What are the plastic mold materials?

Question 1: What are the plastic mold materials? The most important factors of mold materials are thermal strength and thermal stability. Commonly used mold materials: working temperature molding materials.

1000℃ nickel alloy copper-based alloy mold, cemented carbide mold.

Question 2: What are the classifications of plastic molds? According to the different molding methods, the types of plastic processing molds corresponding to different technological requirements can be divided into injection molding molds, extrusion molding molds, plastic suction molding molds, high-expansion polystyrene molding molds and so on.

1, plastic injection (plastic) mold

It is mainly a molding die, which is widely used to produce thermoplastic parts. The processing equipment corresponding to the plastic injection mold is a plastic injection molding machine. The plastic is first heated and melted in the heating cylinder at the bottom of the injection machine, and then enters the mold cavity through the nozzle of the injection machine and the gating system of the mold under the push of the screw or plunger of the injection machine. The plastic is cooled, hardened and shaped, and then demoulded to obtain the product. Its structure usually consists of molding part, pouring system, guiding part, pushing mechanism, temperature control system, exhaust system, supporting part and so on. The manufacturing materials are usually plastic die steel modules, and the commonly used materials are mainly carbon structural steel, carbon tool steel, alloy tool steel and high speed steel. Injection molding is usually only suitable for producing thermoplastic products. Injection molding produces a wide range of plastic products, from daily necessities to various complex machinery, electrical appliances, vehicle parts and so on. It is the most widely used processing method in plastic products production.

2. Plastic die

Include compression molding and injection molding. They are mainly used for molding thermosetting plastics, and the corresponding equipment is pressure molding machine. According to the characteristics of plastic, the molding method is to heat the mold to the molding temperature (generally at 103- 108), then put the measured molding powder into the mold cavity and feeding chamber, and close the mold. The plastic becomes soft and sticky under the action of high temperature and high pressure, and after a certain period of time, it is solidified and molded into the required product shape. The difference between pressure injection molding and compression molding is that there is a separate feeding chamber. Before molding, the mold is closed and the plastic is preheated to a viscous state in the feeding chamber. Under the action of pressure, it is adjusted and extruded into the mold cavity and hardened. The die is also used to shape some special thermoplastics, such as hard-to-melt thermoplastics (such as polyvinyl fluoride) blanks (cold-press molding), resin lenses with high optical properties, and micro-foamed nitrocellulose steering wheels. The die is mainly composed of cavity, feeding cavity, guiding mechanism, ejecting parts and heating system. Injection molds are widely used to package electronic components. The materials used to manufacture the compression mold are basically the same as those used in the injection mold.

3, plastic extrusion die

A mold used for molding and producing continuous plastic products, also known as extrusion head, is widely used for processing pipes, bars, monofilaments, plates, films, wire and cable coatings, special-shaped materials and so on. The corresponding production equipment is a plastic extruder, and its principle is that solid plastic is melted and plasticized under the condition that the extruder screw is heated, rotated and pressurized, and a continuous plastic product with the same cross section and mold shape is made through a mold with a specific shape. Its manufacturing materials are mainly carbon structural steel and alloy tools. Some extrusion dies will be inlaid with wear-resistant materials, such as diamond, in the parts that need wear-resistance. Extrusion process is usually only suitable for producing thermoplastic products, which is obviously different from injection mold and compression mold in structure.

4. Plastic blow mold

It is a mold for molding hollow products of plastic containers (such as packaging containers for beverage bottles and daily necessities). According to the process principle, the main forms of blow molding are extrusion blow molding, injection blow molding, injection stretch blow molding (commonly known as "injection stretch blow molding"), multi-layer blow molding, sheet blow molding and so on. The equipment corresponding to blow molding of hollow products is usually called plastic blow molding machine, and blow molding is only suitable for producing thermoplastic products. The structure of the blow mold is relatively simple, and the materials used are mostly carbon.

5, plastic mold

It is a kind of mold that takes plastic plates and sheets as raw materials to shape some simple plastic products. The principle is that the plastic plates and sheets fixed on the female die or the male die are deformed under the condition of heating and softening, and the required molded products are obtained, which are mainly used for producing some daily necessities, foods and toys. Because of the low pressure during molding, the plastic suction mold is mostly made of cast aluminum or non-metallic materials, and its structure is relatively simple.

