Ceramic tile with dovetail back texture and method of manufacturing the same

Abstract

The application belongs to the technical field of building ceramics, and particularly discloses a ceramic tile with dovetail groove back patterns and a preparation method thereof. The ceramic tile comprises a tile body, and the bottom surface of the tile body is provided with a plurality of center-symmetrical dovetail groove back patterns; the dovetail groove back pattern comprises a convex part and a groove part, wherein: the cross section of the convex part is triangular, and the horizontal inner angle of the triangle away from the center of the tile body is β, and β is not more than 30°; the bottom of the groove part connects the adjacent convex parts end to end, the included angle between the side wall of the groove part away from the center of the tile body and the bottom of the groove part is α, and α is an acute angle; the horizontal inner concave length formed by the groove part and the convex part is e, the horizontal length of the bottom of the groove part is n, and e = n x H%, wherein: H% represents the expansion rate of the green body of the tile body; the vertical height of the groove part is h, and h is 10-20% of the thickness of the tile body. The dovetail groove back pattern of the ceramic tile has a symmetrical structure, and the rivet embedded structure effectively reduces the problems of paving hollowing and falling off.

Description

Technical Field

[0001] This invention belongs to the field of building ceramics technology, and particularly relates to a ceramic brick with dovetail groove back pattern and its preparation method. Background Technology

[0002] Ceramic tiles are prone to hollowing and detachment during installation, severely affecting their performance and safety. Dovetail groove backing is a common anti-detachment structure for ceramic tiles. Currently, the main manufacturing methods for dovetail groove backing ceramic tiles include wet extrusion molding, dry powder pressing molding, and post-processing. Wet extrusion molding is primarily used for thicker ceramic slabs, and its dovetail backing is often a parallel double-sided structure. Post-processing, however, can easily damage the ceramic tile structure, affecting the product's mechanical strength.

[0003] Currently, dovetail groove ceramic tiles formed by dry powder pressing still face challenges such as processing difficulties, difficulty in demolding, and poor adhesion strength. For example, Chinese invention patent CN113756538A discloses a double-sided dovetail groove ceramic tile with a dovetail groove structure on the back, but the hooks of this dovetail groove structure are opposite, making demolding difficult. Chinese patent CN112060290A discloses a concentric ring single-sided dovetail groove ceramic tile, which utilizes the instantaneous expansion of the green body during demolding to form a symmetrical single-sided dovetail groove; the dovetail groove back pattern of this tile is symmetrical around the center of the tile, and the protrusions formed by the back pattern form an acute angle with the horizontal plane, with the angle gradually increasing from the center of the tile outwards. This structural design has certain problems. First, the dovetail hook structure near the center is small, resulting in lower pull-out strength at the actual test center. Second, the acute angles formed in the dovetail back pattern gradually increase from the center of the tile to the outside, causing inconsistent back pattern thickness in different parts of the tile. This increases the inconsistency of the internal structure of the tile, thereby increasing local stress concentration and affecting the mechanical properties and machinability of the tile. Furthermore, the acute angles formed in the dovetail back pattern gradually increase from the center of the tile to the outside, meaning that the structure and size of each dovetail groove are different. This greatly increases the difficulty of processing the corresponding mold and increases the cost of mold preparation.

[0004] Meanwhile, because the volume expansion characteristics of dry-pressed ceramic tile green bodies during demolding are directly related to their specifications, thickness, powder properties, molding pressure, and molding speed, it is difficult to use a uniform method to process dovetail forming molds. Therefore, there is an urgent need to provide specific dimensional parameters for the dovetail groove back pattern that can be customized according to actual conditions, in order to further improve the bonding strength of ceramic tiles and prevent them from falling off. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a ceramic tile with a dovetail groove back pattern and a method for preparing the same. The ceramic tile has a dovetail groove back pattern structure with a specific symmetrical structure, and the rivet embedded structure makes the bonding strength higher, which can effectively reduce the hollowness and detachment of the ceramic tile during installation.

