Material classification of mould
DATE：2022/5/5 8:51:49 / READ： / SOURCE：This station
Material classification of mould
The mold is the molding and shaping equipment for the production of plastic products. The mold used on the injection foaming molding machine is very similar to that used on the ordinary non injection foaming molding machine. It is also composed of moving mold and fixed mold, including concave mold, punch mold, guide, demoulding, sprue, exhaust, heating and cooling and other parts. The design principle of ordinary mold is also applicable to the mold for foaming, but the design of the latter mold must also meet the special requirements of foaming molding process. For example, in order to improve the foaming multiple, uniformity of density distribution and surface quality of products in Hong Kong, it is necessary to pre improve the mold filling speed of melt and shorten the process. Therefore, there are many requirements for the injection skin mold, mainly in the following aspects. Note the shape and size of the system, exhaust system, heating and cooling system and mold cavity. Hollow board production line www.handern.com com
When selecting mold materials for injection foaming molding, appropriate materials must be selected according to the working parts and requirements of the mold. For example, for the process tools used for low-pressure injection foaming molding, the pressure is relatively low when forming, and the material body does not need to be filled with mold control. Therefore, the injection pressure will not be directly transmitted to the mold wall, which only bears the expansion force of plastic melt foaming. This force is much lower than that of ordinary injection without foaming molding. The cavity pressure of ordinary injection molding is 30 ~ 60MPa, while that of injection foaming molding is only 2-7mpa. Therefore, the mold for low-pressure injection foaming molding can adopt materials with low strength and hardness, which reduces the cost. When high-pressure injection foaming molding, the plastic soldering body must be filled into the mold cavity. The injection pressure will be transmitted directly to the cavity wall. However, it is not exactly the same as ordinary non foaming injection molding. Its melt does not need to be in the compaction stage, and the pressure in the mold cavity is the highest in the compaction stage. Therefore, although the mold cavity pressure of high-pressure injection foaming molding is higher than that of low-pressure injection molding, it is lower than that of ordinary non foaming injection molding. Generally, it is 7 ~ 15MPa, and some may be higher, which mainly depends on the mold filling process, Therefore, the mold material for high-pressure injection foaming molding should be the material with certain strength and hardness requirements. In addition, the batch number of foamed products, the corrosivity of product materials, the complexity of product shape, dimensional accuracy, surface gloss and other requirements are the basis for selecting materials. As the thermal conductivity of foamed plastics is low and the wall thickness of products is relatively large, the cooling conditions must be strengthened to shorten the cooling time. Therefore, the materials with high thermal conductivity and small specific heat capacity should be selected as the mold materials. When selecting materials, please refer to the selection principles of ordinary injection molds. The commonly used mold materials are as follows.
(1) the biggest advantage of metal materials is that they have good thermal conductivity and easy processing. They can be rolled or cast. They are light in weight, easy to operate and cheap, so they have been widely used. The disadvantage of this kind of materials is that their surface hardness is low, so they are easy to be damaged and their surface quality is low. Cast aluminum molds are generally used in mold cavities with complex shapes. Correct high-precision castings require only a small amount of machining. Cooling water pipes can be bent into various shapes according to the shape of mold cavities The required shape and cast directly into the mold. In this way, the cooling pipeline can be as close as possible to the mold gas caused by deep ritual perforated hemp high cooling transmission in the mold, so that 10000 pieces and 20 pieces can be rolled. There is a brand. There are great differences, so the application needs to be selected according to specific requirements. Hollow board production line www.handern.com com
(2) The point of material manufacturing is that its surface is hard and high, which is close to steel; The tensile strength and wear resistance are also good; Heat transfer performance can be compared with aluminum; Long service life. The disadvantage of this kind of material is that the price is expensive. Ammonia chicken has strong corrosive effect. Therefore, when using the injection foaming mold of C foaming agent and beryllium alloy, the surface of the mold cavity should be chrome plated to prevent the surface of the mold cavity from being corroded and damaged. The molds made of% of this kind of materials have a service life of 250000 ~ 500000 pieces under normal service conditions.
