Oscillating hot-press sintering process and equipment based on single and double switching

Abstract

The oscillating hot-pressing sintering process and equipment based on single and bidirectional switching includes single-direction oscillating hot-pressing, in which one end of the upper and lower pressure heads is locked, and the other end is used to implement single-direction oscillating hot-pressing on the sintered material; and bidirectional synchronous oscillating hot-pressing, in which the upper and lower pressure heads move synchronously, and implement synchronous bidirectional oscillating hot-pressing on the sintered material. The equipment includes a hydraulic station for providing a hydraulic power source, an upper pressure head and an upper pressure head cylinder, a lower pressure head and a lower pressure head cylinder, a reversing switching valve group for switching the working state of oscillating hot-pressing, and two control valve groups for controlling the pressure and flow of the pressure head cylinder. The input end of the reversing switching valve group is connected with the hydraulic station, the reversing switching valve group has two output ends, and the two output ends are connected with the upper pressure head cylinder and the lower pressure head cylinder through a control valve group, respectively. The oscillating hot-pressing sintering process and equipment based on single and bidirectional switching has the advantages of effectively improving the sintering quality, controllable cost, high efficiency and wide application range.

Description

Technical Field

[0001] This invention relates to the field of oscillating hot pressing sintering technology, and more particularly to an oscillating hot pressing sintering process and equipment based on bidirectional switching. Background Technology

[0002] The vibrating hot pressing sintering furnace is a mechanically pressurized sintering device. This equipment loads ceramic powder into a mold cavity and heats the powder to the firing temperature while simultaneously applying pressure. Because the driving force is supplemented by external pressure, densification can be achieved in a relatively short time, resulting in a microstructure with fine and uniform grains. Therefore, for high-temperature ceramic materials with difficult-to-sinter covalent bonds (such as Si3N4, B4C, SiC, TiB2, ZrB2, etc.), vibrating hot pressing sintering is an effective densification technique.

[0003] Existing oscillating hot pressing sintering furnaces employ either unidirectional oscillating hot pressing or bidirectional synchronous oscillating hot pressing. When using these two existing processes, oscillating sintering promotes the rearrangement of particles in the sintered material, accelerates volume shrinkage, and achieves rapid densification. This can significantly improve the density and density uniformity of the sintered material, greatly increasing work efficiency while reducing energy consumption and sintering time, and also reducing environmental pollution.

[0004] However, existing unidirectional oscillating hot pressing processes, because they apply oscillating hot pressing to the sintered material only from a single direction, result in better density and uniformity on the side closer to the oscillating hot pressing head during particle rearrangement, while the rearrangement effect is relatively weaker on the side farther from the head. This is especially problematic for thicker sintered workpieces, making it difficult to guarantee processing quality. Existing bidirectional synchronous oscillating hot pressing processes, because they forge the sintered material synchronously in both directions from beginning to end, make it difficult for tiny air bubbles located in the center of the sintered material to escape during particle rearrangement. Subsequent inspection revealed residual air bubbles on the material cross-section. Theoretically, the best processing effect is achieved when bidirectional synchronous pressure is applied and the amplitudes offset each other; however, the difficulty in controlling the transmission speed and response accuracy of the hydraulic circuit prevents the sintered material from achieving the ideal optimal processing effect. Summary of the Invention

[0005] This invention provides a oscillating hot pressing sintering process and equipment based on single and bidirectional switching, which can effectively improve sintering quality, control costs, increase efficiency, and have a wide range of applications.

[0006] An oscillatory hot pressing sintering process based on unidirectional and bidirectional switching includes the following steps during oscillatory hot pressing sintering:

[0007] Unidirectional oscillating hot pressing: One end of the pressure head at both ends is locked, and the other end is used to apply unidirectional oscillating hot pressing to the material to be sintered;

[0008] Bidirectional synchronous oscillating hot pressing: The pressure heads at the upper and lower ends move synchronously relative to each other, and synchronous bidirectional oscillating hot pressing is applied to the sintered material;

[0009] The unidirectional oscillating hot pressing and bidirectional synchronous oscillating hot pressing are performed alternately.

[0010] As a further improvement to the above technical solution:

[0011] When performing oscillatory hot pressing sintering, follow these steps:

[0012] S1: Unidirectional oscillating hot pressing;

[0013] S2: Bidirectional synchronous oscillating hot pressing.

