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High-Quality Parts Demand Top-Notch CAD/CAM

Pat Waurzyniak
By Patrick Waurzyniak Contributing Editor, SME Media

The eternal question in manufacturing with CAD/CAM software is how to help builders make their parts faster, cheaper, and better—all the time. With the latest crop of CAD/CAM software releases, developers continue to tweak their offerings by adding new wrinkles including generative design capabilities, more automation of frequently used shop processes, as well as more tools for the emerging area of additive manufacturing.

A programmer uses simulation within NX CAD/CAM design software to help verify the CAM setup for a machining process. (Provided by Siemens Digital Industries Software)

In addition, simulations have become much more critical, with highly complex multi-axis machinery requiring precise calculation of machine tool elements in order to avoid catastrophic collisions during machining processes, making it highly desirable for CAD/CAM to offer built-in visualization capabilities.

Among these latest trends, generative design and additive manufacturing are pushing quickly to the forefront. “We continue to see more applications for additive manufacture, new materials handling capabilities, and increased machine capacity and performance,” noted Paul Brown, senior marketing director, NX Product Engineering, for Plano, Texas-based Siemens Digital Industries Software. “This in turn increases demands on CAD technologies, allowing engineers to explore new designs and embrace the power and flexibility that the new manufacturing methods afford.”

Companies are still looking to streamline their design through manufacturing cycles. There is continued interest in areas such as design for manufacturability (DFM), checking to increase confidence in the ability to make and build what is designed, noted Brown.

Taking the Generative Approach

Generative design has helped manufacturers speed up and refine the design process. It means designing parts in a more efficient manner and developing parts that are more easily manufacturable.

“With manufacturers under more pressure than ever to deliver better products faster and at lower cost, the need to connect and automate design and manufacturing processes to reduce iterations, errors, and delivery times is becoming critical,” noted Sanjay Thakore, business strategy manager, Fusion 360 Go-to-Market Strategy, for Autodesk Inc., a San Rafael, Calif.-based developer of CAD/CAM software.

“The combination of industry convergence and new manufacturing technology is creating newfound automation opportunities,” said Thakore in an interview published in the September issue of Manufacturing Engineering. “Complex design and engineering challenges can be solved at a fraction of the cost [of traditional design processes] with generative design technology as featured in Autodesk Fusion 360.”

Generative design is an exploration tool that simultaneously generates multiple CAD-ready solutions based on real-world manufacturing constraints, product performance demands and cost requirements. “Engineers can explore the design space through consideration of multiple materials and manufacturing methods and choose the option that best balances performance and cost requirements,” he said.

A generative part for a WHILL wheelchair design is shown in Fusion 360 manufacturing software, including simulation of additive toolpaths. (Provided by Autodesk)

Some companies are beginning to use generative approaches to solving design problems, noted Brown from Siemens. “This gives them more opportunity to explore alternative shapes and materials to solve a problem.” The challenge is how to integrate it into a traditional process. “With Convergent Modeling, we have the technology that allows people to use generative designs that are the result of simulation and optimizations as core modeling geometry—combining this with traditional modeling and manufacturing techniques,” said Brown.

This is further fueled by the use of additive manufacturing that allows shapes and approaches that cannot be created using traditional manufacturing techniques, such as lattice structures. These dramatically reduce component weight but maintain mechanical properties of rigidity and other factors.

“Having integrated CNC programming capabilities is critical for producing finished parts, which enables industrialization of additive manufacturing,” said Brown. “The use of these types of integrated technologies is gradually expanding from initial prototype into mass production—that is where Siemens is focused.” He said the company is looking at how it enables AM at an industrial scale, from job size 1 to 1,000.

Generative design techniques produce highly organic shapes, noted Alan Levine, managing director, Open Mind Technologies USA Inc., Needham, Mass., developer of hyperMILL CAD/CAM software. “These shapes may be manufactured with traditional milling techniques or additive techniques,” he said. “When using the additive technique, milling is commonly used as a secondary process to achieve the desired surface finish quality.”

A superior surface finish for a machined part requires precise settings in the CAM system, high-quality toolholders and accurate machine tools, according to Levine. “Most CAM systems commonly use an approximated mesh on top of the model surface topology. The advantage of this method is having a uniform calculation process regardless of how the CAD system or CAD translators define the surface entities,” said Levine. Open Mind recently added a high-precision model to machine directly to the part surfaces, improving surface quality.

Additive manufacturing modules are an option within hyperMILL CAM software. (Provided by Open Mind Technologies USA)

Additive’s Rapid Growth

New techniques for working with additive applications are rapidly growing, especially those within CAM systems for directed-energy (powder or wire) deposition, Levine added. “Some CAM vendors have addressed this market potential with a new additive strategy, or modified techniques that were applied in powder-bed systems,” Levine said. “Using the latter, the toolpath strategies are then somehow limited. Open Mind developed an additive programming process that enables nearly all milling toolpaths to be adapted for additive, and includes the extra technology required for this market. This gives users the freedom to create a programming process, including for 2D and 3D toolpath strategies, as well as five-axis control when needed.”

