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 PC-based CAM systems getting strong reviews Following are highlights from three of the latest product reviews from CIMdata Inc, Ann Arbor, MI. Complete copies of these reviews can be ordered from CIMdata Inc, 3909 Research Pk Dr, Ann Arbor, MI, 48108; phone 313-668-9922; fax 313-668-1957; http://www.cimdata.com Bravo CAD/CAM From Applicon Inc, Ann Arbor, MI, comes Bravo CAD/CAM, which has applications
currently available on multiple platforms, including Windows 95/98 and NT,
Digital Alpha AXP/Open VMS, and Hewlett-Packard/HP-UX. Associativity between
design and manufacturing is provided in Bravo CAM. It is a core element
in the Applicon architecture. With a change in geometry that does not involve
a process change, the toolpath can be automatically regenerated. Bravo CAD/CAM from Applicon Inc, allows associativity between design and manufacturing. BravoIGES supports Bravo design and manufacturing applications. All files, other than ACIS-based SATfiles, are received in BravoDesigner. BravoNCG and BravoNC directly access the BravoDesigner database for subsequent toolpath generation. Full IGES is supported in BravoDesigner, but "flavored" or product-specific IGES translators are not available. Applicon is making effective use of Internet technology; the company currently utilizes the Internet to electronically distribute early versions of the software, make new versions available for downloading, distribute post-processors, and electronically transfer files as appropriate for product support. Applicon provides BravoSolids, an integrated surface modeler for manufacturing modeling built on the ACIS kernel. It is used to create, import, and modify solid and surface models. ACIS algorithms are utilized for blending, shelling, nonuniform scaling such as that required for computing shrinkage in mold design, and for Boolean operations such as unite, subtract, and intersect. A NURBS surface modeler is embedded in BravoSolids. The surface creation capability is competitive with that in other CAM-centric modeling products. Machining of prismatic and round parts is accomplished in BravoNCG. It includes turning, milling, drilling, and general purpose 21/2 axis machining. In BravoNCG, a toolpath can be placed directly on a solid model. Machining operations and tools are listed in the Operations Manager. Z-level or waterline roughing, a commonly used roughing technique, is not currently available in BravoNCG. BravoNCG includes an industry-leading lathe package with capabilities available for 2-axis turning, 4-axis turning, and mill-turning. BravoNCG also supports lathes with multiple turrets and spindles. BravoEDM is an interactive, menu-based application for programming wire electrical discharge machines. It includes a basic 2-axis and 4-axis wire EDM capability. Bravo Sheet Metal Designer and BravoFAB are newly released products for design and manufacturing of sheetmetal parts. For a tool library, the user either defines a cutting tool as the situation requires or uses the BravoTDM (Tool Data Management) System. At the physical level, shopfloor tool management is provided. An on-line crib inventory and actual tool location can be established and monitored. In addition, BravoTDM can be employed as a purchasing module since supplier lists, costs, and all other required information are available. BravoNC provides drilling and multiaxis surface machining. BravoNC now supports flowline machining with untrimmed surface, but not trimmed surfaces. Stepover control in BravoNC is competitive with industry standards. Remachining of material left behind from a larger tool has evolved as a critical requirement for complex multisurface machining of molds and dies. BravoNC supports 4- and 5-axis positioning with 3-axis milling. Since Applicon is not focused on the mold and die market, it is not currently implementing algorithm changes to support high speed machining. BravoVerify simulates the material removal process for CNC programs created using Bravo manufacturing applications or for those imported from third-party solutions. Toolpath verification is performed on the same G codes that will be the input to a machine tool controller. BravoCMM is an interactive menu-based application for programming coordinate measuring machines (CMMs) for dimensional inspection. Applicon is one of the relatively few vendors to provide software to support these machines, as most CAM-centric vendors do not offer this capability. Applicon Inc, Ann Arbor, MI, http://www.applicon.com or circle 381
CATIA Mfg IBM/Dassault, Dallas, TX, has become a major force in the NC software
market. CATIA is evolving from Ver 4 to Ver 5, which is Windows NT-based
and supports the concept of a single design and manufacturing model, and
data associativity between design and manufacturing. CATIA supports IGES
and VDA-FS. When surfaces are received, they are usually maintained as a
surface. They could be converted to a solid, but the geometry does not normally
support the transformation. However, since IBM/Dassault usually provides
an enterprise-wide CAD/CAM capability to large manufacturers, most CATIA
MFG users machine models generated in CATIA. CATIA Version 5, gives customers a real choice. The delivery of the Windows NT-style user interface on UNIX helps to keep user productivity high on either platform. IBM/Dassault is making effective use of Internet and Web technology. The CATWeb Navigator serves as an interface to the Web. It operates in a Java-based Windows environment. CATIA documentation is generated in HTML format allowing the user to place a model on a web site and allow access from any location. Advanced Design and Drafting (ADD) is the standard CATIA product for product design and manufacturing modeling. The use of surface models remains the most common mode to define geometrically complex objects such as car bodies and aerospace structures. CATIA surfaces can be blended together with a given continuity. A manufacturing infrastructure product (NC Base or NCB) is the core component upon which CATIA's manufacturing applications are built. It includes the user interface, manages databases, loads applications, provides for integration of applications, permits the user to move from one application to another, and replays the toolpath. Prismatic Machining Programmer (PMP) and Prismatic Machining Assistant (PMA) are the primary CATIA products for 2- and 21/2 axis milling and drilling of prismatic parts. PMP and PMA are integrated applications, with PMA being based on PMP. PMA is a feature-based application. 