A casting process based on 3D printing to develop a differential

Abstract

The application discloses a kind of based on 3D printing development difference shell's casting process, it is related to the field of difference shell casting.To solve the existing casting process is prone to cause the shelving of mould property and the waste of capacity, the development cycle needed is long.A kind of based on 3D printing development difference shell's casting process, comprising the following steps: S1, output model by 3D printing equipment, S2, clean the uneven place inside casting, dry and demould, S3, after demoulding is completed form sand box, S4, in the cavity and flow passage system inside brush coating water-based paint, S5, the sand box is placed into iron box, molten iron is poured into sand box, S6, after cooling forming casting is separated by cutting, polishing and shot blasting, timely delivery.The application of a kind of based on 3D printing development difference shell's casting process can small batch quickly cast difference shell, greatly reduce the production cost of single piece small batch product, and production cycle is short, can faster deliver sample piece.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of differential housing casting, in particular to a casting process for developing differential housing based on 3D printing. BACKGROUND

[0002] Differential housing, generally refers to the differential housing of automobile rear axle reducer, has the effect of protecting differential. Under the background of economic globalization, with the new changes of automobile industry, the automobile parts industry also presents new development trend. The enterprises of automobile parts basically take the casting and processing of automobile front and rear axle housings, differential reducer parts differential housings, gearbox housings and other cast iron parts as the main, a few enterprises can produce precise gearbox assembly, brake assembly, etc. The process flow of traditional lost wax casting process includes developing metal mold according to product model; operating wax injection machine to form wax; removing excess corners of wax mold; fixing multiple wax molds on wax frame mold head to form wax tree, realizing production of multiple castings at a time, which can improve production efficiency; wax tree is subjected to slurry hanging, sand dipping and drying treatment, and the process is repeated continuously according to different products until the thickness of the shell mold reaches the expected effect; the shell mold is subjected to heating treatment, the temperature reaches the melting point of the wax mold, the wax mold is liquefied, and the wax liquid can be recycled; the shell mold is put into the kiln to make the residual wax mold in the shell mold burn and vaporize; the shell mold is heated, the mold head is used as a cavity, and the molten metal ingot is injected to cool and form; the external shell is broken by using pneumatic jack to separate the castings and the shell mold, and the castings are subjected to sand blasting, shot blasting, cutting, gate grinding, sand blasting and other treatments to obtain the casting blank. This process flow is very complicated, the cycle of product mold development is long, the price is high, the post-processing is troublesome and expensive, especially when the order quantity of differential housing is small, the mold property is left and the production capacity is wasted after DISA line arrangement, in addition, when the project development task is tight, the development cycle required according to the existing mold development progress is too long to meet the needs of customers. SUMMARY

[0003] The present application aims to provide a casting process for developing differential housing based on 3D printing, which uses 3D printing technology to print sand box, has low fixed cost, does not need to develop mold, can quickly cast differential housing in small batches, simplifies the part manufacturing process, saves manufacturing cost and time, greatly reduces the production cost of single small batch product, avoids the problem of difficult mold stripping, has short production cycle and simplified process, and can quickly deliver sample parts to solve the problems in the above background technology.

[0004] To achieve the above purpose, the present application provides the following technical scheme:

[0005] A casting process for developing differential housing based on 3D printing, comprising the following steps:

[0006] S1, upload the 3D product model drawn by computer to the 3D printer, and output the resin sand, adhesive and other related materials into the required model under the control of the program through the 3D printing equipment, and after printing, paint and heat drying.

[0007] S2, clean the uneven places formed inside the casting by hand, remove the support and polish the model surface, and then hang the slurry, dip the sand and dry the shell mold to make the shell mold, and then demold the dried shell mold.

[0008] S3, after demolding, fix the upper mold and the lower mold together to form a sand box by fixing screws, and thicken the upper mold.

[0009] S4, clean the broken sand inside the sand box, and then brush the water-based paint on the forming surface inside the casting cavity and the runner system.

[0010] S5, put the assembled sand box into the pre-buried iron box, fill sand until the upper box is completely covered, and place four iron blocks on both sides of the pouring cup before pouring, and then pour the molten iron into the sand box after the molten iron is treated, and cool it to form.

