Improved compression molding process

Modified compression molding process produces plastic molding compounds that are strong, homogeneous, free of residual stresses, and have improved ablative characteristics. The conventional method is modified by applying a vacuum to the mold during the molding cycle, using a volatile sink, and exercising precise control of the mold closure limits

Transfer molding of PMR-15 polyimide resin

Transfer molding is an economically viable method of producing small shapes of PMR-15 polyimide. It is shown that with regard to flexural, compressive, and tribological properties transfer-molded PMR-15 polyimide is essentially equivalent to PMR-15 polyimide produced by the more common method of compression molding. Minor variations in anisotropy are predictable effects of molding design and secondary finishing operations

Molding process for imidazopyrrolone polymers

A process is described for producing shaped articles of imidazopyrrolone polymers comprising molding imidazopyrrolone polymer molding power under pressure and at a temperature greater than 475 C. Moderate pressures may be employed. Preferably, prior to molding, a preform is prepared by isostatic compression. The preform may be molded at a relatively low initial pressure and temperature; as the temperature is increased to a value greater than 475 C., the pressure is also increased

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Anmeldes af Malene Moldin

Thermoplastics for aircraft interiors

The goal for this contract is the development of processes and techniques for molding thermally stable, fire retardant, low smoke emitting polymeric materials. Outlined in this presentation are: (1) the typical molding types; (2) a program schedule; (3) physical properties of molding types with the test methods to be used; (4) general properties of injection molding materials; and (5) preliminary materials selection

Improved molding process ensures plastic parts of higher tensile strength

Single molding process ensures that plastic parts /of a given mechanical design/ produced from a conventional thermosetting molding compound will have a maximum tensile strength. The process can also be used for other thermosetting compounds to produce parts with improved physical properties

Molding apparatus

Apparatus for compression molding of thermosetting plastics compositions including interfitting hollow male and female components is reported. The components are adapted to be compressed to form a rocket nozzle in a cavity. A thermal jacket is provided exteriorly adjacent to the female component for circulating a thermal transfer fluid to effect curing of a thermosetting plastics material being molded. Each of the male and female components is provided with suitable inlets and outlets for circulating a thermal transfer fluid

Testing of molded high temperature plastic actuator road seals for use in advanced aircraft hydraulic systems

Molded high temperature plastic first and second stage rod seal elements were evaluated in seal assemblies to determine performance characteristics. These characteristics were compared with the performance of machined seal elements. The 6.35 cm second stage Chevron seal assembly was tested using molded Chevrons fabricated from five molding materials. Impulse screening tests conducted over a range of 311 K to 478 K revealed thermal setting deficiencies in the aromatic polyimide molding materials. Seal elements fabricated from aromatic copolyester materials structurally failed during impulse cycle calibration. Endurance testing of 3.85 million cycles at 450 K using MIL-H-83283 fluid showed poorer seal performance with the unfilled aromatic polyimide material than had been attained with seals machined from Vespel SP-21 material. The 6.35 cm first stage step-cut compression loaded seal ring fabricated from copolyester injection molding material failed structurally during impulse cycle calibration. Molding of complex shape rod seals was shown to be a potentially controllable technique, but additional molding material property testing is recommended

Evacuated, displacement compression mold

A process of molding long thin-wall tubular bodies from thermosetting plastic molding compounds is described wherein the tubular body lengths may be several times the diameters. The process is accomplished by loading a predetermined quantity of molding compound into a female mold cavity closed at one end by a force mandrel. After closing the other end of the female mold with a balance mandrel, the loaded cavity is evacuated by applying a vacuum of from one-to-five mm pressure for a period of fifteen-to-thirty minutes. The mold temperature is raised to the minimum temperature at which the resin constituent of the compound will soften or plasticize and a pressure of 2500 psi is applied

Applicability of molding procedures in laboratory mix tests for quality control and assurance of the deep mixing method

The deep mixing method (DMM) has been applied in many construction projects. The laboratory mix test is essential to the quality control and quality assurance (QC/QA) of deep mixing methods. The procedures used for the preparation of specimens in the laboratory mix test greatly affect the physical and mechanical properties of the stabilized soils. Different procedures are applied in different countries/regions. With the increasingly globalized DMM market, it is desirable that a common understanding of the nature of the laboratory mix test and internationally accepted guidelines to conduct it be established in order to guarantee the QC/QA of DMMs. As part of an international collaborative study, the influence of different molding techniques for the laboratory preparation of specimens was studied. Five different molding techniques were tested in four organizations. The results showed that the molding techniques considerably influenced the magnitude and variation of the unconfined compressive strength and the wet unit weight of the stabilized specimens. The applicability of the molding techniques was discussed in terms of their undrained shear strength and the liquidity index of the soil and binder mixture, and the usefulness of the techniques was demonstrated. (C) 2015 The Japanese Geotechnical Societ