Resource Center
Overview
There are many sources for information on die casting design. These include text books, technical papers, literature, magazines, seminars and courses conducted by engineering societies, trade associations and industry. Often, the die caster selected to produce a component part is an excellent source for information.
To gain maximum advantage of the die casting process, it is always a good idea to draw upon the wide-ranging experience of a custom die caster. New designs should be reviewed during the early stage of development. Significant savings may be realized during this interchange of ideas.
GUIDELINES FOR DIE CASTING DESIGN
Advice on designing die castings is usually based upon desirable practices or situations to avoid. However, like most rules, there are exceptions. These affects either costs, appearance and/or quality of final products. Listed below are guides which should be considered when designing for die casting:
1. Specify thin sections which can easily be die cast and still provide adequate strength and stiffness. Use ribs wherever possible to attain maximum strength, minimum weight.
2. Keep sections as uniform as possible. Where sections must be varied, make transitions gradual to avoid stress concentration.
3. Keep shapes simple and avoid nonessential projections.
4. A slight crown is more desirable than a large flat surface, especially on plated or highly finished parts.
5. Specify coring for holes or recesses where savings in metal and overall costs outweigh tooling costs.
6. Design cores for easy withdrawal to avoid complicated die construction and operation.
7. Avoid small cores. They can be easily bent or broken necessitating frequent replacement. Drilling or piercing small holes in die castings is often cheaper than the cost of maintaining small cores.
8. Avoid use of undercuts which increase die or operating costs unless savings in metal or other advantages fully warrant these extra costs.
9. Provide sufficient draft on side walls and cores to permit easy removal of the die casting from the die without distortion.
10.Provide fillets at all inside corners and avoid sharp outside corners. Deviation from this practice may be warranted by special considerations
11.Die casting design must provide for location of ejector pins. Take into consideration the effect of resultant ejector marks on appearance and function. The location of ejector pins is largely determined by the location and magnitude of metal shrinkage on die parts as metal cools in the die.
12.Specify die cast threads over cut threads when a net savings will result.
13.Die castings which affect the appearance of a finished product may be designed for aesthetics, and to harmonize with mating parts.
14. Inserts should be designed to be held firmly in place with proper anchorage provided to retain them in the die casting.
15.Design parts to minimize flash removal costs.
16.Never specify dimensional tolerances closer than essential. This increases costs.
17.Design die castings to minimize machining.
18.Where machining is specified, allow sufficient metal for required cuts.
19.Consider contact areas for surfaces which are to be polished or buffed. Avoid deep recesses and sharp edges.
Industry White Papers
Product Design for Die Casting
Papers from the North American Die Casting Association (NADCA) which can assist OEMs in optimizing die casting component design, specifications, and overall die cast production processing.
The 7th edition of this design source book, revised and updated in 2015, presents a logical structure of how to pursue improvement and cost-reduction programs with a die cast product design. The steps presented are applicable to both new product concepts and upgrading of existing components. The principles and sequences outlined are useful for any strategic approach to product development, design and engineering. They are also integral to emphasis on design for manufacturability. (NADCA, 2015 )
NADCA Die Cast Production & Finishing Checklists
Key factors in specifying the production and surface finishing of die cast parts, based on NADCA Product Standards Manual guidelines. Helps assure clearer communication between OEM purchaser and die caster. (2015)
NADCA Tooling Checklists for Die Casting Dies
Key factors in specifying the production and surface finishing of die cast parts, based on NADCA Product Standards Manual guidelines. Helps assure clearer communication between OEM purchaser and die caster. (2015)
NADCA Pointers for Designing Die Castings
Die castings offer exceptional design freedom while at the same time achieving excellent mechanical properties for a product component. Selected features should be designed to enhance casting quality and avoid unnecessary casting costs. This article offers details on key points to consider in optimizing the cost-performance equation for a die cast part.
NADCA-ADCI Standards Cross-Reference Chart
Cross-reference chart for former superseded American Die Casting Institute (ADCI) and superseded North American Die Casting Assn. #401 (NADCA) Product Standards and current NADCA Product Standards. (2015)
NADCA Standards for High Integrity and Structural Die Casting Process
This manual covers specification, design and production guidance for both users and manufacturers of die castings produced by structural casting processes. The manual presents tooling and processing information, alloy properties, standard and precision tolerances, GD&T, design guidelines, quality assurance provisions and more.
NADCA Product Specifications Standards for Die Casting
This manual covers specification, design and production guidance for both users and manufacturers of conventional high pressure die castings. The manual presents tooling and processes information, alloy properties, standard and precision tolerances, GD&T, design guidelines, quality assurance provisions and more.
