A method for preparing a green chip in a production process of a laminated chip inductor

Abstract

The application discloses a kind of green chip preparation methods in the production process of laminated chip inductor, mainly applied to laminated chip inductor batching, forming, baking and cutting workshop, main role is to form the printing of bar block according to the certain cutting step distance of screen design, cut into certain length and width standard size, and the bar block of cutting printing is processed through disperser, dispersed into one grain one grain with length width and height appearance complete green chip, and the application utilizes flowing hot air to heat and dry bar block, can effectively shorten drying time and improve the drying effect of bar block.

Description

Technical Field

[0001] This invention specifically relates to a method for preparing green wafers during the production process of multilayer chip inductors. Background Technology

[0002] First, in existing technologies, various raw materials such as ferrite powder, plasticizer S-3875, dispersant NK2208, and solvents are quantitatively mixed and then subjected to a first ball milling for 5 to 10 hours and a second ball milling for 25 to 30 hours to uniformly mix them together, forming a slurry system with certain flow characteristics that can form a film with a certain toughness after drying. The slurry is then sent to a casting printing process. After the casting printing blocks are completed, they need to be placed in a drying oven for 24 to 72 hours, or even longer, to dry. Finally, they are cut by a cutting machine, packed into bags, and manually repeatedly thrashed on the ground until the product is dispersed.

[0003] Based on the above-mentioned existing technology, the following disadvantages exist:

[0004] 1) The surface of the molded block is moist, as if a layer of oil is coated on the surface of the block;

[0005] 2) Poor airflow and poor hot air circulation and heat dissipation inside the drying oven result in poor drying effect;

[0006] 3) The blocks are relatively soft, and the chips are not easy to disperse after cutting. There are many defective chips after repeated manual dropping. Most of them are deformed chips with chipped edges and missing corners. The defect rate is between 2% and 5%, depending on the different specifications and sizes of the products. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a method for preparing green wafers in the production process of multilayer chip inductors.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0009] A method for preparing green wafers in the production process of multilayer chip inductors includes the following steps:

[0010] S1. Slurry preparation, specific steps:

[0011] S11, containing the following raw materials in the following weight percentages: 43.4-51.6% ferrite powder, 3.8-4.6% n-propyl acetate, 39.5-43.5% isobutanol, 3-5% Sekisui resin BM-SZ, 2-3% plasticizer DOP and 0.1-0.5% dispersant XL-250;

[0012] S12. First, add 43.4-51.6% ferrite powder, 3.8-4.6% n-propyl acetate, 39.5-43.5% isobutanol, 2-3% plasticizer DOP and 0.1-0.5% dispersant XL-250 into a ball mill and ball mill for 5-10 hours to ensure that the materials are mixed during the ball milling process, and obtain mixture A for later use.

[0013] S13. Add 3-5% of water-soluble resin BM-SZ to the ball mill and mix it with the A mixture prepared in step 12. Then, ball mill again for 20-30 hours to prepare a slurry.

[0014] S2. Drying and Shaping of Bar Blocks: The slurry prepared in step S1 is fed into a drying oven and heated and dried using a hot air circulation heating method. First, it is heated by a nickel-chromium resistance wire at a rate of 10℃ / minute until the temperature inside the oven reaches 200℃, at which point the heating is stopped. During the heating process, a fan motor is used to force airflow in a vertical and horizontal manner, drawing in external air through a natural air inlet and heating it through the nickel-chromium resistance wire. The heated air flows through the slurry inside the oven to preheat, heat up, and dry it sequentially, ensuring uniform temperature inside the oven, which is maintained at 200±3.0℃. The airflow improves the forming speed of the bar blocks. The heated air is discharged through the exhaust port. The heating and drying time lasts for 5-24 hours, resulting in bar blocks with uniform hardness, which are then ready for use.

[0015] S3, block cutting, includes the following specific steps:

[0016] S31. Preheating process for cutting bar blocks: Before cutting, turn on the preheating function of the stage. When the stage temperature rises to 60-80℃, place the bar block obtained in step S2 on the stage surface and preheat it on the stage for 2 minutes to soften the bar block for later use.

[0017] S32. During the process of heating and softening the bar in specific step S31, the cutting blade is preheated at the same time, and the temperature of the cutting blade is controlled at 35-45℃, ready for use.

[0018] S33. After the bar block softens, it is cut by a heated cutting blade under the automatic operation of the device to obtain a bar block with complete length, width and height, and partially adhered, for later use.

