CIMdata Reviews Unigraphics CAM Version 16
By Alan Christman, VP, CIMdata Inc.
Table of Contents
Business segments
Product capability
Operating environment
Data translation emphasized
Manufacturing modeling
Basic machining
Machining supported
3-to 5-axis contour milling
Toolpath verification
The Unigraphics Solutions CAM strategy and the knowledge-based manufacturing approach being implemented in v. 16 is based on embedded architectural change that positions Unigraphics CAM for future growth. A major paradigm shift occurred in Unigraphics v. 16. The result is a CAM software program that is structured, powerful, and comprehensive. CIMdata expects Unigraphics to remain a NC software leader in the year 2000 and beyond.
Unigraphics is developing a process-oriented solution that will encompass all CAM functions from receipt of design data to shopfloor operations. In many respects, it can be viewed as a next generation CAM system. A concept recently introduced by Unigraphics, Predictive Engineering incorporates engineering practice and product life cycle knowledge into the product development environment and provides the umbrella framework for the new UG CAM.
Unigraphics v. 16 employs greater application integration, more automated techniques, and a higher level of process-oriented programming. Knowledge-based manufacturing is at its core. It provides:
• Ability to define and manage the entire machining processes not just NC operations
• Standardization and programming automation through the use of predefined templates and process assistants
• Integrated toolpath generation, verification, and post-processing
• New computational processors for toolpath generation
• New user interface and a new platform for manufacturing automation
Business segments
Unigraphics Solutions is organized by line of business, with CAM being one of the designated business areas. As such, UG has a group assigned to manage, plan, develop and market CM applications. Within CAM, Unigraphics is focused on three specific market segments: die and mold, machinery, and advanced machining.
Each market segment has a distinct application focus. The die and mold emphasis is on 3-axis milling. The machinery segment supports primarily production machining with a focus on turning and 2-axis milling. Simultaneous 5-axis machining is the core operation in advanced machining, a segment that encompasses aerospace, blade manufacturing, tire mold production, and other specific applications areas in which either the part geometry or machine tools employed are particularly complex.
Product capability
UG CAM offers a wide range of product capability including 2- to 5-axis milling, turning, EDM, and support of sheet metal operations. Within each product, UG users are offered the flexibility to perform almost any machining task. This range of offering and product depth is a traditional strength of UG CAM.
Options are available for traditional off-line CAM room programming and for on-line shopfloor programming packages within the die and mold and machinery segments. The shopfloor packages are more automated than traditional software. Users are led through the process, and programming options are restricted. A shopfloor programming package is not yet available for advanced machining.
CIMdata believes that the Unigraphics' areas of relative product weakness in CAM include limitations in advanced turning capability, remachining of material left behind, and options provided for stepover control. Unigraphics v. 16 is probably most appropriate for experienced users as the product's complexity is adversely impacted by the wide range of options available.
Operating environment
The Unigraphics Solutions strategy is to provide a single integrated design and manufacturing solution, as opposed to a collection of applications. All applications employ a common user interface, which UGS has introduced in v. 16. It is modern and fully Windows-compliant and can be relatively complex to use because of its CAM depth. It runs under Windows NT and all major Unix platforms. The user interface under Unix has been modified to have the look and feel of Windows NT and is very iconic. On an NT platform, UG leverages Windows menus and dialogs for standard functions such as printing, file management, color design, and entity selection, as well as providing Explorer-like navigation capabilities.
UG supports the concept of a single design and manufacturing model, full parametric capability, and data associativity between design and manufacturing. These concepts have become increasingly important in CAM. With associativity, a toolpath can be regenerated for an entire body without reselecting geometry when changes to the design have been made. Family of parts machining can be performed.
In manufacturing production operations, it is often desirable to modify the user interface, optimize a process by reducing the number of operations, and/or alter tool movement in order to take time out of the process. Large UGS customers typically customize the software to obtain greater production efficiencies. Customization is now accomplished in UG/Open (User Function), a new C++ customization language.
Data translation emphasized
UGS places considerable emphasis on data translation. Extensive capabilities to interface to third-party design systems are provided, and data transfers can be made in either a solid or a surface format. For Parasolid-based systems like UG, a solid model can be read directly. In this case, associativity is maintained with the transfer. Direct translators are available to read ACIS and CATIA files. Unigraphics is a strong supporter of the STEP initiative for data exchange. V. 16 is STEP compliant. Currently, STEP AP203 and AP214 formats are supported.
UGS is making effective use of Internet and Web technology. Documentation is generated in HTML format, permitting the user to place a model on a website and allow access from any location. Web access in UGS is primarily intended for process planners and other programmers. It can also be used as a vehicle to provide part program documentation to the shopfloor, as well as support manufacturing up and down the supply chain.
Unigraphics software often operates in a network environment. In this mode, UG users utilize or have access to all applications. UGS supports floating licenses for operation on a network. The number of concurrent users at any point in time is measured and controlled. Although this feature is common among CAD/CAM vendors, it is not common with CAM-centric vendors that usually license software to a specific processor.
Manufacturing modeling
CIMdata views manufacturing modeling as being distinct from product design. In manufacturing modeling, software is used to:
• correct geometry received from third-party design systems
Most CAM-centric software systems include manufacturing modeling functionality to satisfy these requirements. In the case of Unigraphics Solutions, the full UG design and drafting products can be employed. As such UGS usually has feature advantage over manufacturing modeling systems provided by CAM-centric vendors. However, in some cases, it can be overkill for the requirement. UGS supports more than one form of geometry. UGS offers users an option of modeling in an integrated wireframe, surface, or solid mode. If a solid model is defined, surfaces can be extracted. If a surface model is generated, a thickness can be added to eliminate ambiguities.
