This page contains a Flash digital edition of a book.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . casting innOVatiOns


Surgical Instrument Features Dime-Sized Castings


handheld articulating laparoscopic forceps to be used in surgery. The in- strument’s design included seven tiny intricate components, the smallest of which measured 0.465 x 0.248 in. The student had looked at several manu- facturing techniques, including micro- machining, and was convinced casting the detailed components would result in better tolerances and quality. The challenge was finding a supplier that could produce the micro-castings. “[The difficulty in producing micro-


A


castings is] getting them to fill, since they are very small, with very thin walls,” said Paul Leonard, chief engi- neer for Aristo-Cast Inc., Almont, Mich., the investment casting company that took on the project. The seven parts featured thin walls


and slots of 0.04-in. thicknesses. One of the parts—the stationary jaw—had a 0.04-in. diameter hidden blind hole in its interior that could not be machined. The parts, which were cast in 316L stainless steel, weighed between 2.4 and 34 grams (the approximate weight of a couple of dollar bills to a stack of seven nickels). The patterns produced for the parts


were fragile and required extra care to handle and clean. It was critical that the patterns were dipped in Aristo-Cast’s proprietary ceramic material so the coating coverage was complete with each step of the process. “Since we can produce a very thin


shell, it helped us be able to fill the parts easier,” Leonard said. Although the laparoscopic instru-


ment parts were prototypes, Leonard believes they could be made in pro- duction volumes via the investment casting process, opening up new op- portunities for applications requiring tiny, intricate parts.


METAL


Visit www.aristo-cast.com for more information.


March/april 2011 Metal casting Design & purchasing 49


The articulating laparoscopic forceps’ design included seven tiny intricate components, the smallest of which measured 0.465 x 0.248 in.


mechanical engineering student thought small when it came to his se- nior design practicum. He aimed to develop a


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60