[0006] To address the aforementioned technical problems, a first aspect of the present invention provides a ceramic tile, comprising a tile body, wherein the bottom surface of the tile body is provided with a plurality of dovetail grooves symmetrical about a central point; the dovetail grooves include:

[0007] The protrusion has a triangular cross-section, and the horizontal interior angle of the triangle away from the center of the brick is β, where β does not exceed 30°.

[0008] The groove portion connects the adjacent protrusions end to end at its bottom. The angle formed by the sidewall of the groove portion away from the center of the brick and the bottom of the groove portion is α, and α is an acute angle. The horizontal concave length formed by the groove portion and the protrusions is e, and the horizontal length of the bottom of the groove portion is n, where e = n × H%, and H% represents the expansion rate of the brick body. The vertical height of the groove portion is h, and h is 10-20% of the thickness of the brick body.

[0009] Specifically, the ceramic tile of the present invention has a dovetail groove pattern on its bottom, comprising a raised portion and a recessed portion. The cross-section of the raised portion is triangular. Compared with the traditional arc-shaped structure, the triangular structure is easier to process, and the triangular structure allows for a wider range of mold movement during demolding, making demolding easier. Simultaneously, the dovetail groove has a larger space during installation, accommodating more adhesive material and resulting in better bonding. The horizontal interior angle β of the triangle away from the center of the tile body is controlled to not exceed 30° to prevent damage to the tip structure of the raised portion during demolding. Furthermore, the horizontal concave length e formed by the groove and the raised portion is determined by the tile's body expansion rate, which not only facilitates demolding but also significantly improves the bonding strength during installation.

[0010] Meanwhile, during the dry-process pressing of the dovetail groove back pattern of the ceramic tile of this invention, the spray-granulated powder is subjected to pressure within the molding cavity, and the powder is pressed into a plate-shaped green body. Due to the characteristics of the mold press, the pressure is greater closer to the center, resulting in the maximum compression ratio at the center. On the one hand, when the green body is demolded, it is pushed out by the mold. Without the constraint of the mold cavity, the size of the green body will expand to a certain extent, and the greater the compression ratio, the greater the expansion. On the other hand, due to the size effect, the position far from the center will accumulate greater displacement. The combination of these two factors ultimately results in the expansion of the entire green body at different positions being basically the same. Therefore, a uniform dovetail groove back pattern can be formed, thereby reducing the processing difficulty of the mold and helping to maintain the integrity of the dovetail groove structure of the green body, further improving the bonding strength of the product.

[0011] Preferably, the value of α is in the range of 70-80°.

[0012] Preferably, the value of β is in the range of 15-30°.

[0013] Preferably, the thickness of the brick is 9-12 mm.

[0014] A second aspect of the present invention provides a method for preparing the above-mentioned ceramic brick, comprising the following steps:

[0015] (1) Determine the molding specifications of the green body: Based on the size of the ceramic tile to be produced, set the molding size of the green body as length × width × thickness = Amm × Bmm × Cmm;

[0016] (2) Determine the molding expansion rate of the green body: Take the spray granulation powder of the ceramic tile to be produced, and press it into shape using a conventional mold without dovetail groove according to the green body molding size set in step (1); the inner cavity size of the lower mold of the conventional mold is length × width = Dmm × Emm, and after molding, a green body with a size of length × width = Fmm × Gmm is obtained; calculate the molding expansion rate H% of the green body, where: the expansion rate in the length direction H1% = (FD) / D × 100%, and the expansion rate in the width direction H2% = (GE) / E × 100%;

[0017] (3) Design mold: Based on the expansion rate calculated in step (2), determine the dovetail groove back pattern size of the ceramic tile to be produced, where: α=tan(h / e), β does not exceed 30°, n=e / H%, then design a positive mold drawing that is consistent with the size of the green body, and then design a negative mold drawing based on the positive mold drawing;

