Motor shell poured based on 3DP technology and machining method thereof
The 3DP process for motor housings addresses limitations in traditional casting by enabling fast, assembly-free sand mold production with high accuracy and reduced defects, enhancing design flexibility and quality.
Patent Information
- Application Number
- CN202411073312.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-06
- Publication Date
- 2025-01-03
AI Technical Summary
Traditional casting processes for motor housings are limited by mold and core structures, leading to longer development cycles and limitations in internal flow channel design, restricting design flexibility and accuracy.
A motor housing cast using a 3DP process with a central segmented bottom pouring method, incorporating a middle mold manufactured by 3DP, and a processing method that includes steps for introducing molten metal, adjusting riser grooves, and using open bottom pouring to compensate for solidification shrinkage, ensuring smooth pouring and high accuracy.
The 3DP technology enables fast sand mold production without assembly, achieves high molding accuracy within 0.3mm, reduces shrinkage defects, and allows for flexible design changes, resulting in high-quality castings with fewer defects.
Smart Images
Figure CN119253916A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of motor casing processing, and in particular to a motor casing cast based on a 3DP process and a processing method thereof. Background Art
[0002] In the process of manufacturing motor housings, traditional casting processes are generally used. Traditional casting processes are affected by the mold and core structure, and the design scheme is often restricted, which makes the development cycle of castings longer. In addition, in the casting process of motor housings with internal flow channel design, traditional casting processes will have a lot of limitations.
[0003] Three-dimensional printing (3DP) is to add a binder or some kind of glue to the powder through the print head, which is more like an inkjet printer. The powder replaces the paper, and the ink is the binder. The print head "prints" the binder on the evenly spread sand. Due to the inherent advantages of 3DP technology, it has brought disruptive changes to the traditional foundry industry and has quietly changed the traditional production methods of foundry companies. Summary of the invention
[0004] To this end, the present invention provides a motor housing cast based on a 3DP process and a processing method thereof to solve the above-mentioned problems in the prior art.
[0005] In order to achieve the above object, the present invention provides the following technical solutions:
[0006] According to a first aspect of the present invention, a motor housing cast based on a 3DP process comprises a motor housing body, a flow channel outer opening is opened at the left end of the front side of the motor housing body, a flow channel entity opened in the motor housing body is arranged on the inner side of the flow channel outer opening, and used as an internal water cooling flow channel, and a liquid inlet is also opened at the upper end of the motor housing body for pouring molten metal into;
[0007] The flow channel entity is manufactured by 3DP process;
[0008] The motor housing body is cast by a central segmented bottom pouring method, and a middle mold is used in the casting process. The middle mold is manufactured by a 3DP process.
[0009] Furthermore, the processing method comprises the following steps:
[0010] Step 1: Determine the casting plan, adopt the center segment bottom pouring, and introduce the molten metal from the second pouring port;
[0011] Step 2: Adjust the riser groove so that the riser groove and the liquid inlet are set correspondingly;
[0012] Step 3: Use open bottom pouring to introduce molten metal from the first pouring port, and cooperate with the introduction of molten metal from the second pouring port in step 1. Set a shrinkage feeder at the top section to compensate for solidification shrinkage. The molten metal is strictly dehydrogenated, and the inner cavity wall is ensured to be unobstructed during the pouring process. The cooling and shrinkage feeding process are well designed;
[0013] Step 4: Wait for cooling;
[0014] Step 5: The sand-falling machine vibrates to clean the sand, and uses X-ray equipment to detect the cleanliness of the internal sand cleaning, and meets the residual sand residue standard. If necessary, abrasive flow polishing is used to further improve the flow channel roughness.
[0015] Furthermore, a first pouring gate is provided at the upper end of the middle mold, and a second pouring gate is provided on the inner side of the middle mold, an inner runner is provided at the left end of the middle mold, a cross runner is provided at the lower end of the first pouring gate, and an inner runner is provided on the inner side of the cross runner.
[0016] Furthermore, a core opening plate is also provided on the outer side of the motor housing body.
[0017] Furthermore, a riser groove corresponding to the liquid inlet is provided on the inner side of the middle mold.
[0018] Furthermore, the processing method of the motor housing also includes bottom pouring, center bottom pouring and edge pressing top pouring.
