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Another Point for Casting Conversion

Shannon Wetzel, Managing Editor

In Metal Casting Design & Purchasing, we share many stories and examples of casting conversions. These are engineered components originally produced with another manufacturing method that are redesigned for the metalcasting process. Typically, the cases involved a multiple part weldment or fabrication re-engineered as a single-piece casting.

The casting process offers many benefits to the designer that centers around the freedom of shape, making it a good choice for intricate parts. The designer can manipulate a component to meet multiple functions, place material and strength where needed, and remove material where it is not for lower weight and cost.

Still, metalcasting is not always the first manufacturing method considered for a new part and it might not be until after production and some time has passed that the case for metalcasting starts to surface. Cost reductions might be sought, or better repeatability is needed.
Metalcasters can be pretty good at spotting potential conversions to metalcasting and often work with customers to do a cost benefit analysis, pinpointing which pieces would decrease costs and improve value the most.
Even after considering the benefits to converting to metalcasting, designers and purchasers have another hurdle: tooling cost. Investing up front on the patterns to make the castings for a component already in production? It is not an easy pill to swallow, and traditional tooling can be expensive.

However, metalcasters are making inroads in reducing those costs. Rapid manufacturing has been building steam and includes CNC machining patterns, 3-D printing sand and wax molds, and now, 3-D printing plastic patterns.

This past year I have visited three metalcasting facilities that print their own patterns in-house, and they report it has been game-changing. The article, “Jump-Start Tooling With 3-D Printing” on page 22 explores the opportunity this technology has for metalcasting and the designers who can take advantage of the process with lower tooling and development costs.

In recent years, 3-D printing equipment and material has become more widespread and less expensive, so the barrier to entry is lowering. Printing patterns is quicker and cheaper than producing them the traditional way, particularly when going through the design and development phases. Often this method is used for very low volumes, such as between one or two pieces, but that is changing. One foundry I visited this summer is using its 3-D printed patterns in its automated green sand machine for up to 500 molds.

As someone who is a customer of foundries, you have the power to encourage your casting sources to further explore 3-D printing their tooling. It can lower your costs and time to market, as well as remove a little bit of the hurdle for redeveloping a part to take advantage of the casting process’ design freedoms.

Click here to see this story as it appears in the November/December 2017 issue of Metal Casting Design & Purchasing