Electronic product shell and forced limiting DMD (Digital Micromirror Device) additive process thereof

Abstract

The invention provides an electronic product shell and a forced limiting DMD additive process thereof, and belongs to the field of material forming. The problem of poor forming and positioning precision of the existing DMD technology is solved. The electronic product shell comprises a shell bottom plate and at least one group of internal structural features, the structural features are formed on the surface of the shell bottom plate by adopting an additive process, and the structural features are formed by limiting a limiting structure of a formed contour in combination with a DMD additive process. The DMD additive process comprises the following steps: S1, preparing; s2, DMD forming preparation is conducted, specifically, limiting structures are constructed on the outer side of a to-be-added material area of the semi-finished product workpiece, the workpiece provided with the limiting structures is placed at a DMD operation device, metal powder / metal wires are melted at the limiting structures and then deposited on the workpiece, the space between the limiting structures is filled, and corresponding set structures are formed; and S3, external processing. The shell of the electronic product is compact in structure, and the forming precision of structural features is improved through the forced limiting DMD material adding technology.

Description

Technical Field

[0001] The invention belongs to the field of material forming, and relates to an electronic product housing and a forced position limiting DMD additive process thereof. Background Art

[0002] DMD (Direct Metal Deposition) is an additive manufacturing technology, also considered a 3D printing technology. It is mainly used in the manufacture of metal parts, especially those that require high precision and complex geometry.

[0003] DMD technology deposits metal powder layer by layer and melts it to form metal layers, ultimately constructing three-dimensional solid parts.

[0004] Specifically: The DMD process usually uses laser as a heat source. A high-power laser beam is used to locally melt the metal powder and deposit it onto a substrate or the previous metal layer, stacking layer by layer to form the desired three-dimensional structure.

[0005] The shell material of traditional electronic equipment is mostly aluminum alloy structure, usually made of a whole aluminum plate, and the inner cavity surface structure of the product is fully milled and formed through multiple CNC processing processes, especially for special-shaped edge strips, threaded columns, positioning columns and other structures. It will not only waste materials and generate a large amount of aluminum scraps, making the post-processing cost high, but also require a long processing time, high carbon emissions, and is not conducive to environmental protection. In order to overcome the serious waste of materials in traditional work, 3D printing additive manufacturing has been gradually applied to shell molding. For example, the whole shell adopts 3D printing additive manufacturing, but due to the overall use of 3D printing, its accuracy is poor and the molding efficiency is low. When the DMD process is used for additive manufacturing, there is a lack of corresponding restriction structure in the additive area, and there are molding accuracy problems when the additive nozzle moves;

[0006] In order to solve the above problems, the present invention proposes a DMD additive process for constructing a limiting structure to meet the molding accuracy and overcome the above defects. Summary of the invention

[0007] The present invention aims to solve the above problems in the prior art and provides an electronic product housing that saves materials and improves structural accuracy, as well as a forced-limited DMD additive process for manufacturing the electronic product housing.

[0008] The first object of the present invention is achieved through the following technical solutions:

[0009] A shell of an electronic device includes a shell bottom plate. A plurality of structural features are arranged inside the shell bottom plate. The structural features are formed by a DMD additive process. During the forming process, a forced limiting structure is arranged. As for the outside of the structural features, the DMD additive equipment operates in the limiting structure to directly deposit and form metal powder or metal wire to form an internal structure.

[0010] The second object of the present invention is achieved through the following technical solutions:

[0011] A forced limited DMD additive process includes the following steps:

[0012] S1. Preparation: prepare the semi-finished workpiece to be processed, pre-process it, and select the corresponding limit structure;

[0013] S2, DMD molding preparation: construct a limiting structure outside the area to be added on the semi-finished workpiece, place the workpiece provided with the limiting structure on the DMD operation device, melt the metal powder / metal wire at the limiting structure and then deposit on the workpiece, and fill between the limiting structures to form a corresponding set structure;

[0014] S3, external processing: the set structure is processed to meet the design requirements, and the workpiece is post-processed to obtain a finished workpiece.

[0015] The limiting structure is formed by combining the DMD mold and the bottom of the shell. The limiting structure corresponds to the structural feature, and the DMD additive process performs additive operations on the inner side of the limiting structure.

[0016] Specifically, the process refinement steps are as follows:

[0017] S1. Preparation: prepare the semi-finished workpiece to be processed, pre-treat it, and select the corresponding mold;

[0018] S20, DMD molding: Put the polished and cleaned workpiece between the upper mold and the lower mold. At this time, the upper part of the workpiece is tightly attached to the lower part of the upper mold. The mold with the workpiece is placed on the DMD working device. The metal powder / metal wire is melted and deposited at the molding hole to form a corresponding set structure on the workpiece.

[0019] S21, auxiliary operation: while the DMD operation device is operating, the temperature of the DMD mold is controlled by a control system during the deposition process.

