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The cause of heat checking in aluminum die casting and die cast dies is the forcing of molten metal under pressure into intimate contact with the die, thus causing the die surface to become very hot in relation to the adjacent metal. The temperature of the steel die surface closely approaches the temperature of the cast metal. The time required to heat the surface of the cavity steel from normal temperature to cast-metal temperature is less than 1/1000 of a second.The actual increase in temperature of the die surface for aluminum die cast metals is 600 to 1000 degrees F. This increase in temperature is accompanied by a corresponding thermal expansion. When the coefficient of expansion of the die steel is multiplied by the several hundred degrees of temperature differential between the surface of the die cavity and the inner metal adjacent to it, the resultant expansion is greater than the elastic deformation the steel can withstand. Therefore, there is some plastic deformation on the surface of the die. When the heat of the surface is removed by conduction through the die and the surface cools to normal die temperature, it contracts; and because of this plastic flow that occurred on heating, the surface is in tension on cooling. After a sufficient number of cycles in the die casting process, cracking results

Sand casting and semi-permanent mold casting are generally more complex than die castings where design features have to be compatible with the opening and closing of dies in the horizontal direction. This does not have to be the case if salt cores are used.   Salt cores are made as die castings and these die cast salt cores are then placed in another die cast machine and another die casting is made that contains the salt core. The salt cores are then washed out and the resulting die casting has features that reverse engineering by competitors can not decipher. 

Die life is critical to profitability of die casting operations. Operating variables such as pre-heating and die lubricant application can make a big difference in die life. Preventive treatments such as stress relief and periodic application of shot-peening are available to preserve die life. When eventually a die is in need of welding repair, using best welding practices can further extend the useful life of a die. Professor David Schwam, Case Western Reserve University, will address methods of die care and maintenance from the perspective of best approaches to preserve and extend die life in this webinar series.   Part 1  Why Dies Fail and How to Prevent Failures - This webinar will provide a concise overview of factors that play a role in failure of dies from cradle to grave. Understanding the failure mechanisms is important not only in the design and fabrication but also in the maintenance and care of the dies. Thermal fatigue is the main mode of failure in aluminum die casting dies. It is sensitive to imperfections in the surface of the dies, and therefore depends on good die maintenance practices. Cleaning and polishing practices will be covered. Soldering and washout are often causing downtime and require replacement of cores. Care of the die surface and proper die lubricant application can prevent costly downtime. It will also address methods of combating these failure modes.     Part 2  The Effect of Softening, Residual Stresses and Stress Concentration Factors on Die Life - This webinar will discuss in detail the effect of stress concentration factors, softening and residual stresses in thermal fatigue, soldering and washout failures. While eliminating tensile residual stresses may be difficult, minimizing them can help in preventing costly failures. Softening is evolving especially in the hottest spots of the die and can lead to premature failures. It will also address the commercially available preventive treatments such as stress relief and periodic application of shot-peening.   Part 3  Repair of Dies - Over time, even the best die will show some cracking. This webinar will address how using best welding practices can go a long way in extending the useful life of welded dies. Pre-heating and post heat treating methods will be covered. In addition we will present novel methods of laser micro-welding cracks during this webinar.   Attending a webinar is an excellent way to obtain vital information without the hassle or cost of travel. Purchasing this three part series together is only $97 for Corporate Members and $247 for Non-Corporate Members! Each 60-minute presentation will not only address important information on the topic but also provide adequate time for questions, answers, and discussion. If you are not interested in attending this webinar series but know someone who might benefit from it, please pass this information along to them.   

Shot tips are critical tooling components for successful cold chamber die casting. Evergreen has created a webinar that will address the various in-service requirements of shot tips, materials commonly used, the variety of tip designs available, casting situations where the various tip designs might be selected, and typical shot tip failure modes. In addition, the interaction between shot tips and shot sleeves (for example, tip lubes, tip cooling, and ring design) will be discussed as appropriate. This webinar covers the following topics: Functions and requirements of shot tips Common shot tip materials and reasons why Overview of shot tip designs and reasons for selection Common shot tip failure modes and underlying reasons for failure

Flashing has always been a challenge in the die casting industry.  There are a number of causes of flash in the die casting process.  Recent works completed by Evergreen's R&D efforts have generated tools that can be used to reduce flashing.  In this webinar, the causes of flash will be discussed as well as ways to identify the source of the flashing, how to reduce the flash, and how to use these new tools. Evergreen's Director of Education, Research and Technology, Steve Udvary will address the following topics in this webinar: Understanding the causes of flash Reducing the impact spike Die design for reduced flash Attending a webinar is an excellent way to obtain vital information without the hassle or cost of travel. As an additional cost saving option we suggest purchasing one webinar login and gathering employees to view the presentation via projector!  These 60-minute presentation will not only address important information on the topic but also provide adequate time for questions, answers, and discussion. If you are not interested in attending this webinar series but know someone who might benefit from it, please pass this information along to them.

The North American Die Casting Association is moving to a new location. Please update your records to replace our previous address with the following new address: North American Die Casting Association 3250 N Arlington Heights Rd - Suite 101 Arlington Heights, IL 60004 Our phone and fax numbers will remain the same. Please make sure they are correct in your files as well: Phone: 847.279.0001 Fax: 847.279.0002  

EVERGREEN  has created a series of webinars that present information on die failure mechanisms, die steel and heat treatment criteria, operational factors that influence die life, die care and maintenance, and new technologies for extending die life.    This three part series was developed to introduce the concept increasing the life of your tool. The series, presented by NADCA's Director of Research, Education & Technology, Steve Udvardy, will help you understand the various aspects associates with increasing die life. The following information will be presented in the remaining two webinars:   Part 2 Influence of Process Parameters and Maintenance on Die Life - There are many factors that influence die life. This webinar will address die spray operation, die temperature, cycle time, and other factors have an impact on die life. Information on care and maintenance of dies will be presented as this is also an important aspect of extending die life.  Part 3 Applying New Technologies - There are new technologies that can greatly assist in extending the life of dies. New technologies include: new coatings, high thermal conductivity materials, new die steels that allow for closer cooling line placement, and computer controlled cooling line water flow. This webinar will provide an overview of each and how they are applied to increase die life