1. Feed machinery and equipment accessories die liner product introduction

In the pelletizing process of feed production, the die ring is one of the key components of the pelletizing machine. It works with the press roller to extrude feed raw materials, which directly affects the quality of feed particles, production efficiency and the overall performance of the pelletizing machine.

2. Structural characteristics

Ring structure

The die liner is annular, and its inner and outer diameters are determined according to the granulator model and production requirements. The inner diameter is usually adapted to the main shaft or related transmission parts of the granulator to achieve accurate installation and positioning; The outer diameter determines the working area of the die liner and affects the molding range of feed particles. The ring structure design enables the die liner to apply uniform pressure to the feed material during rotation, ensuring the consistency of particle shape and density.

Die distribution

The surface of the die liner is covered with numerous die holes, which are channels for the feed raw materials to be extruded into pellets. The shape, size, depth and arrangement of die holes have a key effect on the characteristics of feed particles. Common mold hole shapes are round, square, hexagonal, etc., of which circular mold hole is the most widely used, because it can make the feed particles in the extrusion force uniform, not easy to produce stress concentration, so as to ensure the strength and integrity of the particles. The size of the die hole determines the diameter of the feed particles, which can generally be customized according to the feeding needs of different animals and feed formulations, for example, the diameter of chicken feed particles is usually small, between 3-8 mm, while the diameter of cattle feed particles is relatively large, up to 15-30 mm. The depth of the die hole is related to the length of the particle, and a deeper die hole can produce a longer particle. The arrangement of die holes on the surface of the die liner is usually concentric circle arrangement, spiral arrangement, etc. A reasonable arrangement can improve the strength and wear resistance of the die liner, and ensure that the feed raw materials are evenly distributed to each die hole during the extrusion process.

Positioning and connecting structure

The die liner is provided with a positioning structure, such as a positioning keyway or positioning pin hole, which is used for accurate positioning with the body of the pelleting machine or other related parts to prevent rotation or displacement during the working process, so as to ensure the relative position accuracy between the die hole and the press roll. In terms of connection structure, the die liner is usually connected to the spindle or fixed disk of the pelletizing machine by bolted connection or other fastening methods, and the connection part needs to have sufficient strength and reliability to withstand the huge pressure and torque during the pelletizing process.

3. Material characteristics

High quality alloy steel

Many die liners are made of high quality alloy steel, such as 40Cr, 42CrMo, etc. These alloy steels have high strength, toughness and wear resistance. After the quenching treatment, the hardness of 40Cr alloy steel can reach HRC28-32, which can meet the strength requirements of the press die liner of the general feed pelletizing machine. Its good comprehensive mechanical properties make the press die liner maintain a stable working state when it is under certain pressure and wear. 42CrMo alloy steel contains molybdenum element, further improve the hardenability and strength of the material, after tempering and surface quenching treatment, the surface hardness can be increased to HRC50-55, in the large, heavy duty feed pelletizing machine performance, can effectively resist the extrusion of the press roller and the friction of feed raw materials, reduce the wear and deformation of die holes, Extend the service life of die bushing.

Stainless steel

Stainless steel die lining is widely used in the production of aquatic feed or pet feed where the feed hygiene requirement is high. For example, 304 stainless steel has good corrosion resistance and oxidation resistance, which can prevent the erosion of water, acid and alkali components and microorganisms in the feed, and ensure the quality and safety of feed particles. The stainless steel die liner also has a good surface finish, which is conducive to the smooth extrusion of feed particles and reduce the adhesion and damage of the particle surface.

Special alloy material

For some special feed raw materials or production processes, it may be necessary to use special alloy materials to make die liners. For example, when producing feed containing high fiber or high hardness additives, alloy materials with higher hardness and wear resistance are used, such as tungsten carbide alloy or cobalt-based alloy. These special alloy materials are better able to cope with complex feedstock characteristics, ensuring that the die liner can maintain good performance under harsh working conditions and produce feed pellets that meet the requirements.

4. Manufacturing process

Forged blank

The blank of the die liner is usually prepared by forging process. Forging can refine the grain of the metal material and make the organization more dense, thereby improving the strength and toughness of the material, and eliminating the internal defects caused by the metal in the smelting process. The blank after forging needs to be normalized or annealed to eliminate the forging stress, improve the cutting performance of the material, and lay a good foundation for the subsequent machining process. For example, for 40Cr alloy steel die lining blanks, normalizing treatment after forging can homogenize the organization, moderate hardness, and facilitate turning, drilling and other processing operations.