(3) the advantage of gold material is that it has good flow performance in molten state, which can be used to make high-quality copies. The cooling water pipe of the mold of this material can also be cast into the mold like aluminum alloy mold to improve the cooling conditions and improve the cooling efficiency. In addition, zinc and copper beryllium alloy will be corroded by ammonia. Therefore, measures must be taken to protect the surface layer, otherwise it will affect the service life. In order to cast high precision and deformation For small mold cavity, refined zinc alloy must be used, otherwise impurities mixed into zinc alloy will cause casting deformation and aging performance. Hollow board production line www.handern.com com
(4) Steel (carbon steel and alloy steel) molds made of steel have high mechanical strength and can withstand large clamping force. Especially alloy steel has better mechanical properties than carbon steel. Carbon steel has been widely used because of its low price. The disadvantage of steel is poor thermal conductivity, and the machining amount required in the manufacturing process is relatively large. Carbon steel has poor corrosion resistance. It is often protected by hard chromium plating, and its service life can reach 500000 ~ 1 million pieces. Hollow board production line www.handern.com com
(5) Epoxy resin the mold of epoxy resin direct casting products can make the cavity simply and quickly, which is the outstanding advantage of using epoxy resin to make the cavity. The disadvantages of the mold made of epoxy resin are low strength, easy damage and poor thermal conductivity. Generally, the number of times of use shall not exceed 500. In order to make up for its defects, it can be solved by adding filler. For example, glass fiber, glass fiber fabric and glass beads are added to improve their mechanical properties. In addition, aluminum powder can be added to improve its thermal conductivity. Even so, its thermal conductivity and mechanical strength are still relatively low. The cavity made of epoxy resin with filler is difficult to carry out post-processing.
Bubble, so as not to affect the surface quality and strength of the cavity. Therefore, the holes and inserts in the mold cavity should be cast at one time. During casting, it is necessary to avoid gas formation
(6) Metal shell metal shell is a semi-finished product made of a certain metal material, and then it is used to make the cavity of the mold. It is to cover a layer of metal on the model of the product by metal plating or spraying with low melting point metal
The mold is the molding and shaping equipment for the production of plastic products. The mold used on the injection foaming molding machine is very similar to that used on the ordinary non injection foaming molding machine. It is also composed of moving mold and fixed mold, including concave mold, punch mold, guide, demoulding, sprue, exhaust, heating and cooling and other parts. The design principle of ordinary mold is also applicable to the mold for foaming, but the design of the latter mold must also meet the special requirements of foaming molding process. For example, in order to improve the foaming multiple, uniformity of density distribution and surface quality of products in Hong Kong, it is necessary to pre improve the mold filling speed of melt and shorten the process. Therefore, there are many requirements for the injection skin mold, mainly in the following aspects. Note the shape and size of the system, exhaust system, heating and cooling system and mold cavity. Hollow board production line www.handern.com com
When selecting mold materials for injection foaming molding, appropriate materials must be selected according to the working parts and requirements of the mold. For example, for the process tools used for low-pressure injection foaming molding, the pressure is relatively low when forming, and the material body does not need to be filled with mold control. Therefore, the injection pressure will not be directly transmitted to the mold wall, which only bears the expansion force of plastic melt foaming. This force is much lower than that of ordinary injection without foaming molding. The cavity pressure of ordinary injection molding is 30 ~ 60MPa, while that of injection foaming molding is only 2-7mpa. Therefore, the mold for low-pressure injection foaming molding can adopt materials with low strength and hardness, which reduces the cost. When high-pressure injection foaming molding, the plastic soldering body must be filled into the mold cavity. The injection pressure will be transmitted directly to the cavity wall. However, it is not exactly the same as ordinary non foaming injection molding. Its melt does not need to be in the compaction stage, and the pressure in the mold cavity is the highest in the compaction stage. Therefore, although the mold cavity pressure of high-pressure injection foaming molding is higher than that of low-pressure injection molding, it is lower than that of ordinary non foaming injection molding. Generally, it is 7 ~ 15MPa, and some may be higher, which mainly depends on the mold filling process, Therefore, the mold material for high-pressure injection foaming molding should be the material with certain strength and hardness requirements. In addition, the batch number of foamed products, the corrosivity of product materials, the complexity of product shape, dimensional accuracy, surface gloss and other requirements are the basis for selecting materials. As the thermal conductivity of foamed plastics is low and the wall thickness of products is relatively large, the cooling conditions must be strengthened to shorten the cooling time. Therefore, the materials with high thermal conductivity and small specific heat capacity should be selected as the mold materials. When selecting materials, please refer to the selection principles of ordinary injection molds. The commonly used mold materials are as follows.