[0020] S22, demoulding: after the DMD molding operation is completed, the upper mold and the lower mold are separated, the molded workpiece is taken out, and then the set structure formed on the workpiece is deburred;

[0021] S3. External treatment: The workpiece after deburring is subjected to surface treatment to obtain a finished workpiece.

[0022] In the step S21, a temperature control pipe is provided in the upper mold and the lower mold, and the temperature control pipe heats or cools the upper mold and the lower mold according to the DMD process requirements;

[0023] Furthermore, the shell bottom plate is held fixed by an upper mold and a lower mold, and the upper mold is provided with a hole structure for limiting, and the hole corresponds to the structural feature and is used for filling and limiting in the DMD additive process.

[0024] The control system controls the temperature of the DMD mold, which means that during the deposition process, the temperature of the DMD mold is programmed and controlled in real time, wherein the control system automatically adjusts the heating and / or cooling of the upper mold and the lower mold according to a preset temperature curve or feedback signal to keep the DMD mold within a set temperature range.

[0025] The limiting structure is composed of a prefabricated structure, the outer contour of the prefabricated structure is consistent with the outer contour of the structural feature, the DMD additive process corresponds to the additive in the prefabricated structure, the prefabricated structure limits the DMD additive and forms part of the structural feature in the shell.

[0026] The limiting structure adopts a prefabricated structure, the material of the prefabricated structure is the same as that of the workpiece, and is formed by extrusion;

[0027] The end of the prefabricated structure abuts against the surface of the workpiece, and the side wall forms a limit. The DMD operation fills the prefabricated structure with metal powder, and together with the prefabricated structure, it forms a set structure.

[0028] The post-processing in step S3 is shaping and sandblasting.

[0029] The shell bottom plate is formed by forging and stamping processes.

[0030] Compared with the prior art, the forced limit mold can maintain a relatively high set temperature for the upper mold and a relatively low set temperature for the lower mold during the forming process of the workpiece. Therefore, it can control the condensation speed under different printing occasions, avoid the increase in thermal deformation and stress caused by turbulence and heat accumulation in the thickness direction, and the forming stability of the workpiece is relatively high.

[0031] At the same time, this process operates on a local position of the semi-finished workpiece. Compared with full 3D printing, it has high operating efficiency and relatively low operating costs.

[0032] In addition, since the upper mold is flush with the lower mold, no additional alignment operation is required when the upper and lower molds are buckled together. The mold closing is fast and stable, which can appropriately increase the operating speed. The heat-insulating positioning structure can not only properly position the workpiece, but also prevent the heat from the working part from being transferred to the frame too quickly, further improving its stability.

[0033] Through this manufacturing method, a variety of processing technologies can be combined and stacked, which not only brings out the advantages of traditional processing, but also brings into play the strengths of DMD additive manufacturing, opens up a new molding process, and expands the breadth of product molding.

[0034] By using traditional stamping or forging to process the shell bottom plate, and then 3D printing the shell inner cavity structure on the shell bottom plate, near-net process forming is achieved, which improves material utilization and reduces the amount of waste in the process, thereby achieving the final low-cost and high-precision production of the metal shell.

[0035] The present invention uses traditional processing to process the flat structure of the shell bottom plate, and cooperates with the forced limit structure to ensure the processing accuracy and reduce the processing cost and processing time to the greatest extent. By combining the two processes of forging / stamping the shell bottom plate and the limit DMD additive, the shortcomings of the DMD process inaccuracy can be overcome, forming a more refined structure to achieve in-situ combination of multiple materials, and changing the molding materials of the shell bottom plate and the shell inner cavity structure as needed. Ordinary materials such as SUS and aluminum alloys that are widely used in the past are used, and special materials such as titanium alloys and high-temperature alloys that are high-strength and corrosion-resistant but difficult to process with traditional processing technologies are used to meet the heterogeneous needs of different users, achieve lightweight products, and improve the accuracy of additive manufacturing.

[0036] The temperature rise or fall control can be added to the forced limit fixture to control the condensation speed in different printing situations, avoid the increase of thermal deformation and stress caused by turbulence and heat accumulation in the thickness direction, and further derivative processes based on this;

[0037] A metal cavity is made of the same aluminum material (such as an extruded hollow profile, such as two external retaining walls with fine structures). The DMD process is used in the cavity to connect the cavity structure and the bottom material into a whole using aluminum. This is a rapid additive method. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a three-dimensional structural diagram of the metal shell and its internal additive structure;

[0039] Figure 2 It is a schematic diagram of the top view of the structure of the forced limit mold.

[0040] Figure 3 This is a three-dimensional structural schematic diagram of the forced limit mold, which shows the structural schematic diagram of the shell semi-finished product and the mold structure after installation.

