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Compressing the Moldmaking Design and Production Process

Pat Waurzyniak
By Patrick Waurzyniak Contributing Editor, SME Media

With the latest CAD/CAM and CAE software, moldmakers can greatly speed up design and compress the manufacturing cycle for high-quality molds and die

Moldmakers are under constant pressure to speed up the moldmaking process, improving their processes and product quality while boosting productivity. To meet their goals, moldmakers employ the latest moldmaking software, leveraging new techniques in CAD/CAM and CAE, with vastly improved simulations for conformal cooling and other key features in mold-and-die manufacturing.

Applications used in mold-and-die processes range from CAD/CAM software from most major software developers as well as sophisticated CAE software offering detailed simulations and analyses of a product’s fit-and-finish, thermal performance and key differentiating factors. Among these moldmaking packages are integrated packages that allow running inside the designer’s main CAD/CAM software, enabling easy transitions from design to simulation and analysis of a part’s potential.

Make It Fast and Accurate

Moldmakers’ primary software requirements have remained consistent over the last few years, focusing mainly on higher productivity, noted Ben Mund, senior market analyst, CNC Software Inc. (Tolland, CT), developer of Mastercam CAD/CAM software. “That need extends through the entire process, driving the trends we see in CAD/CAM software development—faster on the machine, faster off the machine, and quality that is as high as possible.

“Another growing trend is connectivity in manufacturing—making sure that software, machines, and shop floor processes all talk to one another,” Mund said. “With CAM, you’ll see that with connections to tooling libraries, inspection, shop monitoring, and other items. It’s all part of making sure shops are ready for the shift to digital manufacturing.”

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Properly programmed, specialty tools like this taper mill can use a large effective cutting radius, delivering faster cut time and a better finish.
Image courtesy CNC Software Inc.

Key to the productivity quest is an efficient CAD/CAM system, Mund said, one that offers users a plethora of tools to do the job fast and easily. “It starts with CAD; shops have an increasing need for specialty CAD tools that help them turn a concept or part model into a production mold,” Mund stated. “This means design tools for model prep, solid model repair, gap filling, fixture creation, and highly focused needs like electrodes, core/cavity model separation, and parting line creation—all things that should happen before a tool even touches metal.”

Once the stock is on the machine, shops continue an aggressive push for faster cycle times, he added. “One of the biggest areas moldmakers look at is the most efficient way to remove bulk material to near-net shape. Advances in ‘smart’ roughing toolpaths continue to dramatically drive down machining time. Of course, the precision and quality of the final mold is what matters most, and here shops are looking more closely at not just new toolpath motion, but new tools, all of which need to be supported by their programming software.”

Features like CNC Software’s “CAD for CAM” prep tools continue to be a focus, Mund said, and the company will have new tools in its upcoming Mastercam release for helping moldmakers quickly and cleanly fix models, patch holes, and correct errors in CAD models they’re given. “These problems can cause long delays and minimizing them helps ensure the mold can get on the machine as quickly as possible.”

In addition to Mastercam’s Dynamic Motion engine, the software also has a new NC programming technique called Accelerated Finishing, Mund added. “It lets shops use new shaped tools in the way they’re intended. We work closely with tool manufacturers in developing cut strategies aimed at oval form cutters, barrel mills, taper cutters, lens-shaped cutters, etc.,” he said. “When programmed correctly, these cutters can allow a small-diameter tool to have a large effective cutting radius, which can reduce cycle time, increase surface finish, or both.”

Finding Easier, Smarter Solutions

Software ease of use ranks at the top among mold designers and builders, said Anthony Yang, president and co-founder of CoreTech System Co. Ltd. (Farmington Hills, MI, and Hsinchu, Taiwan), developer of the Moldex3D CAE suite of moldmaking simulation applications.

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Faurecia applied CoreTech’s Moldex3D eDesign CAE software package for an automotive interior mold application, shown here with CAE overlay on car dashboard. (Below) The software’s warpage prediction gave designers reliable data to reduce gaps and improve flush tolerances on the components.
Images courtesy CoreTech System Co. Ltd.

Features like conformal cooling make the plastic injection molding manufacturing process easier and more efficient, but users are after software that’s far easier to use, Yang noted. “The current trend is toward upfront simulations with DFM [Design for Manufacturability],” he added, “and another main trend is to make the software smarter.”

Today’s software enables users to more easily set up boundary conditions and create a mesh, he said. “You simulate how the mold reacts and you must specify where the heat is coming from. It’s not easy to design.” The easier the software is to use, the better for moldmakers, who are looking for better user interfaces that allow faster, more efficient mold design processes.

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CoreTech’s Moldex3D software is primarily used in engineering departments but also by part designers. The Moldex3D software is integrated with software like NX Mold from Siemens PLM and the company also works with the offerings of major developers such as Dassault Systèmes’ Solidworks and PTC’s Creo CAD/CAM software.