[0011] S6, after the cooled and formed casting is normally cut, separated, polished and shot blasted, detect whether the appearance of the casting is clean and the material is qualified, and deliver the qualified casting in time.

[0012] Further, the sand box is provided with a casting system, and the sand box is composed of an upper mold and a lower mold, the upper mold and the lower mold are pressed together, four iron blocks are placed on the upper surface of the upper mold, exhaust holes are arranged on the upper mold, and a plurality of through holes for adding fixing screws are arranged on the upper mold and the lower mold.

[0013] Further, the casting system comprises a casting, a pouring cup, a sprue, a straight runner, a pouring cup base and a runner system, the pouring cup is arranged on the upper surface of the upper mold, the bottom of the pouring cup is communicated with the straight runner, the end of the straight runner away from the pouring cup is installed on the pouring cup base and communicated with the pouring cup base, the runner system is installed on the pouring cup base, the casting is installed on the runner system, and the sprue is installed on the side surface of the casting.

[0014] Further, the casting is communicated with the runner system, the runner system is communicated with the pouring cup base, the casting is provided with a cavity, and the position of the sprue corresponds to the position of the exhaust hole.

[0015] Further, the upper mold and the lower mold are provided with a positioning beak at the connection position, and the forming surface inside the casting cavity and the runner system are brushed with water-based paint.

[0016] Furthermore, the model in S1 is a hollow model, and the wall thickness of the hollow model is 0.4-3 mm. The slurry coating, sanding and drying in S2 are all performed at least once, and the number of slurry coating, sanding and drying is consistent.

[0017] Furthermore, the demolding in S2 includes pressurized sintering demolding, which involves pressurizing and heating in a sintering furnace to sinter and remove the model to obtain a shell mold for casting. The heating temperature of the pressurized sintering demolding is the melting point of the printing material, and the pressure of the pressurized sintering demolding is 0.5-1Mpa.

[0018] Furthermore, the thickness of the shell mold is 2-8 mm, and the shell mold is composed of a surface layer, a transition layer and a back layer from the inside to the outside, wherein the surface layer is made as follows:

[0019] S101. First, use a silica sol coating with a flow cup viscosity of 30-35s to wet the surface of the sample.

[0020] S102. Spray refractory powder on the surface of the surface silica sol coating of the model to form a surface coating with a thickness of 1-2 mm.

[0021] S103, then put it into a baking oven and dry it at a temperature of 30-65°C for 1-2 hours.

[0022] The method for making the transition layer is as follows:

[0023] S201. Soak the outer side of the surface layer with silica sol paint and then spray refractory powder.

[0024] S202, placing the product in a baking oven and drying it at a temperature of 30-65° C. for 1-2 hours to form a transition layer, wherein the transition layer is 2-6 layers.

[0025] The method for making the back layer is as follows:

[0026] S301. Infiltrate the outer side of the transition layer with water glass paint for 1-4 minutes.

[0027] S302, then spray refractory powder, and then put it into a baking furnace and dry it at a temperature of 65-75°C for 5-9 hours. The refractory powder is mullite powder, corundum powder or quartz powder.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The application discloses a casting process for developing a difference shell based on 3D printing, and the sand box is printed by using 3D printing technology, the fixed cost is low, a mold does not need to be developed, difference shells can be quickly cast in small batches, part manufacturing procedures are simplified, manufacturing costs and man-hours are saved, the production manufacturing cost of single small-batch products is greatly reduced, the problem of mold stripping difficulty is avoided, the production cycle is short, procedures are simplified, and sample parts can be delivered quickly. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 FIG. 1 is a partial structure top view of a casting process for developing a difference shell based on 3D printing according to the application;

[0031] Figure 2 FIG. 2 is a partial structure view of a casting process for developing a difference shell based on 3D printing according to the application;

[0032] Figure 3 FIG. 3 is a sand box view of a casting process for developing a difference shell based on 3D printing according to the application;

[0033] Figure 4 FIG. 4 is a pouring system view of a casting process for developing a difference shell based on 3D printing according to the application;

[0034] Figure 5 FIG. 5 is an upper mold structure view of a casting process for developing a difference shell based on 3D printing according to the application;

[0035] Figure 6 FIG. 6 is a sand box top view of a casting process for developing a difference shell based on 3D printing according to the application.

