Jobs deemed impossible by other manufacturers are all in a day’s work for Cornerstone Prototype Development, a fabrication company that accomplishes what no one else can do.

For General Manager Craig Watkins, whose diverse duties include engineering and programming, the only sure thing is that he’ll never be sure what types of jobs are on the horizon.

“We do a lot of really exotic things that other shops don’t have the knowledge or software, or ability, to do. Everything that we do is different — all of the time.”

Watkins naturally took to engineering as a child and today has nearly 20 years of experience in the manufacturing industry, seven of them at the Pawtucket, Rhode Island-based Cornerstone.

Established in 1996 and billed as a full-service design and fabrication outfit, Cornerstone builds prototypes for virtually any industry or product. Its mission is to “assist companies, inventors and designers in bringing their ideas into tangible concepts and functioning prototypes.”

“We typically sit down with clients to understand what they want to accomplish and where they are so far,” Watkins says. “It’s easy to make a rough prototype, but we want to create something with manufacturability in mind. If something has an electrical component, we want to make sure it’s capable of serving its purpose.”

The roster of prototyping services offered by Cornerstone includes CNC machining, engineering, design, model-making, tooling, rapid prototyping, RTV molding, urethane casting, painting, sculpture, electronics and hair rooting. Hair-rooting services typically apply to doll heads for the creation of characters for TV and film.

The company also offers a range of custom thermoforming services, which include everything from 3-D design to tooling and other production-related items. Most prototypes are produced in metal, foams, plastics, glass and resins, and in quantities of between one and 10.

No Such Thing as “Mission Impossible”Cornerstone Prototype Development utilizes SURFCAM to tackle its exotic workload

About The Company:

Name: Cornerstone Prototype Development

Business: Full-service design, engineering, CNC Machining, rapid prototyping, metal fabrication

Website: cornerstonepd.com

Benefits Achieved:

• Maximization of 3-axis machinery

• Dramatic reduction in programming time for multi-holed thermoform equipment

• Time saved with SURFCAM’s ability to .STL files for verification

Comments:

“We like the functionality and the interface of SURFCAM. We stretch the limits of the capabilities of 3-axis machines and 3-axis software.”

Craig WatkinsGeneral Manager

To accomplish its wide range of exotic feats, Cornerstone uses a selection of CNC machinery and the SURFCAM computer-aided-manufacturing (CAM) solution by Vero Software.

“We like the functionality and the interface of SURFCAM,” Watkins says. “We stretch the limits of the capabilities of 3-axis machines and 3-axis software.”

Cornerstone’s staff of six includes two CNC programmers who are able to program in up to four axes with a horizontal rotary table on a 3-axis mill.

The company’s inventory of machinery includes a Makino V-33 vertical machining center, a high-precision 3-axis mill; a Leadwell V-60 vertical machining center; several Milltronics VM-17 vertical machining centers, one retrofitted with a fourth axis; a CNC ProtoTRAK lathe; and a handful of ProtoTRAK mills. “SURFCAM works well with anything,” Watkins says of Cornerstone’s ability to use a single CAM solution throughout its shop.

For Watkins, getting down to the business of prototyping is both an art and a science. He uses Adobe Illustrator®, a vector-graphics program, and SOLIDWORKS® computer-aided-design (CAD) software, by Dassault Systemes, for the design and engineering portion of his job.

“We do a lot of work from photos,” Watkins says. “A lot of times, I’ll take a photo, extract the edges and bring it into SOLIDWORKS to create a solid model.” If Watkins generates a .dxf file in Illustrator, that file can easily be imported into both SOLIDWORKS and SURFCAM.

Many of Cornerstone’s jobs are consumer products, such as a recent bird-feeder project that involved designing a feeder that could be folded flat for ease in shipping.

Another job entailed the design and production of a full-scale working model of a horse’s leg, complete with anatomically correct muscles, joints and ligaments. Watkins and his team derived all design information from a CAT scan provided by a veterinarian.

The purpose of the working horse model was to test an ankle brace developed by Cornerstone’s customer. “The ligaments and tendons were actually cables that hooked up to gauges and indicators, so if the horse stepped down you could accurately tell how much 100 pounds of pressure, et cetera, would affected the ankle brace,” Watkins explains.

The company has also designed and prototyped a display model for wines, which “looked like a giant wine bottle with shelves in the middle,” as well as a campaign for popular golf-products producer Titleist.

While SURFCAM has simplified the overall process of the company’s prototype work, Watkins cites a number of features that significantly increase efficiency in both programming and machining.

“We do a lot of thermoform tooling for the packaging industry, and all of the tooling is vented with tiny holes of different depths,” he explains. To machine the thermoform production tool, Watkins drills a 1/4” diameter hole on the backside of the tool within .030” of the surface geometry. On the front side of the tool, a tiny drill — which could not machine all the way through the material — is used to create a smaller hole for evacuation. “The 1/4” diameter holes end within .030” from the molds’ surface geometry,” Watkins says. “SURFCAM puts a center line in every single hole, and that center line can be used to determine depth, which makes it a lot easier when we machine the smaller evacuation holes on the flip side. “Once the model is imported, I’m already programming and I don’t have to tell it how deep to go,” he says. “If I couldn’t do that and I had 100 holes, it would be 100 operations — but it becomes just one operation.”

Watkins also saves programming time with SURFCAM’s ability to use .STL files for verification. “From a programming point of view, you can run tools one, two and three, and then save an .STL file for each,” Watkins says. “If you cut a part and then want to make a change, you want to go back and verify that it will work without having to run a complete simulation of every operation.”

In other words, if Watkins wants to make a change only to the third operation, he can skip simulating operations one and two and go straight to the third tool that he wants to adjust. “It’s kind of like a fast forward,” Watkins says. “We have parts that can take a while to verify — though the efficiency of the toolpath helps a lot with that.”