Die Casting Advancements (2016)
Die Casting Advancements (2016)
The process was originally used almost exclusively for manufacturing typesetting pieces, utilizing malleable materials with low melting points, such as zinc, to create products. From typesetting pieces, die casting moved on to produce phonographs, cash register components, and today, many components for the automotive industry.
Comparing Magnesium Die Castings and Plastic Components
Comparing Magnesium Die Castings and Plastic Components (2012)
Die casting is one of the most mature manufacturing processes available. The most common materials die cast are alloys of aluminum, magnesium, and zinc. In recent years, significantly improved technology has enabled the die casting industry to remain very competitive in many market segments.
Technologies and Strategies for Longer Lasting Die Casting Dies
Technologies and Strategies for Longer Lasting Die Casting Dies (2011)
This paper focuses on technologies that can enhance the life of die casting dies. In order to extend die life, it is important to know what is limiting the life of dies so the appropriate technology can be utilized. For years the reasons for retiring a die from service have remained the same. The top reason for dies being retired from service prematurely is thermal fatigue cracking and this has not changed over the years. After thermal fatigue, the primary reasons for retiring a die are: gross cracking, wear and erosion (washout), cavitation, and chemical attack. What has changed over the years is a great reduction in, and near elimination of, the instances of gross cracking. This is primarily due to the increase in the minimum acceptable impact strength (toughness) of the die steel and several new die steels that have the capability of yielding impact strength levels well beyond the minimum requirements of the NADCA Special Quality Steel and Heat Treatment Acceptance Criteria for Die Casting Dies document.
For Efficient Manufacturing, Look to Die Casting
For Efficient Manufacturing, Look to Die Casting
The ecological impact of modern society has become a major issue in today’s world. Buzzwords like green jobs, renewable energy, greenhouse gases, and more are taught in schools, discussed in business, and used political speeches. In manufacturing, process efficiency is the best way to reduce the impact on the environment and sustain production. Die casting sustainably produces cast products with recyclable materials, while conserving energy, and creating a small carbon footprint.
Die Casting’s Advantage’s over Plastic Components
Die Casting’s Advantage’s over Plastic Components
Die casting has a well-established reputation as an efficient, economical process that offers designers a variety of advantages for creating parts and components. These benefits often make die casting the obvious choice when selecting a manufacturing process for a particular part. However, sometimes designers must weigh the advantages of die casting against other processes, such as plastic injection molding.
Collaborative Engineering Reduces Costs Improves Production Efficiency
Collaborative Engineering Reduces Costs Improves Production Efficiency
Manufacturers in many industries are increasingly using the knowledge of their die casters to help design parts that have a lower overall cost, while improving quality and production efficiency. The terms used to describe the process may vary depending upon the die caster, but whether it is called cooperative engineering, collaborative engineering or concurrent engineering, the results are the same – the potential for saving anywhere from 30 per cent to 55 per cent in the cost of a given part.
Five Steps to Improving Die Performance
Five Steps to Improving Die Performance
One of the myths that still affect some designers’ decisions about choosing die casting is that tooling is not reliable or that short die life will impact production. However, research and innovations over the last 10 years have proved that a number of methods are available to extend die life, improve die performance and reduce the overall cost-per-part.
Specialty Alloys Provide a Range of Die Casting Solutions
Specialty Alloys Provide a Range of Die Casting Solutions
Die casters consistently strive to expand applications for die cast products, increase the efficiency of the process or create materials that improve the performance of the finished product. A key element in this quest is the development of specialty alloys that solve a particular problem.
Die Casting Alloys Material Properties Comparison
Comparative mechanical and physical properties of die casting alloys are presented in the table.
1.What are some of the advantages of die casting?
Die casting is an efficient, economical process offering a broader range of shapes and components than any other manufacturing technique. Parts have long service life and may be designed to complement the visual appeal of the surrounding part. Designers can gain a number of advantages and benefits by specifying die cast parts.
High-speed production - Die casting provides complex shapes within closer tolerances than many other mass production processes. Little or no machining is required and thousands of identical castings can be produced before additional tooling is required.
Dimensional accuracy and stability - Die casting produces parts that are durable and dimensionally stable, while maintaining close tolerances. They are also heat resistant.
Strength and weight - Die cast parts are stronger than plastic injection moldings having the same dimensions. Thin wall castings are stronger and lighter than those possible with other casting methods. Plus, because die castings do not consist of separate parts welded or fastened together, the strength is that of the alloy rather than the joining process.
Multiple finishing techniques - Die cast parts can be produced with smooth or textured surfaces, and they are easily plated or finished with a minimum of surface preparation.
Simplified Assembly - Die castings provide integral fastening elements, such as bosses and studs. Holes can be cored and made to tap drill sizes, or external threads can be cast.
