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KNOWING WHEN TO SWITCH TO CASTING


Watch for these signs a new manufacturing process is in order and whether the casting process should be considered.


SHANNON WETZEL, MANAGING EDITOR W


hen you are designing a part to be put to market quickly, sometimes the quickest or most familiar manufactur- ing method is chosen. But time and volumes might begin to highlight defi ciencies in the original manufactur- ing method of choice. At this point, it is time to consider moving to a better optimized manufacturing process.


T e casting process has many advantages, but it might require more tooling and engineering time up front than a weldment or machined component. How- ever, making those investments in tooling and engineering can pay dividends not just in reduced cost, but also improved performance, reduced weight, and even shorter lead-times. Where do you start? Metalcasting facilities well-versed in redesigning parts for


casting are experts at pinpointing what makes good candidates for casting conver- sion. And the examples of successful case studies are bountiful. Read on for signs that a new design is needed and how to know when casting could be the process of choice.


SIGNS A PART NEEDS A NEW METHOD:


1. Insuffi cient dimensional stability. A casting’s dimensional tolerances are generally superior to welded and fabricated assemblies. A rotational and lift control post weldment for the oil market was experienc-


18 | METAL CASTING DESIGN & PURCHASING | Mar/Apr 2017


ing distortion and stresses during fabrica- tion that led to problems in assembly and in service. T e cast version produced by Midwest Metal Products (Winona, Minnesota) eliminated the distortion and stress problems while also reducing cost by 38%. In cycle testing, the cast part demonstrated more than fi ve times a longer life than the welded part.


2. Costly to manufacture and keep track of inventory.


Pier Foundry (St. Paul, Minnesota),


uses onsite visits to help customers identify candidates for castings. In one instance, the metalcaster and customer pinpointed a six-piece universal disc leveler pivot arm as a promising can- didate. Using fi nite element analysis and casting process modeling, the engineers revised the part’s design to be optimized for casting. Converting the weldment to a casting freed up 71 minutes per unit of shop capacity and allowed the customer to focus its ef-


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