[0019] The present invention has the following advantages:
[0020] 1. The motor casting model is made by using 3DP technology, which does not need to consider the mold opening and draft angle; the sand core is printed in one piece, and no assembly is required; the sand mold production efficiency is fast, and the drawing and printing are done on the same day; the molding accuracy is high, and the highest accuracy can be controlled within 0.3mm; the three-dimensional data can be changed at any time for reproduction;
[0021] 2. The use of center segmented bottom pouring combined with open bottom pouring can reduce the scouring of the sand mold and reduce shrinkage defects. The shrinkage and shrinkage holes with large porosity are concentrated in the riser area, so that castings with fewer defects can be obtained while maintaining stable filling. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A stereoscopic diagram of a middle mold of a motor housing cast based on a 3DP process and a processing method thereof provided in some embodiments of the present invention.
[0023] Figure 2 A schematic three-dimensional diagram showing the positions of the riser groove and the liquid inlet of a motor housing cast based on a 3DP process and a processing method thereof provided in some embodiments of the present invention.
[0024] Figure 3A solidified stereoscopic diagram of a flow channel entity of a motor housing cast based on a 3DP process is provided for some embodiments of the present invention. Figure 4 A cross-sectional view of the motor housing body provided by the present invention. Figure 5 A simulation schematic diagram of the bottom injection solution provided by the present invention. Figure 6 This is a diagram of the filling process of molten metal in the bottom pouring solution provided by the present invention. Figure 7 A diagram of the solidification process of aluminum liquid in the bottom pouring solution provided by the present invention. Figure 8 This is a distribution diagram of shrinkage cavities and shrinkage porosity of a casting after solidification in the bottom pouring solution provided by the present invention. Fig. 9 A simulation schematic diagram of the center bottom pouring solution provided by the present invention. Fig.10 This is a diagram of the filling process of aluminum liquid in the center bottom pouring solution provided by the present invention. Fig.11 This is a diagram of the solidification process of aluminum liquid in the center bottom pouring scheme provided by the present invention. Fig.12 This is a distribution diagram of shrinkage cavities and shrinkage porosity of castings in the center bottom pouring solution provided by the present invention. Fig.13 A simulation schematic diagram of the edge pressing and top pouring scheme provided by the present invention. Fig.14 A diagram of the aluminum liquid pouring and filling process in the edge pressing and top pouring scheme provided by the present invention. Fig.15 A diagram of the solidification process of aluminum liquid in the edge pressing and top pouring scheme provided by the present invention.
[0025] In the figure: 1. first pouring gate, 2. cross runner, 3. inner runner, 4. motor housing body, 5. liquid inlet, 6. core head opening plate, 7. runner outer opening, 8. riser groove, 9. middle mold, 10. second pouring gate, 11. inner runner opening, 12. runner entity. DETAILED DESCRIPTION
[0026] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0027] like Figures 1 to 3As shown, a motor casing based on 3DP casting process and a processing method thereof in an embodiment of the first aspect of the present invention include a motor casing body 4, a flow channel outer opening 7 is opened at the left end of the front side, a flow channel entity 12 opened in the motor casing body 4 is arranged on the inner side of the flow channel outer opening 7, and is used as an internal water-cooling flow channel. A core head opening plate 6 is also arranged on the outer side of the motor casing body 4, and a liquid inlet 5 is also opened at the upper end of the motor casing body 4 for pouring molten metal.
[0028] The processing method of the motor housing cast based on the 3DP process includes a middle mold 9 used for casting, a first pouring gate 1 is opened at the upper end of the middle mold 9, and a second pouring gate 10 is arranged on the inner side of the middle mold 9, an inner runner opening 11 is opened at the left end of the middle mold 9, a cross runner 2 is arranged at the lower end of the first pouring gate 1, and an inner runner 3 is opened on the inner side of the cross runner 2, and a riser groove 8 corresponding to the liquid inlet 5 is also opened on the inner side of the middle mold 9.
[0029] In the above embodiment, it should be noted that the longitudinal section of the motor housing body 4 is as shown in FIG. Figure 4 As shown in the figure, the inner flow channel of the metal shell has uneven wall thickness. The wall thickness of the outer part is thinner, so it will solidify first during casting, and then the inner wall surface will solidify. Moreover, the thin wall thickness is easy to cause shrinkage or shrinkage. It is best to solidify the cylindrical parts sequentially during casting to avoid casting defects as much as possible.
[0031] The use of 3DP technology eliminates the need to consider mold opening and draft angles; the sand core is printed in one piece and does not require assembly; the sand mold production efficiency is high, with drawings and printing on the same day; the molding accuracy is high, with the highest accuracy being controlled within 0.3mm; the 3D data can be changed at any time for reproduction.