[0018] (4) Mold processing: According to the positive mold drawing and negative mold drawing designed in step (3), the positive mold and negative mold are processed respectively; then the positive mold and negative mold are matched and assembled, and a soft rubber layer is sandwiched between the positive mold and negative mold to obtain a mold with dovetail groove;

[0019] (5) Pressing the green body: Replace the conventional mold in step (2) with the mold with dovetail groove obtained in step (4), and press the green body with dovetail back pattern with the same spray granulation powder as in step (2) to obtain a green body with the dimensions of length × width = Fmm × Gmm.

[0020] (6) Firing the product: The green body obtained in step (5) is dried and fired to obtain the ceramic brick.

[0021] Specifically, in the preparation of the ceramic bricks of the present invention, the green body forming size (length × width × thickness = Amm × Bmm × Cmm) needs to be determined based on the size of the ceramic brick to be produced. The green body forming size, relative to the size of the ceramic brick to be produced, needs to consider the loss due to firing shrinkage. Taking a ceramic brick to be produced with a length × width = 600mm × 600mm as an example, the green body forming size needs to be based on 600mm × 600mm plus drying and firing shrinkage (approximately 10%), that is, the green body forming size is approximately 660mm × 660mm. Then, based on the green body forming size, the spray-granulated powder of the ceramic brick to be produced is pressed and formed, wherein: the inner cavity size of the lower mold (length × width = Dmm × Emm) is 630mm × 630mm, and the size of the green body after forming (length × width = Fmm × Gmm) expands to approximately 660mm × 660mm due to the volume expansion after the green body is ejected from the lower mold cavity; thus, the green body forming expansion rate H% can be calculated. Based on the calculated volume expansion rate, a mold was designed and processed. This mold was then used to re-press the spray-granulated powder for producing ceramic tiles into green bodies, resulting in green bodies with a size of 660mm × 660mm and dovetail back patterns. After drying and firing, ceramic tiles with a size of 600mm × 600mm and dovetail back patterns were obtained. Simultaneously, a soft rubber layer was placed between the male and female molds to facilitate demolding and prevent powder from adhering to the mold surface.

[0022] Preferably, in step (3), the length of e along the length direction of the brick is e1, and e1 = n × H1%.

[0023] Preferably, in step (3), the length of e along the width direction of the brick is e2, and e2 = n × H2%.

[0024] Preferably, in step (4), the processing of the soft rubber layer is as follows: after heating and melting the soft rubber, it is cooled between the male mold and the female mold to obtain the product.

[0025] Preferably, the hardness of the soft rubber is 75-85A.

[0026] Preferably, in step (4), the thickness of the soft adhesive layer is 0.1-0.5 mm.

[0027] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages:

[0028] (1) The dovetail groove back pattern of the ceramic tile of the present invention has a triangular cross-section of the protruding part. Compared with the traditional arc structure, this not only facilitates processing and demolding, but also provides a larger accommodating space for the groove, resulting in better paving and bonding. At the same time, the uniform texture of the dovetail groove back pattern reduces the processing difficulty of the mold and helps maintain the integrity of the green dovetail groove structure, further improving the paving and bonding strength of the product. In addition, the dovetail groove back pattern of the ceramic tile of the present invention has a centrally symmetrical structure and an embedded rivet structure, which makes the paving and bonding strength even higher and can effectively reduce the problems of hollow spots and detachment of ceramic tiles.

[0029] (2) When preparing ceramic tiles of the present invention, by first determining the molding expansion rate of the green body and then accurately designing the size of the dovetail groove mold, it is not only beneficial to demolding, but also greatly improves the bonding strength of the paving. Attached Figure Description

[0030] Figure 1 This is a schematic cross-sectional view of the ceramic brick of the present invention. Detailed Implementation

[0031] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the invention. Furthermore, any process steps or preparation methods not mentioned in detail below are process steps or preparation methods known to those skilled in the art.