2.5D and 3D features can be intermixed plus compound and wireframe features are supported. In addition, user-defined features can be generated. If CATIA design features are not employed, which is a typical scenario, the feature recognition capability in MFGView searches the B-rep model to identify features. In CATIA Mfg, the user has the option of interactively generating the toolpaths, generating them one at a time, or selecting and batching files for subsequent or nighttime processing. In pocketing, using either PMP or PMA, there are no limits on the number of islands in a pocket. In turning, CATIA Mfg is undergoing a transition. NC Lathe is being phased out and Lathe Machining Programmer (LMP) was introduced in Ver 4.2.0 and is dedicated to turned parts. LMP supports both solid and wireframe geometry. Surface Machining Programmer (SMP) and Mold and Die Machining Assistant (MAD) are the primary CATIA Mfg products for 3-axis multisurface milling. SMP provides a traditional interactive approach to 3-axis multisurface milling. MAD is a semiautomatic, process-oriented machining technique that offers an adaptive approach to knowledge-based machining. A variety of roughing strategies are available in SMP and MAD. Automatic remachining of material left behind is becoming a critical function in mold and die machining. Remachining was recently introduced in MAD, but is not offered in SMP. Multi-Axis Machining Programmer (MMP) supports machining on solid, surface, and wireframe CATIA models or a combination thereof. Multisurface machining is now supported and there are no limits on the number of surfaces that can be machined in a single operation. Dassault offers three options for toolpath verification. They are NC Verify, an integrated verification capability available within CATIA Mfg to interactively replay a toolpath; Vericut, a third-party product from CG Tech, and Virtual NC from Deneb. For a quality simulation, a user must use either Vericut or Virtual NC. IBM/Dassault, Dallas, TX, http://www.catia.ibm.com or circle 382
Virtual Gibbs Gibbs & Associates, Moorpark, CA, offers Virtual Gibbs CAM system which is available under Windows 95, 98, and NT with Windows NT being supported on either PC-based hardware platforms or workstations. Associativity is provided in Virtual Gibbs. Gibbs is in a strong position to receive files generated in third-party design systems. Since Gibbs licenses both Parasolid and ACIS, X_T and SAT files generated by CAD systems using these kernels can be directly accessed by SolidSurfacer. This avoids file translations. When design data is being received from an ACIS-based system, it is first converted to Parasolid format and then brought into Virtual Gibbs. The models can be maintained and machined as a solid for machining. Gibbs is making effective use of Internet technology. It currently electronically
distributes early versions of the software, makes new versions available
for downloading, distributes postprocessors electronically, and electronically
transfers files as appropriate for product support. Gibbs does not yet provide
Help functions in HTML format so that they can be accessed over the web. The SolidSurfacer module in Virtual Gibbs CAM has the ability to analyze, identify, and fix problems with imported IGES files. A wireframe geometry creation capability is included in all modules of Virtual Gibbs. A Geometry Expert option is provided for family-of-parts programming. It presents a spreadsheet of geometric data to the programmer. Changing values in the table changes the geometry. Gibbs has adopted a distinctive approach to solid modeling. While most CAM-centric vendors are embedding their product within specific midrange CAD products such as SolidWorks or Autodesk Mechanical Desktop, Gibbs has elected to follow an independent path. By licensing both Parasolid and ACIS, it provides direct interfaces to Parasolid-based products. SolidSurfacer CAD is provided to create, import, and modify solid and surface models. The Solid Surfacer user has the option of working with solid or surface models. On a given component, the user can work in either solid or surface mode or both. For moldmaking operations, parting lines are automatically determined on solid models. Blending of any number of surfaces or faces is supported. The Virtual Gibbs basic machining products are Production Mill, Advanced Mill, and Production Lathe. Production Mill supports 21/2-axis and single surface 3-axis machining of wireframe geometry. SolidSurfacer CAM can also be employed to provide 21/2-axis machining of solid components and the toolpath can be placed directly on a solid model. Gibbs does not provides a standard tool or material library. Instead, it offers the industry accepted Cutdata machining libraries from IAMS as an optional third-party product. Machining parameters are established within the Virtual Gibbs Operations Manager. Virtual Gibbs Production Turning is one of the industry-leading lathe packages. All basic turning functions are provided. The modeling capability is the same as that in Production Milling. Associativity between the geometry and the toolpath is provided. A mill-turn option is provided. Stepover control in SolidSurfacer CAM is based on either movement of the tool by a constant distance as measured on a plane, or control by setting a maximum scallop height to be left after machining. In collision avoidance, Virtual Gibbs considers the full geometry of the cutting tool. Since Gibbs is not focused on the mold and die market, it is not on the forefront in implementing algorithms to support high speed machining. Unlike most vendors that utilize a third-party product for toolpath verification, Gibbs has internally developed a verification product capability for each machining module. By so doing, Gibbs is able to offer integrated machining and verification. The Cut Part Rendering function provides industry competitive toolpath simulation and verification. Gibbs & Associates, Moorpark, CA, http://www.gibbs.com or circle 383 Originally published in the March 1999 issue |
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