The compression ratio of the pellet machine die refers to the ratio of the effective length of the die hole of the die to the die diameter, and is an index reflecting the extrusion strength of the pellet machine.
Pellet machine mold compression ratio = mold hole diameter / effective working length of mold hole
For a mold with a straight hole, the effective length of the mold hole is the total thickness of the mold, and the small diameter is the diameter of the mold hole itself.
Assumption: The diameter of the die hole is 6mm, and the thickness of the ring die is 45mm.
The ring mode compression ratio is 1:7.5
For the release step hole and the outer tapered hole, the effective length of the die hole is the total thickness of the mold minus the length of the release hole or the length of the outer tapered hole, and the aperture of the small diameter section is the aperture for calculating the compression ratio.
Assumption: the diameter of the ring die hole is 8mm, the die thickness is 66mm, and the release hole is 18mm
The ring mode compression ratio is 1:6
Compression ratio is a ratio. For the same compression ratio, its aperture and effective working length may be different.
1. The aperture size and output of the mold are closely related to the inner diameter of the pellet machine mold and the composition of the raw materials. The standard aperture of 8-10 mm generally used in the industry is called conventional data. The pellet machine larger than 10 mm requires greater pressure for molding. , Relatively speaking, the wear is also large, users generally call it a biomass rod making machine or a rod making machine.
2. The effective thickness of the mold is very important for the molding of raw materials. If the mold is too thick, the molding time of the raw material is longer, the density of the particles is relatively large, the extrusion is more difficult, the mold is thin and easy to break, and the density of the particles is relatively small. The pressing temperature is low, the output is high, but the molding rate is low or the molding is poor.
3. The compression ratio of abrasive tools is determined according to the raw materials. The compression ratio of poplar wood is 1:6, the compression ratio of pine wood is 1:7, the compression ratio of hard wood is 1:5, and the compression ratio of shavings is 1. : 5.5, the compression ratio of corn stalk is 1:6.5. From these simple figures, the compression ratio of different raw materials is different. The harder the raw material, the smaller the compression ratio, and the fluffy the raw material, the greater the compression ratio. That is to say, the more fluffy the raw material, the easier it is to be molded. The more fluffy raw material contains more fibers, and the more fiber-containing materials are easier to shape.
4. Each small hole directly has 6 mm, 8 mm, and 10 mm. This 1 represents the diameter of each small hole. If the diameter of the ring die hole is 8 mm, then this 1 represents 8 , And 6 represents the effective aperture. The effective aperture is equal to the diameter of the hole multiplied by the effective aperture length, which is 6*8=48, which is 8:48, 8:48 is simplified to 1:6, 1: 6 is the compression ratio of poplar wood. It is converted in this way. The quality of the biomass pellet machine’s output depends on the compression ratio of the ring die. But if the customer does not have high requirements for the molding rate of your pellets, then you can appropriately Reduce the compression ratio, which can not only increase the output, but also reduce the service life of the mold and the pressing wheel.
5. Roughness is also an important indicator to measure the quality of ring die. Under the same compression ratio, the greater the roughness value, the greater the extrusion resistance of the sawdust particles, and the more difficult it is to discharge the material. Excessive roughness also affects the quality of the particle surface. The appropriate roughness value should be 0.8-1.6. between.
What to do if the mold compression ratio is too large?
1.Experienced operators will adjust the moisture content of the raw materials or adjust the gap between the ring molding rollers, and the pellets can be smoothly discharged without changing the compression ratio. The process needs to be recorded and tested step by step.
2.In addition, the second pressurization can make the mold with a larger compression ratio smaller, but modifying the ring mold will affect the hardness of the ring mold, so it needs to be determined according to the actual wear of the mold.
The roughness of the die hole of the pellet machine is also an important indicator to measure the quality of the mold, and the appropriate roughness value should be between 0.8-1.6. Under the same compression ratio, the larger the roughness value, the greater the particle extrusion resistance, and the more difficult it is to discharge the material. Excessive roughness also affects the quality of the particle surface. If you have any confusion about mold use, please leave a message to exchange.