[0014] When performing step S1, the lower pressure head is locked, and the upper pressure head is used to perform unidirectional oscillatory hot pressing on the sintered material; or the upper pressure head is locked, and the lower pressure head is used to perform unidirectional oscillatory hot pressing on the sintered material.

[0015] When performing step S1, first lock one end of the pressure head, and use the other end of the pressure head to perform the first unidirectional oscillating hot pressing on the sintered material. Then switch the working state of the two end pressure heads and perform the second unidirectional oscillating hot pressing in the opposite direction.

[0016] When implementing step S1, the duration of one unidirectional oscillating hot pressing is T1, and the duration of one bidirectional synchronous oscillating hot pressing is T2, with 5min≤T1≤20min and 5min≤T2≤20min.

[0017] An oscillating hot pressing sintering device based on bidirectional switching includes a hydraulic station for providing a hydraulic power source, an upper pressure head and an upper pressure head cylinder, a lower pressure head and a lower pressure head cylinder, a reversing valve group for switching the oscillating hot pressing working state, and two sets of control valve groups for controlling the pressure and flow of the pressure head cylinders. The input end of the reversing valve group is connected to the hydraulic station, and the reversing valve group has two output ends, which are respectively connected to the upper pressure head cylinder and the lower pressure head cylinder through a set of control valve groups.

[0018] As a further improvement to the above technical solution:

[0019] It also includes a controller, two pressure sensors for real-time detection of the pressure of the upper and lower pressure head cylinders respectively, and two displacement sensors for real-time detection of the displacement of the upper and lower pressure heads respectively. The pressure sensors and displacement sensors are electrically connected to the controller and transmit the collected information to the controller. The controller is electrically connected to two control valve groups and controls the operation of the two control valve groups according to the collected information.

[0020] The controller is electrically connected to the reversing valve group and controls the reversing valve group to switch between oscillating hot pressing working states according to the control command.

[0021] The control valve assembly includes an oscillating pressure-flow module and a constant pressure-flow module.

[0022] The present invention relates to an oscillating hot pressing sintering process based on unidirectional and bidirectional switching. This process alternates between unidirectional and bidirectional synchronous oscillating hot pressing, fully utilizing the advantages of both methods. Unidirectional oscillating hot pressing improves the degassing effect during the particle rearrangement process of the sintered material, preventing residual air bubbles in the sintered product. Bidirectional synchronous oscillating hot pressing enhances the density and density uniformity of the sintered material, significantly improving processing quality and yield, especially for thicker sintered workpieces. Furthermore, the alternation between unidirectional and bidirectional synchronous oscillating hot pressing further improves the sintering yield and efficiency.

[0023] The oscillating hot pressing sintering equipment based on unidirectional and bidirectional switching of the present invention can switch the oscillating hot pressing working state by switching the switching valve group, and realize the state switching between unidirectional oscillating hot pressing and bidirectional synchronous oscillating hot pressing. Thus, multiple sintering states can be adjusted on a single oscillating hot pressing sintering equipment, providing hardware support for realizing the unidirectional and bidirectional switching oscillating hot pressing sintering process. Attached Figure Description

[0024] Figure 1 This is a flowchart of an embodiment of the oscillating hot pressing sintering process based on bidirectional switching of the present invention.

[0025] Figure 2 This is a schematic diagram of an embodiment of the oscillating hot pressing sintering equipment based on bidirectional switching of the present invention.

[0026] The labels in the diagram represent:

[0027] 1. Lower pressure head; 2. Upper pressure head; 3. Hydraulic station; 4. Reversing valve assembly; 5. Control valve assembly; 51. Oscillating pressure and flow module; 52. Constant pressure and flow module; 6. Upper pressure head cylinder; 7. Lower pressure head cylinder; 8. Controller; 9. Pressure sensor; 10. Displacement sensor. Detailed Implementation

[0028] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0029] The oscillating hot pressing sintering process based on unidirectional and bidirectional switching in this embodiment is as follows: Figure 1 As shown, the process of performing oscillatory hot pressing sintering includes:

[0030] Unidirectional oscillating hot pressing: One end of the pressure head at both ends is locked, and the other end is used to apply unidirectional oscillating hot pressing to the material to be sintered;

[0031] Bidirectional synchronous oscillating hot pressing: The pressure heads at the upper and lower ends move synchronously relative to each other, and synchronous bidirectional oscillating hot pressing is applied to the sintered material;

[0032] Unidirectional oscillating hot pressing and bidirectional synchronous oscillating hot pressing are performed alternately.