6, high foaming polystyrene molding die

It takes expandable polystyrene (bead material composed of polystyrene and foaming agent) as raw material, and forms various foam plastic packaging materials into molds with required shapes. Its principle is that expandable polystyrene can be steam molded in the mold, including two types: simple manual operation mold and hydraulic press straight-through foam mold, which are mainly used for ... & gt

Question 3: Material selection of plastic mold 1, working conditions of plastic mold Due to the development of plastic and plastic molding industry, the quality requirements of plastic mold are getting higher and higher, so the failure of plastic mold and its influencing factors have become an important research topic. The main working parts of plastic mold are molded parts, such as punch and die, which form the cavity of plastic mold to shape various surfaces of plastic parts and directly contact with plastic, and bear the effects of pressure, temperature, friction and corrosion. 2. Failure analysis of plastic mold materials General mold manufacturing includes mold design, material selection, heat treatment, processing, debugging and installation. According to the investigation, among the factors of die failure, die material and heat treatment are the main factors affecting its service life. From the perspective of total quality management, the factors that affect the service life of molds should not be measured by the sum of polynomials, but by the product of many factors. In this way, the quality of mold materials and heat treatment is particularly important in the whole mold manufacturing process. From the analysis of common phenomena of mold failure, plastic mold will have wear failure, local deformation failure and fracture failure in the process of use. The important failure forms of plastic molds can be divided into wear failure, local plastic deformation failure and fracture failure. 3. Performance requirements of plastic die steel With the rapid development of manufacturing industry, plastic die is an indispensable tool in plastic molding, and its proportion in the total die output is increasing year by year. With the development and continuous production of high-performance plastics, there are more and more types and uses of plastic products, and the products are developing towards precision, large-scale and complexity. With the rapid development of molding production, the working conditions of molds are becoming more and more complicated. Wear and corrosion of 1) cavity surface The plastic melt flows in the cavity under a certain pressure, and the solidified plastic parts come out of the mold, which all cause friction and wear on the molding surface of the mold. The fundamental reason for the wear failure of plastic mould is the friction between mould and material. However, the specific form and process of wear are related to many factors, such as pressure, temperature, material deformation speed, lubrication conditions and so on. When the materials and heat treatment used in the plastic mold are unreasonable, the surface hardness of the plastic mold cavity is low and the wear resistance is poor, which shows that the surface size of the cavity is out of tolerance due to wear and deformation; Due to napping, the roughness value becomes higher and the surface quality deteriorates. Especially when solid materials are used to enter the cavity of plastic mold, the wear of the cavity surface will be aggravated. In addition, chlorine, fluorine and other components contained in plastic processing are decomposed into corrosive gases HC 1 and HF by heating, which makes the cavity surface of plastic mold corrode and wear, leading to failure. If there is wear damage at the same time, the coating or other protective layer on the surface of the cavity will be destroyed, thus promoting the corrosion process. The interaction of two kinds of damage accelerates the corrosion and wear failure. 2) Plastic deformation failure The cavity surface of the plastic mold is heated under pressure, which will cause plastic deformation failure, especially when the small mold works on large-tonnage equipment, it is more prone to overload plastic deformation. The strength and toughness of the materials used in plastic molds are insufficient, and the deformation resistance is low; Another reason of plastic deformation failure is that the hardened layer on the surface of the die cavity is too thin, the deformation resistance is insufficient or the working temperature is higher than the tempering temperature, which leads to the early failure of the die. 3) The main causes of fracture are the microstructure stress and thermal stress caused by microstructure and temperature difference, or the microstructure stress caused by insufficient tempering, which makes the residual austenite transform into martensite at the service temperature, causing local volume expansion and internal stress in the die. The working conditions of plastic molds are different from those of cold molds. Generally speaking, they must work at the temperature of 150℃-200℃, which is affected by both temperature and pressure. There are many kinds of failure forms of the same mold, and even the same mold may have many kinds of damage. Judging from the failure form of plastic mold, it is very important to choose plastic mold materials and heat treatment reasonably, because they are directly related to the service life of the mold. Therefore, steel for plastic molds should meet the following requirements: 1) heat resistance With the appearance of high-speed molding machinery, the running speed of plastic products is accelerated. Because the molding temperature is between 200-350℃, if the fluidity of plastic is not good and the molding speed is fast, the molding surface temperature of mold parts will exceed 400℃ in a short time. In order to ensure the precision and small deformation of the die in use, the die steel should have high heat resistance. 2) Sufficient wear resistance With the expansion of the application range of plastic products, inorganic materials such as glass fiber are often added to plastics to enhance plasticity. Due to the addition of additives, the fluidity of plastics is greatly reduced, which leads to the wear of molds, so chess is required to have good wear resistance. 3) Excellent ... >>

Question 4: What are the common injection molding materials? PE PP PS ABS PC PA POM PBT PMMA and so on.

Question 5: What material is better for the mold? 3Cr2NiMo(P44 10) plastic die steel.

P44 10 steel has good machinability such as turning, milling and grinding in the hardness range of 32 ~ 36 HRC.

P44 10 steel can also be quenched by local flame at 800 ~ 825℃. When it is cooled in air or compressed air, the local surface hardness can reach 56 ~ 62 HRC, which can prolong the service life of the die. The die can also be chrome plated, and the surface hardness is increased from 370 ~ 420 HV to 1000HV, which significantly improves the wear resistance and corrosion resistance of the die.

