Die Casting Process

See MACHINING below.

Pattern. If patterns and core boxes are available, the request for a quotation should indicate the type, condition and set up of the equipment. See PATTERNS below. 
Production/delivery schedules required. Present and anticipated need should be included in quotation requests.Beyond these basics, there are levels of customer requirements that could include supplier foundry liabilities, which affect the casting cost drastically. These could include receiving inspection acceptance and back charge policy, casting return policy, expediting procedures, and sophisticated controls not normally associated with the standard inquiry. A complete understanding of these areas is best developed by an open relationship between the customer and the supplier foundry representative, and the professional ymii outsourcing attitudes and experiences that both can provide during the quotation evaluation phase.DesignTo achieve the most efficient production and the highest quality product, the part should be designed to take advantage of the flexibility of the casting process. The supplier foundry must have either the designer's drawings or pattern equipment and know the length of the run (number of parts to be made).Castings are generally furnished with un-machined as-cast surfaces, unless otherwise specified. To take advantage of the casting process, the supplier foundry should also know which surfaces are to be machined and where datum points are located. The acceptable dimensional tolerances must be indicated when a drawing is provided. Tolerances are normally decided by agreement between the supplier foundry and customer. Close cooperation between the customer's design engineers and the supplier foundry is essential to optimize the casting design.

Material SpecificationsIndustry standard specifications provide the casting customer with the tools necessary to establish criteria for almost any casting application. These specifications do not preclude special requirements that the customer's technical staff members may require. Variations from standard specifications can result in misunderstandings, higher costs and disqualification of potential supplier foundries. If exception is taken to a provision in the main body of a specification requirement (as opposed to taking exception to a supplemental requirement of a specification), the resulting casting cannot be held to compliance with that specification.Mechanical properties may be verified by the use of test bars cast either separately or attached to the castings. The mechanical properties obtained represent the quality of the steel, but do not necessarily represent the properties of the castings themselves, which are affected by solidification conditions and rate of cooling during heat treatment, which in turn are influenced by casting thickness, size and shape. In particular, the harden ability of some grades may restrict the maximum size at which the required mechanical properties are obtainable. Short of destructive testing of an actual casting sample, the use of a test bar is the best measure of the steel quality.SoundnessSoundness of metal components refers to the level of freedom from impurities and/or discontinuities such as sand inclusions, slag inclusions, macro porosity, and shrinkage.Steel castings begin to solidify at the mold wall, forming a continuously thickening envelope as heat is dissipated through the mold-metal interface. The volumetric contraction that occurs within a solidifying cast member must be compensated by liquid feed metal from an adjoining heavier section, or from a riser which serves as a feed metal reservoir and which is placed adjacent to, or on top of, the heavier section.