Pressure control during injection

Vacuum pump set, one roots blower, two oil-free pumps in series, end pressure < 1 x 10 mbar, evacuation time of loaded plant down to 0.08 mbar 12 min. Pressure control during MD either by injection of dry N2 or by closing and opening the valve between condenser and pump set ... 

Operation pressure control during MD (Nt injection) 0.08 resp. O.lSmbar (Table 1)... 

Pressure control in the injection molding process is a very important aspect to achieve excellent part quality. The injection pressure is a very important pressure control. During the plastic filling of the mold during... 

An injection molding machine is operated by hydraulic power and equipped with an dectric motor and hydraulic pump. The maximum hydraulic oil pressure is ca 14 MPa (2000 psi). A hydraulic cylinder opens and closes the mold and holds the mold dosed during injection another cylinder forces the screw forward, thereby injecting the mdt into the mold. A separate hydraulic motor turns the screw to plasticate, homogenize, and pressurize the mdt. Control of these movements is a combined function of the hydraulic and electrical systems (35—37). 

Flow control is highly desirable if not essential during temperature progr nming with padced columns and can be used to advmtage with on-column injectors on capillary coliunns. Pressure control, with metal diaphragms, is the only practical means of gas control for capillary work with split injection. 

So, all penetration thresholds of order 2 to n explain fluctuations capillary pressure phenomena during Hg-invasion in pore-space. Figure 7 shows in one simple pore segment and of primary complexity the time-controlled injection of mercury and the associated trend in Pc. Mercury volume versus time V(t). During the mercury injection in pore space the volume... 

Another fundamental state variable that can be regulated during the cycle is cavity pressure. Closed loop control of cavity pressure could automatically compensate for variations in melt viscosity and injection pressure to achieve a consistent process and consistency of molded products. Adaptive control methods have been developed to track the cavity pressure profile at one location in the mold. In these earlier works, cavity pressure control was handicapped by the absence of actuators for distributed pressure control, as conventional molding machines are equipped with only one actuator (the screw), which prevents the simultaneous cavity pressure control at multiple points in the mold. This problem has been solved with the development of dynamic melt flow regulators that allow control of the flow and pressure of the polymer melt at multiple points in the mold.[ °l... 

During injection well pressure releasing, the open flow discharge must be controlled under the value in order to prevent casing damage. 

Pressure too low] injection pressure too low/loss of injection pressure during the cycle/feed control set too high causing lower injection pressure. 

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