[0032] like Figure 1 As shown, a ceramic tile includes a tile body 100. The bottom surface of the tile body 100 is provided with multiple dovetail grooves symmetrical about a center. The dovetail grooves include raised portions 110 and recessed portions 120. The raised portion 110 has a triangular cross-section. Compared to the traditional arc-shaped structure, the triangular structure is easier to process, and the triangular structure allows for a wider range of mold movement during demolding, making demolding easier. Simultaneously, the recessed portion 120 has a larger space during installation, accommodating more adhesive material and resulting in better adhesion. Furthermore, the horizontal interior angle of the triangle furthest from the center of the tile body is β, which does not exceed 30°. If the angle β is too large, the tip of the raised portion 110 may be damaged during demolding. In a preferred embodiment, the value of β ranges from 15 to 30°.

[0033] The bottom of the groove 120 connects the adjacent protrusions 110 end to end. The angle formed by the sidewall of the groove 120 away from the center of the brick and the bottom of the groove 120 is α, and α is an acute angle; in a preferred embodiment, the value of α is in the range of 70-80°. The horizontal concave length formed by the groove 120 and the protrusions 110 is e, and the horizontal length of the bottom of the groove 120 is n, where e = n × H%, and H% represents the expansion rate of the brick blank; the vertical height of the groove is h, and h is 10-20% of the brick thickness. In a preferred embodiment, the thickness of the brick is 9-12 mm. Meanwhile, the horizontal length of the bottom of the protrusion 110 is f, and the value of f is determined by α, β, and h.

[0034] Example 1

[0035] A method for preparing a ceramic tile with dovetail groove back pattern includes the following steps:

[0036] (1) Determine the molding specifications of the green body: Based on the dimensions of the ceramic tiles to be produced (length × width × thickness = 600mm × 600mm × 10.6mm), set the molding dimensions of the green body (length × width × thickness = 660mm × 660mm × 11.7mm), and select a molding press that can press green bodies with a length × width × thickness of 660mm × 660mm × 11.7mm;

[0037] (2) Determine the molding expansion rate of the green body: Take the spray granulation powder of the ceramic tile to be produced, and press it into shape using the molding press selected in step (1) with a conventional mold without dovetail groove; the inner cavity of the lower mold of the conventional mold is length × width = 630mm × 630mm, apply a pressure of 3200N to the upper mold, and press it into shape. The green body is ejected by the lower mold to obtain a green body with a length × width = 660mm × 660mm; calculate the molding expansion rate H% of the green body, where: the expansion rate in the length direction H1% = (660-630) / 630×100% = 4.76%, and the expansion rate in the width direction H2% = (660-630) / 630×100% = 4.76%;

[0038] (3) Design mold: Based on the expansion rate of 4.76% calculated in step (2), determine the dimensions of the dovetail groove back pattern of the ceramic tile to be produced, where: α=78.69°, β=30°, e=0.3mm, h=1.5mm, n=6.3mm, f=8.5mm, then design a positive mold drawing that is consistent with the dimensions of the green body, and then design a negative mold drawing based on the positive mold drawing;

[0039] (4) Mold processing: According to the positive mold drawing and negative mold drawing designed in step (3), process them into a positive mold and a negative mold respectively; then fit the positive mold and the negative mold together and leave a gap of 0.15mm between the positive mold and the negative mold; then heat and melt the soft rubber with a hardness of 75A, pour the melted soft rubber into the gap, wait for it to cool, and obtain a soft rubber layer; finally, attach the soft rubber layer to the textured surface of the negative mold to obtain a mold with dovetail grooves;

[0040] (5) Pressing the green body: Replace the conventional mold in step (2) with the mold with dovetail groove obtained in step (4) to complete the mold installation of the press; and use the press to apply pressure of 3200N to the upper mold with the same spray granulation powder as in step (2) to press and shape it, and then eject the green body to obtain a green body with dovetail back pattern with dimensions of length × width = 660mm × 660mm;

[0041] (6) Firing product: The green body obtained in step (5) is dried and fired to obtain a ceramic tile with a dovetail back pattern with a length × width of 600mm × 600mm.

