Prototyping Strategies for Die Casting - Sunrise Metal Technology Co., Ltd

Q&A

Prototyping Strategies for Die Casting

When it was first introduced as a production method in the mid-1800s, die casting was used almost exclusively to make type for printers. Die casting enabled manufacturers to produce the individual letters and punctuation marks printers needed for their typing machines faster while maintaining size and quality consistency. These enhanced production capabilities reduced printing errors as well as the time it took printers to set up their printing equipment, which led to unprecedented growth in the printing industry.

By the early 1890s, manufacturers began to expand their use of die casting and started to make dies that could be used in other industries to produce consumer goods as well as the parts industrialists needed to fabricate those goods. The predominant materials used by early die casters were lead and tin, but additional alloys such as copper and magnesium alloys were introduced over the ensuing decades. These available alloys meant die casting could be used to produce items with different characteristics, such as greater heat and erosion resistance, as needed.

Strategies for Die Casting Prototyping

Just as die casting has expanded into many industries and new alloys have been introduced over time, additional die casting techniques and strategies have been developed since the process was first employed to make type for the burgeoning printing industry. While a high-pressure die casting technique is typically used today, other casting methods are often used in the die cast prototyping process.

Current die casting prototyping methods include the following:

1 – Single-Cavity Prototype Die

If you're going to conduct extensive testing, the single-cavity prototype die process is likely your best choice from among all of the current die casting prototyping strategies except for actual die casting. Arguably, the biggest advantage of this process is that it allows you to thoroughly evaluate your end product's critical characteristics, including the finish on its exposed surface.

With approximately 75 percent of production dies requiring either minor or major changes, another benefit of the single-cavity prototype die process is that you can make certain changes to the design of your prototype's die after the initial round of parts is produced, thus avoiding costlier changes down the line.

The original die's insert can often be used in the final production phase as well. With the single-cavity prototype die process, it normally takes less time to create your final dies as well as your secondary trim tools compared to other die casting prototyping strategies.

Due to the cost involved and the time it sometimes takes to create dies, the single-cavity prototype die process may not be suitable if you don't have sufficient lead time or if there are uncertainties regarding the design of your product.

2 – Gravity Casting

The gravity casting process is the most popular choice to create die cast prototypes because it is less expensive than the single-cavity prototype die strategy for small amounts of product. The gravity casting process also doesn't require as much lead time as single-cavity prototyping does. Gravity casting includes most investment casting and plaster molding casting strategies.

While gravity casting may be more affordable, it has some drawbacks that need to be considered when you're deciding which die casting prototyping strategy you're going to use. Since they generally have less porosity, a gravity casting typically has greater fatigue strength than a die casting does, for instance. Die casting can produce an end product with precise dimensions, but additional machining will be required to achieve the same exacting dimensions when gravity casting is used. Gravity casting also cannot achieve the very thin wall widths that can only be produced by die casting, although the casting technique can yield walls with greater widths.

3 – Rapid Prototyping

Rapid prototyping for die casting is often associated with various processes, including stereolithography, laser sintering and fused deposition modeling. Contingent upon a prototype's geometry, prototyping for die casting parts using one of these methods can usually yield an initial part in as little as 5-8 weeks. These prototyping strategies for die cast parts use a sterolithography model to create H-13 steel dies using pressure die casting instead of gravity fed die casting.

Since the alloys as well as the physical and thermal properties used in rapid prototyping are the same as in the production run, rapid prototyping enables you to perform a thorough and accurate analysis of your product before you invest in the construction of intricate, expensive die casting dies. For the same reason, rapid prototyping is typically your best choice if you want to produce up to several thousand units while your production dies are being fabricated.

Die casting rapid prototyping is often referred to as the "steel process." This method is not usually appropriate for work involving thin and/or tall standing detail on parts. It's also not the ideal choice for a project requiring cast-in water lines.

4 – Plaster Mold Prototyping

Also known as rubber plastic mold casting, or RPM, plaster mold prototyping is a gravity-based casting strategy that works with aluminum, magnesium, zinc and ZA alloys. Working with a stereolithography model, an initial prototype can be produced in just a few weeks. This technique enables you to make any necessary changes to a part's geometry quickly and simply. With a cost that is only about 10 percent of the cost to construct a production die, plaster mold prototyping can be more economical than other strategies for die casting prototyping.

Although it can produce parts in many sizes, RPM is generally most appropriate if your part is in the range of two to 24 cubic inches. Plaster mold prototyping is capable of producing a few or up to several thousand working die cast prototypes, making it an appropriate method to use to make a prototype if the quantity of product you need is not large enough to justify the cost of hard tooling.

Plaster mold prototyping is able to replicate any castable geometry as well. While that is an obvious benefit, it can also lead to problems because it allows designers to erroneously use geometry that can drastically increase die casting costs or make a shape that is ultimately impossible to die cast.

5 – Machining From Similar Die Castings

Machining from similar die castings involves creating prototypes from existing die castings that have a size and shape similar to the prototype you want to have made. If you want multiple prototypes of small parts, it's possible for them to be machined out of a single large die casting's heavier areas using this strategy. Appropriate for creating small gears and screw-machined items, among other parts, machining from similar die castings is a good choice if you need a large number of prototypes and have access to the automatic machining processes and materials needed to make them.

While this approach to die casting prototyping may seem convenient, it does have drawbacks that can be significant. First, the dimensions and shape of the prototype you want to make are restricted by the size and form of the die castings that are on hand. This die casting method also removes the dense, thick skin a production die casting normally has.

In the paper, The Significance of the Die Cast Skin Pertaining to the Fatigue Properties of ADC12 Aluminum Alloy Die Castings, Briggs & Stratton reported that when their skin was machined off, the yield strength and fatigue strength of die castings made from aluminum were reduced by more than 10 percent and 39 percent, respectively. Additionally, a study performed by the U.S. National Energy Technology Laboratory revealed that if all or a portion of the skin was removed from a zinc die casting, the casting's yield strength dropped by almost 10 percent.

6 – Machining From Wrought or Sheet

The list of strategies for die casting prototyping includes machining from wrought or sheet when you want a prototype made from sheet or extracted aluminum and magnesium. When compared to die casting, wrought and sheet materials have higher ductility and lower compressive yield strength, however. These materials may also have an undesirable directional quality caused by the direction of the sheet or the extracted alloys used to make them.

Pre Page: Picking the Best Die Cast Prototyping... Next Page: What kind of Industries do We Serve?

Product (968)

Equipment (1)

News (12)

More about die casting (9)

Q&A (30)

Quality Assurance (2)

Credit Report

Products Index

Company Info

Q&A