumble and break during solidification, all of which negatively impact the forming efficiency of aero-engine fuel regulator housings. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method for casting a fuel regulator housing using a 3DP sand core, which effectively shortens the casting production process and improves the production efficiency of aero-engine fuel regulator housings.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for casting a metal mold for a fuel regulator housing based on a 3DP sand core, specifically including the following steps:

[0007] Step 1: Draw the casting drawing corresponding to the metal mold casting of the shell part;

[0008] Step two: Design the mold for forming the outer contour of the shell part, as well as the gating system and riser system located on the parting surface of the mold;

[0009] Step 3: Design a sand core for forming the inner cavity of the shell part, and manufacture the sand core using 3DP technology. For sand cores with a diameter of less than 3mm, the sand core consists of 0.25% curing agent, 1.5% to 1.8% binder, and the remainder is composed of quartz sand with an average particle size of 0.15mm.

[0010] Step four: Assemble the mold and sand core, melt the alloy, and perform metal mold casting of the shell parts.

[0011] Furthermore, in step two, the mold is a left-right opening mold, and the material is 4Cr5MoSiV1 or 30CrMo.

[0012] Furthermore, in step two, the gating system and the riser system are vertically arranged on the parting surface, and the height of the exposed riser that is in contact with the atmosphere is the highest.

[0013] Furthermore, in step three, the sand-laying speed is 25-30 seconds per layer.

[0014] Furthermore, in step four, the alloy being smelted is ZL101A alloy, the casting temperature is 720℃, and the casting time is 3-5 seconds.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. The use of 3DP technology to form sand cores for metal mold casting of aero-engine fuel regulator housings avoids the design and manufacturing of core boxes, greatly solving the forming problem of complex sand cores, especially for sand cores with three-dimensional cantilever and hollow structures, which has great advantages.

[0017] 2. It simplifies the complexity of the process, shortens the casting production process, and improves the production efficiency of aero-engine fuel regulator housings. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings:

[0019] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The following specific embodiments may be combined or substituted with each other according to the actual situation, and the same or similar concepts or processes may not be described again in some embodiments.

[0022] Example 1

[0023] like Figure 1 As shown, the present invention provides a method for casting a metal mold for a fuel regulator housing based on a 3DP sand core, specifically including the following steps:

[0024] Step 1: Draw the casting drawing corresponding to the metal mold casting of the shell part;

[0025] Step two involves designing the mold for forming the outer contour of the shell part, as well as the gating and riser systems located on the parting surface of the mold. A slit gating system is adopted to ensure smooth filling of the molten metal. Specifically, the mold is left-right open, and the material is 4Cr5MoSiV1 or 30CrMo. The gating and riser systems are vertically set on the parting surface to avoid gas entrapment and scouring of the sand core, simplifying mold processing. During pouring, the molten metal can smoothly enter the cavity from both sides of the parting surface simultaneously, and the height of the visible riser in contact with the atmosphere is the highest. This ensures smooth flow of the molten metal during filling and also facilitates the riser's function at the highest point.

[0026] Step 3: Design the sand core for forming the inner cavity of the shell part, and manufacture the sand core using 3DP technology. For sand cores with a diameter of less than 3mm, the sand core consists of 0.25% curing agent, 1.5%~1.8% binder, and the remainder is quartz sand with an average particle size of 0.15mm. Using quartz sand with an average particle size of 0.15mm provides a larger specific surface area, allowing the binder to more effectively coat each sand grain, forming a stronger bond bridge, thereby obtaining higher sand core strength and a smoother surface finish. The sand laying speed is 25~30 seconds / layer, which can ensure the quality of each layer of sand powder, fundamentally guaranteeing the formability and reliability of the final sand core.

[0027] It is worth noting that the actual diameter of the slender structure of the sand core formed by 3DP will be smaller than the design value. Therefore, in this example, the designed diameter of the slender structure of the sand core is uniformly increased by 0.3mm.

[0028] Step four: Assemble the mold and sand core, melt the alloy, and perform metal mold casting of the shell parts; specifically, the melted alloy is ZL101A alloy, the pouring temperature is 720℃, and the pouring time is 3 to 5 seconds.

[0029] In summary, this invention effectively solves the core problems of traditional casting methods, such as the difficulty in manufacturing sand cores, easy breakage, and low assembly accuracy caused by the slender, cantilevered, and hollow structures, by using 3DP (three-dimensional printing) technology to integrally form the complex sand cores required for casting the metal mold of the aero-engine fuel regulator housing. Furthermore, by utilizing optimized 3DP process parameters combined with dimensional compensation in the sand core structure design, the strength and precision of the sand core are significantly improved, ensuring the complete forming of the internal flow channels as fine as 3mm.

[0030] Meanwhile, by setting the gating system perpendicular to the riser on the parting surface and ensuring the riser height is maximized, the molten metal filling and feeding process is further optimized, improving the density of the casting. Ultimately, while eliminating the traditional core box design and manufacturing process, the process flow for complex shell castings is simplified, the production cycle is shortened, and the overall forming efficiency is improved, making it particularly suitable for the rapid manufacturing of small batches of high-precision complex structural parts in the aerospace field.

[0031] In addition to the preferred embodiments described above, the present invention has other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection claimed by the present invention.

Claims

1. A method for casting a fuel regulator housing metal mold based on 3DP sand cores, characterized in that, Specifically, the steps include the following: Step 1: Draw the casting drawing corresponding to the metal mold casting of the shell part; Step two: Design the mold for forming the outer contour of the shell part, as well as the gating system and riser system located on the parting surface of the mold; Step 3: Design a sand core for forming the inner cavity of the shell part, and manufacture the sand core using 3DP technology. For sand cores with a diameter of less than 3mm, the sand core consists of 0.25% curing agent, 1.5% to 1.8% binder, and the remainder is composed of quartz sand with an average particle size of 0.15mm. Step four: Assemble the mold and sand core, melt the alloy, and perform metal mold casting of the shell parts.

2. The method for casting a fuel regulator housing metal mold based on a 3DP sand core according to claim 1, characterized in that, In step two, the mold is left-right open, and the material is 4Cr5MoSiV1 or 30CrMo.

3. The method for casting a fuel regulator housing metal mold based on a 3DP sand core according to claim 2, characterized in that, In step two, the gating system and the riser system are set vertically on the parting surface, and the height of the open riser that is in contact with the atmosphere is the highest.

4. The method for casting a fuel regulator housing metal mold based on a 3DP sand core according to claim 3, characterized in that, In step three, the sand-laying speed is 25-30 seconds per layer.

5. The method for casting a fuel regulator housing metal mold based on a 3DP sand core according to claim 4, characterized in that, In step four, the alloy being smelted is ZL101A alloy, the casting temperature is 720℃, and the casting time is 3-5 seconds.

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