machining

Machining is the key link of die lining manufacturing, including turning, milling, drilling, boring, grinding and other processes. First, the outer circle, inner hole and end face of the blank are machined to the design size through turning processing, and the features such as positioning keyway or positioning pin hole are machined. In the turning process, it is necessary to strictly control the precision and surface roughness of each size to ensure the precise fit of the die liner and other parts of the granulator. Then the milling process is used to process some special shapes or structures on the surface of the die liner, such as the entrance chamfer of the die hole. For the processing of die holes, usually using the drilling and boring process, the initial hole is drilled first, and then the hole is refined through the boring process to ensure the dimensional accuracy, cylindricity and surface roughness of the die holes. Finally, the key mating surfaces of the die liner, such as the outer circle and the end face, can be refined using the grinding process to further improve the surface accuracy and finish, ensuring stability and sealing after installation. In the machining process, it is necessary to use high-precision machine tools and tools, and strictly control the processing parameters of each process to ensure the manufacturing quality of the die liner.

Heat treatment

Heat treatment is an important step to improve the performance of die liner. For the alloy steel die liner, the general use of tempering treatment, that is, quenching after high temperature tempering, so that the die liner to obtain good comprehensive mechanical properties, improve its strength and toughness matching degree. For die liners with higher surface hardness requirements, such as those made of 42CrMo alloy steel, it is necessary to carry out surface quenching treatment after tempering treatment, so that the surface hardness reaches HRC50-55, and enhance its wear resistance and fatigue resistance. In the heat treatment process, it is very important to accurately control the heating temperature, holding time, cooling speed and other process parameters, otherwise it will easily lead to defects such as deformation, cracking or uneven hardness of the die liner. For example, when the 42CrMo alloy steel die liner is tempered, the quenching temperature needs to be precisely controlled between 850-900 ° C, the tempering temperature is between 550-650 ° C, and the quenching medium and cooling speed during surface quenching should also be reasonably selected to obtain the ideal surface hardness and core toughness.

5. Performance advantage

High precision forming

The die hole of the die liner is precisely machined to ensure the shape and dimensional accuracy of the feed particles. Whether round, square or other shaped die holes, feed particles can be extruded with a high degree of consistency to meet the strict requirements of different animal feed particle specifications. For example, in the production of pet feed, the precise particle shape and size have an important impact on the feeding habits and digestion and absorption of pets, and the high-precision molding ability of the die liner can ensure that the pet feed particles produced meet the market demand and improve the competitiveness of the product.

High wear resistance

High wear resistance is an important performance advantage because the die hole of the die lining needs to be in constant contact with the feed material and the press roller during the pelleting process and is subjected to great pressure and friction. Using high quality alloy steel, stainless steel or special alloy materials, combined with appropriate heat treatment and surface treatment process, the die liner can effectively resist wear and reduce the deformation and damage of the die hole. In the long-term use process, the high wear resistance of the die liner can significantly reduce the maintenance cost and downtime of the equipment, and improve production efficiency. For example, in a large feed pelletizing plant, a set of high-quality die liners can operate continuously for thousands of hours without frequent replacement, ensuring stable operation of the production line.

Good compressive strength

In the pelletizing process, the die liner is subjected to tremendous pressure from the press roller to squeeze feed raw materials through the die hole to form pellets. Its high-quality material and reasonable structural design make the die liner have good compressive strength, and can work stably under high pressure environment without cracking or deformation. This is essential for the production of high-density, high-strength feed pellets, such as aquatic feed and ruminant feed, which need to have a certain hardness and density to adapt to the preservation and digestion requirements in water or in the animal rumen, and the good compressive strength of the die lining ensures the production of feed pellets that meet the quality standards.

6. FAQ

Q: What is the main material of the die liner?

A: Die liners are usually made of high-strength steel or alloy steel to ensure that they have sufficient strength and wear resistance. These materials can withstand high loads and long periods of use.

Q: What are the surface treatment processes for die liners?

A: Common surface treatment processes for die liners include quenching, carburizing and nitriding. These processes can improve the hardness and wear resistance of the surface and extend the service life.

Q: How to ensure the transmission efficiency of the die bushing?

A: In order to ensure the transmission efficiency of the die liner, the matching accuracy between the shaft and the liner should be ensured, the lubrication system should be checked and maintained regularly, and the lubricating oil should be kept clean and appropriate.

Q: What problems may occur during the use of die bushing?

A: The die liner may have problems such as wear, fracture, deformation or poor fit during use. These problems are usually caused by overload, inadequate lubrication, or material defects.

Q: How long is the replacement cycle of die bushing?

A: The replacement cycle of the die bushing depends on the frequency of use, the working environment and the operating condition of the equipment. In general, when it is found that significant wear, deformation or can not be effectively driven, it should be considered to replace the new die liner.

Q: What are the special requirements of die bushing in different application scenarios?

Answer: In different application scenarios, the die bushing may have different special requirements. For example, die liners used in high temperature environments need to have high temperature resistance; For use in corrosive environments, corrosion-resistant materials are required.