[0041] Figure 4 It is a schematic diagram of the cross-sectional structure of the forming hole in the forced limiting mold.

[0042] Figure 5It is a three-dimensional structural schematic diagram of the semi-finished workpiece in the forced limit mold.

[0043] Figure 6 It is a schematic diagram of the structure when the prefabricated structure and the additive area in the forced limiting mold are not connected.

[0044] Figure 7 This is an example illustration of the prefabricated structure in this mandatory limitation.

[0045] Figure 8 Illustration of the limitation of the additive area due to the combination of prefabricated structure and semi-finished shell.

[0046] Fig. 9 It is an additive structure formed by cooperating with DMD when the prefabricated structure is used as a limiting structure.

[0047] In the figure, 1. upper mold; 2. lower mold; 3. temperature control pipe; 4. shell; 5. structural features; 6. additive area. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0049] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly mounted on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more related listed items.

[0051] Embodiment 1;

[0052] An electronic product housing comprises a housing and a bottom plate.

[0053] At least one set of internal structural features, wherein the structural features are formed on the surface of the bottom plate of the shell by using an additive process, and the structural features are formed by a limiting structure that limits the molding contour and combined with a DMD additive process.

[0054] For the shell structure in this embodiment, the additive process includes the following steps:

[0055] S1. Preparation: prepare the semi-finished workpiece to be processed, pre-process it, and select the corresponding limit structure;

[0056] In this embodiment, the semi-finished product to be processed is an electronic product housing, which is made of metal material and is formed by forging or stamping.

[0057] When the mold is selected by the limiting structure, the mold is positioned and the DMD additive accuracy is improved in conjunction with the forming holes.

[0058] S20, DMD molding: Put the polished and cleaned workpiece between the upper mold and the lower mold. At this time, the upper part of the workpiece is tightly attached to the lower part of the upper mold. The upper mold and the lower mold position and clamp the semi-finished product to provide stability during the operation. The mold with the workpiece is placed on the DMD operating device. The metal powder / metal wire is melted and deposited at the molding hole to form a corresponding set structure on the workpiece.

[0059] S21, auxiliary operation: while the DMD operation device is operating, the temperature of the DMD mold is controlled by a control system during the deposition process.

[0060] Specifically, cooling is performed in the area where materials are added, and preheating is performed in the area to be added;

[0061] In this step, the upper mold and the lower mold are provided with temperature control pipes, and the temperature control pipes heat or cool the upper mold and the lower mold according to the DMD process requirements;

[0062] Furthermore, crisscross partition grooves are arranged on the upper mold, the lower mold and the semi-finished product structure surface to form a cold bridge, so as to improve the adjustment sensitivity and accuracy of the temperature control area;

[0063] The shell bottom plate is fixed by the upper mold and the lower mold. The upper mold is provided with a hole groove structure for limiting. The hole groove corresponds to the structural feature and is used for filling and limiting in the DMD additive process.

[0064] The control system controls the temperature of the DMD mold, which means that during the deposition process, the temperature of the DMD mold is programmed and controlled in real time, wherein the control system automatically adjusts the heating and / or cooling of the upper mold and the lower mold according to a preset temperature curve or feedback signal to keep the DMD mold within a set temperature range.

[0065] For example, the control system can detect the temperature in the DMD operating area. After detecting the above temperature, the control system sends out corresponding control information, namely: controlling the temperature of the corresponding temperature control pipes at the upper mold and the lower mold, and finally achieving the specific control of the upper mold and the specific temperature of the lower mold under the action of the temperature control pipes.

[0066] S22, demoulding: after the DMD molding operation is completed, the upper mold and the lower mold are separated, the molded workpiece is taken out, and then the set structure formed on the workpiece is deburred;

[0067] S3, external treatment: the workpiece after deburring is subjected to surface treatment to obtain a finished workpiece. The surface treatment in this step is shaping and sandblasting.

[0068] like Figure 1 and Figure 2 As shown, the forced limit mold includes two mold bodies that cooperate with each other, such as a lower mold 1 and an upper mold 2. After the upper mold 1 is snap-fitted and connected to the upper part of the lower mold 2, the semi-finished workpiece can be positioned between the upper mold 1 and the lower mold 2. The upper mold 1 has a through forming hole 1b1, and both the upper mold 1 and the lower mold 2 have a temperature control mechanism. Under the action of the temperature control mechanism, when it is necessary to maintain the temperature, the upper mold 1 and the lower mold 2 can maintain a set temperature of 200°C to 300°C when high temperature is required, and when it is necessary to keep cooling, the upper mold 1 and the lower mold 2 maintain a set temperature of -20°C to 20°C.

[0069] The heating temperature can be selected as any temperature value of 200° C., 210° C., 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C. and 300° C. Of course, it can also be any temperature value in the temperature range other than the above examples, and it can be adjusted and set according to the ambient temperature required by the DMD additive process, and this embodiment does not list them one by one.

