I often receive calls or requests for quotes from designers or purchasing people who need a die casting but are not sure of the final part design or the tolerances they need for the product.
I receive a lot of questions on industry wide practices and standards which are all part of the North American Die Casting Association Product Standards that is available to the general public at a nominal cost from the NADCA publications department.
These specification guidelines and standards for die castings have been formulated to aid product designers through the execution of die cast components. Significant advances in the capabilities of North American process technology, and the introduction of an expanded number of die casting alloys, have created new opportunities for cost-effective die cast designs.
To achieve net-shape or near net-shape components, designers today are using die casting to capitalize on improved dimensional accuracy and stability, cosmetic surface quality, and more dependable product performance. To best capitalize on all of these advantages, designers and specifiers should consult the guidelines in the NADCA Product Standards at an early design stage, in collaboration with a qualified die caster.
Today’s die casting process can offer significant reduction in, or elimination of, part machining costs through its ability to cast dimensions, holes and features to precision tolerances at high volumes. Such major cost reductions can also often make die castings practical in lower production volumes.
Through parts consolidation, die castings can reduce finished product assembly costs and improve product integrity and operation. Selected alloys can allow bearing properties to be integrally incorporated into a part, eliminating the need for inserts. The established strength and durability of die castings can allow undamaged disassembly, refurbishing or remanufacture to extend a product’s useful life.
And at the end of a product’s life cycle, die castings allow for optimum reclamation with eventual remelting and realloying, followed by die casting back into high-level applications — without degradation of properties.
The first section of the Product Standards, Process & Material Selection for Product Recyclability, presents the facts on this important new product requirement for process and material selection.
The Tooling Section will familiarize engineers, especially those new to the process, with the unique characteristics of die casting tooling requirements.
The Alloy Data Section provides an updated reference to die casting materials commercially available for component design specification in North American production. These material families include the aluminum alloys; aluminum metal matrix composites; copper alloys including brass and bronze; magnesium alloys; zinc (Zamak) alloys; and zinc-aluminum (ZA) alloys. Lead and tin are rarely die cast because of relatively low mechanical properties. Ferrous-metal die casting is carried out on a limited production basis, with very high melting temperatures necessitating the use of special refractory metals for dies and other special procedures. Alloy tables provide data for comparison of chemical composition and properties for each alloy and their characteristics in die casting and post-casting operations. Poisson’s Ratio, where available, is included to aid finite element analysis (FEA).
Replacing the former ADCI/NADCA “E” Series are the comprehensive Engineering and Design Sections. These present die casting coordinate dimensioning specifications for “Standard” Tolerances and “Precision” Tolerances, with values up to 65% tighter than the former “E” Series. In addition, guidelines for Geometric Dimensioning are presented as they relate to die casting part designs.
Sections on Quality Assurance and Commercial Practices will aid the specifier and die caster in reaching agreement on the procedures and practices that should be followed to assure purchaser satisfaction.
More than one section of the Product Standards should be reviewed in making product and process decisions. The special features and geometry of an individual component to be die cast, it’s dimensional, functional, finishing and end-use requirements — considered in relation to production parameters — must be carefully weighed.
The appropriate tooling, engineering and quality assurance guideline information provided should be evaluated in combination with alloy data. The benefits of early consultation with an experienced die caster are obvious.
If you have any parts you would like Premier to review, please send your drawings or files to email@example.com
By Leonard Cordaro, President of Premier Engineered Products