Shop Solutions: Motorcycle Engines Get Electronic Makeover
Cometic Gasket (Concord, OH), which got its start in 1989 in an 800 ft2 (74 m2) facility with limited production capability, today employs 50 and occupies a 70,000 ft2 (6503 m2) facility. Cometic supplies stock and custom gaskets for all kinds of motorsports, serving OEMs, NHRA, NASCAR, as a licensed product, and individual motorsports enthusiasts with gaskets for automobiles, watercraft, snowmobiles, stock cars and motorcycles of every brand.
According to Jeff Gorman, Cometic’s operations manager, nearly every car in NASCAR uses some type of Cometic gasket and 90% run Cometic gaskets top to bottom. The company earns additional bragging rights with a guaranteed two-day turnaround on making the tooling and delivering finished custom gaskets, whether quantity of one for the serious hobbyist, or multiple pieces for race teams, OEMs or retailers.
In recent years, Cometic has entered into partnerships with some companies and acquired others to extend the brands and expand its own product lines and services. These partners and acquisitions moved operations into Cometic’s larger facility to share resources. For example, Salazar Rubber Co., a manufacturer of rubber engine gaskets and seals, is now fully absorbed into the Cometic brand, while partner Advanced Sleeve, cylinder sleeve manufacturer and service provider for various motorsports, shares manufacturing and engine-service resources.
"Advanced Sleeve always had a strong knowledge base, driven by a chief executive really experienced in manufacturing from design through final-stage production and backed by very smart people," said Gorman. "They maintained great electronic records, so transition was very smooth and completed quickly."
A more recent partnership was developed to improve and extend the product line of Delkron Manufacturing, known for high-performance, after-market V-Twin engines and custom bolt-on cylinder and head kits for Harley Davidson motorcycles. "Before our involvement, Delkron was already a strong company, but unlike Advanced Sleeve, Delkron presented challenges. There was no record retention—prints, electronic data, CAD files—and most of the information was tribal knowledge. A great part of the project has been rebuilding products nearly from scratch," said Gorman.
Cometic’s traditional solid-modeling platform has been SolidWorks, which came heavily into play for the Delkron project, as did Cometic’s CAM system. Because the Delkron transition required developing machining processes, designing and machining workholding fixtures, plus all associated NC programming, a great deal of the work fell to Scott Asbury, toolroom supervisor and lead NC programmer. He had used GibbsCAM for three years before moving to Cometic five years ago.
By then, Cometic was already using GibbsCAM to program turning centers and its two Haas VF-3 and VM-3 machining centers. Jeff Gorman said that choosing a CAM system had been a lengthy process. "In choosing any software platform, our primary requirement is that it easily interchanges data with customers and suppliers. We need to speak the same language. Compatibility with SolidWorks was also very important," Gorman said.
Gorman’s team spent a lot of time surveying other manufacturers to determine what they used for CAM. "By the time we completed our survey, there was no question. By a huge margin, GibbsCAM was the most recommended, and the SolidWorks compatibility was fantastic," he said. The company uses SolidWorks for part design and revision control. Part models from SolidWorks open directly in GibbsCAM, which Asbury uses to program parts and develop workholding for machining. He likes GibbsCAM for its ease of use and flexibility in generating toolpaths.
"The molds we make are solid models," Asbury said. "I brought them into GibbsCAM Solid Surfacer, which I had never used before, and by playing with it, I figured out how to generate toolpath the way I felt was optimal for machining. It’s easy, and if I have a new situation that I can’t figure out in a few minutes, I call our GibbsCAM Reseller, who responds quickly. If he’s out of town, I contact Gibbs tech support. In my five years here, I’ve used them twice."
Delkron engine production continued uninterrupted while the Delkron project team developed the bill of materials for the engines, began CAD modeling, and developed a strategy to bring components in house. With all new parts, Asbury determines how to make workholding economically and quickly. He uses both SolidWorks and GibbsCAM for modeling, depending on whether he needs models quickly, only for use by his group. For quick restricted use, he uses GibbsCAM. If other departments will use the models, he makes it more convenient for them by using SolidWorks.