2. Die Casting vs other processes
Die casting is an efficient, economical process which, when used to its maximum potential, replaces assemblies of a variety of parts produced by various manufacturing processes at significant savings in cost and labor.
DIE CASTING VS. PLASTIC MOLDING
Die casting produces stronger parts with closer tolerances that have greater stability and durability. Die cast parts have greater resistance to temperature extremes and superior electrical properties.
DIE CASTING VS. SAND CASTING
Die casting produces parts with thinner walls, closer dimensional limits and smoother surfaces. Production is faster and labor costs per casting are lower. Finishing costs are also less.
DIE CASTING VS. PERMANENT MOLD
Die castings can be made to closer dimensional limits and with thinner sections; holes can be cored; die castings are produced at higher rates with less manual labor; have smoother surfaces and usually cost less per die casting. Permanent mold casting involves somewhat lower tooling costs, and can be made with sand cores, yielding shapes not available in die casting.
DIE CASTING VS. FORGING
Die casting produces more complex shapes with closer tolerances, thinner walls and lower finishing costs. Cast coring holes are not available with forging. Die casting can better accommodate parts with more complex shapes and geometries. Die cast parts can also be much more refined and defined than forged parts, and can be produced at faster speeds and greater volumes.
DIE CASTING VS. STAMPING
Die casting produces complex shapes with variations possible in section thickness. One casting may replace several stampings, resulting in reduced assembly time. Metal stamping is more economical when it is used for parts with simpler geometries. Stamping is capable of producing very complex parts, but at a cost: The more complex a part is, the more components the tool and die require – the more tool and die components there are, the higher tooling costs become.
DIE CASTING VS. SCREW MACHINE PRODUCTS
Die casting produces shapes that are difficult or impossible from bar or tubular stock, while maintaining tolerances without tooling adjustments. Die casting requires fewer operations and reduces waste and scrap.
3.What is structural or high integrity die casting?
Structural die castings (sometimes referred to as High-integrity, Low Porosity die-casting) are variations of the die casting process used to produce castings for specific applications(typically requiring minimized gas porosity in the casting). These include:
High Vacuum Die Casting - The die is sealed and a vacuum is used to remove gas from the die cavity (< 50 mbar) while the metal is injected, reducing the amount of gas that can be trapped in the casting. Parts produced with high vacuum have higher mechanical properties and can be heat treated. The high vacuum process should not be confused with vacuum assist, which uses vacuum to help with the filling of a trouble area in the die.
Squeeze Die Casting - Liquid metal is injected at slower speeds to eliminate turbulence. High pressure is used to “squeeze” the metal into die, creating high quality castings that can be heat treated.
Semi-Solid Die Casting (or Semi-Solid Molding) - A semi-solid (between the melting temperature and the solidification temperature) billet is injected into the die. The metal’s semi-solid state reduces the amount of gas that is picked up during injection, creating dense, heat treatable castings.
4.What is the difference between high-pressure die casting,low-pressure die casting？
High pressure casting and high-pressure die casting are terms used in Europe and countries other than the U.S. for what is referred to in the U.S. simply as the die casting process. The terms low-pressure die casting and gravity die casting are terms used outside the U.S. for what in the U.S. is called low-pressure permanent mold and gravity permanent mold casting. Although they each use metal dies, because of the lower pressures involved they are restricted to heavier section parts, often resulting in higher cost because of the less efficient use of the alloys involved and the slower processing time. They also require a sprayed-on protective coating on the die cavities, which means looser tolerances and rougher surface finishes.
5.What is semi-solid metal casting?
Semi-solid metal casting (SSM) is a near net shape variant of die casting. The process is used today with non-ferrous metals, such as aluminum, copper, and magnesium, but also can work with higher temperature alloys for which no currently suitable die materials are available. The process combines the advantages of casting and forging. The process is named after the fluid property thixotropy, which is the phenomenon that allows this process to work. Simply, thixotropic fluids flow when sheared, but thicken when standing. There are three different processes: thixocasting, rheocasting, thixomolding.
Essentially, semi-solid metal casting depends upon a property known as “thixotropy” observed in certain gels which become fluid when shaken or stirred and semi-solid again when not agitated. Metallurgists applied this observation to the casting process using certain non-ferrous metal alloys containing elements such as copper, aluminum or magnesium.
Semi-solid metal casting requires the use of low-viscosity fluid (yet not molten) materials. Casting occurs at temperature ranges in which some 30% to 65% of the metal remains in a solid-state and 70% to 35% has become viscous. Semi-solid metal casting will occur at variable temperatures, based upon the composition of the alloys in use. It combines many of the advantages of casting and forging. It typically produces stronger and less porous parts than die casting within tighter net tolerances.
