Large-size ceramic plate blank and pressing method thereof, ceramic plate

Abstract

The present invention discloses a large-size ceramic plate blank and a pressing method thereof, and a ceramic plate, and relates to the technical field of pressing and forming. The pressing method comprises: (1) providing ceramic plate powder, testing its fluidity and gradation distribution; (2) distributing the ceramic plate powder into a mold cavity formed by a lower mold core and a mold frame; the ceramic plate powder divides the mold cavity into a distributing cavity and a pier cavity; (3) calculating the required pier cavity depth H 1r And the depth of the pier cavity H 1p (4) Determine the pressing scheme according to the relationship between the required cavity depth and the cavity depth. The implementation of the present invention can optimize the exhaust during the pressing process of large-sized ceramic slabs, improve the uniformity of the ceramic slabs, and reduce the probability of pressing defects.

Description

Technical Field

[0001] The invention relates to the technical field of a press and press forming technology, and in particular to a large-size ceramic plate blank and a pressing method thereof, and a ceramic plate. Background Art

[0002] Large-size ceramic panels are a major innovation in the field of ceramic tiles in recent years. One of its main features is that they are larger in size. Common specifications include 800×1200mm. 2 , 1200×1200mm 2 , 1200×1600mm 2 、1200×2400mm 2 、1800×2400mm 2 Etc. The thickness of traditional ceramic tiles is generally around 10mm (GB / T4100), but the thickness of large-sized ceramic panels varies greatly, ranging from 5mm to 25mm, and there is no relevant standard to unify its thickness. For such large-sized ceramic panels, there are generally two significant problems in their pressing and forming: one is the exhaust problem. Due to the large size of large-sized ceramic panels, the powder carries a lot of gas after laying, making exhaust difficult. The second is the uniformity problem. Due to the large size of large-sized ceramic panels, the laying uniformity is relatively poor. The flow range of the powder during the pressing process is limited, which can easily lead to poor uniformity of the ceramic panel blank after forming.

[0003] In the prior art, in order to solve the exhaust problem, a floating mold frame and an exhaust mold core are generally used. However, the control scheme of the floating mold frame is relatively complicated, and the oil circuit structure is complicated. The exhaust mold core itself has a complex structure and high cost. In addition, during the pressing process, it is necessary to control the ejection of ejectors in multiple exhaust mold cores, and the control scheme is more complicated than that of the floating mold frame.

[0004] On the other hand, in the prior art, in order to improve the uniformity of pressing large-sized ceramic plates, generally after laying, a certain height (height of the material) is left in the upper part of the mold cavity to form a material cavity; during pressing, the upper mold core is quickly pressed down to compress the air in the material cavity, so that the unpressed powder in the mold cavity flows to a certain extent, thereby improving uniformity. When this solution is adopted, there are two problems: first, the air in the material cavity also needs to be exhausted, which increases the exhaust volume; second, the height of the material cavity is currently obtained through multiple debugging by on-site debugging personnel, which is often only applicable to a specific working condition (such as a ceramic plate of a specific thickness, a powder of a specific particle size distribution). When the working condition changes (such as the thickness of the ceramic plate changes, that is, the thickness of the material changes), it is often more likely to cause defects in the green body stratification. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a pressing method for a large-sized ceramic slab body, which can effectively improve the uniformity of the large-sized ceramic slab body.

[0006] Another technical problem to be solved by the present invention is to provide a large-sized ceramic slab body.

[0007] Another technical problem to be solved by the present invention is to provide a large-sized ceramic plate.

[0008] In order to solve the above problems, the present invention discloses a method for pressing a large-sized ceramic slab body, which comprises:

[0009] (1) Provide ceramic plate powder and test its fluidity and gradation distribution;

[0010] (2) distributing the ceramic plate powder into a mold cavity formed by a lower mold core and a mold frame; the ceramic plate powder divides the mold cavity into a distribution cavity and a support cavity;

[0011] (3) Calculate the required pier cavity depth H according to the following formula 1r And the depth of the pier cavity H 1p ;

[0012] H 1p =H C -εh t

[0013]

[0014]

[0015] Among them, H 1p H is the depth of the pier cavity, 1r H is the required depth of the pier cavity. C is the cavity depth, h t is the thickness of the large-size ceramic plate blank, ε is the compression ratio, f is the fluidity of the ceramic plate powder, d is the equivalent diameter of the ceramic plate powder, and x i A is the proportion of ceramic plate powder with mesh size greater than 200 on each level of sieve. i The aperture of the sieve used to detect the gradation distribution of ceramic plate powder;

[0016] (4) If H1<H 1r , first lower the lower mold core to a height of H2, and then drive the upper mold core to press;

[0017] If H 1p =H 1r , then directly drive the upper die core to press;

[0018] If H 1p >H 1r , first lift the lower mold core to a height of H3, and then drive the upper mold core to press;

[0019] Among them, the descending height H2 and the lifting height H3 are calculated according to the following formula:

[0020] H2=H 1r -H 1p

[0021] H3=H 1p -H 1r

[0022] Among them, H2 is the descending height of the lower mold core, H3 is the lifting height of the lower mold core, and H 1p H is the depth of the pier cavity, 1r The required depth of the pier cavity.

