The correct method of selecting and buying the mould temperature machine is:

One, select the appropriate model temperature controller: random selection model temperature control products DC high voltage generator can bring 20% profit loss at any time, so we must consider the needs of production in detail, and strictly determine the ability of the model temperature controller, in order to make a decision. Unfortunately, people often overlook the extremely important part of the injection molding technology. They often wake up when productivity and quality problems arise.

Two. When choosing the mold temperature controller, the following points are the main considerations.

1. the size and capacity of the pump. 2. the size of the internal throat. 3. heating capacity. 4. cooling capacity. 5. form of control.

Three. Learn how to calculate:

A, pump size: from the known amount of heat needed for each cycle we can easily calculate the required volume flow velocity of the coolant and then get the correct cooling capacity. The manufacturer of the DC high voltage generator of the model temperature controller provides the calculation of the minimum pump velocity formula. Table 4.1 is very useful when selecting pumps. It accurately lists the heat dissipation capacity of different plastics. The following rule of experience for the pump to provide the minimum flow rate is determined as follows: if the temperature difference between the surface of the cavity is 5 C, the temperature difference at 0.75gal/min/kW @5 C or the temperature difference at 151/min/kW @5 C. If the temperature difference on the surface of the mold cavity is 1 degrees, the minimum velocity required is five times greater than the ratio of 3.75gal/min/kW or 17.031/min/kW. In order to obtain the stability of the product quality, many injection companies should control the temperature difference of the cavity surface at 1-2, but in fact many of them may not know the importance of the temperature difference or the best range of temperature difference at 5-8.

To calculate the volume flow rate required for coolant, the following procedures should be used:

1. to calculate the plant a plastic / die combination of the city to drain away the heat in the PC Cup: as an example, the actual needs of the heat is dispersed: the first mock exam gross (g) / cooling time (s) = 208/12 = 17.333g/s PC = 368J/g is the heat dissipation rate is 368kJ/kg or so every week to disperse the heat = 368 * 17.33/1,0 00 = 6.377kW.

2. the volume velocity needed to be calculated again: according to the above rule of experience, if the temperature difference between the cavity surface of the mold cavity is 5, the velocity =6.377 * 0.75=4.78gal/min or the =6.377 x 3.41=21.751/min if the temperature difference between the mode cavity is 1 C and the velocity =4.78 * 5=23.9gal/min or =21.75 x 5=108.731/min.

3. pump flow rate regulation: in order to get good heat dissipation, the flow capacity of the pump should be 10% more than the calculated result, so 27gal/min or 120/min pump should be used.

4. pump pressure regulation: the operating pressure of the general model temperature controller is 2 - 5bar (29-72.5psi), which will affect the volume velocity of the coolant in the condition of insufficient pressure (the flow resistance produces pressure loss), so the higher the pressure of the pump, the more stable the flow rate. For a very small mold of the cooling pipe (for example, the diameter of the pipe is 6mm/0.236in), the pump pressure needs to have a 10bar (145psi) to provide sufficient cooling rate (that is, the speed of the coolant). In general, the higher the volume liquid velocity of coolant is, the smaller the diameter of the pipeline is, the greater the pump output pressure is. Therefore, in general, the pressure of the mold temperature controller should exceed 3bar (43.5psi).

B, heating capacity:

1. the heating capacity of a mold with a weight of 500kg to 50 C is 3kWhr.

2. the heat capacity required to heat the heavy 700kg mold to 65 C is 6.5kW/hr. In general, the stronger the heating capacity, the lower the heating time required, the doubling of heating capacity and the reduction of heating time. It provides a useful information for injection manufacturers, and can immediately find out the heating requirements of any mold, so as to obtain the correct heating capacity of the mold temperature controller. It is often because the capability of the mold temperature controller is too low to cause the mold to fail to achieve the best temperature. To know the actual performance of the mold temperature controller, we can compare its actual and calculated mold heating up time.

C, freezing capacity:

The design of the Cryo circuit of the mold temperature controller and the precise control of the component parts on the mold temperature are important. When the temperature of the mold or heating liquid rises to the set value, the model temperature controller must be able to avoid the temperature rise rapidly and effectively, by introducing another low temperature liquid, which is controlled by the solenoid valve. Therefore, the elimination and stability of the temperature overshoot depends on the size of the solenoid valve. The aperture of the cooling solenoid valve can be calculated by the following formula: the valve freezing capacity of the inlet pump (gal/min) =kW x 3.16/ delta t here the difference between the production temperature and the freezing water temperature set by the delta t= model temperature controller: kW = the following table of heat required to be discharged by the die list lists the volume velocity of the different solenoid valve bore diameter: Electromagnetism Valve aperture volume flow velocity in mm gal/min 1/min 0.25 6.35 0.7 3.18 0.375 9.53 1.2 5.45 0.500 12.70 3.3 14.98 0.750 5.45 0.500 12.70 The heat to be discharged is that the setting temperature of 6.377kW production is 90 degrees centigrade freezing water at 18, T = 90-18 = 72, so the refrigeration capacity = 6.377 x 316/72=0.28gal/min or 1.271/min can provide sufficient volume velocity for the solenoid valve with an aperture of 6.35mm/0.250in, which is suitable for use in the range of + 1 centigrade temperature control. Precise requirements. The pressure drop of the valve of the solenoid valve affects the flow rate. The velocity of the upper table is based on the pressure drop of 1bar (14.5psi).