Virtually Competitive For

FEBRUARY 2004 / VOLUME 56 / NUMBER 2 focus: moldmaking BY BILL KENNEDY, CONTRIBUTING EDITOR Advanced software gives Virtually moldmakers a boost. Competitive roducing injection molds is chal- After the customer pro- lenging. A typical mold is a com- vides a 3-D model of the part, Pplex structure made up of a highly the moldmaker uses CAD contoured core and cavity housed in an software to create the mold intricate mold base, gate and hot-runner core and cavity, as well as the system. Moreover, since one mold often mold base and the mechani- constitutes a “run,” there is no room for cal components required to trial and error. operate the mold and trans- Key to moldmaking survival and suc- port the plastic into it. CAM cess is application of technologies that software generates toolpaths permit maximum utilization of employ- for machining the cavity and ees and resources. Such technologies mold components, as well as include advanced machine tools and the toolpaths for cutting the part-handling equipment that permit electrodes needed to electri- unattended operation, and cutting tools cal discharge machine fine that facilitate high-speed machining. mold details. Another major contributor to com- Challenges often appear petitiveness is moldmaking software. It immediately. Designers may augments the mold-design phase, facil- conceive of parts that would itates the automation and optimization be expensive—or even impos- of machining processes, and enables sible—to mold. A certain fea- the user to simulate and verify mold ture, for example, may pre- manufacture and operation. vent a part from being re- moved from a mold. Design Development Matt Wallace, owner of Ac- Mold design begins with designing celerated Mold Technologies, the part that the mold will eventually Monroe, N.C., makes molds Delcam form. Today, part design usually exists for inventors and entrepre- Five-axis machining of an automotive bumper mold is electronically as a 3-D CAD model. neurs who want to bring new accomplished with toolpaths created in Delcam’s John Callen, vice president of mar- products to market. Often, he PowerMILL CAM software. keting at CAM software developer Gibbs said, “we wind up doing pro- and Associates, Moorpark, Calif., said duct development before we go into the model from a customer’s design sys- most moldmakers “couldn’t imagine actual mold design. We [can keep] the tem and, if necessary, alter it. The more creating the parts they make outside of cost down on the mold by designing a direct the path from the customer’s a digital environment, and many can’t part that is manufacturable.” model to the moldmaker’s software conceive of doing the parts without This is achieved with software that package the better. It’s possible to con- using 3-D solid models.” allows a moldmaker to import a CAD vert models into the least-common- denominator IGES file when transfer- SURFCAM [to program toolpaths]. If Delcam offers a “Power Solution” ring data between software packages, I make a revision in the part, add a boss package that includes PowerSHAPE but some information may be lost. Ac- or something, it is updated in my mold CAD and PowerMILL CAM software. cordingly, software programs include design. But when I go to [revise] the The package enables direct data import direct translators that are capable of program for machining, I have to ex- from design systems, including reading proprietary CAD-data formats, port it again and import all the infor- CATIA, UG, Pro/E and SDRC. Within circumventing the need for a shop to mation. It’s almost like starting over.” PowerSHAPE are tools designed to buy a copy of the exact CAD program As a result, Wallace is looking to correct any problems with the part de- that produced the data. move to a single “fully associative” sign and modify features in order to fa- To further facilitate direct transla- software package, in which changes in cilitate efficient mold production. tions, CAM packages are starting to the part model are reflected automati- Delcam’s PS-Moldmaker incorpo- come with plug-ins for transferring cally in the CAM toolpaths. rates DieWizard, which automatically CAD data. For example, to enable the Peter Dickin, marketing manager for designs the core and cavity halves of a exchange of design data from main- software provider Delcam International mold, the mold base and other compo- stream, PC-based CAD systems, Gibbs Inc., Windsor, Ontario, agrees that nents. Data on specific mold features and Associates’ GibbsCAM software across-the-board integration is desirable. can also be extracted and used to de- features custom plug-ins for popular He warned, though, against assum- sign EDM electrodes. CAD systems, including Autodesk In- ing that associativity always exists be- At Concept Models