How to Extend the Service Life of Ring Die?

Aug. 26, 2020

Effectively increase the output of the feed ring die. In addition to the quality of the ring die itself, correct operation and maintenance can effectively increase the life of the ring die.

One. Regular maintenance of the pellet machine

1. Because the pellet machine is the main equipment of the feed factory, the manufacturer should first perform daily, weekly, and monthly maintenance work on the host to ensure that the pellet machine maintains a good, stable, and non-jittering working condition. If the equipment has malfunctions or some vulnerable parts Wear and tear, especially the beating wear of the transmission wheel and main shaft, should be repaired and replaced in time to ensure the normal use of the concentric circles of the ring die.

2. Install an iron suction device at the feed entrance to prevent metal foreign objects from falling into the pelleting chamber, causing serious damage and cracking of the ring die.

3. When installing the ring die, check the drive key, hoop, wear-resistant bushing ring of the drive wheel, wear-resistant bushings at both ends of the pressure roller shaft, clearance wheel, feeding scraper, cutter, etc. in the pelletizing chamber. The worn parts should be replaced in time to ensure the normal operation of the pellet machine. If the hoop wear cannot hold the ring die tightly, the vibration of the pellet machine will increase, which will seriously affect the service life of the ring die and even crack the ring die. It should be replaced in time. In addition, the abrasion of the feed scraper will reduce the output of the pellet machine.

Two. Ring mold work maintenance

1. Due to the different types of feed produced, which involve the difference in ring die material, opening rate, inner cone hole, die hole effective length, and pressure relief hole design, it is necessary to find a company with advanced professional technology to combine feed raw materials and actual use. Design and customize ring molds with different processes according to the situation, so as to ensure the maximum use value of ring molds.

2. When using a new ring die for prawn material, it must be replaced with a new pressure roller processed by a concentric mill.

3. The gap between the pressure roller and the ring die must be controlled between 0.1-0.3mm. Do not let the eccentric pressure roller touch the surface of the ring die or the gap on one side is too large. This is a size that is not easy to detect with the naked eye and during installation, so as to avoid This causes increased wear of the ring die and pressure roller or no discharge.

4. When the pellet machine is started, the feeding amount must be from low speed to high speed. Do not run at high speed from the beginning, which may cause damage to the ring die and pellet machine or blockage of the ring die due to sudden overload.

Feed Ring Die

Feed Ring Die

Three. Maintenance of ring die

1. When the Feed Pellet Ring Die is not used for a period of time, the original feed should be squeezed out with non-corrosive oil, otherwise, the heat of the ring die will dry the feed originally left in the die hole It hardens, resulting in the following situations: (1) When starting to run, the die hole is blocked and the material cannot be extruded; (2) When starting production, the ring die is subjected to high stress and its strength is weakened, which may cause ring die cracking; (3) Part of the die hole is blocked, the output is reduced, and the benefit is reduced.

2. After the ring die has been used for a period of time, check whether there is a local protruding part on the inner surface of the ring die. If this phenomenon occurs, use a sander to grind off the protruding part to ensure the output of the ring die and the service life of the pressure roller.

3. If the die hole is blocked and the material cannot be discharged, use oil soaking or oil cooking and then re-granulate. If it still can not be granulated, use an electric drill to drill out the blocked material, and then use oily material and fine sand for grinding and polishing.

4. When loading and unloading the ring die, do not use a hammer or other hard steel tool to beat the surface of the ring die.

5. The use record of each shift of the ring die should be made so as to calculate the actual service life of the ring die.

6. The ring die must be stored in a dry and clean place. If it is stored in a damp place, the die hole will be corroded, which will reduce the service life of the ring die or will not discharge the material.

Four. Summary of granulation technology for different materials

With the promotion and application of pellet feed in livestock and poultry, aquaculture and other emerging industries as well as compound fertilizers, hops, chrysanthemums, wood chips, peanut shells, cottonseed meal and other emerging industries, more and more units use ring mold pelletizers. Different formulas and regional differences, users have different requirements for pellet feed. Each feed manufacturer requires good pellet quality and highest pelleting efficiency for the pellet feed it produces. Due to the different feed formulas, the selection of ring die parameters when suppressing these pellet feeds is also different. The parameters are mainly reflected in the selection of material, hole diameter, hole shape, aspect ratio, and opening rate. The selection of ring mold parameters must be determined according to the chemical composition and physical properties of various raw materials that make up the feed formula. The chemical composition of raw materials mainly includes protein, starch, fat, cellulose, etc. The physical properties of raw materials mainly include particle size, moisture, and capacity.

