Boat Parts Production Is More Precise With Five-Axis Machining Software

With Mastercam and Vericut CNC simulation software, this company was able to produce even the tightest of tolerances for its demanding boat parts.

Perched on her side on a street in industrial Seattle is Miss Elam, one of the fastest hydroplane boats in the world. She owes her existence, in large part, to Mastercam, CGTech software and a lucky event that occurred in March 1960.

That year, Sven Ellstrom and his bride were on their way from Sweden to Alaska. When they ran out of money in Seattle, they decided to stay there. Sven started making laminate panels and, in fact, made the first laminate flooring in the United States. His company, Ellstrom Manufacturing (Seattle, Washington), still makes laminate wall panels used in airports, as well as insulated glass parts for the trucking, marine and aerospace industries. According to Erick Ellstrom, vice president of the company and Sven's son, the company produces a half million parts per month.

It's the company's proximity to water, however, that led Mr. Ellstrom to build his first hydroplane boat out of wood when he was 12. Eventually, Mr. Ellstrom and his brother Tom built a prototype that would become Miss Elam. As work on the boat progressed, the two brothers couldn't find anyone to make many of the parts they needed, nor could they find anyone to make parts at the exact standards that would translate into the speed they sought. To solve the problem, they decided to build the parts themselves. The company had considerable talent to draw from. It employed 175 people and already used Mastercam software from Mastercam/CNC Software, Inc. (Tolland, Connecticut) to machine parts. So the company continued to use this software to create the part programs for Miss Elam and had successful results. "The second time it was in the water, it won a race," Mr. Ellstrom says.

Two of the company's proudest innovations are its propeller and its T53 and T55 case halves used to house gas turbine compressors. "We like to make high precision stuff anyway," Mr. Ellstrom says. Still, the company needed some help getting to the tenth of a thousandth of an inch. The brothers turned to Steve Kidd and his staff at Cimtech (Fife, WA), the company's Mastercam dealer. Cimtech helped reverse engineer and design programs with the tight tolerances the Ellstroms were looking for. "The better the tolerance, the better the miles per hour," Mr. Ellstrom explains.

"We draw it all and cut it in Mastercam using a five-axis Mazak Variaxis 630 to machine the parts. When we made the move to more complex five-axis programming, we also invested in Vericut CNC simulation software from CGTech (Irvine, California) to verify that the programs were accurate and protect the machine," says Greg Thayer, a programmer at Cimtech.

After creating the NC programs in Mastercam, the company began simulating the machining process in Vericut by simulating the G-code data. "There often can be a difference between the motion as programmed and the code after it's run through the post processor, especially on a five-axis machine." Mr. Thayer says. "The smart way, and the real power of Vericut, is to simulate the post-processed G code." Mr. Ellstrom verifies G codes on everything they run.

The combination of Mastercam and Vericut has been very successful and has impacted the bottom line, both in terms of speed on the water and time and money saved in the shop. When the company tried a new propeller a few months ago, the speed improved by 6 mph, which, according to the company, is a significant increase when racing is concerned. Last year, Miss Elam was second in national high points and set records in five of the six courses she raced with speeds exceeding 150 mph.

"We stayed with Mastercam because it does everything, and it's easy," Mr. Ellstrom says. "Some people say if it's easy to use, it must not be very sophisticated. That's not true. Version 9 does everything we want. The proof is the pudding."

Vericut also saves the company's employees a lot of time on the five-axis machine. "Before investing in Vericut, a new propeller part would take about a week on the machine," Mr. Thayer explains. "We'd run the machine at around 10 percent and watch carefully to be sure there were no incorrect moves. With Vericut, we can see the piece and how it will be cut—a big benefit in five-axis machining. After running it through the software, we just load and go, and it's off the machine in a day. It also offers high-end part measurement tools and the ability to simulate the entire machine. This helps us avoid problems like over travel or interferences with the table or fixtures."

The company adds that Vericut's analysis capabilities enable Ellstrom engineers to ensure that the cut part will exactly match the design model before the part is even loaded on the machine. These digital measurement tools enable them to verify the dimensional accuracy of the "as cut" part by measuring stock thickness, volumes, angles and more. The software also offers the ability to "embed" the design model inside the cut stock and automatically report any differences, such as gouged or excess material left behind by the cutter.

Its latest innovation is an improved propeller strut. "When you blow a propeller, it's usually the end of the strut, too. Our new strut has survived four propeller breaks. It has less drag, and it's more efficient," Mr. Ellstrom says. Now the company is building the same strut for six competing hydroplane boat teams. "If they beat us we know we're not good enough," he says. He and his employees will never settle for that.