[0023] As an improvement of the above technical solution, if H1<H 1r , first lower the lower mold core to a height of H2, then keep the lower mold core stationary, and only drive the upper mold core for pressing.

[0024] As an improvement of the above technical solution, if H 1p >H 1r , then the suppression methods include:

[0025] 1) Raise the lower mold core to a height of H3;

[0026] 2) Drive the upper mold core down to the surface where the ceramic plate powder is located;

[0027] 3) driving the upper mold core and the lower mold core to descend simultaneously to press the ceramic plate powder.

[0028] As an improvement of the above technical solution, in step 3), the descending speed v1 of the upper mold core and the descending speed v2 of the lower mold core satisfy the following relationship:

[0029]

[0030] Among them, v1 is the descending speed of the upper die core, v2 is the descending speed of the lower die core, ε is the compression ratio, h t is the thickness of the large-size ceramic slab body, and H3 is the lifting height of the lower mold core.

[0031] As an improvement of the above technical solution, in step 3), the descending speed v1 of the upper mold core and the descending speed v2 of the lower mold core satisfy the following relationship:

[0032]

[0033] Among them, v1 is the descending speed of the upper die core, v2 is the descending speed of the lower die core, ε is the compression ratio, h t is the thickness of the large-size ceramic slab body, H3 is the lifting height of the lower mold core, and k is a constant, and its value is 1.5~3.

[0034] As an improvement of the above technical solution, when the surface area of ​​the large-sized ceramic slab is ≤1m 2 When k is 1.5 to 2, when the surface area of ​​the large-sized ceramic slab is greater than 1m 2 When , the value of k is 2 to 3.

[0035] As an improvement of the above technical solution, when measuring the gradation distribution of the ceramic plate powder, sieves of 20 mesh, 60 mesh, 100 mesh and 200 mesh are used.

[0036] As an improvement of the above technical solution, the test method for the fluidity of the ceramic plate powder is:

[0037] Place a glass cylinder with a diameter of 30 mm and a height of 50 mm on a glass plate, fill it with ceramic plate powder and scrape it flat, then lift the cylinder. After the ceramic plate powder disperses naturally, record the maximum height H of the pile. s , then liquidity is calculated as follows:

[0038] f=50-H s

[0039] Among them, f is the fluidity of ceramic plate powder, H s It is the maximum height of the pile formed during the flowability test.

[0040] Correspondingly, the present invention also discloses a large-sized ceramic slab body, which is obtained by pressing using the above pressing method.

[0041] Correspondingly, the present invention also discloses a large-sized ceramic plate, which is prepared from the large-sized ceramic plate blank mentioned above.

[0042] The implementation of the present invention has the following beneficial effects:

[0043] After a lot of practice, the inventors of the present invention have quantified the depth of the piers of ceramic plates of different specifications based on powders of different properties, and based on the quantitative data, proposed a new pressing method for large-sized ceramic plate blanks. Based on the pressing method, the exhaust during the pressing process of large-sized ceramic plate blanks can be optimized, the uniformity of the ceramic plate blanks can be improved, and the probability of the occurrence of pressed interlayer defects and fracture defects can be reduced. In addition, based on the pressing method of the present invention, when pressing ceramic plate blanks of different thicknesses, interlayer defects can be greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of a large-sized ceramic slab body in one embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0046] The present invention discloses a method for pressing a large-sized ceramic slab body, which comprises the following steps:

[0047] S1: Provide ceramic plate powder and test its fluidity and gradation distribution;

[0048] Specifically, the fluidity test method of ceramic plate powder is as follows:

[0049] Place a glass cylinder (or smooth metal cylinder, smooth ceramic cylinder, etc., but not limited to) with a diameter of 30mm and a height of 50mm on a glass plate (or smooth metal plate, smooth ceramic plate, etc., but not limited to), fill it with ceramic plate powder and scrape it flat, then lift the glass cylinder, and record the maximum height H of the pile after the ceramic plate powder naturally disperses. s , then liquidity is calculated as follows:

[0050] f=50-H s

[0051] Among them, f is the fluidity of ceramic plate powder, H s It is the maximum height of the pile formed during the flowability test.

