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Design molded reinforced plastics parts

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Design rules Designing molded reinforced plastics parts is difficult because of the large number of variables encountered in the material and the process, and the difficulty of controlling some of them. These variables include: composition of the resin, including fillers, catalysts and gardening agents, geometry of the reinforcing material, resin-reinforcement ratio, degree of saturation of reinforcement by resin, and temperature and time of cure. The cardinal design rule , which cannot be overemphasized, is: consult the custom mold maker in the primary design stages. In addition, follow these general design rules:    Integrate parts.     Make prototypes .    Mold to dimensions; parts cannot be “sprung” after they are molded.    Use stress formulas valid for fiber-reinforced plastics.    Know the conditions of use.    Consider effects of the molding procedure. ...
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Undercuts and Draft

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Undercuts Modern molding practice dictates certain principles of design which should be observed if molded articles are to be produced successfully. Most elementary is the fact that the piece must be easily removed from the mold after it has been formed. https://res.cloudinary.com/dl8a9jvpa/video/upload/v1515562261/Undercuts_ni5xth.mp4   This point is frequently overlooked, and many products are designed with undercuts which make it impossible to eject them directly from the mold cavity. If undercuts are essential, then split molds or removable mold sections are required, and these increase the cost of molds and of the molded articles. Undercuts should always be avoided unless mechanical construction or the function of the piece make such a design an absolute necessity. External Undercuts When undercuts are located in the outside contours of the piece, they are called external undercuts. It would be impossible to withdraw a piece of such a shape from a one-piece mold cavity. Whi...
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history of mold designer

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After the Second World War, people started using plastics more and there was a need for people who could design molds for plastic products. At first, these molds were made by artisans in tool and die maker shops. These artisans were skilled in making accurate steel tools and dies, and they often worked closely with the injection molding company (the person who would use the mold to make the product) to make sure the mold was made correctly. The molder draws a picture of how the mold should look. The boss then oversees the machinists as they make the parts for the mold. Once the mold is finished, the boss tests it to make sure it works well. These molds were usually good for the few existing plastics molding materials at the time and were satisfactory for the low productivity expected from such molds. In the past, plastics were not very good quality and could only be used for a few things. But now there are much better plastics that can be used for lots of different...
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