[0033] In this embodiment, the following steps are performed during oscillatory hot pressing sintering:

[0034] S1: Unidirectional oscillating hot pressing;

[0035] S2: Bidirectional synchronous oscillating hot pressing.

[0036] The present invention relates to an oscillating hot pressing sintering process based on unidirectional and bidirectional switching. This process alternates between unidirectional and bidirectional synchronous oscillating hot pressing, fully utilizing the advantages of both methods. Unidirectional oscillating hot pressing improves the degassing effect during the particle rearrangement process of the sintered material, preventing residual air bubbles in the sintered product. Bidirectional synchronous oscillating hot pressing enhances the density and density uniformity of the sintered material, significantly improving processing quality and yield, especially for thicker sintered workpieces. Furthermore, the alternation between unidirectional and bidirectional synchronous oscillating hot pressing further improves the sintering yield and efficiency.

[0037] In this embodiment, when performing step S1, one end of the pressure head is first locked, and the other end of the pressure head is used to perform a first unidirectional oscillating hot pressing on the sintered material. Then, the working states of both pressure heads are switched to perform a second unidirectional oscillating hot pressing in the opposite direction. In other embodiments, when performing step S1, the lower end pressure head 1 can be locked, and the upper end pressure head 2 can be used to perform unidirectional oscillating hot pressing on the sintered material; alternatively, the upper end pressure head 2 can be locked, and the lower end pressure head 1 can be used to perform unidirectional oscillating hot pressing on the sintered material.

[0038] In this embodiment, when implementing step S1, the duration of one unidirectional oscillating hot pressing is T1, and the duration of one bidirectional synchronous oscillating hot pressing is T2. Typically, the values ​​of T1 and T2 are in the range of 5min≤T1≤20min and 5min≤T2≤20min. In this embodiment, T1 is 15min and T2 is 20min.

[0039] like Figure 2As shown, the oscillating hot pressing sintering equipment based on unidirectional and bidirectional switching in this embodiment includes a hydraulic station 3 for providing hydraulic power, an upper pressure head 2 and an upper pressure head cylinder 6, a lower pressure head 1 and a lower pressure head cylinder 7, a reversing valve group 4 for switching the oscillating hot pressing working state, and two sets of control valve groups 5 for controlling the pressure and flow of the pressure head cylinders. The input end of the reversing valve group 4 is connected to the hydraulic station 3, and the reversing valve group 4 has two output ends, which are respectively connected to the upper pressure head cylinder 6 and the lower pressure head cylinder 7 via a set of control valve groups 5. The oscillating hot pressing sintering equipment based on unidirectional and bidirectional switching of this invention can switch between unidirectional oscillating hot pressing and bidirectional synchronous oscillating hot pressing by switching the oscillating hot pressing working state through the reversing valve group 4, thereby realizing the adjustment of multiple sintering states on a single oscillating hot pressing sintering equipment and providing hardware support for realizing the unidirectional and bidirectional switching oscillating hot pressing sintering process.

[0040] In this embodiment, the system also includes a controller 8, two pressure sensors 9 for real-time detection of the pressure of the upper pressure head cylinder 6 and the lower pressure head cylinder 7, and two displacement sensors 10 for real-time detection of the displacement of the upper pressure head 2 and the lower pressure head 1. The pressure sensors 9 and the displacement sensors 10 are electrically connected to the controller 8 and transmit the collected information to the controller 8. The controller 8 is electrically connected to the two control valve groups 5 and controls the operation of the two control valve groups 5 according to the collected information. By using the pressure sensors 9 and the displacement sensors 10 to detect the pressure of the upper and lower pressure head cylinders and the displacement of the upper and lower pressure heads, the system can provide real-time feedback on the state of the sintered material and the upper and lower pressure heads. The controller 8 can also adjust the two control valve groups 5 in a timely manner according to the collected information, so that the actual pressure and stress state of the sintered material is closer to the ideal state.