[0052] Specifically, the gradation distribution test method of ceramic plate powder is as follows: dry the powder to constant weight, then weigh 100g and place it in a vibrating screen. A number of standard sieves with different apertures are arranged in the vibrating screen. The powder is placed on the top standard sieve. After the vibrating screen is turned on and vibrated for 10 minutes, the weight of the ceramic plate powder on each standard sieve is weighed, and then the vibrating screen is continued until no more than 0.05g of powder passes through the smallest aperture per minute.

[0053] Specifically, the mesh size of the sieve in the vibrating screen can be 20 mesh, 80 mesh, 120 mesh and 200 mesh, or can be 20 mesh, 60 mesh, 100 mesh, 200 mesh; preferably, 20 mesh, 60 mesh, 100 mesh, 120 mesh.

[0054] S2: Distribute the ceramic plate powder into the mold cavity formed by the lower mold core and the mold frame;

[0055] Specifically, after the material is laid, the ceramic plate powder does not completely fill the mold cavity, so the mold cavity is divided into a laying cavity and a pier cavity. After the pier cavity is set, when the upper mold core is pressed down to the top surface of the mold frame, the air flow in the pier cavity is accelerated, which helps to drive the ceramic plate powder to flow from the center to the surroundings and improve uniformity.

[0056] S3: Calculate the required pier cavity depth H 1r And the depth of the pier cavity H 1p ;

[0057] H 1p =H C -εh t

[0058]

[0059]

[0060] Among them, H 1p is the depth of the pier cavity (i.e. the depth of the pier cavity before the lower mold core position is adjusted), H 1r is the required cavity depth (i.e. the cavity depth after adjusting the lower mold core position), H C h is the cavity depth (the cavity depth before adjusting the lower mold core position), t is the thickness of the large-size ceramic plate blank, ε is the compression ratio, f is the fluidity of the ceramic plate powder, d is the equivalent diameter of the ceramic plate powder, and x i A is the proportion of ceramic plate powder larger than 120 mesh on each level of sieve. i It is the aperture of the sieve used to detect the gradation distribution of ceramic plate powder.

[0061] Specifically, the inventors found through a large number of experimental studies that when the depth of the pier cavity is controlled to H 1r At the same time, the exhaust demand and fluidity demand can be balanced, the pressing yield can be improved, and the uniformity of the ceramic slab body after pressing can be improved.

[0062] S4: Determine the pressing scheme according to the relationship between the required pier material cavity depth and the pier material cavity depth;

[0063] Specifically, if H 1p <H 1r , first lower the lower mold core to a height of H2, and then drive the upper mold core to press. The lowering height H2 and the lifting height H3 are calculated according to the following formula:

[0064] H2=H 1r -H 1p

[0065] Among them, H2 is the descending height of the lower mold core, H 1p H is the depth of the pier cavity, 1r The required depth of the pier cavity.

[0066] Furthermore, the lower mold core is first lowered to a height H2, and then the lower mold core is kept stationary, and only the upper mold core is driven downward to complete the pressing.

[0067] Specifically, if H 1p =H 1r , then directly drive the upper die core for pressing.

[0068] If H 1p >H1r , first lift the lower mold core to a height of H3, and then drive the upper mold core to press;

[0069] Among them, the lifting height H3 is calculated according to the following formula:

[0070] H3=H 1p -H 1r

[0071] Among them, H3 is the lifting height of the lower mold core, H 1p H is the depth of the pier cavity, 1r The required depth of the pier cavity.

[0072] Furthermore, when H 1p >H 1r The specific pressing method is:

[0073] S100: lift the lower mold core to a height of H3;

[0074] S200: driving the upper mold core to descend to the surface where the ceramic plate powder is located;

[0075] Specifically, during this process, the upper mold core presses the ceramic plate powder at a faster speed to improve uniformity.

[0076] S300: driving the upper mold core and the lower mold core to descend simultaneously to press the ceramic plate powder;

[0077] Specifically, in one embodiment of the present invention, the upper mold core and the lower mold core first descend at the same speed H3, and then the lower mold core remains stationary while the upper mold core continues to descend to complete the pressing.

[0078] In another embodiment of the present invention, the upper mold core and the lower mold core descend at different speeds. However, in order to ensure the safety of the hydraulic circuit of the pressing system, the descending speed v1 of the upper mold core and the descending speed v2 of the lower mold core satisfy the following relationship:

[0079]

[0080] Among them, v1 is the descending speed of the upper die core, v2 is the descending speed of the lower die core, ε is the compression ratio, h t is the thickness of the large-size ceramic slab body, and H3 is the lifting height of the lower mold core.

