Plastic mold material selection of the Road
Likely that many of my friends do not quite understand the production of plastic products, mold after the customer orders, the first thing to consider is the mold selection of raw materials. From Koriyoshi United States many years of operating experience in plastic products shield, generally do die based on the quality, quantity, structure to determine the selection of the mold. The mold material selection is a very important aspect of the entire mold making process. Mold material selection need to meet three requirements: First, the mold to meet the demand for wear resistance, toughness, etc.; Second, the mold meet the technical requirements; once again, the mold should meet the economic suitability requirements. Seemingly direct impact on the quality of the product late than many plastic products factory ignore the problem, but
How to meet the plastic mold job requirements
1, abrasion resistance
Plastic deformation of the blank in the mold cavity, along cavity surface both current and slide the intense friction generated between the cavity surface and the dough mold thus easily lead to failure due to wear. Accordingly, the abrasion resistance of the material is the basic mold, one of the most important performance.
The hardness is a major factor affecting the wear resistance. Under normal circumstances, the higher the hardness of the mold parts, the smaller the amount of wear, the better the abrasion resistance. In addition, the wear resistance of the type, quantity, shape, size and distribution of the carbide material.
2, strength and toughness
Mold working conditions are mostly very poor, some often withstand greater impact loads, resulting in brittle fracture. To prevent a sudden brittle fracture at work when the mold parts, the mold having a high strength and toughness. Resilience of the mold depends mainly on the carbon content of the material, grain size and organization of the state.
3, fatigue fracture properties
Die working process, the long-term effects of cyclic stress, often leading to fatigue fracture. In the form of many small energy impact fatigue fracture tensile fatigue fracture contact fatigue fracture and bending fatigue fracture.
Fatigue fracture properties of the mold depends primarily on its strength, toughness, hardness, and material inclusions content.
4, high temperature performance
When the working temperature of the mold is higher, causes the strength and hardness decrease, leading to early wear of the mold or plastic deformation and failure. Thus, the mold material should have a higher resistance to tempering stability, to ensure that the mold at the working temperature, has a high hardness and strength.
5, resistance to thermal fatigue performance
Some mold in the work process is repeated heating and cooling state, so that the cavity surface is pulled, pressure stress effect, causing the surface cracking and peeling, increased friction, hinder plastic deformation, reducing the dimensional accuracy, resulting in die failure. Thermal fatigue is one of the main forms of hot work die failure to help this type of mold should have a high resistance to thermal fatigue performance.
6, the corrosion resistance
Some mold plastic mold at work, due to the presence of chlorine, fluorine and other elements in the plastic, heat decomposition precipitation HCI, HF and other strong corrosive gases, the erosion of the mold cavity surface, increasing its surface roughness, increased wear failure.
(B) if the plastic mold process performance requirements
Mold manufacturing to go through the forging, machining, heat treatment processes. In order to ensure the quality of mold manufacturing, reduce production costs, the material should have good malleability, machinability, hardenability and hardenability and grinding; should also have a small oxidation, decarburization sensitivity and quenching deformation cracking tendency.
1, malleability
Has a lower the forging deformation resistance, plasticity, and a wide range of forging temperature and forging crack cold cracking and low tendency to precipitation of carbide network.
2 Process
The ball annealing temperature range, low annealing hardness and small fluctuation range, the ball high.
3, the machinability
Cutting tool wear, low surface roughness.
4, oxidation, decarburization sensitivity
Antioxidant when heated to high temperatures pregnant decarbonization slow, not sensitive to the heating medium, resulting in pitting tendency.
5, hardened
Having a uniform and high surface hardness after quenching.
6, hardenability
Deeper hardened layer after quenching, the use of the relaxation quenching medium can be hardened.
7, quenching deformation cracking tendency
Conventional quenching volume change, warpage shape, slight distortion, a low propensity for abnormal deformation. Conventional quenching cracking sensitivity is not sensitive to the quenching temperature and the shape of the workpiece.
8, can grind
Grinding wheel is relatively small loss, no burn limit the amount of grinding is not sensitive to the quality of the grinding wheel and cooling conditions, less prone to galling, grinding cracks.
(C) how to meet the economic requirements of the plastic mold
To mold material selection, we must consider the economics of this principle, as much as possible to reduce manufacturing costs. Therefore, meet the performance, the first selection of lower-priced, carbon steel can be used without alloy steel, not imported materials can be used domestic materials.
In addition, should also be considered in the selection of the production and supply of the market, the selected steels should be minimal and concentrated, easy to buy.
Understanding of the knowledge of the mold material selection can better play out so that the advantages of the mold. To open a better quality mold.