[0070] The cooling temperature can be selected as any temperature value of -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, 15°C and 20°C. Of course, it can also be any temperature value in the temperature range other than the above examples, and it can be adjusted and set according to the ambient temperature required by the DMD additive process, and this embodiment does not list them one by one.

[0071] The semi-finished workpiece is a plate-shaped shell, and the mold is used to form a corresponding three-dimensional part structure on the semi-finished workpiece.

[0072] The semi-finished workpiece is formed by stamping a metal plate, and the side wall formed by the stamping is used as a limiting structure; the metal plate includes but is not limited to an aluminum alloy plate, a magnesium alloy plate, a titanium alloy plate, and a copper plate.

[0073] After the upper die 1 and the lower die 2 are snap-fitted together, the workpiece is positioned between the upper die 1 and the lower die 2 .

[0074] The positioned workpiece enters the 3D printing operation area along with the mold. When the printing operation is performed at the molding hole, the heating mechanism keeps the upper mold 1 at a relatively high set temperature, and the cooling mechanism keeps the lower mold 2 at a relatively low set temperature.

[0075] In this way, the condensation speed at the printing location of the forming hole 1b can be controlled, and the increase in thermal deformation and stress caused by turbulence and heat accumulation in the thickness direction can be avoided, thereby ultimately improving the yield rate.

[0076] like Figure 1 and Figure 3 As shown, the forming hole 1b1 includes an avoidance portion 1b11 and a forming portion 1b12, the avoidance portion 1b11 is conical and the large-size end of the avoidance portion 1b11 is located at the upper part of the upper mold 1, and the forming portion 1b12 is located at the lower part of the upper mold 1 and is connected to the avoidance portion 1b11.

[0077] The size of the lower port of the avoidance portion 1b11 is larger than that of the forming portion 1b12.

[0078] The avoidance portion 1b11 enables the 3D printing device to smoothly extend into the molding portion 1b12 , thereby preventing the 3D printing device from being blocked by the upper mold 1 .

[0079] The upper mold 1 includes a flat working part 1b and a frame-shaped border 1a. The working part 1b is fixedly connected to the frame 1a and a heat insulation positioning structure is provided between the working part 1b and the frame 1a. When the upper mold 1 is buckled and connected to the lower mold 2, the outer side of the frame is flush with the outer side of the lower mold 2.

[0080] like Figure 4 and Figure 5 and Figure 6 As shown, the semi-finished workpiece is a shell 4 with a cavity inside and an opening at the upper end. The inside of the shell 4 is a flat surface. There is a processed additive area 6 inside the shell 4. This process forms the prefabricated structure 5 in the additive area 6.

[0081] The forced position-limited additive process includes the following steps:

[0082] S1. Preparation: prepare the semi-finished workpieces to be processed, pre-treat them, and select the corresponding molds; pre-treatment such as cleaning, etc.

[0083] S2, DMD molding preparation: construct a limiting structure outside the area to be added on the semi-finished workpiece, place the workpiece provided with the limiting structure on the DMD operation device, melt the metal powder at the limiting structure and then deposit on the workpiece, and fill between the limiting structures to form a corresponding set structure;

[0084] S3, external processing: the set structure is processed to meet the design requirements, and the workpiece is post-processed to obtain a finished workpiece. Post-processing includes surface treatment and the like.

[0085] In this embodiment, in order to ensure the molding quality, the above process is optimized again, specifically:

[0086] This process includes the following steps:

[0087] S1. Preparation: prepare the semi-finished workpiece to be processed, pre-treat it, and select the corresponding mold;

[0088] The above S2 includes the following S20, S21 and S22.

[0089] S20, DMD molding: Put the polished and cleaned workpiece between the upper mold and the lower mold. At this time, the upper part of the workpiece is tightly attached to the lower part of the upper mold. The mold with the workpiece is placed on the DMD working device. The metal powder is melted and deposited at the molding hole to form a corresponding set structure on the workpiece.

[0090] S21, auxiliary operation: while the DMD operation device is operating, the heating mechanism at the upper mold keeps the upper mold at a relatively high set temperature, and the cooling mechanism at the lower mold keeps the lower mold at a relatively low set temperature;

[0091] S22, demoulding: after the DMD molding operation is completed, the upper mold and the lower mold are separated, the molded workpiece is taken out, and then the set structure formed on the workpiece is deburred;

[0092] S3, external processing: the set structure is processed to meet the design requirements, and the workpiece is post-processed to obtain a finished workpiece. In this embodiment, the post-processing is shaping and sandblasting.

[0093] The limiting structure adopts a prefabricated structure, the material of the prefabricated structure is the same as that of the workpiece, and is formed by extrusion;

[0094] The end of the prefabricated structure abuts against the surface of the workpiece, and the side wall forms a limit. The DMD operation fills the prefabricated structure with metal powder, and together with the prefabricated structure, it forms a set structure.

