. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . purchasing pOints
Adding Value Through Casting Conversions Bob Mueller Jr., P&H Mining Equipment, Milwaukee, Wisconsin A
s a purchaser of metal cast- ings, you must add value to your company. One area of opportunity that remains virtually untapped in most
original equipment manufacturing op- erations is the conversion of fabrications into cast components. I spent a good portion of my career
in the metalcasting industry looking for opportunities to convert my customers’ components to metal castings. We had a very high rate of success. Now that I am one of those customers, I have ap- plied that same thought process to parts in my own store. Certainly, not every fabricated part is a cast- ing waiting to emerge from its welded shell. So, what is it that we as purchasing professionals should look for when attempting to identify potential candidates for conversion?
Production Bottlenecks The quest for casting conver-
uct of an engineering staff that is not casting-wise. Engineering departments typically are not designing parts with cost in mind. Rather, they are designing for the processes where their comfort level and experience lie. A casting-wise purchaser can spot fabrications that are the product of multiple processing steps and suggest a casting conversion. Another downside to heavily fab-
ricated parts is the overall lead time. Purchased plate material comes with long lead times, and in the case of cer- tain material grades, like those used in
Finer Features Fabrications do not incorporate
many of the design features a casting can directly provide, such as profiled surfaces to minimize machining, con- toured radial surfaces and surfaces that are free of unappealing weld buildup. On a fabrication, instead of profiled surfaces for machining, the entire sur- face of a plate will require machining. The casting can provide a raised profile only where machining is required. This practice not only will result in significant cost savings, but it will also increase the capacity within your operation. When converting a fabrication
Imagine the faucet on your kitchen sink made up of several plates with large weld beads connecting them. Now look at the casting that is the faucet you use everyday.
sion candidates should begin with a conversation among you and the employees on the manufacturing floor. Those workers can best identify components that are causing problems due to excessive processing, long lead times and lack of material. You will find that addressing a manufacturing problem will provide you with the path of least resistance in your conversion attempts. The resistance that remains will undoubtedly come from your engineer- ing department, which will default to the old line “if it’s not broke, don’t fix it.” The only way to break down these doors is through proof of improvement. Choose your battles well and look for low hanging fruit for your first attempt at a conversion. Once your efforts are realized, future conversions will meet with less resistance.
Processing, Processing, Processing In many cases, fabricated compo-
nents that come to life through an exten- sive number of processes are the prod-
March/april 2010
military applications, the plate may not be available at all. Once the plate is secured, it requires
nesting to assure the maximum number of pieces can be cut from it. These pieces then may require additional processing, such as the addition of weld bevels or bending. This process can take a significant
amount of time, effort and money and still not result in a finished component. Once the plate sections are created, they then must go into what can be a very lengthy welding process that once again may take an OEM out of its core com- petency and reduce its overall capacity. Fabricated products might also need
to undergo a heat treating process to provide the OEM with the mechanical properties it seeks. This again adds time, money and increases the time to market for the component. A cast component can be delivered fully heat treated to meet a wide range of mechanical requirements.
into an engineered cast compo- nent, incorporating the features that cannot be achieved through any other process will yield your highest level of savings.
Appearance Is Everything In many cases, both fabricat-
ed parts and cast components are used in areas visible to our customers. Customers may base their perception of the quality
of your equipment or component on its appearance. Castings can provide a consistent visual appearance that can incorporate company logos and trademarks. Fabrications provide an inconsistent appearance that takes on little visual appeal. Imagine the faucet on your kitchen sink made up of several plates with large weld beads connecting them. Now look at the casting that is the faucet you use everyday. Castings are not the solution for
every engineered metal part, but in many cases they do have advantages over fabrications. On your venture to convert parts into cast components, utilize casting suppliers with strong engineering departments to make your mark.
METAL
Bob Mueller Jr. is casting procurement specialist for mining equipment produc- er P&H Mining Equipment, Milwaukee. He has 23 years of casting experience.
Metal casting Design & purchasing 47
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