PVT (Process Verification Test) relation testing device for plunger cylinder type polymer

Abstract

The invention provides a PVT (Process Verification Test) relation testing device for a plunger cylinder type polymer, which is mainly composed of a conic node, an insulation water pond, cylinders, an electric heating ring, a temperature measuring point, a pressure sensor, an LVDT (Linear Variable Differential Transformer) displacement sensor, an ejector rod, a test sample, a spiral cooling water route, a plunger and a rotary actuator, and a pair of plunger cylinders with annular conic surfaces are formed into thin-wall conic annular sample space required by the test sample; in order to satisfy a strong cooling rate, jacket design is adopted for each application cylinder which is formed by welding an inner sleeve and an outer sleeve, and the spiral cooling water route is arranged inside the application cylinder; and hollow design is adopted for the plunger, and a fountain type cooling water pipe is arranged inside the plunger. According to the PVT relation testing device, the thin-wall conic annular test sample with a parallelogram cross section is adopted, and geometric characteristics of the parallelogram are utilized to reduce the transmission distance of pressure and temperature of the test sample through a certain angle of inclination of a bevel edge; and additionally, the inner and outer surfaces of the test sample are relatively rotated so as to conveniently apply the shearing action to the test sample, a true injection molding process can be simulated well, and compared with a conventional method, the pressure and temperature measurement accuracy is more accurate.

Description

technical field [0001] The invention relates to an off-line plunger cylinder polymer PVT (pressure P-specific volume V-temperature T) characteristic testing device, which is especially suitable for testing the PVT characteristics of polymers under high cooling rate and strong shear rate. Background technique [0002] Pressure, temperature, and time are the main factors affecting the polymer injection molding process. In the case of polymer raw materials, mold structure, and certain circumstances, injection molding process parameters have a direct impact on product quality. The relationship between polymer pressure, specific volume and temperature, that is, the PVT characteristics of the material provides a basis for setting parameters in the injection molding process and analyzing the causes of warpage, shrinkage, bubbles and other defects in product processing. The PVT characteristics of a material depend on the type of material, but in practical applications, even if the ...

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Problems solved by technology

However, the instrument is relatively complicated and bulky, and the pressure transmission medium mercury is poisonous to the human body. In addition, due to the existence of the pressure transmission medium, it is not easy to achieve a high cooling rate, and at the same time, it is very difficult to apply shear.

[0006] In the actual injection molding process, the molding of polymers is often accompanied by strong cooling rate and shear action. Due to the insufficient response rate and the limitation of the sample shape, the traditional PVT tester often cannot realize the application of these two effects. Analyze the advantages and disadvantages of the direct pressure method and the indirect pressure method. Since the liquid medium cannot bear the shear force, the direct pressure method is easier to apply these two effects, but the traditional direct pressure method uses a cylindrical sample, and the sample The internal temperature gradient is large, and it is not easy to apply strong cooling to the sample. Even if it can be applied under high-speed cooling conditions, a large temperature gradient is generated inside the sample, and accurate temperature collection becomes impossible.

In addition, the cylindrical sample cannot find two relatively moving surfaces to exert a strong enough shearing action, and the pressure distribution is not uniform

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