[0081] Preferably, in one embodiment of the present invention, S300 includes:

[0082] S301: The upper mold core descends at a speed of v1, and the lower mold core descends at a speed of v2;

[0083] Specifically, the descending speed v1 of the upper mold core and the descending speed v2 of the lower mold core satisfy the following relationship:

[0084]

[0085] Among them, v1 is the descending speed of the upper die core, v2 is the descending speed of the lower die core, ε is the compression ratio, h t is the thickness of the large-size ceramic slab body, H3 is the lifting height of the lower mold core, and k is a constant, and its value is 1.5~3.

[0086] Preferably, when the surface area of ​​the large-sized ceramic slab is ≤1m 2 When k is 1.5 to 2, when the surface area of ​​the large-sized ceramic slab is greater than 1m 2 When , the value of k is 2 to 3.

[0087] S302: After the upper mold core and the lower mold core are lowered to a height of H3, the lower mold core is controlled to remain stationary, and the upper mold core continues to be pressed down to complete the pressing process.

[0088] Based on the above pressing scheme, when the upper mold core and the lower mold core are pressed down at different speeds, pressure is applied to the ceramic plate powder, which promotes the flow of the ceramic plate powder, improves the pressing yield, and improves the uniformity of the finished ceramic plate blank after pressing.

[0089] It should be noted that the compression ratio ε in the present invention is a constant well known to those skilled in the art, and its specific value can be determined based on experience.

[0090] Correspondingly, the present invention also discloses a large-sized ceramic slab body, which is obtained by pressing using the above pressing method.

[0091] Correspondingly, the present invention also discloses a large-sized ceramic plate, which is made of the large-sized ceramic plate blank. Specifically, it is obtained by glazing, firing, and post-processing (edge ​​grinding, polishing, cutting, etc.) the large-sized ceramic plate blank, but is not limited thereto.

[0092] The present invention is described below with specific embodiments:

[0093] Example

[0094] This embodiment provides a method for pressing a large-sized ceramic slab body, which includes the following steps:

[0095] (1) Providing powder and measuring its fluidity and gradation distribution;

[0096] Specifically, the method for measuring fluidity is:

[0097] Place a glass cylinder with a diameter of 30 mm and a height of 50 mm on a glass plate, fill it with ceramic plate powder and scrape it flat, then lift the glass cylinder. After the ceramic plate powder disperses naturally, record the maximum height H of the pile. s. Then the fluidity f=50-14.5=35.5mm.

[0098] The method for determining the gradation distribution is as follows: dry the ceramic plate powder to a constant weight, then weigh 100g and place it in a vibrating screen. Set up multiple standard screens with different apertures (20 mesh, 60 mesh, 100 mesh, 200 mesh) in the vibrating screen. Place the powder on the top standard screen, start the vibrating screen and vibrate for 10 minutes, then weigh the weight of the ceramic plate powder on each standard screen, and then continue vibrating until no more than 0.05g of powder passes through the smallest aperture per minute. The specific measurement data is as follows:

[0099]

[0100] (2) distributing the ceramic plate powder into a mold cavity formed by a lower mold core and a mold frame; the ceramic plate powder divides the mold cavity into a distribution cavity and a support cavity;

[0101] Specifically, the thickness h of the formed ceramic plate t is 10mm, and the compression ratio ε is 2; the height of the original cavity H C is 50mm.

[0102] (3) Calculate the required pier material cavity depth and pier material cavity depth;

[0103] Among them, the depth of the pier cavity is H 1p =50-10×2=30mm;

[0104] Required pier cavity depth H 1r =19.75+(35.5÷0.215÷20)-0.95×10=18.5mm.

[0105] (4) Determine the suppression plan.

[0106] Due to H 1p >H 1r , first lift the lower mold core to a height of H3 (30-18.5=11.5mm), and then drive the upper mold core to press. Specifically include:

[0107] 1) The upper die core descends at a speed of v1, and the lower die core descends at a speed of v2; and v2 = 1.8 × 11.5 ÷ [1.8 × 11.5 + (2-1) × 10] × v1 = 0.674v1.

[0108] 2) After the upper and lower mold cores drop to a height of H3, the lower mold core is controlled to remain stationary, and the upper mold core continues to press down to complete the pressing process.

[0109] Comparative Example

[0110] In this comparative example, the ceramic plate powder material used is the same as that in the embodiment, except that the lower mold core of this comparative example remains stationary, and only the upper mold core is driven downward to complete the pressing.