The die made of P44 10 steel can also be repaired by repair welding after local damage. The welding quality is good and can be processed.

P44 10 steel is used in pre-hardening state (30 ~ 36 HRC) to prevent heat treatment deformation, and is suitable for manufacturing large, complex and precise plastic molds. The steel can also be subjected to chemical heat treatment such as nitriding and boronizing, and after treatment, higher surface hardness can be obtained, which is suitable for making high-precision plastic molds.

8Cr2MnWMoVS(8Cr2S) steel

8Cr2MnWMoVS is a kind of free-cutting precision plastic forming die steel, which is designed to meet the urgent needs of precision plastic die and thin plate seamless precision blanking die. Its composition design adopts the principle of high carbon, multi-element and small amount alloying, and sulfur is the free-cutting element. The chemical composition and properties of 8Cr2S steel are introduced in the second section of the first chapter, and its application is further introduced here.

1. Characteristics of steel

(1) The heat treatment process is simple, and the hardenability is good: the air cooling quenching diameter is above φ 100mm, the air cooling quenching hardness is 6 1.5 ~ 62 HRC, and the heat treatment deformation is small. When quenched at 860 ~ 900℃ and tempered at 160 ~ 300℃, the total axial deformation rate is less than 0.09% and the total radial deformation rate is less than 0. 15%.

(2) Good cutting performance: the annealing hardness is 207 ~ 239 HBS, and the processing time can be shortened by more than 1/3 compared with ordinary tool steel. Turning, milling, planing, boring and drilling with high-speed steel or cemented carbide tools in the hard state of 40 ~ 45 hours RC, its cutting performance is equivalent to that of quenched and tempered carbon steel, and its hardness is about 30HRC, far superior to that of Cr 12MoV steel with annealing hardness of 240HBS.

(3) Good mirror grinding and polishing performance: under the same grinding process, the surface roughness is 1 ~ 2 grade lower than that of general alloy tool steel, and the lowest surface roughness is Ra 0. 1 micron. ..

(4) Good surface treatment performance: good nitriding performance. Generally, the depth of nitriding layer is 0.2 ~ 0.3 mm, and the adhesion of boronizing is strong.

2. Application

As a kind of pre-hardening steel, 8Cr2S is suitable for making various plastic molds, bakelite molds, ceramic molds and punching molds for printed boards. Compared with other alloy tool steels, the die made of this steel has high matching accuracy of 1 ~ 2 orders of magnitude, low surface roughness of 1 ~ 2 orders of magnitude, and its service life is 2 ~ 3 times longer, and some even several times higher.

5CrNiMnMoVSCa(5NiSCa) steel

5NiSCa is a kind of free-cutting and high-toughness plastic die steel, which has good toughness and machinability in pre-hardening state (35 ~ 45 hours RC). Good mirror polishing performance, low surface roughness, reaching Ra 0.2 ~ 0. 1 micron, and strong surface roughness retention ability during use; Good etching performance, clear and realistic; It has good hardenability and can be used as a plastic mold with complex cavity and high quality requirements. At high hardness (above 50HRC), the steel has small heat treatment deformation, good toughness and good ability to prevent crack propagation.

1. Chemical composition and phase transition point

5NiSCa steel adopts medium carbon nickel, and its main chemical composition is shown in Table 3-9.

Table 3-9 Chemical Composition (Mass fraction) of 5 NISCA Steel (%)

C-Cr-Ni-Mn-Mo-V-S-Ca

0.57 0.89 1.03 1. 19 0.52 0.26 0.028 0.0036

The phase transition point is 695 ~ 735℃ when heating, 378 ~ 305℃ when cooling, and Ms220℃.

2. Process performance

(1) Forging: heating temperature 1 100℃, initial forging temperature1070 ~1100℃, final forging temperature 850℃, and sand cooling after forging.

(2) Spheroidizing annealing: heating temperature is 770℃, heat preservation is 3h, isothermal temperature is 660℃, heat preservation is 7h, cooling with the furnace to 550℃, and discharging for air cooling. Annealing hardness ≤24 1HBS, and good processability.

(3) Quenching: the quenching temperature is 8...> & gt

Question 6: What are the commonly used plastic die steels for dies: 45#, P20, 4Cr 13? ...

Cold working die steel: Cr 12, Cr 12MoV, D2. ....

Hot working die steel: H65438+5CrMnMo, 3Cr2W8V. ....

Huangshi Dongxin Special Steel Co., Ltd. produces steel for tools and molds. Century Daye Special Steel Technology.

Question 7: What strength, hardness, heat treatment performance, product quantity, corrosion resistance, etc. What is the basis for choosing plastic mold materials?