[0095] The operating area of ​​this forced-limited additive process is the forming hole of the upper mold. It can be understood that the printing operation is carried out at the set position of the semi-finished workpiece, and the printing operation is forced to be limited by the forming hole, which can ensure that the corresponding part structure is stably formed at the set position of the semi-finished workpiece.

[0096] During the printing process, since the upper template has a relatively high temperature and the lower template has a relatively low temperature, the printing operation can avoid the condensation speed of the part structure at the printing operation after being subjected to the above-mentioned effects, and avoid the increase in thermal deformation and stress caused by turbulence and heat accumulation in the thickness direction, thereby effectively improving the printing effect.

[0097] In this embodiment, the mold is tested for DMD before operation, and the test conditions are:

[0098] Substrate: 3mm7075 aluminum alloy as an example;

[0099] Aluminum wire: ER7075, D=1.2mm;

[0100] Protective gas: xenon 5L / min;

[0101] Scanning speed: 40mm / s;

[0102] Laser power: 2600W;

[0103] Wire feeding speed: 1600mm / min;

[0104] Batch operations will only be carried out after 3D printing operations can be stably implemented.

[0105] This process has the following characteristics:

[0106] (1) Faster deposition rate

[0107] For the deposition wall without forced limited cooling and heating, in the early stage of deposition, since the two sides of the molten pool are in contact with air, the molten pool flows dynamically to the two sides, and the speed of the molten pool flowing to the two sides is greater than the speed of flowing to the middle; in the middle and late stages of deposition, the trends of the molten pool flowing to the middle and to the two sides reach a dynamic balance. Therefore, the deposition speed of the deposition wall gradually decreases in the early stage, and remains basically unchanged after reaching equilibrium. In a unit deposition cycle, the average deposition height is 4.2 mm.

[0108] For the deposition wall with forced limiting cooling and heating, during the entire deposition process, due to the existence of side limiting, the tendency of the molten pool to flow dynamically to both sides is limited, and dynamic reflux occurs to the middle, so that the molten pool is concentrated in the set spatial area. Therefore, the deposition speed of the deposition wall remains basically unchanged during the entire deposition process, and the average deposition speed is greater than that of the wall without forced limiting cooling.

[0109] The upper mold temperature is 250° C. under the action of the heating mechanism, and the lower mold temperature is 0° C. under the action of the cooling mechanism. In a unit deposition cycle, the deposition height is 5.2 mm.

[0110] (2) Higher utilization rate of deposited materials

[0111] For the deposition wall without forced limit cooling and heating, the material utilization of the deposition wall is low due to the absence of forced limit. In the height direction of the deposition wall, the side depression and side convexity of the deposition wall are more serious, and the average material utilization rate is 78.2%.

[0112] For the deposition wall with forced limit cooling and heating, the material utilization of the deposition wall is high due to the existence of forced limit. In the height direction of the deposition wall, the side concave and side convex phenomena of the deposition wall are not obvious, and the material utilization rate is 83.2%.

[0113] (3) Better deposition quality

[0114] There is no forced limited cooling and heating of the deposition wall. On the lower side of the deposition wall, since the deposition process is in the initial stage, the heat input accumulation of the lower wall is small, the pore escape rate is fast, and the porosity of the wall here is small. In the middle of the deposition wall, since the deposition process is in the middle stage, the heat input accumulation of the middle wall increases, the pore escape rate slows down, and the porosity of the wall here increases. On the upper side of the deposition wall, since the deposition process is in the final stage, the heat input accumulation of the upper wall is the largest, the pore escape rate is the slowest, and the porosity of the wall here is the largest.

[0115] There is forced limited cooling and heating of the deposition wall. Due to the forced limited cooling process, the heat transfer of the wall is faster during the deposition process, the cumulative effect of the heat input of the deposition wall is not obvious, the pore escape rate is faster, the pore degree of the deposition wall is smaller, and it remains basically consistent. The pore defect of the deposition wall is alleviated.

[0116] Embodiment 2

[0117] The shell additive structure of this embodiment is different from that of the first embodiment in that the structural feature is located in the middle of the shell bottom plate and is larger in size than the structural feature in the first embodiment.

[0118] The shell of the electronic product includes a shell bottom plate and a group of structural features located in the middle area of ​​the shell bottom plate. The structural features are structures such as a frustum, a rectangular boss, and a special-shaped boss. The minimum wall thickness of the internal structure is not less than 0.8 mm. The structural features are formed accordingly by extrusion profiles. The extrusion profiles are cut to a length that is highly consistent with the structural features and are fixed to the shell bottom plate by a fixture to form a limiting structure. The positioning accuracy is improved, and the DMD additive process is performed within the structural features to fill the metal powder / metal wire into the limiting structure.

