|Todd Cuffaro (right) and Brian Toth in front of Miller CNC’s 5-axis Hermle C30U.|
|Open Mind application engineer Scott McLeland (right) confers with Miller CNC president Todd Cuffaro.|
|Miller CNC specializes in tight-tolerance 5-axis parts, like this prosthetic weightlifting device.|
| Automated five-axis drilling in hyperMILL uses feature recognition to reference drilling operations with differing inclinations, and locate the best possible path. |
Winning races, with bikes, cars, or even trucks, involves much hard work and effort from a variety of sources. There’s the engineering and construction of the vehicle and all its components (engine, frame, tires). Track conditions, fuel strategies, pit performance, and many other variables all play a part. At the heart of it all, though, is a driver and the driver’s will to win.
Todd Cuffaro once drove racecars, and now as president of San Diego-based Miller CNC he is driving his company to finish first in quality, turnaround time, and sales, of course. Mainly, Cuffaro wants to be buyers’ first choice for complex parts.
“We’ve been in business part-time since 2007 and went full-time in mid-2009 when we began getting out of racing,” according to Cuffaro. A dirt bike racer as a kid, Cuffaro, 26, was spending half his time racing and half running a racecar prep business. “My uncle, a lifelong hobby machinist (and the ‘Miller’ of Miller CNC), left his job to launch his own shop,” Cuffaro says. “We partnered up, bought some equipment (lathe, mill, and other necessary tools), and started learning the machining business.”
Just at the time Cuffaro was getting experience on some pretty tricky racecar parts, like brake hub assemblies and other steel and aluminum parts, his uncle injured his back and had to return to his former job. Cuffaro faced a fork in the road. “Through racing, we were able to store a little money away,” he said. “We were getting busier as a shop and made the decision to sell of our racing equipment and go full-bore as a machine shop. Part of that decision was to go CNC and high quality from the start, which for us meant 5-axis machining. That’s where we dedicated the majority of our attention.”
The centerpiece of the shop is a Hermle C30U five-axis CNC machining center with a work area of 650 mm in X, 600 mm in Y, and 500 mm in Z; an NC-controlled swiveling rotary table; and a 32-tool magazine. Other equipment includes three Haas vertical machining centers with four- and five-axis capability, a Haas CNC turning center, two Hwacheon CNC lathes, and a Brown and Sharpe CMM.
The new company began casting about for more business, billing itself as a quick-turn, high-tech job shop for competitive service on complicated parts. “Our philosophy is really simple,” Cuffaro explained. “Give 110% no matter what. We’re a young business and we simply transferred our competitive spirit from racing into the machine shop. We’re eager to take on difficult parts and challenge ourselves.
“With our 5-axis capabilities and the software we’re running, we can be very competitive with most types of milled parts, not just true 5-axis parts,” he continued. “If the part has more than two ops on a vertical, we throw it on a dovetail fixture in the 5-axis mill and handle it in a single setup. Accuracy is much better, part handling is reduced, and we maintain short lead times, which we’ve found is a huge advantage in a slow overall economy.”
CAM just as critical as equipment
As Cuffaro and his team were investigating 5-axis equipment in earnest, it became apparent to them that the CAM system running the machine was as important as the machine itself. “If the two can’t work in unison, you’ve got a huge mess on your hands, spending too much time working around problems to be competitive,” Cuffaro pointed out. “We needed to be able to create fixtures and toolpaths without too much wasted motion. We also wanted flawless machining simulation with the goal of eliminating setup time and running 100% on the first part.”
After kicking the tires on a number of popular CAM systems, Miller CNC purchased the Hermle machining center and a seat of hyperMILL from OPEN MIND at the same time. “We were counting on the personal service we were promised after the sale,” Cuffaro detailed. “We were taking some really big steps in a really short amount of time, and I wanted to avoid any disruptions that would result in moving backward as opposed to the huge leap forward we wanted.”
Open Mind Technologies develops CAD/CAM software and postprocessors for designing and manufacturing complex molds and parts. Its products range from 2D feature-oriented solutions for milling standard parts through to software for five-axis simultaneous machining. (A video demonstration of Open Mind’s five-axis drilling capability is posted online.)