[0042] Comparative Example 1

[0043] A method for preparing a ceramic tile with dovetail groove back pattern includes the following steps:

[0044] (1) Determine the molding specifications of the green body: Based on the dimensions of the ceramic tiles to be produced (length × width × thickness = 600mm × 600mm × 10.6mm), set the molding dimensions of the green body (length × width × thickness = 660mm × 660mm × 11.7mm), and select a molding press that can press green bodies with a length × width × thickness of 660mm × 660mm × 11.7mm;

[0045] (2) Determine the molding expansion rate of the green body: Take the spray granulation powder of the ceramic tile to be produced, and press it into shape using the molding press selected in step (1) with a conventional mold without dovetail groove; the inner cavity of the lower mold of the conventional mold is length × width = 630mm × 630mm, apply a pressure of 3200N to the upper mold, and press it into shape. The green body is ejected by the lower mold to obtain a green body with a length × width = 660mm × 660mm; calculate the molding expansion rate H% of the green body, where: the expansion rate in the length direction H1% = (660-630) / 630×100% = 4.76%, and the expansion rate in the width direction H2% = (660-630) / 630×100% = 4.76%;

[0046] (3) Design mold: Based on the expansion rate of 4.76% calculated in step (2), determine the dovetail groove back pattern size of the ceramic tile to be produced, where: α gradually decreases from the center of the tile to the edge of the tile, and α = 70-80°, β = 30°, n = 6.3mm, f = 8.5mm. Then design a positive mold drawing that is consistent with the size of the green body, and then design a negative mold drawing based on the positive mold drawing.

[0047] (4) Mold processing: According to the positive mold drawing and negative mold drawing designed in step (3), process them into a positive mold and a negative mold respectively; then fit the positive mold and the negative mold together and leave a gap of 0.15mm between the positive mold and the negative mold; then heat and melt the soft rubber with a hardness of 75A, pour the melted soft rubber into the gap, wait for it to cool, and obtain a soft rubber layer; finally, attach the soft rubber layer to the textured surface of the negative mold to obtain a mold with dovetail grooves;

[0048] (5) Pressing the green body: Replace the conventional mold in step (2) with the mold with dovetail groove obtained in step (4) to complete the mold installation of the press; and use the press to apply pressure of 3200N to the upper mold with the same spray granulation powder as in step (2) to press and shape it, and then eject the green body to obtain a green body with dovetail back pattern with dimensions of length × width = 660mm × 660mm;

[0049] (6) Firing product: The green body obtained in step (5) is dried and fired to obtain a ceramic tile with a dovetail back pattern with a length × width of 600mm × 600mm.

[0050] Comparative Example 2

[0051] A method for preparing a ceramic tile with dovetail groove back pattern includes the following steps:

[0052] (1) Determine the molding specifications of the green body: Based on the dimensions of the ceramic tiles to be produced (length × width × thickness = 600mm × 600mm × 10.6mm), set the molding dimensions of the green body (length × width × thickness = 660mm × 660mm × 11.7mm), and select a molding press that can press green bodies with a length × width × thickness of 660mm × 660mm × 11.7mm;

[0053] (2) Determine the molding expansion rate of the green body: Take the spray granulation powder of the ceramic tile to be produced, and press it into shape using the molding press selected in step (1) with a conventional mold without dovetail groove; the inner cavity of the lower mold of the conventional mold is length × width = 630mm × 630mm, apply a pressure of 3200N to the upper mold, and press it into shape. The green body is ejected by the lower mold to obtain a green body with a length × width = 660mm × 660mm; calculate the molding expansion rate H% of the green body, where: the expansion rate in the length direction H1% = (660-630) / 630×100% = 4.76%, and the expansion rate in the width direction H2% = (660-630) / 630×100% = 4.76%;

