plastic material

We often say that the plastic, are all collectively referred to plastic varieties, its application is extensive and, therefore, classification is also different. By end-use can be roughly divided into two general types of plastics and engineering plastics. General plastic such as polyethylene (PE), polypropylene (PP), polystyrene (PS), modified polystyrene (such as: SAN, HIPS), polyvinyl chloride (PVC), which are day-to-day the most widely used Materials, modest performance and low cost. Engineering refers to a number of mechanical parts or engineering structural materials such as industrial quality plastic. Its mechanical properties, electrical properties, on the chemical environment of tolerance, high temperature, low temperature tolerance, etc. are more superior characteristics, even at the project is technically able to replace some plastic mold or other materials. Common there is ABS, polyamide (abbreviated PA, commonly known as nylon), polycarbonate (PC), polyoxymethylene (POM), polymethyl methacrylate (PMMA), polyester resin (such as PET, PBT) and so on, the former four the fastest-growing species for the four internationally recognized engineering plastics.By heating the process performance, plastics also can be divided into thermosetplastics and themoplastics two categories. After the thermosetting plastic in the heat into the molecular structure of mesh size and curing or molding, hardened after heating, even if it can not be softened again. The characteristics of such materials are hard, heat resistance, and size of relatively stable, and do not dissolve in solvent. There is a common phenolic resin (PF), epoxy resin (EP), unsaturated polyester (UP) and so on. Thermoplastics soften at the heat under the conditions of melting, cooling after the stereotypes, and repeatedly and consistently one hand, the effects of processing are physical changes. Common there is PVC (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS) and its modified varieties, ABS, nylon (PA), polyoxymethylene (POM), poly carbonate ester (PC), polymethyl methacrylate (PMMA) and so on. This type of plastic must plasticization at the appropriate temperature and pressure so plastic molding process is relatively easy, the plastic products have different physical properties and mechanical properties.

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runner stick

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What is the runner stick runner stick refer to a phenomenon in which the runner of the molded article fails to separate from the mold. If the holding pressure is applied for a long time ,so that the size of the runner is increased, or the runner path portion of the mold is scratched or undercut, resistance is generated, so that the runner cannot be peeled off when the mold is opened. Reasons for the  runner sticking Insufficient solidification of runner When the main runner is not fully cured, the shrinkage is small at this moment, and the runner is close stick to the mold, and the strength is also low. Therefore, if the runner is to be ejected at this time, it will be very easy to break. In this way, the runner will remain on the channel. Resin temperature, mold temperature, and cycle (cooling time) have an effect on the solidification of the main flow.  Excessive  pressure holding The main runner channel is separated from the barrel nozzle directl...
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How to Join Plastic Parts

After plastic mold is ready,Splicing is arguably the most mature and simplest ways of fabricating or fastening two injection molding pieces together. Infact, splicing methods have been known even before other methods like welding, bolting or soldering. The concept of splicing involves the connection of pieces by using the surface adhesion between the plastic molding parts and the adhesives’ firmness or cohesiveness. One of the best features in splicing is an even distribution of stress. In addition, other benefits are that totally different materials can be brought together, large splicing areas can be made quickly, and the adhesive itself fills uneven surfaces. Nevertheless, splicing also involves certain pitfalls. In certain cases, the strength is limited and not all materials are suitable for splicing (Polyolefins), and proper storage of the chemicals is vital. Changes in temperatures will render problems for moist adhesives. Also, a different expansion between the plastic and the...
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Primary Parting Plane Runners

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In many cases, the mold design dictates the gating position, although ideally, the optimum gate position should be determined based on part requirements and afterwards the mold design should be selected to provide for the gate desired position. Available gating positions, and gate designs, are significantly influenced by whether the runner travels along the primary parting plane of the mold (the parting plane where the part forming cavity is defined) or whether it does not travel along this plane. In the dominant runner type used in the industry the runner and part forming cavities are located along the same primary parting plane. Primary parting planes, often referred to as the parting lines, are where the mold opens and closes to allow ejection of the molded part and/or of the runner. The primary parting plane is the one where the molded part is formed and ejected. The primary parting plane runner is used in two plate cold runner molds. A cold runner mold is defined as a mold i...
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