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Tactics for Optimal Product Design for Die Casting

CWM Engineer Determines Tactics for Optimal Product Design for Die Casting

Developing an optimum product design for die casting is similar, in most respects, for any material/process combination. In capitalizing on today’s advanced die casting processes, however, specific attributes of die casting alloys and the die casting process offer opportunities for distinct product advantages and cost reductions that require somewhat different tactics. These should be applied when a totally new product is being developed, and are critical when an existing product made from another material or process is being redesigned for die casting.

When a custom die casting design (or any design) is started from a clean sheet of paper, the designer must disassociate the design constraints from the materials and processes traditionally employed. This is the path to the optimum cost-effective results. Three principles are helpful:

• Think function, before traditional form.
• Performance must be sufficient, not equal.
• Match material properties to performance specifications.

Function Before Traditional Form
In many cases form does not reflect function, but is instead determined by the traditional material and process employed. Therefore, it is essential to think of the function(s) that the component is to perform, and disregard the traditional or previous process form. For example:

• A powdered metal part may have relatively thick walls in structural areas, with throughholes to remove excess material. A die casting typically achieves maximum structural properties by utilizing thin walls with corrugated sections or rib reinforcements.

• An injection molded plastic component may be attached with through bolts and nuts, which are required because the viscoelastic (relaxation) behavior of the plastic makes it necessary to apply only compression loads. Or it may utilize metal inserts. A die casting with superior creep and relaxation properties can employ tapped threads to an advantage.

• A billet machined part may have block like features to obtain functions, for example: square pockets, sharp edges, flat and cylindrical surfaces. The same part designed as a custom die casting may obtain function with smooth filleted pockets, generously radiused edges and contoured and shaped surfaces.

The function before traditional form principle can often be applied to die castings made a few years ago. In many cases, wall thicknesses have been dictated by the limitations of then existing casting technology, so that the die casting component was over designed in terms of functional and structural criteria. Yesterday’s die castings can often be redesigned and produced by today’s advanced, custom die casting technology with thinner walls, reduced draft, and closer tolerances that more nearly reflect the functional criteria.

It is important to note that the definition of form in “function before traditional form” is the traditional shape that is required by specific manufacturing processes. This is not to be confused with a purposely designed form or shape that may provide value or function to the product design. The die casting process easily produces complex design shapes that may be difficult, costly or impossible to produce with other manufacturing processes.

CWM Wins 2013 NADCA Casting Competition

CWM Wins NADCA Award for projector housing

For the third year in a row, CWM won an award in NADCA’s annual International Die Casting Competition. In 2013, CWM won in the Magnesium Over 2 lbs. category for a projector housing.

Rob Malarky, CWM Engineering Project Manager, worked with our customer’s engineering team to convert two magnesium components into a single unit. Internal features of this magnesium die cast part were redesigned to make it simpler and easier to manufacture. After the redesign, the customer gained a 40% cost reduction. This was realized by eliminating a second casting, die trim, additional machining and dowel pin insertion. The magnesium die cast part also incurred an 8% weight reduction due to the change in geometry.  Rob talks about the process in this exclusive interview, also located on our YouTube channel.

Click here to view the .PDF

Still Believe That Magnesium Die Casting is Too Expensive?

Magnesium Myths

The reality is, die casting metal materials are priced and purchased by the pound. In engineered part designs, their material content is based on the volumes actually used in the part. When objective material cost evaluations are based on “equal volume” comparisons, magnesium die casting becomes cost-competitive due to its low density, excellent strength, stiffness and energy absorption characteristics. Magnesium has the highest strength-to-weight ratio of any structural metal.

Magnesium’s thinwall die casting capabilities routinely allow housing walls to be cast to 0.12 in. (3 mm), with many walls cast as thin as 0.03 in. (0.76 mm). The results are lower magnesium part weights and material costs comparable to reinforced plastics. Automated hot-chamber magnesium die casting technology, exclusively used by CWM, delivers faster cycle times (30% greater than aluminum processing, plus die life from two to four times longer).

Cost and other so-called “knowns” about magnesium related to the die casting process may be keeping you from realizing the considerable benefits of today’s die cast processing in magnesium. Download CWM’s paper and get the facts on die casting with magnesium.  The paper is free to any Die Cast Design Center subscriber.

Explore the advantages of die casting with Magnesium and see if its unique properties can be employed in your new design or conversion from another process.  View our recorded webinar titled, “Magnesium Die Casting: Solutions for Today’s Markets.”  This 50-minute video reviews:

  • Mg properties and benefits
  • How Magnesium die casting stacks up to other manufacturing options
  • When Mg die casting is a smart choice
  • Prototyping and finishing options
  • Loads of case studies!

The webinar is available to any subscriber of CWM’s Die Casting Design Center – DC2.  Subscription is free and offers 75-plus technical papers including die cast design assistance, design specifications, and component sourcing resources. View the webinar now.