Nested mold for extruding silicon carbide
By designing nested molds, the inner mold feed end and extrusion channel with smooth curved surface design solves the serious wear of traditional molds, improves product yield and reduces economic losses.
Patent Information
- Application Number
- CN202420163293.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-23
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-01-23
AI Technical Summary
Traditional silicon carbide extrusion dies have severe wear due to high hardness, which leads to changes in the mold size and can no longer be used, resulting in economic losses.
Design nested molds, and a smooth curved surface design is adopted between the feed end and the extrusion channel of the inner mold, which reduces friction, avoids product cracks and bubbles, and reduces wear of the inner mold. The cost of replacing the inner mold is only 10 of the entire set of molds. %.
It improves product yield, reduces economic losses caused by mold wear, and reduces the cost of internal mold replacement.
Smart Images
Figure CN222222942U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of silicon carbide extrusion production, in particular to a nested die for silicon carbide extrusion. Background Art
[0002] Silicon carbide wafer boats are made of silicon carbide (SiC) and are used to carry semiconductor wafers. They are wear-resistant, hard, corrosion-resistant, resistant to high-temperature shock, high-temperature bearing capacity, high thermal conductivity, small thermal expansion coefficient, and not prone to bending and deformation after long-term use. The main component of the silicon carbide wafer boat, the water drop column, needs to be produced by extrusion molding due to its special structure.
[0003] Due to their high hardness, silicon carbide products cause extremely severe wear on the mold during extrusion molding. Traditional molds are scrapped due to their overall characteristics when they are worn to a certain extent during use and can no longer be used. The mold loss cost caused by the increase in mold size due to wear and tear is one of the important components of extrusion molding. Therefore, how to solve the economic losses caused by mold loss has certain economic value and research significance. Utility Model Content
[0004] In view of the technical problems existing in the silicon carbide extrusion die in the prior art, the first aspect of the utility model proposes a nested die for silicon carbide extrusion, comprising:
[0005] An outer mold, wherein the outer mold is provided with a slot extending from a feed end to a discharge end;
[0006] An inner mold is installed in the slot from the feeding end of the outer mold, and an extrusion channel is provided inside the inner mold for limiting the fed material to a predetermined shape;
[0007] The first end face of the feed end of the outer mold is an oblique line in the radial section of the mold, and the second end face of the feed end of the inner mold is a curve convex toward the axial direction in the radial section of the outer mold.
[0008] Preferably, the second end face of the feeding end of the inner mold is an arc line convex toward the axial direction in the radial section of the outer mold.
[0009] Preferably, the distance between the second end face and the inner edge of the first end face and the outer edge of the extrusion channel in the direction of the mold axis is defined as A, and the depth of the groove is greater than A.
[0010] Preferably, the ratio of the outer diameter of the inner mold to the outer diameter of the outer mold is 0.3-0.5.
[0011] Preferably, the outer diameter of the inner mold is configured so that the inner mold can be circumferentially fixed to the outer mold after being inserted into the slot, and is axially fixed along the material extrusion direction.
[0012] Preferably, the size of the end face of the feeding end of the inner mold is larger than the size of the end face of the discharging end.
[0013] Preferably, the outer diameter of the inner mold is configured into a regular polygonal shape.
[0014] Preferably, the regular polygon has rounded corners.
[0015] Preferably, the discharge end of the inner mold extends to the middle section of the outer mold and is limited by the step surface at the bottom of the slot, and the outer mold is provided with a channel in the extension direction of the extrusion channel.
[0016] Preferably, the discharge end of the inner mold extends to the discharge end of the outer mold.
[0017] Compared with the prior art, the advantages of the utility model are:
[0018] The present application designs a nested mold, and the second end face of the inner mold is designed to be a smooth curved surface. The silicon carbide slurry is subjected to uniform friction before entering the extrusion channel, and no stretching or compression occurs inside. Therefore, no cracks or bubbles occur on the surface of the extruded rod-shaped product, which can improve the product yield. In addition, this design can reduce the wear of the inner mold. Even if the inner mold needs to be replaced due to wear, due to the small size of the inner mold, the replacement cost is only 10% of the entire mold, which can reduce the economic loss caused by mold wear. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the utility model will be described by way of example and with reference to the accompanying drawings, in which:
[0020] Figure 1 It is a schematic structural diagram of a nested die for silicon carbide extrusion shown in the first embodiment of the utility model;
[0021] Figure 2 It is a structural schematic diagram of the outer mold shown in the first embodiment of the utility model;
[0022] Figure 3 It is a structural schematic diagram of the card slot in the outer mold shown in the first embodiment of the utility model;
[0023] Figure 4 It is a structural schematic diagram of the inner mold shown in the first embodiment of the utility model;
[0024] Figure 5 It is a radial section structure diagram of a nested die for silicon carbide extrusion shown in the first embodiment of the utility model;
[0025] Figure 6 It is a radial section structure diagram of a nested die for silicon carbide extrusion shown in the second embodiment of the utility model. DETAILED DESCRIPTION
[0026] In order to better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.
