Multiple-cavity mold

Blow mold usually consists of two halves, each containing cavities which, when the mold is closed, define the exterior shape of the BM (Chapter 17). Multiple cavity molds are used. Because the process produces a hollow article, there are no cores to define the inner shape. Mold details and actions will vary considerably according to the geometry of the product and the BM process in use. Even though the following review concentrates on EBM, the information can also be applied to IBM. The two halves that meet on a plane are known as the parting line. The plane is chosen so that neither cavity half presents an... 

When compared with compression molding, transfer molding provides better product consistency, shorter cycle times, and better bonding of rubber to metal [55]. However, considerable amount of material is lost as scrap in the transfer pad, sprues, and flash. The basic three-plate multiple cavity mold is more complex and expensive than a comparable compression mold but is suited better for intricate parts or securing inserts [56]. 

Sprue. (1) The main feed channel that runs from the outer face of an injection mold to the gate in a single-cavity mold or to the runners of a multiple-cavity mold. The hquid polymer is forced through this orifice from a nozzle till the mold is filled to capacity. Some polymer remains in the sprue after the mold is closed, leaving a projecting piece that must be removed after the product is ejected. The viscosity of the polymer must be low enough to permit it to pass through the sprue readily. 

In multiple-cavity molds, series and parallel cooling circuits are used. Series cooling enters and cools one cavity, then moves to the next until all the cavities are cooled. The temperature of the water increases as it moves through the mold, and this results in non-uniform cooling. Parallel cooling, on the other hand, enters and exists all cavities simultaneously, thereby cooling all cavities at a uniform rate. Parallel cooling is thus the preferred method but it is not always possible due to limitations. 

Unbalanced cavity layout in multiple cavity mold Nonuniform cooling not properly appKed Poor or no venting... 

Single control valve for multiple cavity mold halves... 

Multicavity mold (multiple-cavity mold, multiple-impression mold) n. A mold having several to hundreds of cavities so that many parts may be molded with each shot. In many cases, the parts are identical, but that need not be so. In a type of multicavity mold known as a family mold, some of the cavities may be identical while others are different, or they may all be different. 

Molds are also distinguished by the number of cavities cut in the mold. Single-cavity molds contain one cavity, while multiple-cavity molds can mold several parts simultaneously. In family molds (Fig. 5.68 ), several different parts are molded at one time. 

Multiple-Cavity Mold. A mold with two or more mold impressions, i.e., a mold which produces more than one molding per molding cycle. 

Multicavity Mold n (multiple-cavity mold, multiple-impression mold) A mold having several to hundreds... 

Multiple cavity mold increases production rate. 

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