Additive manufacturing and hybrid manufacturing (additive and subtractive on the same machine) are growing in popularity. Why? Most additive processes for metal do not leave a suitable surface finish. Hybrid solutions enable a milled finish on the same machine and set-up that produced the additive portions.

“These machines are interesting to end users. Open Mind is active in additive manufacturing processes based on directed-energy deposition developments,” said Levine. Usage includes demonstrations with machine partners, university and research activities, he added, and also some early adopter industrial end-users that are working with additive and hybrid machining of metals.

“The additive manufacturing trend is leading us towards hybrid CAM systems,” said Chuck Mathews, executive vice president, DP Technology Corp., Camarillo, Calif., the developer of ESPRIT CAM software. “As an example, ESPRIT Additive for Direct Energy Deposition is available within the full-spectrum ESPRIT CAM system, offering programming, optimization and simulation for additive and subtractive processes in one integrated solution.”

With many “CAD for CAM” features, Mastercam makes things easy for part designers to make a part design, then quickly produce it, without hiccups. (Provided by CNC Software)

Mathews said ESPRIT’s Additive App provides programming for multi-tasking, multi-function, multi-channel, mill-turn, additive and subtractive machine tools. Additive and subtractive processes are programmed, optimized and simulated together within a single interface.

Additive techniques are finding their way into nearly every CAD/CAM product, as additive manufacturing gives users a design freedom not to be found in traditional subtractive methods.

“These new techniques have opened innovative ways of creating parts that could not be done in the past,” said Ben Mund, senior market analyst, CNC Software Inc., the Tolland, Conn.-based developer of Mastercam software. “By combining the high-precision surfaces obtained with subtractive manufacturing in process with the additive techniques, you achieve the best of both processes,” said Mund.

The CAD/CAM software needs to enable the engineer to control the additive process as much as the subtractive, with similar tools. Mund said to look for features such as support material, graded material definition, along with techniques like 3D nesting and optimized part orientation, allowing the software user to control all aspects of the manufacturing process.

“Additive manufacturing is part of our heritage at 3D Systems, and we’re seeing a lot of side-by-side and integrated additive and subtractive manufacturing in the industry,” noted Daniel Remenak, product manager–GibbsCAM, for additive machine builder 3D Systems Inc., Rock Hill, S.C. “As these workflows become more common, that’s influencing customer expectations for programming software, which needs to be able to help programmers efficiently connect these technologies. Our 3DXpert product is dedicated to primarily additive workflows, leveraging our companywide CAD experience for support and lattice generation, and our subtractive machining expertise for an advanced slicing engine and post-print machining.”

Remenak said that the GibbsCAM team has been working with CNC machine vendors and researchers on developing dedicated techniques for programming hybrid subtractive and deposition additive machines for the past few years.

Strategies for Fast Production

The “bread and butter” of machining may lie in automating frequently used functionality for shop-floor users that need fast, accurate results in order to make their parts with high quality, often in high volumes, and on time, all the time. Key to those goals are in-CAD simulations, which keep shops humming by ensuring part programs run properly, with zero costly collisions, and the somewhat more mundane realm of CAD tools that are dubbed “CAD for CAM” and give users the nuts-and-bolts options needed to make their parts quickly.

A simulation shows an eccentric turning operation in the latest GibbsCAM 13 software. (Provided by 3D Systems)

“The primary focus of every one of our CAD functions and enhancements is based on the idea of ‘CAD for CAM,’ which means getting the part ready for manufacturing,” said CNC Software’s Mund. “It is our number one goal. Whether a user has created a complex part from scratch inside of Mastercam, or they need to analyze and repair problem areas of a part generated in another CAD system, our suite of wireframe, surfacing, and solid tools are available to get everything machine-ready without delay.”

Mund said several factors influence CAD/CAM design, but most involve innovation, driving down costs, speeding time to market, and improving efficiency. “We are constantly listening to our customers’ needs regarding the parts they are working with, and the problems they may be encountering, to develop new tools to make more things possible inside of the Mastercam CAD suite of tools,” Mund said. “The quicker a user can create a new part or make edits to an imported one in support of the manufacturing process, the quicker it can be programmed and on a machine for cutting.

Speeding up time to market is key, he added. “Many adjustments can be made inside of Mastercam with our CAD tools, saving the time and expense of sending it back to the originating CAD system. In this case, we allow CAM programmers to make changes that support the machining process, whether it’s designing a fixture, building temporary in-process geometry, or repairing problems in the original CAD file.

