Selection, use and maintenance of feed plant pelleitzer ring die

With the growth of the national economy and the improvement of people’s living standards, the market’s demand for various feeds continues to rise, and the demand for the main vulnerable part of the pellet machine-ring die is also increasing, and the quality of its quality directly affects the feed producers. The production cost and the quality of feed pellets. According to incomplete statistics, the cost of pellet mill ring die wear accounts for more than 30% of the maintenance cost of the entire feed production workshop, and the quality of feed pellets has a great impact on feed sales. It can be seen that the correct selection, rational use and effective maintenance of ring molds are extremely important to feed producers. 　　

Feed pressing ring die is a porous ring-shaped wearing part, with thin wall, dense die holes, and high assembly dimensional accuracy. When working, the feed is extruded from the inner wall through the die hole into a strip under the squeeze of the rotating ring die and the pressure roller, and then cut into the required length by the cutter. The following is an analysis on the selection, use and maintenance of ring molds for your reference.

1. Selection of ring die 　　

Ring dies are generally made of carbon steel or alloy structural steel, or stainless steel through forging, machining, drilling die holes and heat treatment. At present, the popular ring dies in the domestic market are high or low, mainly due to differences in material selection, process selection and control. The ring dies produced by some domestic small factories are mainly made of carbon steel or alloy structural steel through forging, twist drills to drill the die holes, and then processed by ordinary heat treatment. Such ring molds usually have problems of one kind or another during the production process, such as the long-term mold washing process required by the new mold assembly machine, high energy consumption, low output, poor pellet quality, and mold explosion. Another more serious problem is that it has a low service life and is not wear-resistant. According to an investigation, the feed produced by these ring molds has a high iron content, which greatly affects the feed formula. Caused by the poor wear resistance of the ring die. 　　

With the continuous development of the market economy and China's accession to the WTO, only cheap and good-quality feed can have market competitiveness. For feed producers, reducing production costs and improving the quality of feed pellets are urgently needed, and the level of these qualities is largely guaranteed by the quality of the ring die. According to the working status of the ring die, the feed producer should choose those ring die produced by the production plant with reasonable selection of materials, advanced equipment and reasonable technology.

Stainless steel ring dies should be used, and stainless steel forging blanks should be used for ring dies, which is the essential guarantee for the long service life of the ring dies; die holes processed by gun drills should be used, and the die holes should be processed by multi-station gun drills to ensure the die holes Smooth, without forming crooked holes (that is, the center line of the die hole is different from the center line of the ring die circumference), so that the ring die can be discharged quickly and the pellet quality is good (the pellet surface is smooth, the pellets are uniform, and the feed powdering rate is small, etc.) And other characteristics; should choose the ring die after vacuum heat treatment, vacuum heat treatment of the ring die is a further guarantee for the processing quality of the first few procedures, it ensures the high wear resistance and high strength of the ring die material, and the smoothness of the die hole The temperature is effectively protected (avoid the oxidation of the die hole). 　　

In summary, the rational selection of high-quality ring molds is the key to feed producers to reduce production costs and improve pellet quality.

2. How to choose the suitable feed pelletizer ring die 　　

First of all, on the premise of selecting high-quality feed mill ring die, appropriate die hole form, opening rate and compression ratio (compression ratio = effective length of die hole/diameter of die hole) should be selected according to the type of feed, formula and output. Generally speaking, straight holes and stepped holes are suitable for processing compound feed; outer tapered holes are suitable for processing high-fiber feeds such as defatted bran; inner tapered holes are suitable for processing feeds with light specific gravity such as grass powder. On the premise of ensuring the strength of the ring die, try to increase the opening rate of the ring die. For some types of feed, under the condition of ensuring a reasonable compression ratio, the wall of the ring die is too thin, so that the strength of the ring die is not enough, and explosions will occur during production. Mold phenomenon, at this time, under the premise of ensuring the effective length of the mold hole, increase the thickness of the ring mold and increase the pressure relief hole.

Generally speaking, compound feed with high grain content should choose a compression ratio between 5-8; heat-sensitive feed and urea feed should choose a compression ratio between 5-8; concentrated feed with high natural protein content is suitable for choosing a compression ratio between 5-11 The compression ratio of milk cow compound feed is suitable to choose the compression ratio between 7~15. In addition, after considering the basic feed formula, the specific compression ratio can be adjusted according to the feed quality required by the producer. For example, choosing a slightly lower compression ratio is beneficial to increase output, reduce energy consumption, and reduce wear of the ring die. It will reduce the quality of the feed. If the pellets are not strong enough, the appearance is loose and the length of the feed is different, the pulverization rate of the feed is high. On the contrary, it is beneficial to the pellet quality (the pellets are smooth and shiny, and the pulverization rate is small), but it will increase. The production cost of the product. 　　