Inc., a shop in ventor, Mechanical Desktop, Solid tween a design and machine toolpaths. Livermore, Calif., owner Bob Hallock Edge and SolidWorks. The plug-ins “Automatic associativity will probably produces molds and prototype parts. allow users to seamlessly transfer de- give the correct result for simple geo- He said he brings customer files into signs from their CAD systems directly metric changes, such as moving the po- PowerSHAPE to modify them for ma- into GibbsCAM for programming. sition of a hole in a plate,” he said. chining. “I look at the part’s design and Translation between a moldmaker’s “However, when making any changes things like moldability and wall thick- internal CAD and CAM software can to the core or cavity surface, it is dan- ness,” he said. “If you don’t have a con- also be an issue. For mold design, Wal- gerous to rely on an automated regen- stant wall, you could have sink.” A per- lace said he uses Unigraphic’s Mold- eration of the toolpath. Particularly fect IGES file, he continued, can “go Wizard software, while one of his col- with larger molds, there will usually be right into the CAM program, but if you leagues prefers CADKEY. “I have to a need to change the size of the cutter need to create any kind of geometry, export from the CAD software in an or the strategy to be used to give the it’s easier to do that in PowerSHAPE.” IGES, DXF, Parasolid or STEP file,” most efficient machining. Associative When it is ready to cut, he moves the Wallace said, “then pull it into my systems will not make these changes.” CAD file into the CAM program. “Any- thing you do in PowerSHAPE can be sent over to PowerMILL for toolpath generation by selecting it and then clicking on the PowerMILL icon,” he said. Dickin said an important trend in mold design is the move to designing entirely with 3-D models rather than using 3-D just for the core and cavity and making 2-D drawings for the rest of the tool. “Moving to 3-D design offers some time savings in the creation of the mold design, and even more significant im- provements can be made through elim- inating mistakes, and therefore rework time and costs, during both design and manufacture,” he said. Dickin added that performing all design work in 3-D also enables a mold to be designed in its entirety by one group Accelerated Mold Technologies Mold Accelerated or one individual in an organization, Matt Wallace of Accelerated Mold Technologies designed this mold for a police hel- saving time and reducing the chances met chin guard with Unigraphic software, using a standard mold base from D-M-E for error. Co.’s CAD files. Regarding the actual machining of the mold, Dickin said the small lot sizes typical of mold manufacturing put pressure on moldmakers to pro- Color-coded gram toolpaths correctly. “Many molds simulations enable are ‘one-offs,’ so they must be right the users of Part first time,” he said. Adviser software The machining part of the software to determine the must, therefore, have the ability to manufacturability of quickly compare the different machin- plastic part designs ing strategies that could be used, so early in the that the most efficient combination is design process. selected. Even more important is elim- inating the possibility of the mold being gouged. In a production run, Moldflow gouges only affect the first of many tooling cost.” Simulations allow a man- enough, very small percentages in cycle parts (assuming that the operator no- ufacturer to determine a product’s man- time savings or material savings can tices and stops the machine). In mold- ufacturability and, thereby, its cost, and add up to tens, or hundreds, of thou- making, a gouge during the finishing “reduce risk by being fairly certain that sands of dollars a year.” of the mold can lead to many weeks of the investment in tooling is going to Conveniently, Moldflow software work being scrapped. provide a payback,” he said. works directly with the user’s 3-D solid Moldflow Corp., Wayland, Mass., model program. Other simulation soft- Automation and Simulation offers software that simulates the flow ware requires the 3-D model to be Increasingly, mold-design software is of plastic into a mold. Peter Rucinski, translated into an FEA (finite element incorporating automation-related func- the company’s director of product mar- analysis) mesh model, a process that tions, including basic core and cavity keting, said, “You want to run these can take days or weeks. creation, selection of the mold block simulations before you cut the steel.” For infrequent and first-time users, and choosing the requisite mechanical Moldflow’s Part Adviser software is Moldflow offers an Internet-enabled components from suppliers’ catalog its most basic simulation tool.

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