At Faurecia Interior Systems India Pvt. Ltd. (Pune, India), the automotive seating and interiors design used Moldex3D simulations to reduce plastic-injection-molded interior parts’ warpage to improve dimensional precision. The company used the software on one dashboard center console fascia with results that included: avoiding weld lines in visible areas; reducing part deflection to keep the gap and flush well maintained within the tolerance for the part assembly; a 68% reduction in tool tuning cost; and lowering a traditionally high scrap rate to a negligible number. This was enabled in part by Moldex3D’s warpage prediction simulations.

Complexity Drives Processes

As tooling for complex products has increased, mold-and-die shops, along with other manufacturers, are turning toward advanced manufacturing processes. “Automation and integration are enablers for our customers to make tooling improvements, with tool design workflow optimization and validation tools to make products more accurate,” noted Himanshu Iyer, NX product marketing manager, Siemens PLM Software (Plano, TX). Paramount for manufacturers, he said, is “making sure that errors, if any, are captured as early as possible in the design cycle. We all know how expensive it is to deal with those later on in the process, and we have to make the process more efficient.”

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The many levels of a mold are shown in this NX mold assembly simulation from Siemens PLM Software. The latest NX offers new tools for moldmakers, including conformal cooling techniques and mesh capabilities.
Image courtesy Siemens PLM Software

Poor communication between OEMs and suppliers often causes pain down the line in product development. “One of the issues is involving customers early in the design phase,” noted Daks Azhagappan, product manager for NX Mold Wizard. “You have to look at all of the manufacturability issues. It costs them time and money unless they work very closely. A lot of our customers, most of the tool shops, ask how do I work with OEMs early on?”

Using CAE tools in NX, powered by the Moldex3D engine, users can improve meshes to gain better overall designs. “One thing in the past was to go through tryouts,” Azhagappan said. “A problem they face is warpage. One thing is to come back into the design and change the cooling. Then they may say ‘how can I compensate for the warpage?’” The mesh transformer added to NX 10 enables users to optimize meshes and bring that information into their CAD environment.

The latest tools allow users to do mesh transformations in two stages, in the design stage and in the CAE software, he noted. With the Moldex3D moldflow analysis, “we have a lot of [those] capabilities integrated into NX,” Azhagappan added.

Faster machining techniques in NX CAM also play a huge role in boosting moldmaking productivity and achieving faster machining times with high-speed technology, noted Sashko Kurciski, Siemens product marketing manager, manufacturing solutions and NX CAM. “We’re reducing machining times by 60% in some cases,” he said. “It can [also] extend tool life by four times.”

With the latest NX 12 CAM, Siemens has added an internally developed high-speed roughing strategy that uses component technology. “It’s a new technology for us that’s similar to Volumill but in some cases is better,” Kurciski said. “It’s not an add-on.”

Additive technology is another important factor. “It will have several impacts on the tool industry, in our opinion. One of those areas is conformal cooling,” Iyer said. “With additive techniques, we see customers already thinking about things differently.”

With hybrid subtractive/additive machines in the market, the advantage is being able to automate processes on either side of the machine and between those sides, Kurciski said. A shop can build a mold with the additive side with internal cooling channels, and then “you can use the same machine to achieve the high quality surfaces they need for molds.”

Speeding Machining, Adding AM

Machining faster is key for moldmakers, and CAD/CAM developers offer multiple ways to get there. “It’s no major revelation that moldmakers are under as much pressure today as they’ve ever been,” noted Clinton Perry, product marketing manager for PowerMill at Autodesk Inc. (San Rafael, CA). “They face the daily challenge of meeting customer expectations: reducing delivery times, maintaining or improving part quality and minimizing costs, all to offer a [high] level of customer service. At the same time, moldmakers have to keep an eye on the types of emerging tech that could give them a competitive edge.”

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An Autodesk Moldflow simulation shows the conforming helical cooling in a water pump housing component. Autodesk has added access to over 10,000 materials in the public material database, providing users the ability to see the impact on their final part shape and manufacturability.
Image courtesy Autodesk Inc.

To meet these demands, moldmakers need software that rapidly converts customer designs into high quality tooling. “Speed is undoubtedly the number one challenge here. CAD/CAM/CAE software needs to streamline the whole design, simulation and manufacturing workflow to shorten overall time to market,” Perry said. “Improvements in hardware capability have certainly helped—such as 64-bit processors, multicores and cloud computing—but there’s something more fundamental. Autodesk and other software companies continue to develop modeling tools that help import customer models and rapidly convert them into usable tooling. This process often requires a degree of model repair work to fix faults in imported data.”

CAD modeling products, such as Autodesk PowerShape, offer tools to prevent repairs from causing delays, he added. The most capable modeling software can analyze imported CAD files to identify and (automatically) fix problems that could complicate downstream manufacturing, Perry said, and surface, solid and direct modeling tools allow moldmakers to then rapidly convert customer designs into tooling.

