Understanding how parts are positioned in three-dimensional space is the first step toward prototyping a part. But the ability to precisely verify how a new part fits into the design envelope is the quantum leap in product development.
Chris Kelley, president of California Cycleworks, exemplifies the small business owner who envisioned opportunity and took a leap of faith. While Chris was working at CA Cycleworks as a college student, the company’s second owner left in 1997. Chris stepped in with the intention of serving existing customers, finishing work orders, and shutting down the operation upon the completion of his college education. On the brink of closing the cycle business, though, the website featuring his 1992 Ducati 900 Supersport began to generate email. More than a few people asked how and where he got parts for his motorcycle. He explained that local independent Japanese bike shops could source the parts with the vendor. Then a Ducati enthusiast asked the magic question, “Can I just buy the parts from you, and have you ship them to me?” Chris followed his instincts to make a run at the parts business, and never looked back.
Today, if a buyer goes to their local Ducati dealer and a part is unavailable, or they want a better quality or competitively priced part, they go to CA Cycleworks. The largest factory in the world produces the rubber timing belts that are unique to Ducati motorcycles. Ignition coils are produced to exacting specs. And three aftermarket fuel tanks are rotationally molded with 40 to 50 produced at a time for particular Ducati motorcycles.
Understanding where motorcycle components are positioned in three-dimensional space is the first step toward prototyping a part. But the ability to precisely verify how a new part fits into the design envelope is the quantum leap in product development. Kelley turned to a portable ROMER Stinger II articulating arm for his 3D scanning requirements. This dimensional verification tool can be used for many applications such as alignment for assembly, CAD-to-part comparison, reverse engineering, scanning, prototyping, tube geometry inspection, and more. Its flexibility is ideal for a small shop environment needing on-demand measurement capability for workpieces that are large, difficult to move, or cannot be moved to an offline inspection station.
The first application of the portable arm was Kelley’s second custom gas tank with a metal fuel pump flange bolted to the bottom with 6 bolts on a 140 mm circle. The mold had to be changed three times because the inserts would not lineup properly. The arm was brought into the shop and used to map the original part, the gas tank, and the mold. The data generated from all three parts were aligned in a 3D coordinate system, and then analyzed to determine where to relocate the holes on the next iteration of the mold. The next mold was perfect…the holes lined up on the center as measured and confirmed by the arm.
At first glance, the articulating arm looks and moves like a human arm. It weighs less than 10 pounds and lets you probe and scan with precision. Its infinite rotation of principle axes makes it easy to inspect hard to reach areas on a part or assembly. The arm integrates Zero-G counterbalance, which offsets the weight of the arm and facilitates one-handed operation during data acquisition.
For the custom gas tank, Kelly had to accommodate an air induction system that interfered with one of their gas tanks. Said Kelley, “So I gathered all the air intake kits sold on the market, mounted them on the bike, and scanned them. I kept modifying the original drawing based on those scans until I created a new floor that misses those air intakes. It sounds easy, but reverse engineering is not as straightforward as it sounds. I experienced the same problem with the location of the filler cap on another tank, but I did not have the metrology arm at the time. I had to solve that problem in 2D with basic geometry and the use of calipers and the QCAD open source program. Not an easy task.”
For economical reasons, part prototyping is conducted in-house. Kelley does all the CAD work using Rhino software and the T-Splines plug-in for modeling the flowing organic surfaces of a motorcycle. Using the ROMER Stinger, he acquires 3D data and begins work in CAD. In the conceptual phase of his newest fuel tank, Kelley initiated three design changes since the model was created. He goes back to the measurement arm to quantify those modifications between the new reality and the original scanned model.
During product prototyping phases, the portable CMM answers his questions quickly, as the accuracy of measuring by hand is not viable and involves too much trigonometry. Most importantly, Kelley uses the arm to map out the motorcycle to understand the boundaries surrounding the gas tank. The ability to define the assembly envelope and interference check other parts is important.
In his shop, the ROMER arm is securely bolted to a metal table on wheels. A motorcycle is placed upon a stand and strapped to the table with ratcheting tie downs. Kelley establishes common reference points on the frame, and performs a gross mapping of the frame with tubes…just enough to verify the location of the frame, so the gas tank would not hit it.
After four years, Kelley is still finding ways to use the portable CMM. “It is really nice to know exactly where a part is located on a bike, especially when you sell parts that other people make. And when I say “exactly” on a motorcycle, within a half a millimeter. A good example of troubleshooting with the arm was our second gas tank. We brought in a customer’s bike, and scanned the head of the engine, the bottom of our gas tank, then the frame. I referenced the data together in Rhino and pinpointed the disparity. As it turned out one of the Ducati engines was taller and the gas tank breached the area. It feels good to prove what happened in reality, and choose a new angle for the bottom of the tank so it did not touch anything.”
“One of the topics I talk about on my online customer forum is you have to understand what you are proving…or not proving. If someone is creating a part to fit another part or assembly, they would be foolish not to have at least the arm that I have. It would be a waste of time, money and effort. For example, the 140 mm circle designated on the original gas tank is not a perfect circle because they cast the flange, which is made by hand. When I design a gas tank mold, I don’t place the holes on a perfect circle. I match them to the error of the part it fits to. I would never have known that condition without the metrology arm.” MPF
Hexagon Metrology, Inc.