For mold design UGS introduced MoldWizard in mid-1999. It provides for automated solid-based design and intelligent assembly of molds including cores, cavities, and mold bases. CIMdata views MoldWizard as an impressive new generation of knowledge-based product. Integrated to Unigraphics, associativity is maintained, which permits changes to a part model to be propagated to the core and cavity.
Basic machining
At the core of the new process-intelligent architecture introduced in v. 16 is a Manufacturing Technology Pipeline, which interacts with the Internet through iMAN/Web, Parasolid, and iMAN. It also maintains decision support information, technical advisory data, operations and group sequences, and supports all data editing and manipulation. All CAM applications communicate with each other through the pipeline. The applications include toolpath generation processors, verification and simulation codes, logic to parametrically change designs, and knowledge-based manufacturing software.
CAM sessions that capture the manufacturing environment form the basis of v. 16. They include the geometry, cutting tool, machine tools, library reference to feeds and speeds, and templates at a setup, group, and operational level. Currently for each machining setup a user creates an NC program by inputting:
• Geometry of the part to be machined including the part model, design tolerances, coordinate system, clearance planes, and stock material including the boundaries;
The Operations Navigation Tool manages this data. Four views of data are provided: by program, by geometry, by method, or by cutting tool. Files for operations, geometry, methods, and tools are maintained independently, permitting the user to change a tool in only one place, as opposed to changing a tool in each operation where it is used.
A key component of UG CAM is found in the programming templates and associated Process Assistants available to obtain a higher level of programming. Processes can be automated and standardized by the use of templates and assistants. Templates can be created at any level, including a full process, setup, sequence, or operation. Moreover, a template could be generated for a method, tool, or geometry. At the highest level, process templates have been established by UGS for die machining, mold machining, welding, 5-axis machining, contour machining, and planar machining.
Unigraphics offers three levels of CAM functionality: traditional CAM room software for dedicated users; a Shop Floor Series designed for programming by machinists or other casual users on the factory floor; highly customized automated applications.
An extensive set of integrated CAM databases is available in UG/Libraries. Libraries are available for cutting tools, machine tools, stock materials, and machining technology. Data such as recommended speeds, feeds, and materials are contained within the technology library.
Machining supported
A full range of cutting tools is supported, including ball, flat end, bull-nosed, and tapered tools. Two basic volume removal or roughing strategies are available for UG milling: Z-level roughing or cavity milling and parallel-plane machining or fixed axis contouring. Plunge roughing, a relatively new roughing technique, is not supported. This type of roughing is appropriate for a deep cavity and is also sometimes used to remove large amounts of material in a short time period.
Unigraphics Solutions provides a strong capability in 2-axis milling. An advanced face milling capability, particularly important for die machining, is provided. Automated 2D-rest milling is provided. The software will automatically remove material that has been left by a previous cut. A toolpath is calculated only for the area in which material remains. UGS CAM supports "tombstone" machining in which parts are machined on different faces of a block.
A totally new turning module has been introduced in v. 16, but advanced turning functionality is not yet provided. The software provides for basic 2-axis turning. Some support is provided for mill-turn operations; however, it is not a single integrated mill-turn package. UGS utilizes separate milling and turning software and then combines the two operations into a sequence in a post-processor. The user can do both milling and turning on a part in the same setup. The simulation shows turning and milling operations separately, as opposed to interspersed turning and milling operations. C-axis rotary milling is provided, but support for Y-axis milling is not in v. 16.
UGS supports interactive toolpath editing. In this mode, one can insert, edit, and delete tool motions such as rapid moves, tool changes, plunge rates, speeds, feeds, hole locations etc. A user has the option of interactively generating a toolpath, generating them one at a time, or selecting and batching files for subsequent or nighttime processing.
3-to 5-axis contour milling
UG primarily facets a solid body or solid sheets for 3-axis machining. UG supports machining directly on surfaces, a solid model, or a solid sheet. A large number of 3-axis multi-surface machining strategies are available in UG CAM for finishing operations, including parallel-plane machining, Z-level machining, fixed axis contouring, flow line machining, area milling, blade milling, and face milling, among others.
Area milling is a new drive method that has been added to fixed axis milling functions in UG CAM. The main feature is to collect the selected faces to be milled and maintain a smooth cutting edge even if the area has a near vertical drop. The user has the ability to identify steep and non-steep topology and then utilize appropriate cutting strategies. In re-machining material left behind from a previous cut, UG CAM provides a basic capability, but it is not an area of product strength.
Collision avoidance and detection consider the geometry of a full cutting tool, tool insert, and toolholder. During toolpath generation, an envelope is mathematically placed around a holder. This is a conservative approach to collision avoidance calculations and particularly important in die manufacture.
In v. 16, standard processes are available for die machining, mold machining, and production machining. In each case, a hierarchy of templates is available for different processing levels including setup, group sequence, and operational sequence.
High-speed machining has become increasingly important in mold and die operations. UGS is one of the industry leaders in supporting this technology and one of the first vendors to introduce NURBS output. The use of a spline, as compared to point-to-point output, has been shown to provide smoother tool movement, improved surface finish, and result in reduced manufacturing time.
UGS is an industry leader in simultaneous 5-axis machining. Machining of complex shapes such as turbine blades or aerospace components has been a traditional area of focus for UG, which provides a multi-surface machining capability.
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• modify a design model for manufacturing
• design the tools required in the production processes
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• Method to be employed including machining sequences, cutting strategies, stepover method and value, stock to be left after each pass, and machining tolerance;
• Tools to be used including the machine tool, cutting tool, tool material, tool position, and part holding devices.
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