Explosion proof castings

Explosion Proof Castings

Cast Lighting Part


This customer inquired if AMFAS could produce acceptable, reliable castings with diecast tools that other suppliers no longer supported. They needed the additional production capacity to support its rapidly growing LED product base. The existing North American and European diecast suppliers found a particularly complex casting difficult to produce; continually struggling with porosity-related quality issues. Prior to approaching AMFAS, the customer had already developed six different casting tools with four different sources. A few suppliers shipped the diecast tools back to this customer after facing many obstacles during startup that could not be overcome.

AMFAS took the opportunity. Instead of starting over, AMFAS reviewed the entire product/process using the same tooling that other suppliers returned. Over the course of weeks, AMFAS finished modifying, and debugging the existing tools, successfully producing parts. Our customer realized cost savings on the diecast part, reduced inventory with AMFAS’ local stocking, and reduced shipping cost with AMFAS logistics resources.

How AMFAS Helped

The casting produced was 16 inches in diameter and weighed 16 pounds. The casting was designed with many thin fins to create airflow, and dissipate LED-generated heat from the fixture. The injection process used by earlier suppliers allowed molten aluminum to flow turbulently through their tools, creating air pockets which leading to the casting being porous. This reduced the strength of the part, complicated machining of threaded holes, and increased the likelihood of a leak path through the casting. Despite this porosity being a well-documented and ongoing issue, none of the existing vendors demonstrated an interest in addressing the root cause. AMFAS took a thorough, systematic approach to resolving the problem; testing and documenting various methods to identify which proved most promising. The DOE (Design Of Experiments) was used. First, AMFAS developed several different shot sleeves to improve the laminar flow of the molten aluminum; then cast and analyzed multiple rounds of sample parts. AMFAS also incorporated a vacuum assist in the mold tool. AMFAS eliminated the porosity that plagued other suppliers by designing a better controlled injection sleeve and actively removing entrapped air during the injection process. Finally, after updating the tools and methods needed to perfect the casting, AMFAS sought to improve its corrosion resistance. AMFAS sourced the highest grade copper-free aluminum for all of our castings, because even a trace amount of copper- as little as 0.4%–can make aluminum susceptible to corrosion. After extensive testing by our customer using an x-ray fluorescence spectrometer, AMFAS parts were found to consistently have the lowest copper readings of any supplier, typically averaging less than 0.1% copper dramatically improving corrosion resistance.

Results and Future Plans

After working with five different suppliers, including AMFAS, and comparing output from a total of 10 different casting tools, this customer found AMFAS’ product to consistently be the highest quality. AMFAS provided the customer flexibility to meet fluctuating supply chain needs, by supplying parts in both as-cast and fully machined options. Our customer saw an improvement in the quality and consistency of its most complex castings, gained access to versatile fulfillment options, saved 20% off the total cost of production and shipping, and reduced inventory by partnering with AMFAS. Clearly the customer was highly satisfied with the result.