Casting of the Year
Torque Converter Housing Monarch Industries Ltd., Winnipeg, Canada
Material: G3000 gray iron. Process: Nobake. Weight: 610 lbs. Dimensions: 37.8 x 29.2 x 26.9 in. Application: Housing for 2,300-hp transmission for
fracture oil drilling. Converted From: Weldment.
• Converted from a 36-piece weldment, the single casting cut total lead time in half. Part numbers, revision numbers, customer logos and date codes, all of which would have been difficult to display on the weldment, were cast-in.
• The casting reduced the high scrap rate suffered by the weldment due to leaks in the many feet of welding in each part.
• By reducing labor, lead time and scrap rate, the casting increased the customer’s overall manufacturing capacity.
• Radii, fillets, curves and increased wall thickness were added where needed to give the casting strength.
demand for its fracking equipment has grown. “Once volumes started to increase, it was determined to be cost eff ective to switch it to casting,” Hudson said. “T e fabrication is labor-intensive, and more than 30 parts had to be welded together. T e conversion was a defi nite cost savings.” Converting to a casting opened up
capacity by cutting lead times from three months to a month or less, Hudson said. With the weldment design, the fabricator needed to order, cut , bend, weld and machine the steel before delivery. “Supplier capacity problems raised
red fl ags [with the weldment],” Hud- son said. “In the casting process, once you’ve got the tooling made, you just make your molds, pour it and send it off to machining.” The casting also improved the
component’s scrap rate. “Going to casting is a defi nite
improvement in quality because it lim- 22 | MODERN CASTING May 2012
ited the leak points that corresponded with the welding paths of the original fabrication,” Hudson said.
Designing for Casting Beyond visiting Caterpillar’s own
metalcasting facility in Peoria, Hud- son’s trip to Monarch’s sand casting facility was his fi rst in conjunction with a specifi c casting job. “We took him to the foundry to
give him an understanding of where we needed to go [with the design],” Downing said. “Once we came back from the foundry, we were able to work from that knowledge.” Hudson’s visit lasted two days, dur-
ing which he and Downing went over the part’s weldment design, shape and function to adjust it for the casting process and meet tooling require- ments. T e team worked around draft angles and set up cores to create internal and external features. “A lot of the issues we addressed were things like ribs and bosses
that might have been helpful from a weldment perspective but weren’t required or made it challenging to cast,” Downing said. “We looked at what we could remove from the weldment and where we might need to position necessary structural ribs and fillets.”
One of the design changes made
during the visit consisted of separat- ing one supporting rib in the middle of the part’s interior into two ribs. T e change allowed Monarch to elimi- nate a loose core piece from one of its initial casting design iterations. After his visit, Hudson returned to
Illinois to make modifi cations to the solid model. “With his new knowledge of how
a casting is made, he could make some of the [castability] changes without us having to bring it up,” Downing said. Hudson said one of the main things he learned during his visit was the importance of avoiding burnt-in
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