Training on hyperMILL involved a week of one-on-one work at Miller CNC, after which the shop had the confidence to make parts on its own. “hyperMILL turned out to have everything we knew we needed plus several features we didn’t appreciate prior to implementation, like stock regeneration and feature recognition,” Cuffaro said. “We’re able to import a 3D model, design a fixture, create efficient toolpaths, simulate the machining process, and post the code to the machine, all in the same program. Any rev change, we just regenerate the solid model and the toolpaths adjust themselves”
From hours to seconds
Feature recognition played a role in helping Miller CNC tackle an amplifier box aerospace part with 600-plus holes. Where the shop had to pick every hole and program for center drilling, drilling, tapping, hole depth, and inclination, machining specialists at Open Mind were able to show Miller’s programmers how to build a macro that would communicate the entire job to the machine tool in a fraction of the time. With feature recognition, existing CAD geometry information is used for CAM programming, and typical and repeating geometries are defined as features. Along with the assigned geometries, features contain all information relevant to production, such as top, bottom, and start point. These are defined once and can then be assigned to the machining strategy.
“From a single programmed coordinate system, the software automatically defines the hole type, depth, and inclination using feature recognition and applies machining parameters with macros based upon the customer‘s shop standards,” said Open Mind account manager Kevin Lewis. The movement between positions, including jumping over bosses, is 5-axis movement collision-checked against the model. “Collision-checked removal of safe position movements save time,” Lewis added. “The result is production machining without the hassle.”
More important, programming the job and communicating all the information to the machine tool is a 20-second task now, versus a three-hour undertaking previously.
Cuffaro also credits hyperMILL programming with landing and keeping a job to produce a complex medical part – a prosthetic weightlifting device for San Diego-based Maxgrip Systems, from a design by San Diego mechanical design firm Luxon Engineering. “It’s an assembly that clamps around a barbell or dumbbell so an amputee can safely lift weights and stay in shape,” he said.
“The parts are fairly complicated and require tight tolerances to make sure the assembly mates together perfectly. The first run was on our three-axis vertical using another CAM system. We completed the part in five operations and needed a custom tool and some fixturing,” Cuffaro recalled. “It definitely took too long. Another order came right as we were implementing the new 5-axis machine and hyperMILL, so we decided to throw the old process out the window and start over. We used the solid model of the part, mated it to our vise, and programmed the part as an assembly so that there was no chance of a tool collision. It was the first part we did on our own with the hyperMILL programming. It didn’t take long at all and we completed the part in two operations.”
“Since we’re creating toolpaths directly off the surfaces of a solid model,” Miller CNC’s president said, “and the model regenerates after each cut, there are very few wasted movements.”
Cuffaro also credited Open Mind for the fact that it keeps capable machinists among its support personnel. “They actually understand machining in addition to the software, so they’re really helpful. They can walk us through our part to answer the actual question, and still show us several different ways to handle the task. The software has so many options as far as toolpaths or machining strategies that it helps sometimes to have a guiding hand point you in the right direction.”
According to the shop’s customer, part quality has improved significantly and the job was completed much more quickly without the need for custom fixturing.
Throughout the process of implementing hyperMILL, Cuffaro said, he learned how valuable the right tools actually can be. “We make several different aluminum housings with intricate pockets, and up to a few hundred tapped holes,” he said. “Previously, we were forced to create our own geometry constantly, to make sure we weren’t slamming end mills into corners, and we had to pick hole locations one by one. Now we can use feature recognition and tell hyperMILL to use a half-inch end mill for roughing these pockets, a quarter-inch end mill for finishing, and then drill/tap all the 2-56 holes on X level. With macros, every time we’re doing a common feature, we use the same tools, and feeds and speeds are already proven. Programming is faster by a significant amount, we aren’t breaking tools during setup, which would force us back into editing the program, and our cycle time is quicker. The burden rate is slightly more, but hyperMILL is so much faster that it instantly creates a return. Jobs are more profitable and we have more machine time available.”
Cuffaro said the cutting-edge capabilities of Miller CNC (the company recently completed ISO 9001 and AS-9100 certifications) have him predicting the shop’s sales will double in each of the next three years. He also believes his process advantages can help him to exploit situations like machining from a solid rather than waiting for castings. Automation and pallet systems are new process capabilities he’s investigating, too. “We want to put out what customers want to see in a shop: quality, process efficiency, quick turnaround, and competitive pricing. We always have to be doing something different.”