[0019] S4. Dispersing the block into green chip: After the block obtained in step S3 is cut and transferred, it is quickly cooled and hardened. The block is then transferred into a disperser, which rotates the block and disperses it by centrifugal force and compression between the blocks to obtain green chip.

[0020] Furthermore, the preferred mass percentages of the raw materials in step S11 are: 47.5% ferrite powder, 4.2% n-propyl acetate, 41.5% isobutanol, 4.0% BM-SZ resin, 2.5% plasticizer DOP, and 0.3% dispersant XL-250.

[0021] The main technical effects of this invention are reflected in the following aspects:

[0022] 1. Improved production efficiency: Reduced drying time for molded blocks increases production efficiency;

[0023] 2. Reduce product appearance defect rate: By changing the material formula and increasing the hardness of the molded blocks, the appearance defect rate of the cut products can be reduced by using an automatic vibration machine. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described below to make the technical solution of the present invention easier to understand and master.

[0025] A method for preparing green wafers in the production process of multilayer chip inductors includes the following steps:

[0026] S1. Slurry preparation, specific steps:

[0027] S11, containing the following raw materials in the following weight percentages: 43.4-51.6% ferrite powder, 3.8-4.6% n-propyl acetate, 39.5-43.5% isobutanol, 3-5% Sekisui resin BM-SZ, 2-3% plasticizer DOP and 0.1-0.5% dispersant XL-250;

[0028] S12. First, add 43.4-51.6% ferrite powder, 3.8-4.6% n-propyl acetate, 39.5-43.5% isobutanol, 2-3% plasticizer DOP and 0.1-0.5% dispersant XL-250 into a ball mill and ball mill for 5-10 hours to ensure that the materials are mixed during the ball milling process, and obtain mixture A for later use.

[0029] S13. Add 3-5% of water-soluble resin BM-SZ to the ball mill and mix it with the A mixture prepared in step 12. Then, ball mill again for 20-30 hours to prepare a slurry.

[0030] S2. Drying and Shaping of Bar Blocks: The slurry prepared in step S1 is fed into a drying oven and heated and dried using a hot air circulation heating method. First, it is heated by a nickel-chromium resistance wire at a rate of 10℃ / minute until the temperature inside the oven reaches 200℃, at which point the heating is stopped. During the heating process, a fan motor is used to force airflow in a vertical and horizontal manner, drawing in external air through a natural air inlet and heating it through the nickel-chromium resistance wire. The heated air flows through the slurry inside the oven to preheat, heat up, and dry it sequentially, ensuring uniform temperature inside the oven, which is maintained at 200±3.0℃. The airflow improves the forming speed of the bar blocks. The heated air is discharged through the exhaust port. The heating and drying time lasts for 5-24 hours, resulting in bar blocks with uniform hardness, which are then ready for use.

[0031] S3, block cutting, includes the following specific steps:

[0032] S31. Preheating process for cutting bar blocks: Before cutting, turn on the preheating function of the stage. When the stage temperature rises to 60-80℃, place the bar block obtained in step S2 on the stage surface and preheat it on the stage for 2 minutes to soften the bar block for later use.

[0033] S32. During the process of heating and softening the bar in specific step S31, the cutting blade is preheated at the same time, and the temperature of the cutting blade is controlled at 35-45℃, ready for use.

[0034] S33. After the bar block softens, it is cut by a heated cutting blade under the automatic operation of the device to obtain a bar block with complete length, width and height, and partially adhered, for later use.

[0035] S4. Dispersing the block into green chip: After the block obtained in step S3 is cut and transferred, it is quickly cooled and hardened. The block is then transferred into a disperser, which rotates the block and disperses it by centrifugal force and compression between the blocks to obtain green chip.

[0036] Specifically, the characteristics of the raw materials are as follows:

[0037] ① Sekisui resin BM-SZ: enables the slurry to form a web and film;

[0038] ② Plasticizer DOP: Improves the toughness of the diaphragm, thus increasing the strength of the magnet;

[0039] ③ Dispersant XL-250: Its molecule is generally a polymer chain with polar functional groups at both ends. One end of the chain has polar functional groups that can be adsorbed onto the surface of ceramic powder particles, while the other end has non-polar functional groups that can freely expand and repel each other in the solvent. This prevents the ceramic powder particles from agglomerating, thus dispersing the slurry. Another function of the dispersant is to reduce the viscosity of the slurry, thereby reducing the amount of solvent needed and increasing the solid content of the slurry.

[0040] ④ Propyl acetate: It has a good effect on dissolving resins and dispersing various materials to prevent them from sticking together. Its evaporation rate is relatively fast.