[0111] The pressing method in the embodiment of the present invention and the pressing method in the comparative example were used to press 100 tablets each, and the yield rate was counted (if interlayer, corner cracks, cracks, etc. were found, it was considered unqualified). The yield rate in the embodiment was 96%, and the yield rate in the comparative example was 73%.

[0112] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A method for pressing a large-sized ceramic slab body, characterized in that: include: (1) Provide ceramic plate powder and test its fluidity and gradation distribution; (2) distributing the ceramic plate powder into the mold cavity formed by the lower mold core and the mold frame; The ceramic plate powder divides the mold cavity into a material distribution cavity and a material pier cavity; (3) Calculate the required pier cavity depth H according to the following formula 1r And the depth of the pier cavity H 1p ; H 1p =H C -εh t Among them, H 1p H is the depth of the pier cavity, 1r H is the required depth of the pier cavity. C is the cavity depth, h t is the thickness of the large-size ceramic plate blank, ε is the compression ratio, f is the fluidity of the ceramic plate powder, d is the equivalent diameter of the ceramic plate powder, and x i A is the proportion of ceramic plate powder larger than 120 mesh on each level of sieve. i The aperture of the sieve used to detect the gradation distribution of ceramic plate powder; (4) If H 1p <H 1r , first lower the lower mold core to a height of H2, and then drive the upper mold core to press; If H 1p =H 1r , then directly drive the upper die core to press; If H 1p >H 1r , first lift the lower mold core to a height of H3, and then drive the upper mold core to press; Among them, the descending height H2 and the lifting height H3 are calculated according to the following formula: H2=H 1r -H 1p H3=H 1p -H 1r Among them, H2 is the descending height of the lower mold core, H3 is the lifting height of the lower mold core, and H 1p H is the depth of the pier cavity, 1r The required depth of the pier cavity.

2. The method for pressing a large-sized ceramic slab body according to claim 1, characterized in that: If H1<H 1r , first lower the lower mold core to a height of H2, then keep the lower mold core stationary, and only drive the upper mold core for pressing.

3. The method for pressing a large-sized ceramic slab body according to claim 1, characterized in that: If H 1p >H 1r , then the suppression methods include: 1) Raise the lower mold core to a height of H3; 2) Drive the upper mold core down to the surface where the ceramic plate powder is located; 3) driving the upper mold core and the lower mold core to descend simultaneously to press the ceramic plate powder.

4. The method for pressing a large-sized ceramic slab body according to claim 3, characterized in that: In step 3), the descending speed v1 of the upper mold core and the descending speed v2 of the lower mold core satisfy the following relationship: Among them, v1 is the descending speed of the upper die core, v2 is the descending speed of the lower die core, ε is the compression ratio, h t is the thickness of the large-size ceramic slab body, and H3 is the lifting height of the lower mold core.

5. The method for pressing a large-sized ceramic slab according to claim 3 or 4, characterized in that: In step 3), the descending speed v1 of the upper mold core and the descending speed v2 of the lower mold core satisfy the following relationship: Among them, v1 is the descending speed of the upper die core, v2 is the descending speed of the lower die core, ε is the compression ratio, h t is the thickness of the large-size ceramic slab body, H3 is the lifting height of the lower mold core, and k is a constant, and its value is 1.5~3.

6. The method for pressing a large-sized ceramic slab body according to claim 5, characterized in that: When the surface area of ​​the large-sized ceramic slab is ≤1m 2 When k is 1.5 to 2, when the surface area of ​​the large-sized ceramic slab is greater than 1m 2 When , the value of k is 2 to 3.

7. The method for pressing a large-sized ceramic slab body according to claim 1, characterized in that: When measuring the gradation distribution of the ceramic plate powder, sieves of 20 mesh, 60 mesh, 100 mesh and 120 mesh are used.

8. The method for pressing a large-sized ceramic slab body according to claim 1, characterized in that: The test method for the fluidity of the ceramic plate powder is: Place a glass cylinder with a diameter of 30 mm and a height of 50 mm on a glass plate, fill it with ceramic plate powder and scrape it flat, then lift the glass cylinder. After the ceramic plate powder disperses naturally, record the maximum height H of the pile. s , then liquidity is calculated as follows: f=50-H s Among them, f is the fluidity of ceramic plate powder, H s It is the maximum height of the pile formed during the flowability test.

9. A large-size ceramic slab body, characterized in that: The product is obtained by pressing according to the pressing method as claimed in any one of claims 1 to 8.

10. A large-sized ceramic plate, characterized in that: The large-sized ceramic slab is prepared from the large-sized ceramic slab body as claimed in claim 9.

Images