Integrated CAD and CAM Boosts Job Shop's Efficiency through Collaboration

Like many other machine shops, Creations Unlimited (Morgan Hill, California) faces increasing pressures from shrinking lead times. “Every customer we have would take things in a week or two if we could do it,” says owner Dennis Rathi. “Everyone wants everything tomorrow.” 

To reduce lead times, the family-operated shop has invested heavily in automation, equipping some of its 15 machine tools (including five-axis machining centers) with machine-tending pallet changers with dozens of pallets and large toolchangers. “We have a lot of equipment that can run unattended,” Mr. Rathi says. “We can do large production batches or one-piece prototypes without change-overs or lengthy setups.” These have been the company’s advantages. “We focus on the more complex parts that other job shops don’t want to make or don’t have the capability to make,” Mr. Rathi says. “That’s how we have grown the company.” 

To realize the best return on its investment in advanced equipment, Creations Unlimited has adopted NX software from Siemens PLM Software. Prior to NX, the shop used separate CAD and CAM systems that were not only lacking in capabilities, but also required file transfers between the software solutions, which hampered overall efficiency. The integrated design and manufacturing capabilities of NX support a more streamlined process that enables the company to go more quickly from CAD part model, to NC programming, to simulation and verification, and finally to finished part.

The Value of Integrated CAD/CAM Software

Whereas the company made the switch to NX primarily because of its integrated modeling capability, there are five advanced features of the software system that Creations Unlimited takes advantage of regularly: 

1. Design for Manufacturability

“Customers would send CAD models that we couldn’t machine: Faces were not tangent, or we had to put check surfaces in, etc.,” he says. “With the modeling capabilities in NX, we can easily fix bad geometry, remove features and do whatever else we need to optimize digital part models for machining.” 

NX supports a master model concept that enables Creations Unlimited to prepare and optimize part models for CAM while leaving the original part intact. In many cases, the shop proposes modifications to improve manufacturability—an important service that improves collaboration with customers and enables the shop to offer more competitive quotes.

2. Machine Setup Modeling

Creations Unlimited also uses the assembly design capabilities of NX to model the complete machine setup, including fixtures, tooling, riser blocks, clamps and other items. With this approach, the company can create a fully detailed and accurate digital model of the machining environment that streamlines the NC programming process.

“When we first started, every time we got a new job we had to start from scratch to build a new riser block or a new fixture or clamp,” Mr. Rathi says. “But with NX, we saved and organized all the components, so now we can pull in complex fixture assemblies and reuse them for other jobs. It’s very rare now to build specialized tooling for a job.”

3. Five-Axis Machining

Creations Unlimited makes extensive use of the advanced five-axis machining capabilities of NX to deliver complex parts with quality surface finishes. For parts with complicated geometry, the shop has found that the key to five-axis efficiency is having an accurate representation—a digital twin—of the entire machine setup and machining process. “For us, it was critical to have all the models of all the fixtures—all the holders, the part in its accurate location in the machine, everything in NX matching everything on the machine,” Mr. Rathi says. “For the majority of five-axis machining, we use the automated tilt tool axis capability,” he says. “It’s easy to create a three-axis tool path and let NX software tilt the tool so we can easily machine difficult parts using five-axis machining.”

4. Adaptive Milling

Adaptive milling is a high-speed machining strategy designed to be ideally suited to the hard materials like steel and titanium that are a focus for the company. Adaptive milling uses a large axial depth and a small radial depth of cut to maintain consistent chip thickness and reduce machining time.

“We’re now using adaptive milling for all high-speed machining,” Mr. Rathi says. “I can program an operation in one tenth the time compared to our previous software. These smooth tool paths shorten the cycle time using higher cutting speeds. But the main benefit is that we can extend tool life by 200 percent. The longer and more predictable tool life helps us reduce the overall manufacturing time because we’re not changing tools as often, and we’re not stopping the machines to check the tools. A lot of people undervalue that time.”

5. Toolpath Simulation and Verification

The machining simulation and verification capabilities of NX, used in conjunction with the digital twin of the machining setup, give Creations Unlimited more confidence in its NC programs. “Integrated simulation means we’re not having to switch to another program to verify the G code,” Mr. Rathi says. “It’s all complete and all in one software, so if we make a change we can instantly verify it. Whatever we see in NX is exactly how the machine performs, all the way to how the machine rotates under certain conditions.”

For all of its machines, Creations Unlimited uses NX to output NC programs that are optimized for the controllers. The NX simulations leverage every detail of the digital twin, including the machine controller code. “Having everything staged in the software saves up to 50 percent of the lead time, depending on the complexity of the job,” Mr. Rathi says. “We have complete confidence in our programs, and have eliminated test runs.”

Manufacturing Efficiency Comes from Collaboration

The shop has also taken advantage of the software to facilitate reuse of machining expertise and best practices. Process templates in NX enable programmers to reapply machining parameters from one job to the next. “We can create geometry groups with a sequence of tool paths such as roughing, semi-finishing, finishing and chamfering. All you have to do is select a feature and NX applies all the parameters—how to enter the pocket, how to machine the corners... All the rest of the tool paths are still there. We can program up to 90 percent faster using NX CAM.”

To provide the shop floor with documentation such as setup sheets and tool lists, Creations Unlimited relies on NCmatic, the product and company name of a Siemens PLM partner that specializes in workflow automation tools that are then integrated with NX.

“We worked with Marek Pawlus, CEO of NCmatic, to customize a work instruction template tailored to our workflow and to create NC reports based on my input,” Mr. Rathi says. “We can simply select a menu button to create a PDF of work instructions that are completely customized to our requirements.” NCmatic also supports Creations Unlimited with postprocessing and simulation tasks.

Creations Unlimited’s involvement with Siemens PLM has even gone so far as to influence development of the software. “We notice that Siemens development has been implementing new NC programming functions at a fast pace,” Mr. Rathi says. “By joining the Siemens early adopter program, we are able to review and influence the development of NX CAM software. For example, as a result of visiting our offices and regular discussions, Siemens has adopted elements of our feedback into new CAM functionality.”