[0041] In this embodiment, the controller 8 is electrically connected to the reversing valve group 4, and controls the reversing valve group 4 to switch the oscillating hot pressing working state according to the control command.

[0042] In this embodiment, the control valve group 5 includes an oscillating pressure and flow module 51 and a constant pressure and flow module 52. The oscillating pressure and flow module 51 is used to control the output of oscillating hydraulic pressure, and the constant pressure and flow module 52 is used to control the output of constant hydraulic pressure.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A oscillating hot pressing sintering process based on unidirectional and bidirectional switching, characterized in that, The process of performing oscillatory hot pressing sintering includes: Unidirectional oscillating hot pressing: One end of the pressure head at both ends is locked, and the other end is used to apply unidirectional oscillating hot pressing to the material to be sintered; Bidirectional synchronous oscillating hot pressing: The pressure heads at the upper and lower ends move synchronously relative to each other, and synchronous bidirectional oscillating hot pressing is applied to the sintered material; The unidirectional oscillating hot pressing and bidirectional synchronous oscillating hot pressing are performed alternately.

2. The oscillating hot pressing sintering process based on unidirectional and bidirectional switching according to claim 1, characterized in that, When performing oscillatory hot pressing sintering, follow these steps: S1: Unidirectional oscillating hot pressing; S2: Bidirectional synchronous oscillating hot pressing.

3. The oscillating hot pressing sintering process based on unidirectional and bidirectional switching according to claim 2, characterized in that, When performing step S1, the lower end pressure head (1) is locked and the upper end pressure head (2) is used to perform unidirectional oscillatory hot pressing on the sintered material; or the upper end pressure head (2) is locked and the lower end pressure head (1) is used to perform unidirectional oscillatory hot pressing on the sintered material.

4. The oscillating hot pressing sintering process based on unidirectional and bidirectional switching according to claim 2, characterized in that, When performing step S1, first lock one end of the pressure head, and use the other end of the pressure head to perform the first unidirectional oscillating hot pressing on the sintered material. Then switch the working state of the two end pressure heads and perform the second unidirectional oscillating hot pressing in the opposite direction.

5. The oscillating hot pressing sintering process based on unidirectional and bidirectional switching according to any one of claims 2 to 4, characterized in that, When implementing step S1, the duration of one unidirectional oscillating hot pressing is T1, and the duration of one bidirectional synchronous oscillating hot pressing is T2, with 5min≤T1≤20min and 5min≤T2≤20min.

6. A oscillating hot pressing sintering device based on bidirectional switching, comprising a hydraulic station (3) for providing a hydraulic power source, an upper pressure head (2) and an upper pressure head cylinder (6), a lower pressure head (1) and a lower pressure head cylinder (7), characterized in that, It also includes a reversing valve group (4) for switching the working state of oscillating hot pressing, and two sets of control valve groups (5) for controlling the pressure and flow of the pressure head cylinder. The input end of the reversing valve group (4) is connected to the hydraulic station (3). The reversing valve group (4) has two output ends, which are respectively connected to the upper pressure head cylinder (6) and the lower pressure head cylinder (7) through a set of control valve groups (5).

7. The oscillating hot pressing sintering equipment based on unidirectional and bidirectional switching according to claim 6, characterized in that, It also includes a controller (8), two pressure sensors (9) for real-time detection of the pressure of the upper pressure head cylinder (6) and the lower pressure head cylinder (7), and two displacement sensors (10) for real-time detection of the displacement of the upper pressure head (2) and the lower pressure head (1). The pressure sensors (9) and displacement sensors (10) are electrically connected to the controller (8) and transmit the collected information to the controller (8). The controller (8) is electrically connected to two control valve groups (5) and controls the two control valve groups (5) to work according to the collected information.

8. The oscillating hot pressing sintering equipment based on unidirectional and bidirectional switching according to claim 7, characterized in that, The controller (8) is electrically connected to the reversing valve group (4) and controls the reversing valve group (4) to switch the oscillating hot pressing working state according to the control command.

9. The oscillating hot pressing sintering apparatus based on unidirectional and bidirectional switching according to any one of claims 6 to 8, characterized in that, The control valve assembly (5) includes an oscillating pressure-flow module (51) and a constant pressure-flow module (52).

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