Covering All CAD Bases : Automotive Design & Production

Siemens PLM Software brings new versions of its CAx packages to market. Here’s a look.

Siemens PLM Software has launched new versions of its CAx systems, providing functionality that is developed to increase design and engineering, whether it is at enterprisewide or medium-sized scale.

NX turns 8

NX is Siemens’s flagship CAx system (siemens.com/nx). The latest version, NX 8, claim company officials, “helps reduce the time spent preparing and solving analysis models by up to 70 percent when compared to traditional CAE tools.” How? New tools, new automation, and new approaches. For instance, coupling the NX thermal solver with its structural complement, NX Nastran, lets designers simulate and solve multi-discipline, heat-related structural problems in one CAE system. New “part modules” technology easily subdivides designs into functional elements for concurrent design operations. And designers can now both create linear and polar patterns, and fill specified boundaries with pattern features and create symmetric patterns in linear layouts. 

Assembly design is easier because designers can group constraint information by component, constraint, and status. The ability to hold components in place (“fix and bond” constraints) is new. New icons in NX’s Assembly Navigator lead to highlighting assembly constraints (and their severity). Sheet metal parts can be modeled in the context of an assembly; for example, designers can create associative flanges using existing geometry to control the extent and angle of a flange. Converting solid models to sheet metal models now has the option to preserve sharp edges with zero bend radius. 

This fourth release of NX’s synchronous technology (ST; the merging of direct modeling with history-based modeling) lets designers change the order of intersecting blends of opposing convex parts with or without a feature history. When deleting faces of a model, designers can heal/notheal the neighboring faces. Such face modifications can result in higherquality curved surfaces. Hole placement is also easier. Holes can be dragged and precisely placed anywhere on a shaft. And the surrounding geometry automatically updates. 

“Mid-sized” only in marketing-speak

Solid Edge ST4, Siemens’s CAx system for small to mid-sized manufacturers (siemens.com/plm/st4), offers an array of new modeling and assembly tools. For example, an offset tool keeps faces a user-specified distance from one another. A horizontal/vertical tool aligns keypoints, features, and faces with other geometry in a model. Faces can be anchored horizontally or vertically, and this relationship can be used to maintain centering between midpoints of 3D faces. Offsets and horizontal/vertical placements in 2D sketches will transfer to the equivalent 3D models. A new assembly tool ensures parts sit centrally between two other parts or faces. This is handy for spacing rollers evenly between mounting brackets. Centering is maintained even if the distance between brackets changes later on. (This works for both parallel and tapered bracket faces.) 

As with NX, ST4 has some new sheet-metal design tricks. Designers can create and use the mid surfaces of sheet metal models in part and assembly simulations; that is, mid surfaces can be extracted at the assembly level and used with regular solids in other parts of the model. These mid surfaces are completely associative to their original sheetmetal models. New Nastran finite element (FE) algorithms unite surface and solid bodies—2D shell and 3D solid elements—thereby improving FE mesh reliability across complex parts. This speeds up analysis considerably. There are also new options to refine and control meshing, such as setting minimum element on edge and max elements for small features, which reinforces the maxim that more accurate (read, detailed) meshing equals more accurate CAE results. (The mid-surface capability and FE meshing also works for thin-walled parts, such as plastic components.)

Annotating fastener stacks is faster through automatic ballooning: A single click on a fastener generates the entire stack of items in a parts list. All the item numbers will match the parts list—even when fasteners are added or removed. ST4 also offers improved photorealistic renderings. Designers can turn on reflections and shadows, as well as a reflective virtual floor. The autosharpen feature matches the computer display performance: Edge quality can be automatically set from “low” for high performance to “ultra-high” for sharp edge details.