Wax pattern mold of 3D printing pouring system

Abstract

The invention provides a 3D printing pouring system wax pattern mold, and belongs to the technical field of investment precision casting, the 3D printing pouring system wax pattern mold comprises an outer wall solid layer, a discontinuous honeycomb structure, a supporting framework and lining plates, the lining plates are arranged on the two sides of the outer wall solid layer, the lining plates and the outer wall solid layer jointly form a closed space, the discontinuous honeycomb structure is contained in the closed space, and the supporting framework is arranged on the outer wall solid layer. The outer wall solid layer comprises a wax mold containing part, the wax mold containing part is concaved into the discontinuous honeycomb structure, the supporting framework penetrates through the discontinuous honeycomb structure, the two ends of the supporting framework are connected with the outer wall solid layer, the outer wall solid layer and the discontinuous honeycomb structure are subjected to 3D printing forming after being pretreated by a polylactic acid material, and the supporting framework and the lining plate are embedded after strengthening treatment. The mold is prepared from the environment-friendly and low-price polylactic acid material, the water cooling channel is constructed in the mold, the problems that the temperature bearing capacity of the material is insufficient and the heat dissipation performance is poor are solved, pouring system wax molds of different sizes, specifications and shapes can be rapidly, accurately and stably formed, and the mold is environmentally friendly, low in cost and rapid in response.

Description

Technical Field

[0001] This invention relates to the field of investment casting technology, and more particularly to a 3D-printed wax mold for a gating system. Background Technology

[0002] With the rapid development of aerospace and other military industries, the number of new engine development tasks is increasing, and the development cycle is getting shorter. Correspondingly, the development of new supporting casting products is diverse and time-sensitive. In investment casting, the assembly and welding of wax patterns during casting trial production requires a large number of wax patterns for the gating system. Traditional metal molds can only meet the requirements for forming wax patterns of one shape and size. However, in the early stages of new casting product development, the size and shape of the gating system change constantly with process adjustments. Directly manufacturing the metal molds for the gating system wax patterns is not only costly and time-consuming, but also risks scrapping the metal molds due to process adjustments during product trial production. If the gating system is directly manufactured using 3D printing, regardless of whether photosensitive resin or PS powder is used, shell expansion is likely during dewaxing, and it also pollutes the environment.

[0003] A review of relevant literature revealed that patent CN 116000240 A, for example, addresses the creation of a mold for circular runner wax models. By replacing movable blocks, a mold capable of forming circular runners of different specifications was developed, overcoming to some extent the limitations of traditional metal molds and meeting the needs for different circular runners in the development of turbine rotors, guide vanes, and casings. However, the high cost, long production cycle, and poor flexibility of metal molds, which prevent them from being fully applicable to the development of new casting products, remain problems.

[0004] Therefore, how to quickly, accurately, and stably form wax molds of different sizes, specifications, and shapes for casting systems, while being green, low-cost, and responsive, is an urgent problem that the industry needs to solve. Summary of the Invention

[0005] A primary objective of this invention is to overcome at least one of the deficiencies of the prior art and to provide a 3D printed wax mold for a gating system that is capable of rapid, accurate, and stable forming of wax molds for gating systems of different sizes, specifications, and shapes, and is also green, low-cost, and has a fast response.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: According to one aspect of the present invention, a 3D printed casting system wax mold is provided. The wax mold includes an outer solid layer, a discontinuous honeycomb structure, a support frame, and a liner. The liner is disposed on both sides of the outer solid layer, forming a closed space together with the outer solid layer. The discontinuous honeycomb structure is housed in the closed space. The outer solid layer includes a wax mold receiving portion, which is recessed into the discontinuous honeycomb structure. The support frame passes through the discontinuous honeycomb structure and is connected to the outer solid layer at both ends. The outer solid layer and the discontinuous honeycomb structure are 3D printed from polylactic acid material after pretreatment, and then reinforced before being inlaid with the support frame and the liner.

