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

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

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

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

Sealing ceramic material in low melting point glass

A structured device placed in an aerated crucible to pack ceramics molding substance that is to be processed was designed. The structure is wrapped by sealing material made of pyrex glass and graphite foil or sheet with a weight attached on top of it. The crucible is made of carbon; the ceramics material to be treated through heat intervenient press process is molding substance consisting mainly of silicon nitride

Simulation of Polymer Flow Using Smoothed Particle Hydrodynamics Method

Reactive rotational molding (RRM) is a process to manufacture hollow plastic articles. Comparing to rotational molding of thermoplastics, it decreases the process cycle time due to the reactivity of the system. However, the number of influent parameters is relatively high and optimization of the process is complex. During RRM, the viscosity is one of the key parameters and varies according to the polymer molecular weight due to chemical reactions. Simulation is a way to optimize this process. Prediction of the reactive flow is of great interest to optimize process conditions and wall thickness distribution of the molded part. We developed a solver based on smoothed particle hydrodynamics method. This Lagrangian meshfree method is well adapted to simulate free surface flows like those occurring in RRM. First, we validated the code comparing the simulation results to analytical Couette flow solution and experimental measurements of dam break problem. Then, we performed two-dimensional (2D) and 3D simulations to observe the influence of the change of viscosity on the flow, due to the chemical reactions. Adhesion of the polymer on the mold surface is modeled by new boundary conditions.Contract grant sponsor : RAIGI society for providing us the reactive materials and the Single Interministerial Fund (FUI)-SAGANE

New compression molding process of thermosetting plastic compounds

Process permits molding of longer, thinner bodies, such as cylindrical rocket motors, while maintaining equal or superior physical properties. Major advantages of process are presented

Flow behavior in liquid molding

The liquid molding (LM) process for manufacturing polymer composites with structural properties has the potential to significantly lower fabrication costs and increase production rates. LM includes both resin transfer molding and structural reaction injection molding. To achieve this potential, however, the underlying science base must be improved to facilitate effective process optimization and implementation of on-line process control. The National Institute of Standards and Technology (NIST) has a major program in LM that includes materials characterization, process simulation models, on-line process monitoring and control, and the fabrication of test specimens. The results of this program are applied to real parts through cooperative projects with industry. The key feature in the effort is a comprehensive and integrated approach to the processing science aspects of LM. This paper briefly outlines the NIST program and uses several examples to illustrate the work

Processibility of black garbage bag as a novel binder system in metal injection molding

The issues to be highlighted here is to fundamentally evaluate the potential of using waste Garbage Bag from High Density Polyethylene (HDPE) as a backbone binder in Metal Injection Molding (MIM.) This is by the fact that the earth has tons of Garbage Bag disposed every day and researcher believes such waste can be converted into more beneficial industrial product. Thus this research investigates the potential uses of garbage bag as a novel binder system in metal injection molding. Stainless steel SS316L was used which is garbage bag (HDPE) and palm kernel acts as binder system. Feedstock with three composition 30%, 40% and 55% powder loading (PL) were injected by injection molding machine with several injection parameter were optimized such as injection temperature (A), barrel temperature (B), injection pressure (C) and Speed (D). The optimum parameter for highest green density, strength were optimized in Taguchi Method orthogonal Array L9 ( 3 ) and analysed by using Signal to Noise Ratio (S/N ratio).Results shows the optimum variables for 30% PL the highest density is A0, B2, C1 and D0 while for green strength are combination of A0, B0, C0, D1. For powder loading 40%, the optimize parameter for highest green part density are A2, B2, C0 and D2 and A0, B0, C1, and D0 for green strength. Besides, the highest green density for 0.55 PL by following the optimum variable are A2 , B2, C0 and D2 while for highest green strength are A2, B2, C2, and D2. Garbage bag are suitable acted as a binder system in metal injection molding. Furthermore, it could reduce the cost of binder system. The suitable volume ratios in mixing process produce a better feedstock in order to produce the green part by injection molding. Taguchi Method is among the best method in optimizing the injection variables as it can reduce the cost, time, improve accuracy and efficienc