What is the difference between high modulus and high hardness in injection molding?
Injection Molding Know-how: Temperature Control in Injection Molding:
1. Barrel temperature: The temperature that needs to be controlled during the injection molding process includes barrel temperature, nozzle temperature and mold temperature. The temperature of the first two passes mainly affects the plasticization and activity of the plastic, while the latter temperature mainly affects the activity and cooling of the plastic. Each kind of plastic has a different activity temperature, the uniform plastic, because of the source or grade difference, its activity temperature and differentiation temperature are different, this is because of the equilibrium molecular weight and molecular weight dispersion difference, the plasticization process of the plastic in the injection machine of the different example is also different, so the temperature of the selected barrel is not similar.
2. Nozzle temperature: The nozzle temperature is usually slightly lower than the highest temperature of the barrel, which is to prevent the "salivation phenomenon" that may occur in the straight-through nozzle. The nozzle temperature should not be too low, otherwise it will cause the early setting of the melt and block the nozzle, or the efficacy of the finished product will be affected because the early set is injected into the mold cavity.
3. Mold temperature: Mold temperature has a great impact on the connotation, efficacy and apparent quality of the finished product. The ruggedness of the mold temperature depends on the presence or absence of the crystallinity of the plastic, the size and layout of the finished product, the efficacy requirements, and other process conditions (melt temperature, injection rate and pressure, molding cycle, etc.).
What is the difference between high modulus and high hardness in injection molding?
The modulus of elasticity is a physical quantity that depicts the resistance of solid materials to deformation. This includes elastic and plastic deformation.
In other words, the data with high modulus is "rigid". It is not easy to twist, or it is not easy to stretch.
Low modulus material, easy to bend, or stretch. This is divided into two conditions, assuming that it is simple elastic deformation but no plastic deformation, which is commonly known as "good elasticity". Assuming simple plastic deformation, it is generally considered to be "soft".
The material with good rigidity is not easy to bend and deform, and generally speaking, it seems that it is hard to be. Not really. Because there is another question of strength.
High modulus data, not necessarily high strength. A little brittleness data, there may also be a high modulus. Within the confines of very little force, the stress-strain curve is steep. But when the force is slightly greater, it immediately cracks, and there is no process of obedience. Does this situation exist? The metaphor is glass, the sugar of crystals, and the rosin. The modulus is probably relatively high, but the strength is very low. The hardness is not high.
Conversely, low-modulus data may also have high strength. It is very simple to stretch and deform, and it can be stretched very long with very little force. But it just doesn't crack, or it doesn't produce obedience.
However, the "high modulus" and "low modulus" here are also relative. It is difficult to have a low modulus of high strength, and it is relatively rare to have the strength of steel wire that can be easily stretched like rubber.
Hardness, on the other hand, is "the ability to press or divide a kind of data into other materials". If you want to be able to press in the rest of the information, you must have a higher level of obedience at the beginning. If it is damaged or plastically deformed, it is pressed into the rest of the material, which means that the hardness is low.
Therefore, considering the question of modulus and hardness alone, I don't think it is very corresponding. More correspondingly, it is probably strength and hardness. Although there may not be a linear correspondence between strength and hardness, there is a definite general trend.
As for the modulus, it is a very good correspondence between the indefinite determination and the hardness.