History and Development
Metallurgists began using semi-solid casting on a selective basis during the 1970s to fabricate very strong metal parts. However, this form of casting did not become widespread until the 1990s, with the introduction of thixocasting in mass-production commercial environments. The new technique involved manufacturing special initial precast billets and then injecting them into a die to obtain parts with reduced porosity. During this century, many manufacturers began using rheocasting, a slightly lower-cost procedure involving the direct casting of parts from a semi-solid slurry.
Today, metal parts fabrication usually relies upon semi-solid casting to generate higher quality components. This casting process works well for the rapid development of strong parts within tight tolerances. It can produce thin-walled intricate components displaying pressure tightness, for example. The process of casting semi-solid materials enables manufacturing facilities to combine many of the advantages of die casting with the tempering effects of forging. It can produce finer, more uniform internal grains within metal parts.
Semi-Solid Metal Casting Processes
There are a number of different techniques to produce semi-solid castings. For aluminum alloys the more common processes are thixocasting and rheocasting.With magnesium alloys, the most common process is Thixomolding.
Four of the most popular current methods are as follows:
Thixocasting
Manufacturers around the world still use thixocasting today to generate very high quality cast metal parts. First, machines form a special pre-cast billet by stirring the molten metal during casting to reduce the presence of air bubbles within the material. A die-casting machine then re-heats the billet to a semi-molten condition before injecting this material directly into a steel die.
Rheocasting
Several methods of rheocasting exist. This process uses molten metal to create a slurry of semi-solid material, in some cases by swirling the mixture at designated rates and adding aluminum chips to the substrate. Following casting, the manufacturer can re-use the excess slurry by returning it to molten form in a die casting furnace (or die casting machine).
Thixomolding
In this process, manufacturers create a metal slurry by feeding chips into a heated barrel at a designated volume under highly controlled conditions. As the chips reach a semi-solid temperature, machines automatically inject the slurry into a die. Some manufacturers use this process to work with magnesium alloys, for instance.
Strain-Induced and Melt Activated Method (“SIMA”)
The Strain-Induced and Melt-Activated process enhances thixomolding today in some settings. Heated metal melts to a designated temperature, then re-crystallizes with a finer internal grain structure within highly controlled environments. Manufacturers cold-roll the material in a partially-tempered condition in order to produce high-quality small metal components.
Applications
Semi-solid casting holds numerous applications in this century. For instance, automakers often rely on this manufacturing process to create high-strength yet lightweight metal parts for vehicles in high volumes. From the production of aluminum suspension mounts to thin-walled magnesium alloy tablet frames, this form of casting holds commercial importance.
SMM Advantages
Advances in semi-solid metal casting have produced a number of key advantages in metals fabrication settings recently.
This type of casting holds significant economic attractions for many manufacturers. Firms using automated production processes can generate a high volume of high-quality metal components in a comparatively brief period of time with very little waste. By using SSM instead of sand die casting, for instance, companies avoid costs associated with environmental site de-contamination and lead-cleanup efforts. The use of lower temperatures places a lesser burden on company facilities. It also usually permits a manufacturer to use a die for a longer span of time. These long-term production cost savings may offset initially higher costs associated with implementing thixocasting or automated rheocasting.
Furthermore, the heat-treatable parts generated through semi-solid casting offer all of the benefits of components manufactured using conventional die casting. They typically demonstrate good mechanical performance and will affix to other components within an assembly.
Also, semi-solid metal casting enables the production of very high-quality metal parts because of reduced porosity and tight tolerances. These components often display a better finish due to these factors. During thixocasting, for instance, the process of re-heating the billet and forcing it by injection into a second die permits the creation of very strong, finer (and more uniformly grained) internal structures. Companies can create both intricate parts and parts with pressure-tight, thin walls by employing this technology.
6.Can magnesium castings be painted?
Yes, die cast magnesium components can be painted using e-coat, spray paint or powder coat processes. The parts require a pre-treatment to ensure adhesion. We've done several consumer drone body structure parts that are painted.
7.Can you provide trace-ability if required?
Trace-ability can be applied if requested.
8.Have you a recognized Quality Assurance Certificate?
We are certified to IATF16949:2016,ISO9001:2015,ISO14001:2015,OHSAS18001:2007, and GB/T 29490:2013 QA System. View our certification here.
9.What quantities can you supply?
Any number from one-off to tens of millions.
10.Do you export your products?
Yes, we are exporting to Japan, South Korea, Europe and North America.
11.Do you have your own tool room, die casting shop, machine shop?
Yes, we have our own tool room to manufacture tools/dies as per customers requirement. Also, we have more than 500 CNC machining centers for critical machining of the components and Injection molding machines for insert-molding of die cast components.