[0036] In the drawings: 1, through hole; 2, runner system; 3, positioning arrow; 4, upper mold; 5, lower mold; 6, sprue cup; 7, sand box; 8, exhaust hole; 9, pressing iron; 10, pouring riser; 11, casting; 12, straight runner; 13, sprue cup base. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0038] To solve the technical problem that when the existing casting process is used to pour difference shells with small order quantity, the mold property is prone to be placed and the production capacity is prone to be wasted after DISA line arrangement, and when a project development task is tight, the development cycle required according to the existing mold development schedule is too long to meet the needs of customers, please refer toFigures 1-6 The embodiment provides the following technical scheme:

[0039] A casting process for developing a difference shell based on 3D printing, comprising the following steps:

[0040] S1, upload the 3D product model drawn by the computer to the 3D printer, and output the resin sand, binder and other related auxiliary materials into the required model under the control of the program through the 3D printing equipment, and after the printing is completed, paint is applied and heated and dried, the model is a hollow model, and the wall thickness of the hollow model is 0.4-3mm.

[0041] S2, clean the uneven places formed inside the casting 11 by hand, remove the support and polish, so that the model surface is smooth, and the polished model is sequentially subjected to slurry hanging, sand dipping and drying treatment to form a shell mold, the dried shell mold is demolded, the slurry hanging, sand dipping and drying are not less than once, and the number of times of slurry hanging, sand dipping and drying is consistent, the demolding includes pressure sintering demolding, and the pressure sintering demolding is sintered by pressure and heating in a sintering furnace to remove the model, so as to obtain a shell mold for casting, the heating temperature of the pressure sintering demolding is the melting point of the printing material, and the pressure of the pressure sintering demolding is 0.5-1Mpa.

[0042] S3, after the demolding is completed, the upper mold 4 and the lower mold 5 are fixed together to form a sand box 7 through fixing screws, and the upper mold 4 is thickened.

[0043] S4, clean the broken sand inside the sand box 7, and then brush water-based paint on the forming surface inside the casting 11 cavity and the runner system 2 inside.

[0044] S5, the assembled sand box 7 is placed in a pre-buried iron box, and then sand is filled until the upper box is completely covered, and four pieces of pressing iron 9 are placed on both sides of the sprue cup 6 before pouring, the molten iron is poured into the sand box 7 after being treated by inoculation, and the molten iron is cooled and formed.

[0045] S6, after the casting 11 cooled and formed is normally cut, separated, polished and shot blasted, whether the appearance of the casting 11 is clean and whether the material is qualified are detected, and the casting 11 is delivered in time after it is confirmed to be clean and qualified.

[0046] The sand box 7 is provided with a casting system, and the sand box 7 is composed of the upper mold 4 and the lower mold 5, the upper mold 4 and the lower mold 5 are pressed together, four pieces of pressing iron 9 are placed on the upper surface of the upper mold 4, the upper mold 4 is provided with an exhaust hole 8, and the upper mold 4 and the lower mold 5 are provided with a plurality of through holes 1 to which fixing screws can be added.

[0047] The casting system comprises a casting 11, a sprue cup 6, a sprue 10, a straight sprue 12, a sprue cup base 13 and a runner system 2, the sprue cup 6 is arranged on the upper surface of the upper mold 4, the bottom of the sprue cup 6 is communicated with the straight sprue 12, the end of the straight sprue 12 away from the sprue cup 6 is installed on the sprue cup base 13 and communicated with the sprue cup base 13, the runner system 2 is installed on the sprue cup base 13, the casting 11 is installed on the runner system 2, the sprue 10 is installed on the side of the casting 11, the casting 11 is communicated with the runner system 2, the runner system 2 is communicated with the sprue cup base 13, the casting 11 is provided with a cavity, the position of the sprue 10 corresponds to the position of the exhaust hole 8, the connecting part of the upper mold 4 and the lower mold 5 is provided with a positioning eagle 3, and the forming surface inside the cavity of the casting 11 and the inside of the runner system 2 are both brushed with water-based paint.

