• Categories:技术答疑
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• Time of issue:2017-07-08
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(Summary description)1.What is vulcanization pressure?

　　 Vulcanization pressure, I think it is equal to the pressure in the cavity, it should be reminded here that the unit of this pressure should be MPa, not kN. A more accurate term should be called pressure, but many people call it more pressure.

　　 is just called stress. The reason why it is called pressure is because it is related to area, which will be explained later. In the vulcanization process, the vulcanization pressure can be equal to the injection pressure (injection) pressure, or the expansion pressure of the rubber

　　Power can also be equal to the reasonableness of the two. This is determined according to the specific process.

　　2. What is the relationship between vulcanization pressure and clamping force and clamping force?

　　 The clamping force must be greater than the vulcanization pressure, so as to ensure the pressure when the rubber is vulcanized. This is basically a theoretical value (regardless of how it is written on the equipment data). The clamping pressure is an application value, usually the clamping force multiplied by one

　　 coefficient (usually between 1.2 and 1.5). That is to say, when the mold pressure (gauge pressure) is 21MPa, the clamping pressure may only be 16MPa.

　　3. What is the relationship between vulcanization pressure and injection (injection pressure) pressure?

　　In the early stage of vulcanization, injection (injection pressure) molding is used (mold filling is more accurate and more appropriate). When the injection (injection pressure) is not completed to just completed (prerequisite, the injection volume must be greater than the cavity volume plus the auxiliary injection volume)

　　Vulcanization pressure = injection (injection pressure) pressure. With different processes, the injection (injection pressure) pressure may peak and then drop to an equilibrium value. As the vulcanization progresses, the rubber will expand when heated.

　　Vulcanization pressure = injection (injection pressure) pressure + rubber expansion force. Someone may ask: In the later stage of vulcanization, if the clamping force is large enough, will the rubber expansion force push the injection piston back? The answer is usually no, because the rubber is vulcanized

After 　　 expands, the friction with the runner makes it enclosed in the mold.

　　 4. How to calculate and set the pressure parameters of the equipment?

　　In simple terms: For a flat vulcanizer, vulcanization pressure = equipment gauge pressure x mold clamping cylinder piston area / product rubber part maximum projected area. According to the calculated vulcanization pressure, forward or backward calculation, select equipment tonnage

　　 and pressure parameters. For injection (injection pressure) machines, the injection (injection pressure) pressure must also be checked.

  Methods as below:

　　 1. Confirm the piston area of ​​the injection (injection) cylinder and the cross-sectional area of ​​the injection (injection) plunger cylinder.

　　2. Injection (injection pressure) pressure = injection (injection pressure) piston area × injection (injection pressure) gauge pressure

　　3. Injection (injection pressure) piston pressure = injection (injection pressure) pressure / injection (injection pressure) piston area

　　4. Approximately calculate the cavity pressure according to Pascal's law = the pressure at the injection (injection) piston / the maximum projected area of ​​the rubber part of the product.

　　 5. Comparison of cavity pressure and vulcanization pressure. The cavity pressure must be less than the vulcanization pressure. The tonnage and pressure parameters of the equipment can be selected based on the positive and negative calculations of the above steps.

　　 Here is an example:

　　 Upper cylinder diameter 310, upper cylinder area 75438.5 Upper cylinder gauge pressure (MPa) 15 Maximum gauge pressure (theoretical value) 12.76047 Actual gauge pressure setting 10.20838

　　 Piston diameter 150 Piston area 17662.5 Piston pressure 64.06667 Maximum piston pressure 54.5014 Projected diameter 267 Projected area 55961.865

　　 cavity pressure 64.06667 cavity pressure 3.58529 maximum cavity pressure 54.5014 main cylinder diameter 430 main cylinder area 145146.5 main cylinder gauge pressure (MPa) 21

　　 Main cylinder pressure 3.048077