Software for Manufacturing Simplifies Design

Sept. 23, 1999
An English company, which claims to have the world’s most technically advanced manufacturing software for producing complex shapes

An English company, which claims to have the world’s most technically advanced manufacturing software for producing complex shapes, is now offering a suite of programs which could have an impact extending well into design and far beyond manufacturing operations.

Delcam Plc, located in Birmingham, U.K., says the key element in its new offering is “hybrid” part modeling. This feature, allowing designers to switch back and forth between surface and solid modeling, is said to greatly simplify the process of defining part geometry. The modeling software, which includes modules for drafting and mold design, interfaces with four other software packages for machining, inspection, digitizing, and the creation of 3D relief surfaces from 2D images. The five packages collectively are called Power Solution.

Delcam originally came to the CAD/CAM scene in 1984 with modeling software called DUCT. The product, along with companion software for machining, was primarily responsible for making Delcam the United Kingdom’s largest supplier of CAD/CAM software. In the area of toolmaking, the firm now has more than 10% of the European market and is the world’s fourth largest vendor of software for this application. The company expects to have more than 3,000 user sites this year.

Focus on Complex Shapes
Delcam is a company that admits to being “different” in that it focuses solely on the design and manufacturing of individual workpieces having complex shapes. It makes no claim to addressing CAD applications for huge assemblies of prismatic parts, as many CAD programs do.

Because of its focus on a niche market, Delcam is not particularly well known in the CAD/CAM community. “Unfortunately, Delcam has been a well-kept secret,” says Hugh Humphreys, managing director of the firm.

One battle Delcam has had to fight is over the reputation DUCT gained for being hard to use. That product is based on surface modeling, something many designers find complicated and not intuitive.

In a sense, the new product can be viewed as the next generation of DUCT. Even though Power Solution is totally new and a hybrid, it employs some DUCT concepts and algorithms.

Delcam officials say it retains the flexibility of DUCT, but is easier to use. It is based on the same database, so existing customers can use it alongside of DUCT. Also, it can be customized by the average user through Visual Basic.

Power Solution is based on the same Delcam kernel used for DUCT. Delcam prefers its own kernel because, according to Tim Mitchell, Delcam international sales director, standard solid-modeling kernels are not suitable for what Delcam wants to do since the primitives used cannot describe complex shapes easily, and they are intolerant of small gaps and overlaps. In addition, says Mitchell, “They are unable to infer topology reliably when converting surfaces to solids. They are also unable to operate without a closed solid.”

Delcam has traditionally provided Unix-based products, and while DUCT runs only on Unix, Power Solution is offered for both Windows NT and Unix. Delcam says there has been a dramatic movement from Unix to NT for its products, and essentially all new seats are now purchased for Windows NT.

A key feature of Power Solution is its ability to handle data from different systems. “We’re at the end of the CAD/CAM food chain and have to accommodate data in any condition from all kinds of systems,” according to Mitchell.

To this end, Delcam offers an array of data translators and direct interfaces, including IGES, DXF, and VDA-FS. Delcam is said to be one of few CAM-oriented vendors to support STEP. Also, direct translators are provided for inputting Pro/Engineer, Catia, Cadds, and Unigraphics files. SDRC I-DEAS files are brought in through IGES.

With Power Solution, solids can be built from trimmed surface faces read in from any of these data exchanges. They can be joined together with coarse tolerances, something conventional solid modelers can’t do, according to Stuart Watson, Delcam CAD development director. In addition, Power Shape can repair a model where IGES has lost topology, showing mismatched edges, gaps, and overlaps. It also detects and highlights poorly trimmed surfaces.

In addition to the toolmaking capabilities, Delcam provides features specially tailored to companies producing bottles or other containers, shoe soles, ceramics, jewelry, and 3D signs. “But we are staying focused on the production of individual complex parts,” says Mitchell. “You won’t see us develop Power Pipe or Power Cable.”

A Changing Market
Delcam’s long-term strategy is based on the fact that many companies already have CAD/CAM systems they want to improve, not replace. Along with this is increased pressure for faster return on investment and less time for training and implementation. Moreover, customers often believe solid modeling is essential, and falling hardware prices are encouraging more casual users that need easy-to-use software. This makes it clear, say Delcam officials, that Windows NT will become the major CAD/CAM operating system.

Helping to shape Delcam’s strategy is the fact that the major CAD/CAM companies seem to be focused on complete solutions for customers in large companies. This also has generated an emphasis on PDM. Officials at Delcam, in contrast, say they will stay focused on small companies, especially toolmakers, or departments within large companies.

Thus, Delcam intends to pitch its product to companies that already have powerful CAD systems but need additional capabilities, as well as to 2D CAD users who need complete replacement systems. Also, because of the firm’s emphasis on toolmaking and complex shapes, it does not pitch its products at general-purpose machining found in the typical job shop.

Why Hybrid?
Solid modelers, being based on standard geometric shapes, are much easier to use than typical surface modelers, according to Mitchell. Solid modelers also have associativity between 3D models and 2D drawings, and design changes tend to be quick and easy. Solid modelers are especially suited to large assemblies of simple components. And about 85% of products or components can be described with a solid modeler.

“Solid modelers can’t do everything,” says Mitchell. “It takes surface modeling to style free-form contours. Such free-forms are required not only for aesthetic styling but also for such features as handgrips and other ergonomic surfaces, an area growing in importance. Surface modeling also is more adaptable to digitizing and reverse engineering.”

“Solid modelers make you think in terms of adding or removing material and don’t let you make local changes to the shape of a surface,” says Watson. “On the other hand, surface modelers make you think in terms of laying a skin of material over a frame and don’t let you work on a complete model at once.”

Mitchell feels hybrid modeling will become important as manufacturers increasingly feel more pressure to differentiate products with distinctive aesthetic designs and shapes. Also, there is pressure to reduce assembly costs by replacing several simple parts with a single, more complex shape, something hybrids handle well. In addition, hybrids fit in better with the trend toward more powerful manufacturing equipment for making larger and more complex parts. At the other extreme, hybrids work well with the miniaturization brought about by the need for smaller, more accurate parts.

In all, hybrid modeling’s short learning curve lets engineers quickly create basic designs. “Complex shapes can be designed and modified without compromises dictated by the type of modeling used,” says Mitchell. “And the same database is used so designers can easily switch between modeling methods.”

Friend of the Toolmaker
At some stage in the design process, a part that is to be molded in plastic, cast in metal, or forged must be handed off to a toolmaker, who has special problems because the part, which up to that point is an “entity,” now becomes a hollow cavity, and the mold or die becomes the solid entity.

Moreover, the cavity must be given special considerations to accommodate the manufacturing process. For example, it must have draft so that the part can be removed from the die. It must not have undercuts to hinder the removal process. And there must be a decision as to where the parting line will be. In addition, where the initial objective is tooling to mold a part, the task becomes one of properly designing the cavity and core halves. They make, respectively, the part’s outside, or appearance surface, and its unseen inner surface.

All of this can be done automatically within Power Solution. In addition, fine details are normally put into the mold by electrical-discharge machining, which requires an electrode shaped like an inside-out version of the shape being reproduced. The geometry for the electrode also is generated automatically from the software.

© 2010 Penton Media, Inc.

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