GibbsCAM has many design features to add or subtract features from solid models, or to create wireframe or solid models for machining. "It all depends on what I need and prefer for a specific job," said Asbury. "Often, when I’m programming, I’ll just take a wireframe surface off a solid, because it’s a quick and easy way to generate position points and other geometry."
The first Delkron components to be made were rocker boxes (valve covers), which begin as two pieces of 6061-T6 aluminum billet, one for the bottom to accommodate valves and springs, and one for the cover. Asbury determined these would be made in two setups each for three-axis machining on the Haas VF-3, and that a fixture would need to be machined first. Using the fixture, he machines the outside and inside of the bottom piece, and completes drilling and tapping on that side. Using the machined holes and pockets for holding the flipped part, he finishes the bottom to size, and machines remaining features. Parts are deburred and cleaned, then polished, satin finished or chrome plated. The cover undergoes similar, but fewer operations.
The cylinders, which came next, would require five-axis positioning for three-axis machining, while additional engine work would require five-axis simultaneous machining, so in late 2012, the shop acquired a Haas VF-3 with rotary and tilt axes. For programming, they added the GibbsCAM five-axis module.
Asbury relies on GibbsCAM’s toolpath verification utility, Cut Part Rendering (Flash CPR), for all machining, because it shows interference and unwanted cuts. When used with simulation, it can verify tool motion against fixtures and clamps. "For molds and dies, I use Flash CPR alone, just to see surface finish. For five-axis work, I use it with machine simulation, because I want to ensure that I have proper workpiece orientation, and that everything moves the way I intended, without interference. It prevents collisions," said Asbury.
A foundry supplies the cylinders as rough A356-T6 aluminum castings with cast iron liners, in both uncoated aluminum and black powder coating. Advanced Sleeve bores the ID and faces one end on a turning center, and then remounts the cylinder to bore the back side of the ID, machine the spiggot OD and face mill the cylinder to length. Asbury uses the ID to locate and fixture the part on the VF-3 machining center, and then bores and taps the bolt pattern and drills the dowel-pin holes for mating the heads and cases. Then he mounts the cylinder on the rotary-tilt table and locates the part to machine all base-locating profiles, base gasket seat, fin profiles, push-rod reliefs, all drilling operations for any custom locating holes and the Delkron logo. Deburring, cleaning and final inspection complete the parts for shipping.
The cylinder head castings are next and undergo similar three-axis machining and profiling on the VF-3’s rotary and tilt axes. The first lot is now completed in all but one final operation that finishes customization of Delkron heads. Five-axis machining of exhaust ports and combustion chambers adds considerable engine torque and horsepower.
When introduced to the five-axis GibbsCAM module for programming and machining ports and chambers, Asbury found that using it for positioning was not difficult, but for five-axis simultaneous work, the reseller provided a few hours of training. "With production demands running high, there’s no time to learn or explore the power of the software through experimentation," he said. "Under these conditions, especially with new projects coming, we’ll take any opportunity to learn the software from someone who knows it."
Jeff Gorman said that the project has been underway for 18 months, and sees completion within two more, one to complete chambers and ports, and another to machine engine cases and minor components. "After that, we have some exciting projects to extend the Delkron line beyond the V-Twin, into other Harley engine components," said Gorman. "To accomplish them, we’ll soon take delivery of another five-axis Haas VF-5. If there is excess capacity, all dependent on product demand, we’ll fill it with five-axis contract machining." [No affiliation exists between Cometic Gasket Inc. or Delkron Manufacturing and Harley-Davidson Inc.] ME
For more information from Gibbs & Associates, go to www.gibbscam.com, or phone 805-523-0004.
This article was first published in the May 2013 edition of Manufacturing Engineering magazine. Click here for PDF.