Secondly, whether the working gap between the ring die and the pressure roller is reasonable or not has an important influence on the effective use of the ring die. Generally speaking, the gap between the ring die and the pressure roller is between 0.1 and 0.3. According to practical experience, it is better for the pressure roller to reach a non-rotating state while the ring die is rotated by hand.

So, how to adjust the gap between the ring die and the pressure roller? Through our practical experience, when the new mold is installed, firstly, loosen the pressure roller adjusting bolt to adjust the pressure roller to a state where the outer circular surface of the pressure roller is close to the inner circular surface of the ring mold; secondly, adjust the eccentric shaft of the pressure roller in turn The gap between each pressure roller and the ring die is appropriate, pre-tighten the adjusting bolts, pull the ring die, and gradually adjust the gap to make the pressure roller reach the working state of non-rotating, and finally tighten the adjusting bolts. When a new mold is installed, it is usually required that the gap between the ring mold and the press roll be slightly larger than what you need, which is conducive to the smooth transition between the new ring mold and the old roll, and wait for the new mold and the old roll to complete a certain running-in period Later, you can adjust the gap to the gap you need.

In use, the ring die is sacrificed at the expense of the press roller. Because the price of the ring die is ten times or even dozens of times the price of the press roller, in use, the hardness of the press roller cannot be achieved when a reasonable gap is selected. Too high, that is to say, the wear resistance of the pressure roller cannot be higher than the wear resistance of the ring die.

Finally, when the operator newly installs or replaces the ring die, for the ring die assembled through the conical surface, when the new die is installed, it is required to avoid bumps and scratches on the conical surface, and to the conical surface and its matching transmission wheel flange. The cone surface is cleaned and assembled with oil. When replacing the ring die, disassemble it without scratching or scratching the cone surface, and it is protected by oiling.

For the pellet machine that often needs to replace the ring die, it is required to check the drive rim regularly to prevent excessive wear and tear of the mold centering pin, because excessive wear will affect the fit between the ring die and the rim , The fit is not tight. When the ring die is working, shearing force will be generated on the centering pin of the mold and cause fracture. When this happens, do not mistake it for insufficient strength of the pin and replace it with a high-strength pin. It can only cause damage to the ring die and frequent breakage of the safety pin. 　　

Therefore, it is quite necessary to protect and regularly inspect the mating cone surface of the ring die and the cone surface of the matching transmission wheel flange. For the hoop-type assembly ring die, the protection and inspection of its assembly surface and its matching components are also quite necessary. When the pressure roller is used for a period of time, it will be worn out, which affects the accuracy of matching with the ring die, thereby affecting the production output of the ring die, and it should be repaired or replaced with a new ring die. 3. Basic maintenance of ring die3. Basic maintenance of ring dieThird, the ring mold substantially maintenance

3. Basic maintenance of ring die 

As the saying goes, sharpening a knife does not accidentally chop wood. Reasonable maintenance of ring molds is part of the economical and effective use of ring molds. In the production process, the operator often finds that the ring die is usually blocked, worn, sealed and turned inward during use. At this time, if the necessary maintenance is not performed on it, it will cause a decrease in output and an increase in energy consumption. Not even out of materials and other phenomena. At this time, the basic maintenance method for the ring die is to first grind the working inner surface of the ring die and then chamfer it.

When replacing the ring die, it is required to fill the die hole with oily material while the hot die is hot, so that the ring die can reach the best condition during the next production.

How to clean the blocked feed mill ring dies? In the production process, the press feed mold is blocked due to power failure or other reasons, especially the small diameter press mold is difficult to clean. It is common for many feed factories to use electric drills to drill the material out, which wastes time and easily damages the finish of the mold hole. I sum up many years of practical experience and believe that a more effective method is to use oil to boil the ring mold, that is, use an iron oil pan, put waste engine oil, put the plugging mold in the oil pan, so that all the plugging holes are immersed in the oil. , And then heat up the bottom of the oil pan until the material in the plugging hole has a popping sound, that is, remove the plugging mold, reinstall the machine after cooling, adjust the gap between the mold rolls, and restart the drive according to the operating requirements of the granulator to quickly plug the mold The material is cleaned up, and the finish of the die hole will not be damaged.

In summary, only the correct selection, rational use and effective maintenance of ring molds can reduce costs, improve efficiency, create particle quality, enhance product market competitiveness, meet challenges, and create more economic benefits for the enterprise.