“Efficiency means using all our tools towards the goal of getting the part ready for the machine—wireframe, surfaces, and solids all working together for that one purpose,” Mund continued. Finally, connectivity matters. “In the CAD world, this can mean reading in parts from every CAD modeler supporting industry standard formats like IGES and STEP and the common proprietary ones like SAT, DXF, DWG, X_T, and so on,”

He also believes it means that the CAD model in a Mastercam part file is associated to the CAM information; change the model and the toolpaths are aware and can be easily updated without having to start from scratch.

ESPRIT CAM software gives users a Digital Twin view of each CNC that includes factory-developed post processors designed to output machined-optimized, edit-free G-code. (Provided by DP Technology)

Other vendors take similar approaches to CAD aimed at traditional CAM users. “Open Mind has designed its hyperCAD-S foundation (within hyperMILL) to be a CAD-for-CAM module. Popular CAD systems do not always provide the best user experience for CAM users,” said Levine. “The focus in hyperCAD-S is to simplify the functions needed to drive a CAM system. Some examples are boundary selections, face extensions, and filter selections such as co-planar and co-axial, and other functions to heal and refit surfaces when needed.”

Open Mind then went further to offer pre-defined sequences of CAD utilities for the CAM user and within the CAM strategies, without the need for the underlying selections, he added.

“For example, in the mold-and-die industry, sharp edges are critical for mating core and cavity geometry to avoid flash during the molding process,” Levine stated. “To obtain a clean edge and avoid a cutter rolling over an edge, it is beneficial to extend these surfaces and guide the cutter properly on and off the part.”

The hyperMILL Z-level shape finishing module includes an automatic tangent extension to streamline this process for the user. The result is machined surfaces and edges without burdensome selections and extra steps in the CAM programming process.

For complex multi-axis machining, simulations are mandatory, and in-CAD simulations have become popular compared to some of the more expensive third-party simulations on the market. “We are continuing to see strong trends towards complex multi-tasking machines and increased use of and reliance upon machine simulation,” said GibbsCAM’s Remenak. “Machine shops are focused on acquiring software that can provide the best programming efficiency, highest on-machine productivity, and strongest validation tools with proven, reliable post-processors.”

Post-Processing Nixes Detours

Without good post-processing, or complete CAD/CAM that works with other manufacturing software solutions, users can end up with unforeseen detours. “What makes a CAM system ‘good’ in our opinion comes down to the quality of its post processor and the vendor’s technical support,” said DP Technology’s Mathews. “When programming questions are answered quickly and accurately, and the system produces good code, programming is simplified and machine utilization goes up, while both setup and cycle times drop.”

DP Technology pushes to provide the best available post processing and technical support, he contends, adding that “the ESPRIT strategy is to work closely with the machine tool builders and build a Digital Twin of each CNC that includes factory-developed post processors designed to output machined-optimized, edit-free G-code,” Mathews said. DP Technology backs up ESPRIT by providing factory-direct training and technical support to its North American customers through a dedicated team of ESPRIT application engineers.

One-Stop Shopping

Complete packages can attract users looking for one-stop shopping in CAD/CAM, combining CAD/CAM with inspection and metrology, or with PLM, ERP and MES solutions.

“One of the latest trends we are hearing from our customers and new prospects is their need for us to provide complete manufacturing solutions, rather than just CAD/CAM software,” said Nick Spurrett, regional director–Americas, Production Software, Hexagon Manufacturing Intelligence, North Kingstown, R.I. “Their requests represent everything from an MES solution to solutions that will take them all the way through to full machine-tool verification. With the addition of NCSIMUL and WORKPLAN, Hexagon Production Software is aligning our business to respond to these latest trends.”

The new EdgeCAM 2020.0 software introduces a five-axis Tilt control strategy, combined with a Barrel Cutter, for fast five-axis machining. (Provided by Hexagon Manufacturing Intelligence)

Hexagon Manufacturing Intelligence recently showcased demos of its digital production solutions that make up the Production Software portfolio, which is comprised of the several CAD/CAM titles of Vero Software, which was acquired by Hexagon a couple years ago, plus NCSIMUL, a high-end simulation and verification package, along with Hexagon’s traditional inspection solutions.

“We continue to develop all of our manufacturing products, including faster toolpath creation and providing Waveform strategies throughout the product set,” said Spurrett of the newly merged lineup. “We’re also delivering Advanced Toolform technology with the introduction of five-axis machining for any tool shape.” He noted that it allows for five-axis tool shapes such as barrels, ovals, parabolic, or any given shape, to be calculated over the part surfaces, including negative offsets (allowances).

“Design for manufacturing is one of the key solutions that we have launched over the last 12 months,” Spurrett added. “We are providing a CAD for CAM, or CAD for Machine Shops, solution for companies that want to take advantage of the CAD data they receive—or to work in a CAD environment that a machine shop, or a CNC programmer, can leverage because it provides the type of functionality they need specifically to do manufacturing. Using direct modeling allows the user to directly modify the geometry by pushing or pulling pieces of the model as the user sees fit.”

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