[0119] S1. Preparation: prepare the semi-finished workpiece to be processed, pre-treat it, and select the corresponding mold;

[0120] S2, DMD molding preparation: construct a limiting structure outside the area to be added on the semi-finished workpiece, place the workpiece provided with the limiting structure on the DMD operation device, melt the metal powder / metal wire at the limiting structure and then deposit on the workpiece, and fill between the limiting structures to form a corresponding set structure;

[0121] The limiting structure is composed of a prefabricated structure, the outer contour of the prefabricated structure is consistent with the outer contour of the structural feature, the DMD additive process corresponds to adding material in the prefabricated structure, the prefabricated structure forms a limit for the DMD additive and forms a part of the structural feature in the shell;

[0122] The limiting structure adopts a prefabricated structure, the material of the prefabricated structure is the same as that of the workpiece, and is formed by extrusion;

[0123] The end of the prefabricated structure abuts against the surface of the workpiece, and the side wall forms a limit. The DMD operation fills the prefabricated structure with metal powder, and together with the prefabricated structure, it forms a set structure.

[0124] S3, external processing: the set structure is processed to meet the design requirements, and the workpiece is post-processed to obtain a finished workpiece.

[0125] The limiting structure is composed of a prefabricated structure, the outer contour of the prefabricated structure is consistent with the outer contour of the structural feature, the DMD additive process corresponds to the additive in the prefabricated structure, the prefabricated structure limits the DMD additive and forms part of the structural feature in the shell.

[0126] The limiting structure adopts a prefabricated structure, the material of the prefabricated structure is the same as that of the workpiece, and is formed by extrusion;

[0127] Specifically, a rectangular convex portion is formed, and the prefabricated structure is extruded into a rectangular tube structure; an L-shaped convex portion is formed, and the prefabricated structure is extruded into a matching L-shaped profile; a circular convex portion is formed, and the prefabricated structure is extruded into a circular tube structure; the structural feature of the additive is located at the inner wall of the shell, and the prefabricated structure is non-closed, and an opening is reserved for combination with the side wall of the shell.

[0128] The end of the prefabricated structure abuts against the surface of the workpiece, and the side wall forms a limit. The DMD operation fills the prefabricated structure with metal powder, and together with the prefabricated structure, it forms a set structure.

[0129] This process has the following characteristics:

[0130] (1) Faster deposition rate

[0131] For the deposition wall without forced limited cooling and heating, in the early stage of deposition, since the two sides of the molten pool are in contact with air, the molten pool flows dynamically to the two sides, and the speed of the molten pool flowing to the two sides is greater than the speed of flowing to the middle; in the middle and late stages of deposition, the trends of the molten pool flowing to the middle and to the two sides reach a dynamic balance. Therefore, the deposition speed of the deposition wall gradually decreases in the early stage, and remains basically unchanged after reaching equilibrium. In a unit deposition cycle, the average deposition height is 4.2 mm.

[0132] For the deposition wall with forced limiting cooling and heating, during the entire deposition process, due to the existence of side limiting, the tendency of the molten pool to flow dynamically to both sides is limited, and dynamic reflux occurs to the middle, so that the molten pool is concentrated in the set spatial area. Therefore, the deposition speed of the deposition wall remains basically unchanged during the entire deposition process, and the average deposition speed is greater than that of the wall without forced limiting cooling.

[0133] The upper and lower molds are heated to 200° C. by the heating mechanism, and cooled to 20° C. by the cooling mechanism. In a unit deposition cycle, the deposition height is 5.4 mm.

[0134] (2) Higher utilization rate of deposited materials

[0135] For the deposition wall without forced limit cooling and heating, the material utilization of the deposition wall is low due to the absence of forced limit. In the height direction of the deposition wall, the side concavity and side convexity of the deposition wall are more serious, and the average material utilization rate is 79.3%.

[0136] For the deposition wall with forced limit cooling and heating, the material utilization of the deposition wall is high due to the existence of forced limit. In the height direction of the deposition wall, the side concavity and side convexity of the deposition wall are not obvious, and the average material utilization rate is 83.2%.

[0137] (3) Better deposition quality

[0138] There is no forced limited cooling and heating of the deposition wall. On the lower side of the deposition wall, since the deposition process is in the initial stage, the heat input accumulation of the lower wall is small, the pore escape rate is fast, and the porosity of the wall here is small. In the middle of the deposition wall, since the deposition process is in the middle stage, the heat input accumulation of the middle wall increases, the pore escape rate slows down, and the porosity of the wall here increases. On the upper side of the deposition wall, since the deposition process is in the final stage, the heat input accumulation of the upper wall is the largest, the pore escape rate is the slowest, and the porosity of the wall here is the largest.

