Die Cast Prototyping – Benefits and Types

In addition to Chicago White Metal’s advanced part design and DFM assistance, CWM offers various prototyping options to bridge the gap between design and production tooled high pressure die casting. CWM’s prototyping process offerings include:

  • 3D printing (resin)
  • CNC machining
  • Gravity casting via the sand, rubber-plaster mold, or investment casting processes
  • Prototype die casting

Reasons to Use Prototyping

Prototyping offers the opportunity for design verification – a chance to identify design flaws before committing to production level tooling. And while it is not necessary to prototype every design, sometimes doing so saves time and money. Generally, the further along in the developmental cycle a design error is discovered, the greater its cost.

When tooling needs to be scrapped or reworked, the impact is evident in terms of costs and delays. However, reworking a die cast die also adds cost in decreased die life and potential negative quality impacts. Using today’s prototyping technologies can help manufacturers avoid these stressful situations.

There are several prototype methods from which to choose. Selecting the best option for your application comes down to tradeoffs. For example, some options, such as 3D printing of a plastic model or machining from billet, are relatively inexpensive for low quantities because no tooling is required. But the mechanical properties of a plastic or machined part are quite different than the properties of a die casting. Assessing what prototype process is best for your needs requires consideration of quantity, timing, mechanical properties, dimensional accuracy, surface finish, wall thickness, cosmetic requirements, etc. A good high pressure die casting supplier should be able to guide you toward the appropriate option.

Prototype Methods

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3D Printed Prototypes

3D printing enables the production of rapid prototypes in many types of plastic, directly from STL design files. Fused Deposit Modeling (FDM) is one form of 3D printing that builds parts layer-by-layer, from resin, directly from 3D computer data. An FDM machine can produce geometrically complex shapes to tolerances of +0.005 in (+.127 mm).

At CWM, we use FDM prototypes for every new die casting project to expedite production and shorten total lead-times. These prototypes give our suppliers and our engineering, production, and quality teams a chance to see parts in advance, ensuring that the part and die cast design is robust. They are also used to develop fixtures, tools, racks, etc., for inspection, machining, assembly, painting, plating, etc. FDM models ensure that the part design results in an efficient manufacturing process and helps reduce overall project lead-time by allowing simultaneous construction of downstream process tooling.

Machined Prototypes

Machined prototypes are widely used because they offer product designers a good combination of physical and mechanical properties, generally short lead-time, and zero to minimal tooling investment. Prototype parts can be machined from billet via CNC machining by working directly from customer CAD files. After transferring a machined prototype to a CAM program interfacing with CNC workstations, we can produce these prototypes in just a couple of days.

CNC machining can produce parts to almost identical part weights and hold exceptional tolerances such that validation of form and fit is assured; we can then perform many functional tests. However, properties are not identical to die castings and parting line conditions, and sometimes the draft required in a die casting is not represented in a machined prototype.

Gravity Cast Prototypes

Sand casting, investment casting, and rubber plaster-mold castings are some of the gravity cast processes used for prototyping. Because of longer solidification times and alloys specific to those processes, various heat treatments are used to approximate a high pressure die casting alloy’s properties.

Compared to high-pressure die casting, sand cast prototypes require thicker walls and larger tolerances, so features that might be “as-cast” in a die casting may need to be machined in a sand casting. These processes utilize lower-cost tooling than high-pressure die casting but have much higher piece prices. These design, property, and cost tradeoffs have to be considered when evaluating the best prototype approach.

Die Cast Prototypes

For those who want a prototype with the same properties, alloy, and geometry designated for production and larger quantities, a high pressure die cast prototype is often the best approach. Prototype die casting dies can be produced in shorter lead-times and at less cost because they utilize standardized components – like an existing die base – and pre-hardened, uncoated tool steels that do not require post machining heat treatment.

The tool will not run as efficiently as a typical production die, and flash will need to be removed by hand instead of with a production trim die, but part costs will be much less than machined or gravity cast prototypes. A prototype tool can provide 1000 or more high-quality pieces that can be used for prototype or even initial production.  

The CWM Difference

Chicago White Metal offers all of these prototype options that you read about today. If you are interested in more information about prototyping or if you would like to speak with one of our team members, email sales@cwmtl.com or call (630) 595-4424.

Aluminum Die Casting Benefits & Die Life Considerations

If you are considering aluminum die casting for a new part, there are several advantages to doing so. Aluminum die castings are lightweight, corrosion-resistant, has high thermal and electrical conductivity, and are very durable. Aluminum die castings remain strong at high temperatures and retain their dimensional stability even if the part has thin walls or is a complex shape.

Aluminum die castings also have excellent mechanical properties, making it a popular alternative to steel and iron. This is especially true for the automotive industry, which is continually looking for lightweight, durable materials.

Benefits of Aluminum Die Casting

Aluminum can be cast in a variety of ways. The benefit of using the high pressure die casting process over other aluminum casting processes is lower part cost. The aluminum high-pressure die casting process can produce a near-net shape in seconds.

Though high pressure die casting tooling is more expensive than other casting processes, the heat-treated steel and water-cooled die cast die might produce 75K-200K “shots” over its life. And depending upon the part size, geometry, and demand, tools can often be built to produce multiple parts in one “shot,” which further reduces the part price and allows the tooling cost to be amortized over very large quantities of parts.  

Aluminum is the most popular die casting material by far because it is economical and provides a good mix of properties. There are a surprising amount of parts from numerous industries – like automotive, medical, alternative energy – that are cast via the aluminum die casting process due to its many valuable properties.

Aluminum Die Casting and Die Life Considerations

To maximize die life, certain considerations must be taken into account before building the die. Factors that contribute to die life include:

  • The overall design of the part
  • Type of tool used to create the die
  • Configuration of the mold
  • Die steel, heat-treating techniques, and die coatings
  • Expectation for part quality

Before a die is built, the customer first presents a concept or existing part to a die caster. A die cast engineer will assess the project from design to end product and work with the customer to optimize the part design for die casting. An initial discussion with the die caster may include topics such as:

  • Functional and cosmetic requirements
  • Tolerances
  • Annual and lifetime volume
  • Alloy choice
  • Mating parts
  • Project timing
  • Optimizing wall thickness

Importance of Partnering with an Experienced Die Caster

An experienced die caster will take the time to consult with you about your application and assist you with product design. They will then design the tooling to produce parts with repeatable dimensions, excellent surface quality, consistent mechanical properties, and long tool life.  

These factors provide the greatest opportunity for cost savings and maximizing value. A less experienced die caster might offer lower initial costs, but this could cost you in the long run, due to quality, delivery, or tool life issues. A die built to lower specifications will likely fail at an inopportune moment, shutting down production and forcing you to spend much more than what you thought you saved initially.

Contact Chicago White Metal Today

Chicago White Metal Casting (CWM) has 83 years of experience providing our customers with excellent service, saving you money, and resulting in products that you and your customers will love. To find out more about our aluminum die casting service, or other capabilities, contact us online today. You can also reach us at +1 630-595-4425 or via email (sales@cwmtl.com) if you have any questions. You can also click here to request a quote online.