Aluminum Metal Matrix Composites (AL-MMC) have significant potential for application in a range of markets. Although a number of studies done in the late 1980’s and early 1990’s identified capable machining technologies, they either did not address, or did not solve the challenge of cost-effectively machining these materials. Polycrystalline Diamond (PCD) coatings for inserts, is an example of the defacto standard for machining this material, that came out of these early studies. This cost-effective challenge has proven to be one of the obstacles to AL-MMC’s wider acceptance in the market place. This is especially true in a number of key markets, such as automotive, that stand to gain the greatest benefits from the properties of this class of materials.
There are exceptions to the lack of studies addressing cost effective machining. Many of the studies through this time period, provided economic analysis that showed competitive or even reduced machining costs when specific applications are converted to AL-MMC’s. Since that time, advances in MMC’s, the understanding of the machining failure mechanisms and tooling material advances have been made. Each of these advances had studies published; each showed promise for advancement of this class of material.
Cost effective machining of Aluminum Metal Matrix Composites has not been proven. Capable machining practices established in the past decade have not been optimized. A solid, accurate, understandable cost model has not been developed to the point of general acceptance. Studies of advancements in the materials show promise for machinability but have not been incorporated into a cost model. The same holds true for tooling. New coatings for tools show great promise for advancing the machinability of this class of material, but have not been factored into any cost models. In addition to the tool coatings, no optimization has been done on the presentation of the tool to the material. Effects of approach geometry (i.e. - rake, lead) have not been incorporated into past studies. Nor has the geometry of the cutting edge of the insert. Past studies showed a significant initial breakdown of the cutting edge. From that point, wear statistics show a gentler slope of the wear development line until end of life is reached. This indicates that some edge prep, other then “up sharp” may be beneficial. That determination remains to be made and optimized.
Many advances have been made in the material and in the tools. It has not yet been proven to industry that these changes have significantly effected the cost of machining this class of materials. This holds true for milling and turning. In addition, these advancements need to be proven in other machining practices also. New tool coatings that allow 3-d application could significantly improve the hole making and tapping operations on these materials. Casting techniques such as “Near Net Shape” will help to diminish the cost of milling and turning. However, fastening these parts to others in assemblies will require efficient, cost effective hole making and tapping.
Sponsorship of a study to implement Alternative Manufacturing Techniques, state of the art materials and tooling, and determine their effects on cost, will help to bring this class of material into wider use in industry. All aspects of the material and tooling must be optimized to gain the greatest benefits in machining cost reduction. Testing and optimization of milling, turning, drilling and tapping operations must be studied and optimized.
With the results of this machining optimization, a comprehensive, understandable and acceptable cost analysis of machining must be completed. With that cost analysis in hand, a case study for a particular application can be completed, showing real world benefits.
This study would require cooperation between members of the Aluminum Metal Matrix Consortium. Given funding, members would commit “in kind” to share the cost of completing this study. The companies in the Consortium are proven leaders in the Metal Matrix Composite arena. The founding members of the Consortium did many of the initial machinability studies. They are the experts in this field.
The project team will consist of Members of the Aluminum Metal Matrix Consortium (http://www.ALMMC.com) working together and providing “in kind” contribution of time, equipment, supplies and material.
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