[0139] There is forced limited cooling and heating of the deposition wall. Due to the forced limited cooling process, the heat transfer of the wall is faster during the deposition process, the cumulative effect of the heat input of the deposition wall is not obvious, the pore escape rate is faster, the pore degree of the deposition wall is smaller, and it remains basically consistent. The pore defect of the deposition wall is alleviated.

[0140] Embodiment 3

[0141] The operation process of this embodiment is the same as that of the first embodiment, except that the temperatures of the upper mold and the lower mold are changed.

[0142] The DMD mold in step S21 includes an upper mold and a lower mold, wherein the upper mold and the lower mold are provided with temperature control pipes, and the temperature control pipes are used to heat or cool the upper mold and the lower mold according to the DMD process requirements;

[0143] Furthermore, the shell bottom plate is held fixed by an upper mold and a lower mold, and the upper mold is provided with a hole structure for limiting, and the hole corresponds to the structural feature and is used for filling and limiting in the DMD additive process.

[0144] The programmed control of the temperature of the DMD mold refers to the programmed real-time regulation of the temperature of the DMD mold during the deposition process through a control system linked to the deposition equipment, wherein the control system automatically adjusts the heating and / or cooling device according to a preset temperature curve or feedback signal to keep the DMD mold within a set temperature range.

[0145] This process has the following characteristics:

[0146] (1) Faster deposition rate

[0147] For the deposition wall without forced limited cooling and heating, in the early stage of deposition, since the two sides of the molten pool are in contact with air, the molten pool flows dynamically to the two sides, and the speed of the molten pool flowing to the two sides is greater than the speed of flowing to the middle; in the middle and late stages of deposition, the trends of the molten pool flowing to the middle and to the two sides reach a dynamic balance. Therefore, the deposition speed of the deposition wall gradually decreases in the early stage, and remains basically unchanged after reaching equilibrium. In a unit deposition cycle, the average deposition height is 4.2 mm.

[0148] For the deposition wall with forced limiting cooling and heating, during the entire deposition process, due to the existence of side limiting, the tendency of the molten pool to flow dynamically to both sides is limited, and dynamic reflux occurs to the middle, so that the molten pool is concentrated in the set spatial area. Therefore, the deposition speed of the deposition wall remains basically unchanged during the entire deposition process, and the average deposition speed is greater than that of the wall without forced limiting cooling.

[0149] The upper and lower molds are heated to 300° C. by the heating mechanism, and cooled to 20° C. by the cooling mechanism. In a unit deposition cycle, the deposition height is 5.1 mm.

[0150] (2) Higher utilization rate of deposited materials

[0151] For the deposition wall without forced limit cooling and heating, the material utilization of the deposition wall is low due to the absence of forced limit. In the height direction of the deposition wall, the side depression and side convexity of the deposition wall are more serious, and the average material utilization rate is 79.2%.

[0152] For the deposition wall with forced limit cooling and heating, the material utilization of the deposition wall is high due to the existence of forced limit. In the height direction of the deposition wall, the side concavity and side convexity of the deposition wall are not obvious, and the average material utilization rate is 83.2%.

[0153] (3) Better deposition quality

[0154] There is no forced limited cooling and heating of the deposition wall. On the lower side of the deposition wall, since the deposition process is in the initial stage, the heat input accumulation of the lower wall is small, the pore escape rate is fast, and the porosity of the wall here is small. In the middle of the deposition wall, since the deposition process is in the middle stage, the heat input accumulation of the middle wall increases, the pore escape rate slows down, and the porosity of the wall here increases. On the upper side of the deposition wall, since the deposition process is in the final stage, the heat input accumulation of the upper wall is the largest, the pore escape rate is the slowest, and the porosity of the wall here is the largest.

[0155] There is forced limited cooling and heating of the deposition wall. Due to the forced limited cooling process, the heat transfer of the wall is faster during the deposition process, the cumulative effect of the heat input of the deposition wall is not obvious, the pore escape rate is faster, the pore degree of the deposition wall is smaller, and it remains basically consistent. The pore defect of the deposition wall is alleviated.

[0156] Embodiment 4

[0157] like Figure 7-9 As shown, the fourth embodiment adopts a prefabricated structure to limit the DMD process. According to the additive structural feature, a profile is extruded as the prefabricated structure. The outer contour of the profile is the same as the outer contour of the structural feature. The prefabricated structure is fixed by a mold and abuts against the shell surface. The mold positions the prefabricated structure in the structural feature area and forms a corresponding limiting structure at the structural feature, and cooperates with the DMD additive process to form the structural feature.