(1) the biggest advantage of metal materials is that they have good thermal conductivity and easy processing. They can be rolled or cast. They are light in weight, easy to operate and cheap, so they have been widely used. The disadvantage of this kind of materials is that their surface hardness is low, so they are easy to be damaged and their surface quality is low. Cast aluminum molds are generally used in mold cavities with complex shapes. Correct high-precision castings require only a small amount of machining. Cooling water pipes can be bent into various shapes according to the shape of mold cavities The required shape and cast directly into the mold. In this way, the cooling pipeline can be as close as possible to the mold gas caused by deep ritual perforated hemp high cooling transmission in the mold, so that 10000 pieces and 20 pieces can be rolled. There is a brand. There are great differences, so the application needs to be selected according to specific requirements. Hollow board production line www.handern.com com
(2) The point of material manufacturing is that its surface is hard and high, which is close to steel; The tensile strength and wear resistance are also good; Heat transfer performance can be compared with aluminum; Long service life. The disadvantage of this kind of material is that the price is expensive. Ammonia chicken has strong corrosive effect. Therefore, when using the injection foaming mold of C foaming agent and beryllium alloy, the surface of the mold cavity should be chrome plated to prevent the surface of the mold cavity from being corroded and damaged. The molds made of% of this kind of materials have a service life of 250000 ~ 500000 pieces under normal service conditions.
(3) the advantage of gold material is that it has good flow performance in molten state, which can be used to make high-quality copies. The cooling water pipe of the mold of this material can also be cast into the mold like aluminum alloy mold to improve the cooling conditions and improve the cooling efficiency. In addition, zinc and copper beryllium alloy will be corroded by ammonia. Therefore, measures must be taken to protect the surface layer, otherwise it will affect the service life. In order to cast high precision and deformation For small mold cavity, refined zinc alloy must be used, otherwise impurities mixed into zinc alloy will cause casting deformation and aging performance. Hollow board production line www.handern.com com
(4) Steel (carbon steel and alloy steel) molds made of steel have high mechanical strength and can withstand large clamping force. Especially alloy steel has better mechanical properties than carbon steel. Carbon steel has been widely used because of its low price. The disadvantage of steel is poor thermal conductivity, and the machining amount required in the manufacturing process is relatively large. Carbon steel has poor corrosion resistance. It is often protected by hard chromium plating, and its service life can reach 500000 ~ 1 million pieces. Hollow board production line www.handern.com com
(5) Epoxy resin the mold of epoxy resin direct casting products can make the cavity simply and quickly, which is the outstanding advantage of using epoxy resin to make the cavity. The disadvantages of the mold made of epoxy resin are low strength, easy damage and poor thermal conductivity. Generally, the number of times of use shall not exceed 500. In order to make up for its defects, it can be solved by adding filler. For example, glass fiber, glass fiber fabric and glass beads are added to improve their mechanical properties. In addition, aluminum powder can be added to improve its thermal conductivity. Even so, its thermal conductivity and mechanical strength are still relatively low. The cavity made of epoxy resin with filler is difficult to carry out post-processing.
Bubble, so as not to affect the surface quality and strength of the cavity. Therefore, the holes and inserts in the mold cavity should be cast at one time. During casting, it is necessary to avoid gas formation
(6) Metal shell metal shell is a semi-finished product made of a certain metal material, and then it is used to make the cavity of the mold. It is to cover a layer of metal on the model of the product by metal plating or spraying with low melting point metal
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