24th April 2015 by David Mason
Last week, we looked back at Maruti Suzuki’s 2014 Altair Enlighten Award entry in which the company used design optimization technology to drive down the weight of a rear engine mounting bracket. This week, let’s review Grede’s work to reduce the weight of a truck spring hanger bracket.
The nomination concerned the product performance and cost improvement achieved by switching the manufacturing process used for a tractor tandem rear air suspension frame bracket. In the traditional process, a green sand molding process is used to cast the frame bracket. In an effort to remove material and weight from the bracket, Grede adopted a lost foam casting process, which allowed for increased design freedom.
With the lost foam casting process, wall sections were reduced with a near net shape result eliminating additional machining previously required. Draft angles were reduced, and a number of holes were cast directly into the design from the outset, instead of having to machine the material out later. This allowed Grede to reduce the manufacturing time, material waste and most importantly the cost by 27%.
The original casting design weighed 39 lbs. whereas the new casting design weighs just 30 lbs., a 23.1% decrease in weight.
New manufacturing methods such as 3D printing make a huge amount of headlines and the technology has a very exciting future ahead of it. However the technology is not without its shortcomings with manufacturing scale and speed being just two disadvantages today. What impressed the judges here was Grede’s ability to utilize a variant of a very traditional method for manufacturing metal parts; adapting the design to take advantage of the casting method and producing a component with impressive weight characteristics. These methods may not get tremendous press coverage, but they can provide new opportunities for automotive manufacturers to design weight out of components – today.