[0027] Based on production experience, the inventors found that after about 10 hours of continuous extrusion, the current mold will suffer severe wear, resulting in the size of the subsequent extruded product exceeding the standard, and the area where the most serious wear occurs is the area of the extrusion mold close to the extrusion channel. Once wear occurs, it will aggravate the wear and lead to inconsistent extrusion pressure, causing the extruded mud to stratify and other phenomena.
[0028] The present application aims to design a nested mold in view of this feature, in which the inner mold is arranged in the transition area between the feed end face and the extrusion channel which is most prone to wear, and a smooth arc surface is designed between the feed end face and the extrusion channel to make the pressure of the mud extrusion consistent.
[0029] Combination Figure 1-5 As shown, the first aspect of the utility model proposes a nested mold for silicon carbide extrusion, including an outer mold 10 and an inner mold 20, the outer mold 10 is provided with a slot 102 extending from the feed end to the discharge end; the inner mold 20 is installed in the slot 102 from the feed end of the outer mold 10, and the interior of the inner mold 20 is provided with an extrusion channel 201 for limiting the fed material to a predetermined shape.
[0030] Optionally, the inner mold 20 is made of 316L stainless steel.
[0031] In this way, when the material to be extruded, such as silicon carbide mud, is extruded from the feed end of the outer mold 10 toward the discharge end, the mud is squeezed at the feed end end faces of the outer mold 10 and the inner mold 20, and is finally extruded from the discharge end of the mold through the extrusion channel 201. In this process, the mud rubs against the feed end end faces of the outer mold 10 and the inner mold 20, and when it is about to enter the extrusion channel 201, the friction force on the mold end face is the largest.
[0032] Therefore, the present application specifically designs the feeding end faces of the outer mold 10 and the inner mold 20 differently, combining Figure 5As shown, the first end face 101 of the feed end of the outer mold 10 is an oblique line in the radial section of the mold, and the second end face 202 of the feed end of the inner mold 20 is a curve convex to the axial direction in the radial section of the outer mold 10.
[0033] Since the second end face 202 is a curved surface, a smooth transition is made between the first end face 101 and the extrusion channel 201. When the clay is extruded toward the extrusion channel 201, the friction force applied to the second end face 202 is much smaller than that applied to a surface with a sharp "fold line" or corner edge. Therefore, the extrusion pressure of the clay is uniform here, and the texture of the rod entering the extrusion channel 201 and being extruded is uniform. At the same time, the second end face 202 is not easily worn.
[0034] Preferably, the second end face 202 of the feeding end of the inner mold 20 is an arc line protruding toward the axial direction in the radial section of the outer mold 10. The arc surface can better complete the transition between the first end face 101 and the extrusion channel 201, reduce the pressure of the mud at this place, and thus reduce the friction.
[0035] Combination Figure 5 As shown, the distance between the second end face 202 extending from the inner edge of the first end face 101 to the outer edge of the extrusion channel 201 in the mold axis direction is defined as A, and the depth of the card slot 102 is greater than A.
[0036] Since the area prone to wear is mainly the transition area extending from the inner edge of the first end face 101 to the outside of the extrusion channel 201, the length of the inner mold 20 only needs to be greater than the length A. However, the closer to the exit of the extrusion channel 201, the smaller the probability of wear. Therefore, the length of the inner mold 20 can be appropriately increased.
[0037] In addition, by controlling the size of the inner mold 20, the replacement cost of the inner mold 20 as a wearing part can also be reasonably controlled. At the same time, the friction force of the mud on the second end face 202 is also taken into consideration when the second end face 202 is of appropriate size. Preferably, the ratio of the outer diameter size of the inner mold 20 to the outer diameter size of the outer mold 10 is 0.3-0.5.
[0038] Furthermore, since the cross-section of the extruded rod is a teardrop shape, the circumferential directions of the inner and outer molds must be well matched, and the outer diameter of the inner mold 20 is constructed so that when the inner mold 20 is inserted into the slot 102, it can be circumferentially fixed to the outer mold 10 and fixed axially along the material extrusion direction.
