CAD Takes Models to Mold Fast

Manufacturing Engineering, Mar 2007

Innovative Casting Technologies Inc. (ICT; Franklin, IN) is a small, ISO-certified agile company that claims it can accelerate its customers' product development cycles and help them reduce time to market.

ICT's business includes fast-turnaround on prototypes and low-production castings in grey iron, ductile iron, and aluminum for customers such as Cummins, Deere, Tecumseh, Caterpillar, and Parker-Hannifin. Services include NC programming and machining, CMM verification, and use of CAD/CAM software to speed product turnaround.

One of the major tools it uses to accomplish its mission on a daily basis is CAD/CAM software from Delcam International (Windsor, ON, Canada).

ICT specifically uses PowerMILL CAM software and PowerSHAPE, to manipulate the surface form of CAD models so that the company can ship machined prototype parts within three to four weeks of receiving the customer's CAD file.

According to ICT, the Delcam software allows it to create models and secondary tooling in a day or even hours in some cases. Since 2005, the company has used the Delcam software to deliver cost-effective prototypes to its customers to check form, fit, function, and to evaluate a new product design visually. Most of the prototype work is manifolds and brackets of various descriptions.

"For a customer who needed parts for an engine right away, we shipped five six-port exhaust manifolds 13 days after receiving the CAD file," says owner Jack Laugle. He is a second-generation patternmaker with experience at another casting company before starting his own company in 1997 to make patterns and prototype castings.

Once a pattern is designed, the company uses a series of machining centers to create patterns, core boxes, and finished machined castings. Haas mills are used to machine the patterns, and two Mazak machining centers are available for prototype machining. Castings and machining can be verified with a Brown and Sharpe CMM, comparing the measured data to the CAD file.

"Previously we used another software package, but have found that the options available through Delcam PowerSHAPE make the pattern design and machining process much easier, including creating surfaces for the parts," says Tony Luenebrink, panera designer.

"When we get a pattern to work with, such as bracket or manifold, we bring the customer's part file into PowerSHAPE, usually from Pro-E. We then easily break out the component parts, [cores, the outside shape and the core boxes] in order to create a pattern we can use to produce the prototype parts," Luenebrink explains.

PowerSHAPE saves hours of pattern design time at ICT with a feature called Smart Surfacing. It blends fillets and radiuses automatically. PowerSHAPE has always provided a number of alternative methods for constructing a surface from a given set of lines, arcs, or points. But with Smart Surfacing, the choice of method is made automatically by the software to give the best possible (smoothest) surface.

Smart Surfacing also permits the software's selection to be updated automatically as information is added to the design. As any additional lines or points are inserted into the model, PowerSHAPE reviews the chosen surfacing method and regenerates the surface automatically, giving an alternative solution if a better one exists.

"Then, once the file is imported into PowerMILL," Luenebrink says, "it is easy to program the machining in layers to suit the lengths of our cutters. Many of our patterns can be 10-12'' [254-305-mm] tall, and our cutters are 4-5'' [101.6-127-mm] long, so programming in layers allows us to program the machining efficiently, avoiding cutting air. This saves all kinds of time, which is important to our business of speed.

"The programming time is similar to our previous method, but once we start machining, that's where we can really see the difference," says Luenebrink. "The machining strategies in PowerMILL help us avoid cutting air, so machine time is chip-making time. The result is that the whole pattern-making cycle is much shorter so we can turn around a pattern 30% faster. For example, a pattern that used to take us 12 hr to program and machine on our Haas mill now takes us less than 8 hr."

ICT usually produces 3-5 different patterns a week, depending on the size and complexity of the patterns. The machining programs take less time because they are shorter. "You can tell they are shorter," Laugle says, "because there are many fewer lines of code. It's just more efficient software than what we had been using. Toolpaths are much more concentrated."

To assure safe, time-saving machining, PowerMILL automatically checks for potential collisions of the cutting tools, while contact-point analysis allows ICT to ensure that only the cutting edges touch the pattern or prototype part.

Once a prototype casting is delivered and evaluated by the customer, its file can be changed and returned to ICT. "The Delcam software makes its easy to overlay the 3-D model from the customer and to see any changes in the new casting file we get back," says Luenebrink. This is a big advantage to the prototyper. It makes it easier to select the areas of a pattern that only need machining then to modify the PowerMILL file accordingly, so the machine will concentrate only on the area of concern-saving a lot of time in reprogramming and machining.