[0054] (3) Mold design: Based on the expansion rate of 4.76% calculated in step (2), determine the dimensions of the dovetail groove back pattern of the ceramic tile to be produced, where: α=78.69°, β=45°, e=0.3mm, h=1.5mm, n=6.3mm, f=8.5mm, then design a positive mold drawing that is consistent with the dimensions of the green body, and then design a negative mold drawing based on the positive mold drawing;

[0055] (4) Mold processing: According to the positive mold drawing and negative mold drawing designed in step (3), process them into a positive mold and a negative mold respectively; then fit the positive mold and the negative mold together and leave a gap of 0.15mm between the positive mold and the negative mold; then heat and melt the soft rubber with a hardness of 75A, pour the melted soft rubber into the gap, wait for it to cool, and obtain a soft rubber layer; finally, attach the soft rubber layer to the textured surface of the negative mold to obtain a mold with dovetail grooves;

[0056] (5) Pressing the green body: Replace the conventional mold in step (2) with the mold with dovetail groove obtained in step (4) to complete the mold installation of the press; and use the press to apply pressure of 3200N to the upper mold with the same spray granulation powder as in step (2) to press and shape it, and then eject the green body to obtain a green body with dovetail back pattern with dimensions of length × width = 660mm × 660mm;

[0057] (6) Firing product: The green body obtained in step (5) is dried and fired to obtain a ceramic tile with a dovetail back pattern with a length × width of 600mm × 600mm.

[0058] Comparative Example 3

[0059] A method for preparing ceramic tiles includes the following steps:

[0060] (1) Determine the molding specifications of the green body: Based on the dimensions of the ceramic tiles to be produced (length × width × thickness = 600mm × 600mm × 10.6mm), set the molding dimensions of the green body (length × width × thickness = 660mm × 660mm × 11.7mm), and select a molding press that can press green bodies with a length × width × thickness of 660mm × 660mm × 11.7mm;

[0061] (2) Pressing green body: Take the spray granulation powder of ceramic tile to be produced, and press it according to the molding press selected in step (1) using a conventional mold without dovetail groove; the inner cavity of the lower mold of the conventional mold is length × width = 630mm × 630mm, apply pressure of 3200N to the upper mold to press it, and the green body is pushed out by the lower mold to obtain a green body with a length × width = 660mm × 660mm;

[0062] (3) Firing product: The green body obtained in step (2) is dried and fired to obtain a ceramic tile with a length × width of 600mm × 600mm.

[0063] Performance testing

[0064] The ceramic tile samples prepared in Example 1 and Comparative Examples 1-3 were laid and cured using the same adhesive. Test blocks of 50×50mm were cut at different locations of the ceramic tile samples. The bond strength (pull-out strength) between each test block and the adhesive was tested using the standard JC / T 547-2017 "Ceramic Tile Adhesives". The test results are shown in Table 1.

[0065] Table 1:

[0066]

[0067] As shown in Table 1, in Comparative Example 1, α gradually decreases from the center of the brick towards the edge, resulting in more complex mold processing and a higher difficulty coefficient. In Comparative Example 2, when the β angle is 45°, the resulting dovetail groove structure has defects, leading to relatively low bonding strength at different sampling locations. Comparing the 28-day bonding strength data of several samples, the bonding strength of the dovetail groove back pattern structure is higher than that of the conventional back pattern sample (Comparative Example 3), indicating that the dovetail groove back pattern is more effective in preventing tiling hollowing and detachment. For the dovetail groove back pattern samples, the sample at the center position forms a symmetrical dovetail structure, resulting in the highest pull-out strength. In Comparative Example 1, due to the non-uniformity of the dovetail structure, the strength is higher near the edge. In Comparative Example 2, the strength is reduced due to damage to the dovetail structure. Example 1, with its uniform dovetail structure and good dovetail groove integrity, has the best pull-out strength.