[0041] ⑤ Isobutanol: It needs to be used in combination with n-propyl acetate, with the optimal ratio generally being 10:1. Isobutanol has a relatively slow evaporation rate, and the combination of n-propyl acetate and isobutanol can effectively control the evaporation rate, which is beneficial for film formation. In addition, isobutanol also plays a key role in the film formation and highlighting effect.

[0042] Example 1

[0043] In this embodiment, the specific mass percentages of the raw materials are: 47.5% ferrite powder, 4.2% n-propyl acetate, 41.5% isobutanol, 4.0% Sekisui resin BM-SZ, 2.5% plasticizer DOP and 0.3% dispersant XL-250.

[0044] Example 2

[0045] In this embodiment, the specific mass percentages of the raw materials are: 43.4% ferrite powder, 4.6% n-propyl acetate, 43.5% isobutanol, 5% Sekisui resin BM-SZ, 3% plasticizer DOP and 0.5% dispersant XL-250.

[0046] Example 3

[0047] In this embodiment, the specific mass percentages of the raw materials are: 51.6% ferrite powder, 3.8% n-propyl acetate, 39.5% isobutanol, 3% Sekisui resin BM-SZ, 2% plasticizer DOP and 0.1% dispersant XL-250.

[0048] Example 4

[0049] In this embodiment, the specific mass percentages of the raw materials are: 48.6% ferrite powder, 4% n-propyl acetate, 41% isobutanol, 3.5% Sekisui resin BM-SZ, 2.5% plasticizer DOP and 0.4% dispersant XL-250.

[0050] Example 5

[0051] In this embodiment, the specific mass percentages of the raw materials are: 50% ferrite powder, 4.2% n-propyl acetate, 41.8% isobutanol, 3.6% Sekisui resin BM-SZ, 2.2% plasticizer DOP and 0.4% dispersant XL-250.

[0052] Experimental Example

[0053] Existing technologies:

[0054] Experimental Example 1

[0055] First, the ingredients, including ferrite powder, plasticizer S-3875, dispersant NK2208, and solvent, are mixed in different quantities. Then, the mixture is ball-milled once for 5 to 10 hours and again for 25 to 30 hours to form a slurry system with certain flow characteristics. After drying, it forms a thin film with a certain degree of toughness. The slurry is then sent for casting and printing. After the printing blocks are completed, they are placed in a drying oven at 60 to 65 degrees Celsius for 10 to 24 hours to dry. Finally, they are cut by a cutting machine, placed in bags, and manually repeatedly thrashed on the ground until the product is dispersed.

[0056] Experiment Example 2

[0057] First, the ingredients, including ferrite powder, plasticizer S-3875, dispersant NK2208, and solvent, are mixed in a specific quantity. Then, the mixture is ball-milled once for 5 to 10 hours and again for 25 to 30 hours to achieve uniform mixing, forming a slurry system with certain flow characteristics. After drying, it forms a thin film with a certain degree of toughness. The slurry is then sent for casting and printing. After the printing blocks are completed, they are placed in a drying oven at 60 to 65 degrees Celsius for 24 to 72 hours. Finally, they are cut by a cutting machine, placed in bags, and manually repeatedly thrashed on the ground until the product is dispersed.

[0058] Experimental Example 3

[0059] First, the raw materials, including ferrite powder, plasticizer S-3875, dispersant NK2208, and solvent, are mixed in a specific quantity. Then, the mixture is ball-milled once for 5 to 10 hours and then a second time for 25 to 30 hours to achieve uniform mixing, forming a slurry system with certain flow characteristics. After drying, it can form a thin film with a certain degree of toughness. The slurry is then sent for casting and printing. After the casting and printing blocks are completed, they need to be placed in a drying oven at 60 to 65 degrees Celsius for 24 to 72 hours to dry. Finally, they are cut by a cutting machine, and then placed in a ball mill jar. A certain proportion of zirconium balls are added according to the product quantity. The product is then dispersed by high-speed operation of a ball mill or a vibratory mixer.

[0060] Experiment Example 4

[0061] First, the raw materials, including ferrite powder, plasticizer S-3875, dispersant NK2208, and solvent, are mixed in a specific quantity. Then, the mixture is ball-milled once for 5 to 10 hours and then a second time for 25 to 30 hours to achieve uniform mixing, forming a slurry system with certain flow characteristics. After drying, it can form a thin film with a certain degree of toughness. The slurry is then sent for casting and printing. After the casting and printing blocks are completed, they need to be placed in a drying oven at 70 to 75 degrees Celsius for 24 to 72 hours to dry. Finally, they are cut by a cutting machine, and then placed in a ball mill jar. A certain proportion of zirconium balls are added according to the product quantity. The product is then dispersed by high-speed operation of a ball mill or a vibratory mixer.