[0032] Therefore, according to the above motor housing and its corresponding mold design, its processing method includes the following steps:
[0033] Step 1: Determine the casting scheme, adopt the center segmented bottom pouring, and introduce the molten metal from the second pouring port 10, which will cause less scouring of the sand mold and less shrinkage defects. The shrinkage and shrinkage holes with large porosity are concentrated in the riser part, so that castings with fewer defects can be obtained;
[0034] Step 2: Adjust the riser groove 8 so that the riser groove 8 and the liquid inlet 5 are arranged correspondingly;
[0035] Step 3: Use open bottom pouring to introduce molten metal from the first pouring port 1, and cooperate with the introduction of molten metal from the second pouring port 10 in step 1 to reduce the impact on the sand mold and maintain stable filling. Set a shrinkage feeder at the top section to compensate for solidification shrinkage. The molten metal is strictly dehydrogenated, and the inner cavity wall during the pouring process ensures smooth exhaust. The cooling and shrinkage feed process are well designed;
[0036] Step 4: Wait for cooling;
[0037] Step 5: The sand-falling machine vibrates to clean the sand, and uses X-ray equipment to detect the cleanliness of the internal sand cleaning, and meets the residual sand residue standard. If necessary, abrasive flow polishing is used to further improve the flow channel roughness.
[0038] In addition to the above-mentioned pouring scheme that is most suitable for inner runner design, the following methods are also included for reference: Option 1: Ante The same plan Figure 5 As shown in the figure, the bottom pouring method is used for pouring, which has the advantages of stable filling of molten metal, less oxidation, and avoiding splashing of molten metal. The solidus of AlSi10Mg is 571ºC and the liquidus is 593ºC. Scheme 1 only designs one inner runner. Due to the high pouring speed, the molten aluminum has a large impact on the inner wall of the sand mold at 0.4s. After that, the molten aluminum fills the mold smoothly, and the liquid level gradually rises steadily. The mold can be fully filled at 4.9s. The filling process of molten aluminum is shown in the figure. Figure 6 shown.
[0042] The solidification process of Al liquid is as follows Figure 7 As shown in the figure, about 10 seconds after the start of pouring, the aluminum liquid begins to solidify, and the solidification begins at the part of the reinforcement rib, which is caused by the thinness of this part. At about 20.4 seconds, the bottom begins to solidify significantly, and at the same time, the upper part of the inner flow channel begins to solidify significantly, which is due to the long time of release of this part of the molten metal from the sand mold and the large temperature drop. At 30.4 seconds, the amount of solid phase increases, and after the time reaches 35.4 seconds and 40.4 seconds, it finally solidifies near the reinforcement rib, where shrinkage is very likely to form. After the time reaches 60.4 seconds, the casting is basically solidified.
[0043] Shrinkage distribution diagram Figure 8 As shown in the figure, a large number of shrinkage cavities and shrinkage pores are formed in the riser part which solidifies last, and larger shrinkage cavities are formed near the reinforcement ribs, which will reduce the mechanical properties of the casting and is not conducive to the service life of the casting.
[0047] Option 2: Center bottom pouring In order to enhance the flow and mixing of molten metal during bottom pouring and make the temperature field more uniform, this scheme sets up multiple ingates, and considering that the upper part of the casting is an important part, the model is inverted and bottom pouring is also adopted. In addition, in order to prevent the temperature field of the sprue from affecting the surface solidification sequence of the casting, the sprue is moved to the center. Fig. 9 shown.
[0048] The maximum filling rate adopted in this scheme is 0.035kg / s, and the pouring rate within 0~2s increases linearly with time. Fig.10 As shown in the figure, when the filling time is 1.5s, the distribution of the aluminum liquid in the cross runner is not balanced, resulting in a large flow rate of the aluminum liquid, which rushes out quickly from the inner runner. When the time reaches 2.0s and 3.5s, it can be found that the convection of the aluminum liquid is very strong, the flow field changes greatly, and the scouring effect of the sand mold is relatively strong. With the extension of the pouring time, the convection intensity of the aluminum liquid casting decreases, and the aluminum liquid gradually rises, and finally completely fills the mold cavity at about 11.1s.
[0049] Fig.11 This is the aluminum liquid solidification process of Scheme 2. At about 18.6s, the aluminum liquid begins to solidify at the reinforcement rib and the top. The solidification at the top is early, mainly because the wall thickness here is also thinner. At 20.6s, the top solidification area begins to expand significantly, and it expands significantly at 28.6s. At about 35.6s, the inner flow channel also solidifies significantly, showing a solidification feature of fast top and slow bottom, which is not conducive to shrinkage compensation. At about 44.6s, post-solidification occurs at the bottom, and obvious shrinkage holes or shrinkage cavities will appear here. At 61.6s, it gradually solidifies completely.
