Casting: Pattern, Mold and Core Design

Pattern, Mold and core design involves orientation and parting. The parting line is influenced by designs of patterns and cores, number of voids in the mold, location of feeders, orientation of the part and locations of channels of gating, cooling and venting. Orientation and parting line A parting line is usually defined as the part of the mold that divides the segments to create cavities with the mold section and remove the final product from its mold as in die casting.

• Geometry of the component to be molded.
• Number of cavities required within the mold sections.
• The nature of the runner system .
• The kind of gating required and
• The method of ejecting the final product from its mold

Analysis of Parting Line : The parting line is supposed to coincide with the estimated borderline of the casting when viewed along the draw direction. To attain the parting line, the corners of the castings are projected perpendicular to the plane in the parting direction. Also, the outermost boundary's perimeter is considered overlooking the innermost sections of the projected corners. This is anticipated back to the casting and the respective landing points are estimated. Then these landing points are joined to each other in the same order to form parting line.

Multiple substitutes of parting lines are required to be figured out in case of multiple landing points. And when varied alternatives are available, then to identify the most appropriate parting line is the one that meets the set of designed criteria. They generate the values of either 0 or 1 and are dimensionless.

Pattern Design A design pattern in general is a reusable solution to commonly occurring problems. However, mathematically pattern design is defined as a sequence of alterations beginning from the artifact's shape to finally achieving the shape corresponding to the mould cavity.

Core features :
Core is considered as an individual unit sited in a mould to fabricate a corresponding cavity, hole or undercut in the casting process. Cores are also used for producing complex features which cannot be produced otherwise, by using a pattern or mould individually. Some of the core features are identified on the basis of following factors:

• Edge Classification.
• Hole Recognition
• Undercut Recognition

Core Design Analysis :
Core print design involves following assumptions :

• To make the core stay in place during the process of molding assembly, the print must balance the body.
• The print should not trample and must endure the buoyancy energy of the metal.
• While the process of mould filling is working, the print must not shift.
• Minimized diversion of the core is to be achieved.
• Maximized heat transfer from the core print to the mould is required.
• The inner gases should be allowed to be produced with in the core to flee away to the mould.
• To prevent incorrect units, uneven holes should have full proof prints.
• Adjoining cores are combined to form single core.