[0007] According to one specific embodiment of the present invention, the polylactic acid material comprises L-lactide units with a mass fraction of 70% or more.

[0008] According to a specific embodiment of the present invention, the discontinuous honeycomb structure includes alternating honeycomb structures and partitions. The honeycomb structure includes horizontally arranged honeycomb pillars. Each honeycomb pillar includes vertically stacked honeycomb blocks. Each honeycomb block is a regular polygonal hole pillar. Each sidewall of the hole pillar is provided with a circular hole. The diameter of the circular hole is D. The side length of the regular polygon of the hole pillar is L, and 0.3L≤D≤0.6L.

[0009] According to a specific embodiment of the present invention, the thickness of the outer wall solid layer is T, the thickness of the sidewall of the hole column is W, and W=kT, where k is 0.5-1, 1mm≤T≤5mm.

[0010] According to a specific embodiment of the present invention, there is a flow gap between the partition and the outer wall solid layer, and the flow gap is arranged alternately to form a "U"-shaped cooling passage in the enclosed space.

[0011] According to a specific embodiment of the present invention, the enclosed space is provided with an inlet and an outlet on two opposite sides, and the outlet is higher than the inlet. Cooling water is introduced into the enclosed space through the inlet, and the cooling water flows out from the outlet through the cooling passage.

[0012] According to a specific embodiment of the present invention, the pretreatment of the polylactic acid material includes a drying process, wherein the drying temperature is 80-100℃ and the drying time is 4-6h.

[0013] According to a specific embodiment of the present invention, the 3D printing is FDM printing, the printing layer thickness is 0.1mm-0.3mm; the filling rate of the outer wall solid layer and the partition is ≥98%, and the filling rate of the honeycomb structure is ≥40%; the nozzle temperature is 190-230℃, the heated bed temperature is 40-60℃, and the printing speed is 400mm / s-600mm / s.

[0014] According to a specific embodiment of the present invention, the strengthening treatment includes polishing and annealing. The polishing is acetone vapor polishing for 30-120 seconds. The annealing is a stepped annealing: holding at 60℃-80℃ for 0.5-1h → holding at 100℃ for 1-2h → furnace cooling to room temperature.

[0015] According to a specific embodiment of the present invention, the support frame is strip-shaped, and the liner is disposed on the end face of the mold in the mold closing direction. The liner is made of stainless steel or aluminum and is used for the stress support of the mold.

[0016] As can be seen from the above technical solution, the advantages and positive effects of the 3D printing casting system wax mold of the present invention are as follows: This invention uses green, environmentally friendly, and low-cost polylactic acid (PLA) material to prepare molds, eliminating the need for complex equipment. By constructing water-cooling channels inside the mold, the problems of insufficient heat resistance and poor heat dissipation of the material are solved, thereby enabling rapid, accurate, and stable forming of wax molds for casting systems of different sizes, specifications, and shapes. It is also green, low-cost, and has a fast response time. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the first embodiment of the wax mold of the 3D printing casting system of the present invention; Figure 2 This is a schematic diagram of the honeycomb block structure of the first embodiment of the wax mold of the 3D printing casting system of the present invention; Figure 3 This is a schematic diagram of the discontinuous honeycomb structure of the wax mold of the 3D printing casting system of the present invention in the first embodiment; Figure 4 This is a schematic diagram of the internal cavity of the wax mold of the 3D printing casting system of the present invention in the first embodiment; Figure 5 This is a schematic diagram of the second embodiment of the wax mold of the 3D printing casting system of the present invention.