Question 8: How many kinds of molds are there? Mould can be divided into metal mould and nonmetal mould. Metal molds are divided into: casting molds (non-ferrous metal die casting, steel castings) and forging molds; Non-metallic molds are divided into plastic molds and inorganic non-metallic molds. According to the different materials of the mold itself, the mold can be divided into sand mold, metal mold, vacuum mold, paraffin mold and so on. Among them, with the rapid development of polymer plastics, plastic molds are closely related to people's lives. Generally, plastic molds can be divided into injection molds, extrusion molds and gas-assisted molding molds. Mass production of non-sheet metal steel parts-cold heading, die forging, metal die, etc. Die sheet metal discharging-hot rolling, cold rolling, hot rolling, cold rolling sheet metal processing-stretching, forming, bending, punching, blanking non-ferrous metals-die casting, powder metallurgy plastic parts-injection molding, blow molding (plastic bottles), extrusion (pipe fittings) dies Other categories: alloy dies, sheet metal dies, plastic dies, stamping dies, casting dies, forging dies.

Question 9: What are the materials commonly used in molds and what are their prices? 6 18 Pre-hardened Plastic Die Steel

28 yuan/kg

7 18 Pre-hardened Plastic Die Steel

40 yuan/kg

7 18H pre-hardened plastic die steel

44 yuan/kg

S 136 high-quality corrosion-resistant mirror die steel

80 yuan/Jin

S 136H high-quality corrosion-resistant mirror die steel

85 yuan/kg

8402 hot working die casting die steel

64 yuan/kg

8407 Hot Working Die-casting Die Steel

88 yuan/kg

DF-2 Non-deformation Wear-resistant Petroleum Steel

35 yuan/kg

ASSAB 88 special cold die alloy steel

68 yuan/kg

XW-5 High Carbon and High Chromium Tool Steel

120 yuan/kg

XW- 10 high carbon and high chromium tool steel

1 10 yuan/kg

XW-4 1 high carbon and high chromium tool steel

1 10 yuan/kg

XW-42 High Carbon and High Chromium Tool Steel

69 yuan/kg

ASP60 powder high speed steel

780 yuan/Jin

Japan Datong YK30

Advanced carbon tool steel

28 yuan/kg

NAK80 pre-hardened high quality plastic die steel

53 yuan/kg

PX5 high quality plastic mould steel

26 yuan/kg

DC-53 Special Cold Working Die Steel

63 yuan/kg

NAK55 pre-hardened advanced plastic die steel

52 yuan/kg

420 high-quality corrosion-resistant mirror die steel

85 yuan/kg

H3 100 Sambo copper

98 yuan/Jin

Japan Hitachi SLD

Special cold die alloy steel

52 yuan/kg

DAC(SKD-6 1) high-quality hot-working cast alloy steel

56 yuan/kg

DAC55 high quality hot working cast alloy steel

1 15 yuan/kg

FDAC special heat-resistant die-casting die steel

80 yuan/Jin

SKH-9 Special High Quality High Speed Steel

150 yuan/kg

SKS3 wear-resistant and non-deformable alloy tool steel

28 yuan/kg

SKD 1 1 special cold-working die steel

44 yuan/kg

HPM38 corrosion-resistant mirror die steel

85 yuan/kg

German Sastre.

Gerriets

23 1 1 plastic die steel

20 yuan/kg

2738 Pre-hardened plastic die steel

25 yuan/kg

23 16 Hardened Corrosion Resistant Mirror Die Steel

60 yuan/kg

2083 corrosion-resistant mirror die steel

48 yuan/kg

2344

Hot work die casting die steel

60 yuan/kg

25 10 non-deformation wear-resistant petroleum steel

30 yuan/kg

2379 special cold die alloy steel

55 yuan/kg

2083ESR corrosion-resistant mirror die steel

65 yuan/kg

2738HH high quality plastic mould steel

29 yuan/kg

2767 high quality plastic mould steel

67 yuan/kg

Pohang, Korea

STD 1 1 Maximum thickness 200mm 40 yuan/kg.

STD6 1 Maximum thickness is 600 mm..

55 yuan/kg

The thickness of PSTW2 is as high as 230mm.

55 yuan/kg

The maximum thickness of STP4 is 600 mm.

23 yuan/kg

The maximum thickness of STP4M is1100 mm.

28 yuan/kg

Japan Gao zhoubo

KDA 1S high quality hot working cast alloy steel

Eighty-five

KAP65

High quality plastic die steel

25

KD 1 1 Special cold-working die alloy steel

Fifty two

KPMAX

High quality plastic die steel

38

KRCX

Special cold die alloy steel

60

KAP88

High quality plastic die steel

50

KD2 1 Special Cold Working Die Steel

63

KD 12 Special Cold Working Die Steel

55

KPH25K high quality plastic die steel

70...& gt& gt