[0048] The thickness of the shell mold is 2-8 mm, and the shell mold comprises a surface layer, a transition layer and a back layer from inside to outside, wherein the surface layer is made by the following method:

[0049] S101, first use a silicon sol paint with a flow cup viscosity of 30-35 s to soak the surface of the mold.

[0050] S102, spray refractory powder on the surface of the surface layer silicon sol paint of the mold to form a 1-2 mm thick surface layer coating.

[0051] S103, then put it into the baking oven and dry it at a temperature of 30-65 DEG C for 1-2 hours.

[0052] The transition layer is made by the following method:

[0053] S201, soak the silicon sol paint on the outside of the surface layer, and then spray the refractory powder.

[0054] S202, then put it into the baking oven and dry it at a temperature of 30-65 DEG C for 1-2 hours to form a transition layer, and the transition layer is 2-6 layers.

[0055] The back layer is made by the following method:

[0056] S301, soak the water glass paint on the outside of the transition layer for 1-4 minutes.

[0057] S302, then spray refractory powder, and then put it into the baking oven and dry it at a temperature of 65-75 DEG C for 5-9 hours, and the refractory powder is mullite powder, corundum powder or quartz powder.

[0058] Specific, through the upper die 4 and the lower die 5 junction setting positioning 3, can reduce the upper die 4 and the lower die 5 when the box type probability, ensure the molding effect of sand box 7, the molding surface inside the cavity of the casting 11 and the flow passage system 2 inside are brushed with water-based paint, ensure that the 3D printing sand box 7 can have enough refractoriness to prevent sand, the exhaust hole 8 can discharge the pressure in the cavity, avoid the cavity full of molten iron buoyancy too large, and then make the cavity pressure too large lead to sand box 7 cracking, by increasing the number of fixing screws on the sand box 7 and the thickness of the upper die 4, at the same time, before pouring, four blocks of pressure iron 9 are placed on the upper surface of the upper die 4, effectively avoid the upper die 4 from both sides cracking, causing the leakage of the box, and the molten iron in the pouring cup 6 rapidly sinks, and the pouring is also useless, and the parting place is lifted seriously after opening the box, and the solid iron plate of nearly 20mm is poured out, and the blank and the iron plate are in an integrated state.

[0059] In summary, the application of a kind of based on 3D printing development differential shell casting process, using 3D printing technology to print sand box 7, fixed cost is low, no need to develop mould, at the same time avoid the problem of mould demoulding difficulty, and the production cycle is short, process is simplified, can quickly deliver sample, for some urgent and important development project, undoubtedly add new way, suitable for small batch differential shell production, the exhaust hole 8 can discharge the pressure in the cavity, avoid the cavity full of molten iron buoyancy too large, and then make the cavity pressure too large lead to sand box 7 cracking, by increasing the number of fixing screws on the sand box 7 and the thickness of the upper die 4, at the same time, before pouring, four blocks of pressure iron 9 are placed on the upper surface of the upper die 4, effectively avoid the upper die 4 from both sides cracking, causing the leakage of the box, and the molten iron in the pouring cup 6 rapidly sinks, and the parting place is lifted seriously after opening the box, and the solid iron plate of nearly 20mm is poured out, and the blank and the iron plate are in an integrated state.

[0060] The above is only the preferred embodiment of the application, but the protection scope of the application is not limited to this, any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the application within the technical range disclosed by the application, which should be covered in the protection scope of the application.