[0050] The final distribution diagram of shrinkage cavities and shrinkage porosity of the casting is as follows: Fig.12 As shown in the figure, near the outlet of the inner flow channel at the bottom of the casting, there are shrinkage cavities and shrinkage with visible lines, and there are also large shrinkage cavities and shrinkage cavities near the inner flow channel. The quality of the casting is very poor. The main reason for this problem is that the upper part of the casting is relatively thin, so it solidifies first, resulting in the last solidification position appearing in the important area of the part. The above results show that when processing the sand mold, the base of the part needs to be at the bottom.
[0057] Option 3: Edge pressing and top pouring like Fig.13 As shown, the top pouring with press edge can achieve better top pouring and sequential solidification effects with a very simple casting sand mold design. The pouring rate can be adjusted by the gap size of the press edge. The molten metal is easy to fill the mold. After filling, the upper temperature is higher than the lower temperature, and metal can be saved to a great extent.
[0058] The pouring and filling process of Scheme 3 is as follows Fig.14As shown in the figure, the pouring speed is constant at 0.014937kg / s. It can be seen from the figure that the convection intensity of the aluminum liquid is low during pouring. Due to the low pouring speed, the aluminum liquid rises steadily during the filling process. However, it can be seen that after the aluminum liquid enters the mold cavity, it will have a greater impact and scouring effect on the inner flow channel sand mold, which may cause the sand mold to be damaged. Finally, the aluminum liquid fills the sand mold after 19.7s.
[0059] The solidification process of aluminum liquid in scheme 3 is as follows Fig.15 As shown in the figure, it can be seen that the sequential solidification characteristics of the molten metal are very obvious. At about 67s, the inner flow channel sand mold at the bottom of the casting begins to solidify and gradually expands upward, and finally solidifies completely at 107s.
[0060] Option 3 also shows that the shrinkage cavities and shrinkage in the main part of the casting are relatively small, and most of them are concentrated in the riser near the pouring cup. The height of the riser can be further increased, which can avoid shrinkage cavities and shrinkage in the main part of the casting.
Claims
1. A motor housing cast based on 3DP process, characterized in that: The motor housing body (4) comprises a flow channel outer opening (7) at the left front end thereof, a flow channel entity (12) opened in the motor housing body (4) is arranged inside the flow channel outer opening (7) and serves as an internal water cooling flow channel, and a liquid inlet (5) is also provided at the upper end of the motor housing body (4) for pouring molten metal into the motor housing body (4); The flow channel entity (12) is manufactured by using a 3DP process; The motor housing body (4) is cast by a central segmented bottom casting method, and a middle mold (9) is used in the casting process. The middle mold (9) is manufactured by a 3DP process.
2. According to claim 1, a motor housing cast based on the 3DP process, the processing method thereof comprises the following steps: Step 1: Determine the casting scheme, adopt the central segmented bottom pouring, and introduce the molten metal from the second pouring port (10); Step 2: adjusting the riser groove (8) so that the riser groove (8) and the liquid inlet (5) are arranged correspondingly; Step 3: adopt open bottom pouring, introduce molten metal from the first pouring port (1), cooperate with the introduction of molten metal from the second pouring port (10) in step 1, set a shrinkage feeder on the top section to compensate for solidification shrinkage, strictly perform the dehydrogenation operation of the molten metal, and ensure that the inner cavity wall is unobstructed during the pouring process, and the cooling and shrinkage feeding process are well designed; Step 4: Wait for cooling; Step 5: The sand-falling machine vibrates to clean the sand, and uses X-ray equipment to detect the cleanliness of the internal sand cleaning, and meets the residual sand residue standard. If necessary, abrasive flow polishing is used to further improve the flow channel roughness.
3. The motor housing cast based on 3DP process according to claim 1 is characterized in that: The upper end of the middle mold (9) is provided with a first pouring gate (1), and the inner side of the middle mold (9) is provided with a second pouring gate (10); the left end of the middle mold (9) is provided with an inner runner (11); the lower end of the first pouring gate (1) is connected to a runner (2), and an inner runner (3) is provided on the inner side of the runner (2).
4. The motor housing cast based on 3DP process according to claim 1 is characterized in that: A core opening plate (6) is also provided on the outer side of the motor housing body (4).
5. The motor housing cast based on 3DP process according to claim 1 is characterized in that: The inner side of the middle mold (9) is also provided with a riser groove (8) arranged corresponding to the liquid inlet (5).
6. The motor housing cast based on 3DP process according to claim 2, characterized in that: The processing method of the motor housing also includes bottom pouring, center bottom pouring and edge pressing top pouring.