[0018] Drawing number explanation: 1: Outer wall solid layer; 11: Inlet; 12: Outlet; 13: Wax injection port; 2: Discontinuous honeycomb structure; 21: Honeycomb structure; 22: Partition; 3: Wax mold; 4: Support frame; 5: Liner. Detailed Implementation

[0019] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0020] First Embodiment

[0021] like Figures 1 to 4 As shown, the 3D printed casting system wax mold provided in this embodiment includes an outer solid layer 1, a discontinuous honeycomb structure 2, a support frame 4, and a liner 5. The liner 5 is disposed on both sides of the outer solid layer 1, forming a closed space together with the outer solid layer 1. The discontinuous honeycomb structure 2 is housed in the closed space. The outer solid layer 1 includes a wax mold receiving part, which is recessed into the discontinuous honeycomb structure 2. The support frame 4 passes through the discontinuous honeycomb structure 2 and is connected to the outer solid layer 1 at both ends. The wax mold 3 is poured into the wax mold receiving part, which has a wax injection port 13. The preparation steps include: S10, pretreatment of polylactic acid (PLA) material; S20, 3D printing of the outer solid layer 1 and the discontinuous honeycomb structure 2 as a single unit; S30, strengthening treatment of the outer solid layer 1 and the discontinuous honeycomb structure 2; S40, embedding the support frame 4 and the liner 5.

[0022] Specifically, the mold is made of a polylactic acid (PLA) matrix, which contains 75% L-lactide units by mass.

[0023] Specifically, the discontinuous honeycomb structure 2 includes alternating honeycomb structures 21 and partitions 22. The honeycomb structure 21 includes horizontally arranged honeycomb pillars, each pillar comprising vertically stacked honeycomb blocks. Each honeycomb block is a regular hexagonal pillar with a circular hole on each sidewall. The diameter of the circular hole is D, and the side length of the regular hexagon is L, where D is 4 mm and L is 10 mm. The outer solid layer thickness is T, and the sidewall thickness of the pillar is W, where T is 2 mm and W is 1 mm.

[0024] There is a flow gap between the partition 22 and the outer wall solid layer 1. The flow gaps are arranged alternately, forming a "U"-shaped cooling passage in the closed space. The closed space has an inlet 11 and an outlet 12 arranged opposite to each other on two sides, and the outlet 12 is higher than the inlet 11. Cooling water is introduced into the closed space through the inlet 11, and the cooling water flows out from the outlet 12 through the cooling passage.

[0025] Specifically, the PLA material is dried at 80℃ for 4 hours.

[0026] Specifically, the printing process involves FDM printing with a layer thickness of 0.1 mm; the outer solid layer 1 and partition 22 have a fill rate of 98%, and the honeycomb structure 21 has a fill rate of 40%; the nozzle temperature is 200℃, the heated bed temperature is 40℃, and the printing speed is 400 mm / s.

[0027] Specifically, acetone vapor polishing was used for 50 seconds; the annealing was a stepped annealing: 60℃ for 0.5 hours → 100℃ for 1 hour → furnace cooling to room temperature.

[0028] Specifically, the honeycomb blocks are hexagonal, the length of the honeycomb pillars is kept flush with the mold surface at both ends, the liner 5 is embedded on the outer surface in the mold closing direction, and the material is 6065 aluminum.

[0029] Additionally, it should be noted that the wax mold for the gating system provided in this embodiment is suitable for manual wax pouring and can produce two wax molds for the gating system at the same time.

[0030] Second Embodiment

[0031] like Figure 5 As shown, based on the above embodiments, the following further features are also included.

[0032] Specifically, the mold is made of a polylactic acid (PLA) matrix, which contains 80% L-lactide units by mass.

[0033] Specifically, T is 3mm and W is 3mm.

[0034] Specifically, the honeycomb structure 21 and the partition 22 are arranged in an alternating pattern of one layer of honeycomb and one layer of partition 22; the honeycomb block structure is hexagonal, and there is a through channel between adjacent honeycomb blocks, with a channel diameter D of 3mm.

[0035] Specifically, the PLA material is dried at 80°C for 6 hours.

[0036] Specifically, the FDM printing process is as follows: the printed layer thickness is 0.1 mm; the solid layer and partition 22 have a 100% fill rate, and the honeycomb structure 21 has a 60% fill rate; the nozzle temperature is 210℃, the heated bed temperature is 50℃, and the printing speed is 400 mm / s.