[0062] Experimental Example 5

[0063] First, the ingredients, including ferrite powder, plasticizer S-3875, dispersant NK2208, and solvent, are mixed in a specific quantity. Then, the mixture is ball-milled once for 5 to 10 hours and again for 25 to 30 hours to achieve uniform mixing, forming a slurry system with certain flow characteristics. After drying, it forms a thin film with a certain degree of toughness. The slurry is then sent for casting and printing. After the printing blocks are completed, they are placed in a drying oven at 70 to 75 degrees Celsius for 24 to 72 hours. Finally, they are cut by a cutting machine, placed in bags, and manually repeatedly thrashed on the ground until the product is dispersed.

[0064] The green chips prepared in Examples 1-5 above are compared with the green chips prepared in the prior art 1-5. The specific data are shown in the table below:

[0065] Chip hardness testing instrument: Digital hardness tester

[0066]

[0067]

[0068] in conclusion:

[0069] Based on the data comparison in the table above, the hardness of the cut core has been improved by at least 61% and the proportion of defective cut chips has been reduced by at least 2.6% through this invention.

[0070] The main technical effects of this invention are reflected in the following aspects:

[0071] 1. Improved production efficiency: Reduced drying time for molded blocks increases production efficiency;

[0072] 2. Reduce product appearance defect rate: By changing the material formula and increasing the hardness of the molded blocks, the appearance defect rate of the cut products can be reduced by using an automatic vibration machine.

[0073] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing green wafers during the production of multilayer chip inductors, characterized in that, Includes the following steps: S1. Slurry preparation, specific steps: S11, containing the following raw materials in the following weight percentages: 43.4-51.6% ferrite powder, 3.8-4.6% n-propyl acetate, 39.5-43.5% isobutanol, 3-5% Sekisui resin BM-SZ, 2-3% plasticizer DOP and 0.1-0.5% dispersant XL-250; S12. First, add 43.4-51.6% ferrite powder, 3.8-4.6% n-propyl acetate, 39.5-43.5% isobutanol, 2-3% plasticizer DOP and 0.1-0.5% dispersant XL-250 into a ball mill and ball mill for 5-10 hours to ensure that the materials are mixed during the ball milling process, and obtain mixture A for later use. S13. Add 3-5% of water-soluble resin BM-SZ to the ball mill and mix it with the A mixture prepared in step 12. Then, ball mill again for 20-30 hours to prepare a slurry. S2. Drying and Shaping of Bar Blocks: The slurry prepared in step S1 is fed into a drying oven and heated and dried using a hot air circulation heating method. First, it is heated by a nickel-chromium resistance wire at a rate of 10℃ / minute until the temperature inside the oven reaches 200℃, at which point the heating is stopped. During the heating process, a fan motor is used to force airflow in a vertical and horizontal manner, drawing in external air through a natural air inlet and heating it through the nickel-chromium resistance wire. The heated air flows through the slurry inside the oven to preheat, heat up, and dry it sequentially, ensuring uniform temperature inside the oven, which is maintained at 200±3.0℃. The airflow improves the forming speed of the bar blocks. The heated air is discharged through the exhaust port. The heating and drying time lasts for 5-24 hours, resulting in bar blocks with uniform hardness, which are then ready for use. S3, block cutting, includes the following specific steps: S31. Preheating process for cutting bar blocks: Before cutting, turn on the preheating function of the stage. When the stage temperature rises to 60-80℃, place the bar block obtained in step S2 on the stage surface and preheat it on the stage for 2 minutes to soften the bar block for later use. S32. During the process of heating and softening the bar in specific step S31, the cutting blade is preheated at the same time, and the temperature of the cutting blade is controlled at 35-45℃, ready for use. S33. After the bar block softens, it is cut by a heated cutting blade under the automatic operation of the device to obtain a bar block with complete length, width and height, and partially adhered, for later use. S4. Dispersing the block into green chip: After the block obtained in step S3 is cut and transferred, it is quickly cooled and hardened. The block is then transferred into a disperser, which rotates the block and disperses it by centrifugal force and compression between the blocks to obtain green chip.

2. The method for preparing green wafers in the production process of multilayer chip inductors according to claim 1, characterized in that: The specific mass percentages of the raw materials in step S11 are: 47.5% ferrite powder, 4.2% n-propyl acetate, 41.5% isobutanol, 4.0% BM-SZ resin, 2.5% plasticizer DOP and 0.3% dispersant XL-250.

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