Tooling Design for Die Casting

Introduction
Die casting or mold is a closed vessel, is injected into the molten metal under high pressure and temperature, then rapidly cooled to solidification ed part is sufficiently rigid to allow the expulsion of the mold.To in this environment, diecasting mold must meet are constructed from tool steel of high quality for the required hardness and structure of heat treatment, machining with the dimensions of the punch and cavity demanding cation. The two mold halves in a die casting machine operation, which is operated at the temperatures and pressures necessary to produce a quality part of net shape or near net shap customers specifications.The products customer product design requires direct impact on the size , type, equipment, and the cost of the tools. The elements of the decision tool plate, covering the number of cavities, the number of core or slide, the weight of the matrix, machining, finish requirements, ie painting, polishing, plating, to name a few. A useful checklist for casting considerations for use in discussions with their own molding, end this section.Explanation of key terms related to the design are to die down.

The various alloys available for die casting,from aluminum to zinc, require unique and special features in the die that produces them. Because of these differences, the descriptions and parameters described in this text are generic. Where possible, options are listed but should be used only as a general guide, with the final decisions discussed between the customer and the die caster.

1 Types of Die Casting

Dies There are various types of die casting dies and each serves a critical need for the customer. The choice of which type of die casting die the customer requires is usually determined by the following:
• Size of the part to be cast
• Volume of parts required
• Requirements for “family” sets of parts
• Desirability of core slides
• Requirements for cast-in inserts.

   

 Prototype Dies Prototype dies are usually requested by the customer to produce a small number of castings under production conditions. They enable thorough product testing and market exposure before committing to full production dies. For eventual high-volume programs more than one prototype die may be produced.Only production from an actual die casting die can yield a part with precise die cast characteristics. However, there is a range of prototyping strategies that can be employed to approximate a die cast part for eventual production die casting. Among them: gravity casting, including the plaster mold process; machining from previously die cast parts or from wrought and sheet stock; and new rapid prototyping techniques such as stereolithography.

Production Dies These are the most common types of tools produced. They range from a single-cavity die, with no slides, to a mulitple-cavity die with any number of slides. The cavities are made from high-quality tool steel, retained in a quality holder block.Production dies are built to critical dimensions, coring the maximum amount of stockfrom the casting, and allowing the agreed upon amount of machining. A unit die is aspecial type of production die.

 Unit Dies A unit die is a lower cost production tool that has a standardized main die frame and replaceable cavity units. These replaceable units are designed to be removed from the main die frame without removing the standard frame from the die casting machine. The most common commercial types of unit dies are single and double unit holders. These types of dies are generally used for smaller parts, or a family of parts, with no slides or a minimum number of slides. Unit dies limit the use of core slides because of the configuration needed for interchangeable unit inserts and the limited space available.

Trim Dies The trim die is a tool that trims the runner, overfl ows, and fl ash from the casting. The trim dies are single or multiple cavity tools, made in the same confi guration as the die casting die.Depending on the shape of the casting,the trim die may be a simple open-and-closetrim die or it may include as many slides asthe die casting tool. In some cases multiple station trim dies will be used for successive trimming operations.Trim dies require as much attention to detail in design as the die casting tools andthe use of quality materials should be specified to extend their productive life.