plastic mould and custom injection moulding tips

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...

Flash Lines Flash is defined as that portion of the material which flows from or is extruded from the mold during the molding. The designer must design specifically for molding. For example, it is impracticable to duplicate, by molding, the appearance of a handle which has been fabricated from wood or metal by machining. To design a molded piece of good appearance calls for a knowledge of the molding technique and of mold-construction. In compression molds, the closing or telescoping of the two parts of the mold results in flow of material into the clearance between these parts. This material is known as flash and occurs at the parting line of the molds. The removal of flash from the article leaves a flash line, which is unavoidable and generally unsightly. The problem of flash lines is one that requires careful consideration by the designer, as the attractiveness of the product may depend to a large degree on a careful location of the flash line where it will not be seen. When a pie...

Scope There is no easy solution to the problems encountered in designing molded articles of plastics. The design will often hinge on what is the best process of molding for the piece in question. The selection of the molding process is, in turn, determined by the choice of the molding material best suited to provide the desired physical properties in the finished molded piece. Often the necessity for certain elements in the design, such as thin sections or long delicate inserts, or requirements of exact concentricity or of accuracy of dimensions and working tolerances, make it desirable to use one technique of molding rather than another. The problem is complicated by the facts that there are two types of molding materials in general use, i.e., the thermosetting and the thermoplastic, and three basic methods of molding commonly used, i.e., compression, transfer and injection molding Frequently in the problem of design it is necessary to put the cart before the horse; we must k...