Electric-hydraulic compression press

Automatic press n. Hydraulic press for compression molding or an injection machine which operates continuously, being controlled mechanically, electrically, hydraulically, or by a combination of any of these methods. 

A small sample of expl was placed betw an anvil and plunger of a small hydraulic press where it was compressed in the form of a tablet to ca 2500kg/cm. Then the press with the tablet was placed in an electric oven where it was heated for exactly 3 minutes at the temp close, but below, temp of decomposition reported in the literature. Then the sample was cooled to RT and dropped on the bottom of a metallic dish preheated to the temp slightly above the one used in the test. Parallel with this test, a 2nd sample of the same expl was compressed in cold to ca 25000 kg/cm, removed from the press and heated for 3 mins at atm pressure and at the... 

Riabinin (Addnl Refs K M) investigated in Russia the influence of high pressures on the rate of decompn of expls. For this a small sample of a solid expl was compressed at ca 25000kg/cm in the form of a thin tablet and this was placed in a small cylinder provided with a plunger. The air in this container was maintained at atmospheric pressure. A second tablet of the same expl, compressed in the same manner as above, was placed inside a small hydraulic press where the air was maintained at ca 2500kg/cm2. Each container was heated in an electric oven until a slight decompn took place in one of the tablets. 

NR was added mixing continued for 4 min when DCP was added, and the system was mixed for additional 2 min. The blends were sheeted using a laboratory mill at 1.25-mm nip setting. The sheets were cut into small pieces and re-mixed at 150°C for 1 min and sheeted out again in the laboratory mill. The blended sheets were compression-molded into the dumbbell specimens (2 0.2 mm) in an electrically heated hydraulic press at 150°C for 3 min. The specimens under compression were quenched in cold water (which should keep the crystallinity at a low level). The irradiations were done at T = 25°C, in the y-chamber-900 at BARC, Mumbai. 

There is a variation of compression molding wherein the so-called toggle press is used. Instead of using a hydraulic press, one uses an electrically operated press, which is opened and closed mechanically via toggles. The molds are built into the specialized press. The most important press of his type is used for molding tires (wherein a pressurized steam-fiUed bladder or bag is used as a collapsible core). 

When a two-roll mill is used for mixing, the components are not melted. The ingredients are compounded on an open two-roll mill and then compressively moulded in an electrically heated hydraulic press to the optimum cure the moulding conditions are previously determined from torque data with a... 

The major mechanical component of the grid is a press imit. The three major compression methods used to compress the product onto the fixture are hydraulic, pneumatic, and electric. The total force requirement can be quite large. The spring probes employed in grids usually require a force in the range of 4 to 10 oz. each. A large, complex board may have 20,000 active points per side. This amormts to 5,000 to 12,500 lb. of force, depending upon the probes used. 

Thermosetting compounds are traditionally compression molded. The molds are mounted in hydraulic presses on steam-, electric-, or oU-heated platens. The molding compound is fed to the heated mold, which closes, maintaining the material under pressure until cured. The part is then ejected from the mold. 

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