CAD/CAM Software Helps Mold Maker Survive And Thrive

Mold making has always been a tough, competitive business.

Case Study From: 9/15/2003 Modern Machine Shop

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Checking the fit

Chicago Mold Engineering specializes in the production of large and complex molds. Here, two employees check the fit of the top of a mold used to form the lid of a large drum.

Mold making has always been a tough, competitive business. Recently, the globe-shrinking effects of advanced transportation and communication technologies, as well as governmentally mandated free trade initiatives, have made it even tougher.

International competition, says Chicago Mold Engineering (St. Charles, Illinois) CEO Ralph Oswald, is “brutal; Canada is so close and convenient, and China is so cheap.” His company, Chicago Mold Engineering, was founded in 1944 with $500 by German immigrant Eric “Ozzie” Oswald. The company has since grown to fill about 40,000 square feet of manufacturing, engineering and office space, and it employs 70 people.

CME produces large single-cavity and complex multi-cavity molds for thermoplastic and thermoset applications, serving manufacturers in the automotive, recreational, consumer electronic and houseware industries. Its molds shape products ranging from toasters to personal watercraft and from automotive lighting components to football helmets for the NFL. CME differentiates itself from both foreign and domestic competitors by taking on, and cost-effectively managing, large and complex moldmaking projects.

Both a small mold for a toaster and a large mold for an automobile bumper must produce parts that are mechanically and cosmetically correct. Customers for either size mold expect their molds to be delivered in a certain period of time. Making large molds does, however, present unique challenges and risks.

Take, for example, the mold CME created for the hull of a personal watercraft. It was 22 inches thick, 5 feet wide, 10 feet long and weighed 80,000 pounds. Manufacturing a mold that large, Mr. Oswald says, requires a definite plan. “You don’t want to be moving the block too many times,” he says. “You have to complete as much as you can on each piece of equipment. Whether it be milling or EDM, you have to keep your setups at a minimum.”

While there may be instances in which more than one copy of a mold is required, Mr. Oswald says most of the company’s molds are one of a kind. Often, the expense involved in making a mold will permit manufacturing of only one example.

In addition to producing large molds, CME seeks out complex projects many shops can’t handle. Multi-color molds are one of its specialties. In the multi-color cycle, hot plastic of one color is injected into the mold and hardens, then the mold is rotated and the second color is injected to complete the part.

To ensure that final molded parts are functionally and cosmetically correct, CME regularly holds tolerances of plus or minus 0.001 inch. Some automotive lighting components, Mr. Oswald says, “have optical surfaces with virtually no tolerance.”

Handling challenging projects cost-effectively requires the company to continually keep pace with technological developments in mold manufacturing. As machine tool technology evolved and computers replaced drawing boards, CME has added new machine tools, used advanced cutting tool technology and evaluated design and manufacturing software packages for maximum utility and productivity.

For example, about 4 years ago, CME acquired a Makino (Mason, Ohio) SN64 high speed graphite machining center to produce electrodes for its EDM operations. After evaluating a number of 3D machining software packages to create tool paths from the engineering group’s CAD mold designs, CME chose the PowerMill package from Delcam International Inc. (Windsor, Ontario, Canada).

“We relied on the input of the machine’s operator,” Mr. Oswald says. “He said the Delcam program reacted better for high speed machining; the exits and entries were more gentle on the machine.”

CME also employed PowerMill software when it added an FPT (Canton, Michigan) five-axis horizontal boring machine, and it uses the package on a Fidia (Troy, Michigan) five-axis machine purchased 3 years ago. “Almost every mold has some aspects that are best cut on a multi-axis machine,” Mr. Oswald says. “Using a five–axis machine significantly reduces setups, cuts production time and improves quality.”

CME machinist and network administrator Chris Saragaglia says “You’re able to create different leads and links and different tool paths. PowerMill is precise in its curve and surface cutting boundary creation, and it enables you to blend your smaller cutters to the larger ones. The result is much less polishing and a nicer finished piece.”

Operator Bill Kloskowski says it takes more time to program all the available options, but adds that he can “spend an extra 15 minutes programming and cut out 1 hour of cutting time. It has been my experience that when the blocks are large, you can save hours in just one path.”

CME uses the PowerMill on the shop floor with Delcam’s PowerShape, a 3D modeling program that enables operators to add or delete CAD features to tailor mold designs for the most efficient manufacturing. Mr. Saragaglia says he uses PowerShape to modify designs on the shop floor—for example, “patching over” details that will be created by EDM. “Before we had PowerShape on the floor, we would have to send the design back upstairs,” he says. “An engineer would have to stop what he was doing, and it usually took a half hour at minimum to get a small patch accomplished.”

“A lot of shops program off-line in a programming department,” Mr. Oswald says. “I elected not to go that way. I give the operators the capability of doing tool paths on the machine. Once the operator is over the learning curve, his machine is always running. When he’s doing his roughing operation, he’s programming his semi finish or finish operations. It represents a lot of saved time and saved footsteps. CAM on the shop floor is becoming more common; people are seeing the benefit of it.” Operator Ben Harkins says that using the CAM software on the shop floor “minimizes communication problems and misunderstanding between engineering and the machining floor.”

Chicago Mold Engineering continues to seek challenging jobs while also acquiring the manufacturing technology to handle them efficiently.

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