[0158] Further, the prefabricated structure is fixed on the shell by laser welding and corresponds to the structural feature for DMD molding of the structural feature;

[0159] Furthermore, the prefabricated structure is formed into a mold for fixing the prefabricated structure through a molding process, and the prefabricated structure is formed and positioned through the above mold, and the structural features are formed and prefabricated in cooperation with the DMD process;

[0160] Furthermore, the prefabricated structure is forged / stamped on the surface of the shell structure to form a corresponding protrusion structure for positioning, and the structural features are formed in cooperation with the DMD process;

[0161] Furthermore, the prefabricated structure can form a heat conduction structure with the temperature control system on the mold to heat and cool the DMD area, improve the molding quality during the DMD additive process, and cooperate with the prefabricated structure to perform high-precision molding of structural features.

[0162] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0163] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, appropriate changes and modifications to the above embodiments are within the scope of protection claimed by the present invention.

Claims

1. An electronic product housing, characterized in that: include Shell and base plate, At least one set of internal structural features, wherein the structural features are formed on the surface of the bottom plate of the shell by using an additive process, and the structural features are formed by a limiting structure that limits the molding contour and combined with a DMD additive process.

2. A forced position limiting DMD additive process according to claim 1, characterized in that: The process includes the following steps: S1. Preparation: prepare the semi-finished workpiece to be processed, pre-process it, and select the corresponding limit structure; The limiting structure includes a combination of one or more of a mold structure, a prefabricated structure, and a semi-finished main structure; S2, DMD molding preparation: construct a limiting structure outside the area to be added on the semi-finished workpiece, place the workpiece provided with the limiting structure on the DMD operation device, melt the metal powder / metal wire at the limiting structure and then deposit on the workpiece, and fill between the limiting structures to form a corresponding set structure; S3, external processing: the set structure is processed to meet the design requirements, and the workpiece is post-processed to obtain a finished workpiece.

3. According to the forced limiting DMD additive process described in claim 2, its feature is that the limiting structure is formed by combining the DMD mold and the bottom of the shell, the limiting structure corresponds to the structural feature, and the DMD additive process performs additive operations on the inner side of the limiting structure.

4. A forced position-limited DMD additive process according to claim 3, characterized in that: This process includes the following steps: S1. Preparation: prepare the semi-finished workpiece to be processed, pre-treat it, and select the corresponding mold; S20, DMD molding: Put the polished and cleaned workpiece between the upper mold and the lower mold. At this time, the upper part of the workpiece is tightly attached to the lower part of the upper mold. The upper mold and the lower mold position the workpiece. The mold with the workpiece is placed on the DMD working device. The metal powder / metal wire is melted and deposited at the molding hole to form a corresponding set structure on the workpiece. S21, auxiliary operation: while the DMD operation device is operating, the temperature of the DMD mold is controlled by a control system during the deposition process. S22, demoulding: after the DMD molding operation is completed, the upper mold and the lower mold are separated, the molded workpiece is taken out, and then the set structure formed on the workpiece is deburred; S3. External treatment: The workpiece after deburring is subjected to surface treatment to obtain a finished workpiece.

5. A forced position limiting DMD additive process according to claim 4, characterized in that: The upper mold and the lower mold in step S21 are provided with a temperature control system, and the temperature control system heats or cools the upper mold and the lower mold according to the DMD process requirements; Furthermore, the shell bottom plate is held fixed by an upper mold and a lower mold, and the upper mold is provided with a hole structure for limiting, and the hole corresponds to the structural feature and is used for filling and limiting in the DMD additive process.

6. According to claim 5, a forced position-limited DMD additive process is characterized in that: The control system controls the temperature of the DMD mold, which means that during the deposition process, the temperature of the DMD mold is programmed and controlled in real time, wherein the control system automatically adjusts the heating and / or cooling of the upper mold and the lower mold according to a preset temperature curve or feedback signal to keep the DMD mold within a set temperature range.

7. According to claim 2, a forced position-limited DMD additive process is characterized in that: The limiting structure is composed of a prefabricated structure, the outer contour of the prefabricated structure is consistent with the outer contour of the structural feature, the DMD additive process corresponds to adding material in the prefabricated structure, the prefabricated structure forms a limit for the DMD additive and forms a part of the structural feature in the shell; Furthermore, the prefabricated structure is open and combined with the product side wall to form a closed loop structure to limit the DMD additive.

8. A forced position-limited DMD additive process according to claim 7, characterized in that: The limiting structure adopts a prefabricated structure, the material of the prefabricated structure is the same as that of the workpiece, and is formed by extrusion or bending; The end of the prefabricated structure abuts against the surface of the workpiece, and the side wall forms a limiting structure. The DMD operation fills the prefabricated structure with metal powder / metal wire, and together with the prefabricated structure, it forms a set structure.

9. A forced position-limited DMD additive process according to claim 8, characterized in that: The surface treatment in step S3 is shaping and sandblasting.

10. A forced position-limited DMD additive process according to claim 9, characterized in that: The shell bottom plate is formed by forging or stamping process.

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