[0037] Specifically, acetone vapor polishing was used for 80 seconds; the annealing was a stepped annealing: 80℃ for 0.5 hours → 100℃ for 1.5 hours → furnace cooling to room temperature.

[0038] The mold provided in this embodiment is suitable for hot press molding of gating systems. Using this mold, it is no longer necessary to create traditional wax molds or metal molds for casting systems when developing new products. Furthermore, all printing materials used in this mold are inexpensive and biodegradable, and the supporting frame and liner used can be reused, causing no environmental pollution.

[0039] Those skilled in the art should understand that the specific structures and processes shown in the above detailed embodiments are merely exemplary and not restrictive. Furthermore, those skilled in the art can combine the various technical features described above in various possible ways to form new technical solutions or make other modifications, all of which fall within the scope of this invention.

Claims

1. A wax mold for a 3D printed casting system, characterized in that, The wax mold includes an outer solid layer, a discontinuous honeycomb structure, a support frame, and a liner. The liner is disposed on both sides of the outer solid layer, forming a closed space together with the outer solid layer. The discontinuous honeycomb structure is housed in the closed space. The outer solid layer includes a wax mold receiving portion, which is recessed into the discontinuous honeycomb structure. The support frame passes through the discontinuous honeycomb structure and is connected to the outer solid layer at both ends. The outer solid layer and the discontinuous honeycomb structure are 3D printed from polylactic acid material after pretreatment, and then reinforced before being inlaid with the support frame and liner.

2. The wax mold of the 3D printing casting system according to claim 1, characterized in that: The polylactic acid material contains L-lactide units with a mass fraction of 70% or more.

3. The wax mold of the 3D printing casting system according to claim 1, characterized in that: The discontinuous honeycomb structure includes alternating honeycomb structures and partitions. The honeycomb structure includes horizontally arranged honeycomb pillars. Each honeycomb pillar includes vertically stacked honeycomb blocks. Each honeycomb block is a regular polygonal hole pillar. Each side wall of the hole pillar is provided with a circular hole with a diameter of D. The side length of the regular polygon of the hole pillar is L, and 0.3L≤D≤0.6L.

4. The wax mold of the 3D printing casting system according to claim 3, characterized in that: The thickness of the outer solid layer is T, and the thickness of the sidewall of the hole column is W, where W=kT, k is 0.5-1, and 1mm≤T≤5mm.

5. The wax mold for the 3D printing casting system according to claim 3, characterized in that: There is a flow gap between the partition and the outer wall solid layer. The flow gaps are arranged alternately, forming a "U"-shaped cooling channel in the enclosed space.

6. The wax mold for the 3D printing casting system according to claim 5, characterized in that: The enclosed space has an inlet and an outlet on two opposite sides, with the outlet being higher than the inlet. Cooling water is introduced into the enclosed space through the inlet and flows out through the outlet via the cooling passage.

7. The wax mold for the 3D printing casting system according to claim 3, characterized in that: The pretreatment of the polylactic acid material includes drying, with a drying temperature of 80-100℃ and a drying time of 4-6 hours.

8. The wax mold for the 3D printing casting system according to claim 7, characterized in that: The 3D printing is FDM printing, with a printing layer thickness of 0.1mm-0.3mm; the fill rate of the outer wall solid layer and the partition is ≥98%, and the fill rate of the honeycomb structure is ≥40%; the nozzle temperature is 190-230℃, and the heated bed temperature is 40-60℃. Printing speed: 400mm / s-600mm / s.

9. The wax mold for the 3D printing casting system according to claim 8, characterized in that: The strengthening treatment includes polishing and annealing. The polishing is acetone vapor polishing, and the polishing time is 30-120s. The annealing is a stepped annealing: holding at 60℃-80℃ for 0.5h-1h → holding at 100℃ for 1h-2h → furnace cooling to room temperature.

10. The wax mold for the 3D printing casting system according to claim 1, characterized in that: The support frame is strip-shaped, and the liner is set on the end face of the mold in the mold closing direction. It is made of stainless steel or aluminum and is used for the stress support of the mold.

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