[0068] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. A method for preparing ceramic bricks, characterized in that, The ceramic tile includes a tile body, and the bottom surface of the tile body is provided with a plurality of dovetail grooves that are symmetrical about the center. The dovetail groove back pattern includes: The protrusion has a triangular cross-section, and the horizontal interior angle of the triangle away from the center of the brick is β, where β does not exceed 30°. The groove portion connects the adjacent protrusions end to end at its bottom. The angle formed by the sidewall of the groove portion away from the center of the brick and the bottom of the groove portion is α, where α is an acute angle. The horizontal concave length formed by the groove portion and the protrusions is e, and the horizontal length of the bottom of the groove portion is n, where e = n × H%, and H% represents the expansion rate of the brick body. The vertical height of the groove portion is h, where h is 10-20% of the brick body thickness. The preparation method includes the following steps: (1) Determine the molding specifications of the green body: Based on the size of the ceramic tile to be produced, set the molding size of the green body as length × width × thickness = Amm × Bmm × Cmm; (2) Determine the molding expansion rate of the green body: Take the spray granulation powder of the ceramic tile to be produced, and press it into shape using a conventional mold without dovetail groove according to the green body molding size set in step (1); the inner cavity size of the lower mold of the conventional mold is length × width = Dmm × Emm, and after molding, a green body with a size of length × width = Fmm × Gmm is obtained; calculate the molding expansion rate H% of the green body, where: the expansion rate in the length direction H1% = (FD) / D × 100%, and the expansion rate in the width direction H2% = (GE) / E × 100%; (3) Design mold: According to the expansion rate calculated in step (2), determine the dovetail groove back pattern size of the ceramic tile to be produced, where: α=tan(h / e), β does not exceed 30°, n=e / H%, then design a positive mold drawing that is consistent with the size of the green body, and then design a negative mold drawing based on the positive mold drawing; (4) Mold processing: According to the positive mold drawing and negative mold drawing designed in step (3), the positive mold and negative mold are processed respectively; then the positive mold and negative mold are matched and assembled, and a soft rubber layer is sandwiched between the positive mold and negative mold to obtain a mold with dovetail groove; (5) Pressing the green body: Replace the conventional mold in step (2) with the mold with dovetail groove obtained in step (4), and press the green body with dovetail back pattern with the same spray granulation powder as in step (2) to obtain a green body with length × width = Fmm × Gmm. (6) Firing product: The green body obtained in step (5) is dried and fired to obtain the ceramic brick.

2. The method for preparing ceramic bricks according to claim 1, characterized in that, The value of α is in the range of 70-80°.

3. The method for preparing ceramic bricks according to claim 1, characterized in that, The value of β ranges from 15 to 30°.

4. The method for preparing ceramic bricks according to claim 1, characterized in that, The thickness of the brick is 9-12mm.

5. The method for preparing ceramic bricks according to claim 1, characterized in that, In step (3), the length of e along the length direction of the brick is e1, and e1 = n × H1.

6. The method for preparing ceramic bricks according to claim 1, characterized in that, In step (3), the length of e along the width direction of the brick is e2, and e2 = n × H2%.

7. The method for preparing ceramic bricks according to claim 1, characterized in that, In step (4), the processing of the soft rubber layer is as follows: after heating and melting the soft rubber, it is poured into the gap between the male mold and the female mold, and after cooling, it is obtained.

8. The method for preparing ceramic bricks according to claim 7, characterized in that, The hardness of the soft rubber is 75-85A.

9. The method for preparing ceramic bricks according to claim 1, characterized in that, In step (4), the thickness of the soft adhesive layer is 0.1-0.5 mm.

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