[0039] Furthermore, the size of the end surface of the feeding end of the inner mold 20 is larger than the size of the end surface of the discharging end. In this way, when the inner mold 20 is inserted into the slot 102 from the feeding end, it can be directly positioned.
[0040] In an optional embodiment, the outer diameter of the inner mold 20 is configured to be a regular polygon. Preferably, the regular polygon is provided with rounded corners.
[0041] Combination Figure 2-4 As shown, in the first optional embodiment, the outer diameter of the inner mold 20 is configured as a regular quadrilateral with rounded corners. The discharge end of the inner mold 20 extends to the middle section of the outer mold 10 and is limited by the step surface 103 at the bottom of the slot 102. The outer mold 10 is provided with a channel 104 in the extension direction of the extrusion channel 201.
[0042] In this way, the inner mold 20 is installed in the slot 102, so that the extrusion channel 201 and the channel 104 can be aligned with each other, and the corners at the junction of the first end face 101 and the second end face 202 can be reduced to avoid stress concentration during the extrusion of the clay material.
[0043] Combination Figure 6 As shown, in the second optional embodiment, the discharge end of the inner mold 20 extends to the discharge end of the outer mold 10. In this way, it is not necessary to set the step surface 103 at the bottom of the slot 102 during manufacturing, and the inner mold 20 can be directly inserted into the outer mold 10, and there is no risk of wear of the outer mold 10.
[0044] In combination with the above embodiments, the present application designs a nested mold, and the second end face of the inner mold is designed to be a smooth curved surface. The silicon carbide mud is subjected to uniform friction before entering the extrusion channel, and no stretching and compression will occur inside. Therefore, no cracks or bubbles will appear on the surface of the extruded rod-shaped product, which can improve the product yield. This design can reduce the wear of the inner mold. Even if the inner mold needs to be replaced due to wear, due to the small size of the inner mold, the replacement cost is only 10% of the entire mold, which can reduce the economic loss caused by mold wear.
[0045] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.
Claims
1. A nested die for silicon carbide extrusion, characterized in that: include: An outer mold (10), wherein the outer mold (10) is provided with a slot (102) extending from a feeding end to a discharging end; An inner mold (20) is installed in the clamping groove (102) from the feeding end of the outer mold (10), and an extrusion channel (201) is provided inside the inner mold (20) for limiting the fed material to a predetermined shape; The first end face (101) of the feed end of the outer mold (10) is an oblique line in the radial section of the mold, and the second end face (202) of the feed end of the inner mold (20) is a curve convex in the axial direction in the radial section of the outer mold (10).
2. The nested die for silicon carbide extrusion according to claim 1, characterized in that: The second end surface (202) of the feeding end of the inner mold (20) is an arc line protruding toward the axial direction in the radial section of the outer mold (10).
3. The nested die for silicon carbide extrusion according to claim 1, characterized in that: The distance between the second end face (202) and the inner edge of the first end face (101) and the outer edge of the extrusion channel (201) in the direction of the mold axis is defined as A, and the depth of the groove (102) is greater than A.
4. The nested die for silicon carbide extrusion according to claim 1, characterized in that: The ratio of the outer diameter of the inner mold (20) to the outer diameter of the outer mold (10) is 0.3-0.
5.
5. The nested die for silicon carbide extrusion according to claim 1, characterized in that: The outer diameter of the inner mold (20) is configured so that when the inner mold (20) is inserted into the slot (102), it can be circumferentially fixed to the outer mold (10) and is axially fixed along the material extrusion direction.
6. The nested die for silicon carbide extrusion according to claim 5, characterized in that: The size of the end face of the feeding end of the inner mold (20) is larger than the size of the end face of the discharging end.
7. The nested die for silicon carbide extrusion according to claim 5, characterized in that: The outer diameter of the inner die (20) is configured in a regular polygonal shape.
8. The nested die for silicon carbide extrusion according to claim 7, characterized in that: The regular polygon is provided with rounded corners.
9. The nested die for silicon carbide extrusion according to claim 1, characterized in that: The discharge end of the inner mold (20) extends to the middle section of the outer mold (10) and is limited by the step surface (103) at the bottom of the slot (102). The outer mold (10) is provided with a channel (104) in the extension direction of the extrusion channel (201).
10. The nested die for silicon carbide extrusion according to claim 1, characterized in that: The discharge end of the inner mold (20) extends to the discharge end of the outer mold (10).