pieces of square and round tubing and plasma/laser cut plates. As the customer designed new pieces or new sizes and variations, the family of weldments grew to 17 diff erent part numbers with a total of about 136 subcomponents. Each part number had to be kept in inventory for production and service requirements. Monarch worked with its customer to reduce the number of parts, optimize part strength and lower tooling and part costs. In the end, the customer converted its family of weld- ments into three castings used across equipment such as fi eld cultivators, solid fi nishers, chisel plows and disc chisels. T is provided an average reduc- tion to cost of 30%, greater dimensional stability, improved aesthetics, and more plant capacity in the customer’s welding and fabrication departments.
4
Requires an excess of machining.
Machining time is not inex-
pensive or particularly quick. Creating a design that reduces or eliminates the need for CNC machining frees up the equipment for other parts. In the case of an originally machined-from-billet steel part used in a piece of machinery, producing it in the investment casting process freed up valuable machine capacity for other critical applications. T e conversion resulted in a 22% cost reduction. It also meant as-cast
plasma/laser cut plates. As the customer
This fabrication to casting conversion for tillage equipment resulted in a 30% reduction in cost, greater dimensional stability and improved aesthetics.
internal heat transfer capabilities could be added which were not pos- sible when machining from solid. T e casting supplier, Signicast Investment Castings (Hartford, Wisconsin) was able to incorporate a cooling internal passage with a turbine style directional cooling fl ow feature and rib features that enabled the part to be cast in steel rather than copper, which would have cost more with lower wear resistance.
5
The assembly is labor-intensive.
A planter row unit for farm
machinery was originally made as a 30-piece weldment that utilized fi ne thread nylock nuts for attachment. T is made assembly time consum- ing and problematic. In addition, the stamped steel components had to be moved and stored multiple times
throughout the production process. Dotson Iron Castings (Mankato, Min- nesota) worked with its customer to redesign the row unit as a seven-cast- ing assembly. T is redesign included reducing 17 stamped steel parts of the main shank to three castings. T e savings in assembly takt time ended up between 5 and 10%. Other benefi ts included improved seed placement accuracy and a more robust part.
“In many cases there are quality issues with assembled parts by the time it is all welded together,” said Mark Hildebrand, director of sales, Monarch Industries. “T e heat makes the metal warped and twisted. With casting, the holes and features will always line up.”
6
The cast version (foreground) of this pivot arm for agriculture equipment freed up 71 minutes of shop capacity per unit.
turer identifi ed a need for a high-end arm for reclining dental chairs and conducted surveys to fi nd out what its customers wanted. T e primary desires included an attractive part that was lightweight yet strong, ergo- nomic and cost eff ective, could hide tubes and wires, and provide a wide range of motion. To achieve these goals, the company departed from the typical bent tube/weldment combo and worked with L A Aluminum (Hayden, Idaho) on a cast aluminum version. T e redesigned articulating arm assembly of aluminum castings has a hollow body for electrical wires and pivot points at each end to adjust the height.
7 June 2017 MODERN CASTING | 33
The market is ready for an improvement.
A dental furniture manufac-
Too much variation occurring from assembly to assembly.
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