Livestock and poultry feed mainly contains wheat and corn, with high starch content and low fiber content. It is a high-starch feed. The pressing of this type of feed must ensure that the starch is fully gelatinized to reach high temperature and processing conditions. The thickness of the ring die is generally thick, and the aperture The range is wide, and the aspect ratio is generally between 1:8-1:10. Broilers and ducks are high-energy feeds with high fat content and easy pelleting. Generally, the length and diameter are relatively large, between 1:10-1:13.

Aquatic feed mainly includes fish feed, shrimp feed, turtle feed, etc. The crude fiber content in fish feed is relatively high, while the crude fiber content in shrimp feed and turtle feed is relatively low and the protein content is high, which is a high protein feed. Aquatic materials require long stabilization time, uniform diameter and regular length of particles in water. This requires fine particle size and high maturity when granulating materials, using pre- and post-curing processes. The aperture of the ring die used for fish feed is generally between θ1.5-θ3.5, and the ratio of length to diameter is generally between 1:10-1:12. The aperture range of the ring die used for shrimp feed is between θ1.5-θ2.5, and the ratio of length to diameter is between 1:11-1:20. The ring die used for turtle feed has a large aperture, ranging from θ3-θ8. Due to the high protein content, the length-to-diameter ratio ranges from 1:12-1:20. The selection of the specific parameters of the length-to-diameter ratio must be based on each formula. Nutrition indicators and user requirements to determine. At the same time, the design of the hole shape of the die hole does not use stepped holes as far as possible under the conditions of strength permitting to ensure that the cut particles are neat in length and consistent in diameter.

The compound fertilizer formula mainly consists of inorganic fertilizer, organic fertilizer, minerals, etc. The inorganic fertilizer in the compound fertilizer, such as urea, is more corrosive to the ring die, while the mineral wears the ring die hole and the inner cone hole badly, and the extrusion force Larger. The diameter of the compound fertilizer ring die is generally larger, ranging from θ3-θ6. Because the friction coefficient is difficult to discharge from the large die hole, the long diameter is relatively small, generally between 1:4-1:6. Containing bacteria, the temperature should not exceed 50 degrees -60 degrees, otherwise it is easy to kill the vaccine. Therefore, compound fertilizer requires a lower granulation temperature, and generally the wall thickness of the ring die is thinner. Because compound fertilizer wears badly to the ring die hole, the requirement of the aperture is not too strict. Generally, the ring die is scrapped when the pressure roller gap cannot be adjusted. Therefore, the length of the stepped hole is used to ensure the aspect ratio and improve the final service life of the ring die.

Hops have a high content of coarse dimension and contain bacteria, and the temperature generally cannot exceed 50 degrees. Therefore, the wall thickness of the ring die for pressing hops is relatively thin, and the length and diameter are relatively short, generally about 1:5, and the particle diameter is larger, at θ5- between θ6.

Chrysanthemum, peanut shells, cottonseed meal, and sawdust contain a lot of coarse brazing, the content of coarse brazing is more than 20%, the oil content is less, the friction resistance of the material through the die hole is large, the granulating performance is poor, and the hardness of the particles The requirement is low, generally it is difficult to meet the requirements if it can be formed. The particle diameter is large, generally between θ6-θ8, and the aspect ratio is generally about 1:4-1:6. Because this type of feed has a small bulk density and a large die hole diameter, the outer circle of the die hole area must be sealed with tape before pelleting, so that the material can be fully filled into the die hole and then formed, and then the tape is torn off.

For the pelleting of various materials, dogma must not be rigidly followed. The correct ring die parameters and operating conditions must be selected according to the characteristics of the material and the specific characteristics of each feed manufacturer, and measures to local conditions can be used to produce high-quality feed.

Analysis of the reasons for broken mold (generally small enterprises choose continuous casting billet will cause broken mold):

1. The wear of the matching surface of the transmission wheel causes the ring die to crack;

2. The ring die is cracked due to wear or deformation of the die liner.

3. The drive key is worn and the ring die is hit and cracked.

4. The deteriorating effect of the iron removing device causes metal indentation on the working surface of the ring die, which causes the ring die to crack.

5. The gap between the ring die and the pressure roller is too small, causing the ring die to crack.

6. For fish material molds with short compression ratio and small aperture, the user requires no pressure relief holes, causing the ring mold to crack.


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