Another major trend is physics-based simulation, said Mark Hennebique, Autodesk simulation business line manager. Simulation allows designs to be “signed-off” before a block of steel has been machined.

Simulation software like Autodesk Moldflow’s analytical tools can be used in the development process to help optimize the manufacturability of the part design and the performance of the mold tooling at an early design stage, Hennebique said. “Simulation allows multiple designs to be tried and tested, with rapid feedback to confirm the impact on molding cycle and part quality. Variables such as gate position, wall thickness, molding process, cooling circuit design, and material properties can all be modified with rapid feedback to build confidence that the mold will deliver expected results on the first molding cycle.”

In the latest Moldflow release, users now have access to over 10,000 materials in the public material database, he said. “With access to more materials, users will be able to see the impact of the manufacturing process on final part shape and manufacturability, giving them the ability to choose the right process/material combination in order to meet the project needs. Users will also see other performance improvements, ranging from solver speed to operational speed, making it even easier to move toward a solution.” Additionally, Moldflow will ship with Autodesk Fusion 360, providing users with access to improved interoperability and CAD/CAE capability to iterate on designs and share data, among other benefits.

The emergence of 3D printing as a manufacturing tool offers moldmakers the opportunity to change how molds are designed and made, Perry added. “One great example sees 3D printing being used to design molds that include cooling circuits that more closely follow the forms being molded. These conformal cooling circuits allow molding cycle times to be slashed.” Moldmakers like Fado, Perry said, now use Autodesk design and manufacturing software to add conformal cooling to an increasing number of their molds.

New Mold Module

Another new update from Vero Software is the VISI 2018 R1 that introduces a new Mold Tool module based on VISI’s Assembly-Ng technology. This redeveloped module provides greater flexibility when constructing supplier and non-standard tool configurations. Customizable templates, including the management of blank and predrilled plates, allow for easy tool layout creation and enhanced editing at any design stage.

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The updated VISI 2018 R1 update from Vero Software features enhancements that include a plastic flow warpage prediction module that helps moldmakers improve accuracy and speed performance with reduced calculation times.
Image courtesy Vero Software

“The new Mold Tool provides a greater level of flexibility for both tool creation and advanced editing. This allows for adjustments at any stage of tool design. All assembly components are automatically updated when plate adjustments are made, including component cavity manufacturing data,” said Marco Cafasso, Vero’s VISI product manager.

Enhancements have been made within the plastic flow warpage prediction module to improve result accuracy for complex technical polymers. These improvements have been achieved by a complete revision of the algorithms for the holding phase, the company said. Pressure and flow rate calculation adjustments, combined with the new shape solver, can reduce calculation times for the process by up to 40%.

Verifying Simulations

Mold designers have tight tolerances, so preventing small errors and gouges are important, noted Gene Granata, Vericut product manager for CGTech (Irvine, CA). “Mold programs are typically many and large, so offline verification is key for keeping machines running. Users can run simulations in batch process to ensure [all of] the NC programs will create the final mold that you expect them to. Also, with more manufacturing methods available to create molds [machining, AM, EDM die sinking, etc.], simulation software can provide valuable information to help shops predict manufacturing times and maintain optimal production rates.”

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Planar roughing by an insert end mill, machining an automotive body panel mold made from D2 steel, in CGTech’s Vericut software. Force optimization in Vericut reduced machine time for this tool by 24%, seen in bar graphs and force charts, showing original versus optimized data. Spikes in force have been corrected and optimized feed rates maintain a more consistent maximum chip thickness for time savings, extended tool life, and better part finishes. Image courtesy CGTech

Compressed time schedules mean moldmakers are looking for ways to work leaner and faster, he added. “Vericut Force is a physics-based NC program module that micro-analyzes cutting conditions and optimizes program feed rates to achieve ideal chip thicknesses, but without exceeding the tool’s force limits or the machine’s spindle power. Force optimization creates the most effective NC program possible for a given cutting tool, stock material, and machining conditions. The result is significant time savings, higher quality parts with better surface finishes, and improved cutting tool and machine life,” he said.

The interest in AM among moldmakers is keen, Granata noted, and the new Vericut Additive Module simulates both additive material deposition and traditional machining capabilities on new hybrid CNC machines. “AM on hybrid machines can make building certain precision molds, and mold repairs, easier and faster. And with additive programming software becoming more capable, we are seeing a new trend: the desire to simulate any manufacturing process, in any order, to obtain the confidence [they will] make the final part that was intended,” Granata said. “Users rely on our software to ensure all NC programs will run correctly, and optimally, on their CNC machines. To do the best job, users [should] choose simulation software that is driven by the same NC code that will drive the machine, thereby ensuring the highest level of verification possible.”

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