Claims

1. A casting process for developing a differential shell based on 3D printing, characterized in that: The following steps are involved: S1. Upload the 3D product model drawn by the computer to the 3D printer, and use the 3D printing equipment to output the resin sand, adhesive and related auxiliary materials into the required model under the control of the program. After printing, apply paint and heat and dry; S2, manually cleaning the uneven areas inside the casting (11), removing the supports and polishing the model to make the surface smooth, and then sequentially subjecting the polished model to slurry coating, sanding and drying to form a shell mold, and demoulding the dried shell mold; S3. After demoulding is completed, the upper mold (4) and the lower mold (5) are fixed together by fixing screws to form a sand box (7), and the upper mold (4) is thickened; S4, cleaning the broken sand inside the sand box (7), and then brushing water-based paint on the molding surface inside the casting (11) cavity and the inside of the runner system (2); S5. Place the assembled sand box (7) into the iron box pre-buried with sand, and then fill the sand until the upper box is completely covered. At the same time, before pouring, place four iron weights (9) on both sides of the pouring cup (6). After the molten iron is inoculated, pour it from the transfer bag and pour it into the sand box (7), and cool it to form the shape. S6. After the casting (11) is cooled and formed, it is subjected to normal cutting, separation, grinding and shot blasting, and the appearance of the casting (11) is inspected to see whether it is clean and whether the material is qualified. After confirming that the casting (11) is clean and qualified, it is delivered in time; A casting system is provided in the sand box (7), and the sand box (7) is composed of an upper mold (4) and a lower mold (5). The upper mold (4) and the lower mold (5) are pressed together, and four weights (9) are placed on the upper surface of the upper mold (4). An exhaust hole (8) is provided on the upper mold (4), and a plurality of through holes (1) capable of fixing screws are provided on the upper mold (4) and the lower mold (5). The thickness of the shell mold is 2-8 mm. The shell mold is composed of a surface layer, a transition layer and a back layer from the inside to the outside. The surface layer is made as follows: S101, first use the silica sol coating with a flow cup viscosity of 30-35s to infiltrate the sample surface; S102, spraying refractory powder on the surface of the surface silica sol coating of the model to form a surface coating with a thickness of 1-2 mm; S103, then put it into a baking oven and dry it at a temperature of 30-65°C for 1-2 hours; The method for making the transition layer is as follows: S201, soaking the outer side of the surface layer with silica sol paint, and then spraying refractory powder; S202, then put it into a baking oven and dry it at a temperature of 30-65°C for 1-2 hours to form a transition layer, the transition layer is 2-6 layers; The back layer is made as follows: S301, soaking the outer side of the transition layer in water glass paint for 1-4 minutes; S302, then spray refractory powder, and then put it into a baking furnace and dry it at a temperature of 65-75°C for 5-9 hours. The refractory powder is mullite powder, corundum powder or quartz powder.

2. A casting process for developing a differential shell based on 3D printing as claimed in claim 1, characterized in that: The casting system comprises a casting (11), a pouring cup (6), a pouring riser (10), a sprue (12), a pouring cup base (13) and a runner system (2); the pouring cup (6) is arranged on the upper surface of the upper mold (4); the bottom of the pouring cup (6) is connected to the sprue (12); the end of the sprue (12) away from the pouring cup (6) is installed on the pouring cup base (13) and is connected to the pouring cup base (13); the runner system (2) is installed on the pouring cup base (13); the casting (11) is installed on the runner system (2); and the pouring riser (10) is installed on the side of the casting (11).

3. A casting process for developing a differential shell based on 3D printing as claimed in claim 1, characterized in that: The casting (11) is connected to the runner system (2), the runner system (2) is connected to the pouring cup base (13), a cavity is provided in the casting (11), and the position of the pouring riser (10) corresponds to the position of the exhaust hole (8).

4. A casting process for developing a differential shell based on 3D printing as claimed in claim 1, characterized in that: A positioning hook (3) is provided at the connection between the upper mold (4) and the lower mold (5), and the molding surface inside the mold cavity of the casting (11) and the inside of the flow channel system (2) are both painted with water-based paint.

5. The casting process for developing a differential shell based on 3D printing according to claim 1, characterized in that: The model in S1 is a hollow model with a wall thickness of 0.4-3 mm. The slurry application, sanding and drying in S2 are performed at least once, and the number of slurry application, sanding and drying is consistent.

6. The casting process for developing a differential shell based on 3D printing according to claim 1, characterized in that: The demolding in S2 includes pressurized sintering demolding, which involves pressurizing and heating in a sintering furnace to sinter and remove the model to obtain a shell mold for casting. The heating temperature of the pressurized sintering demolding is the melting point of the printing material, and the pressure of the pressurized sintering demolding is 0.5-1 MPa.

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