Spin doctors

Recent CAD releases have led to improvements ranging from a customised dragster clutch for easier maintenance to a two-gear wheelchair drive for navigating ramps and hills. Charles Clarke reports

First Sweden used SolidWorks to design the Koenigsegg super-car, and now a leading European drag racing team is using a customised clutch unit, designed with IronCAD.

Leanders Brothers Racing, from Alfta, Sweden, is using the unit – one of many pieces that its chief engineer, Jörgen Leanders, created using the system. There are no bolted facings on the clutch, claimed to improve heat dissipation during races and make maintenance easier.

Pit crews have a limited time to inspect and replace parts between races, so serviceability is important. Even clutch arms can be removed or changed without having to disassemble the unit. Additional technological advances include using four floater plates in the three-disc clutch, which as well as adding additional heat dissipation, also ensure all contact surfaces are equal.

‘Our clutch is a result of experimentation with different designs, something we couldn’t have done without IronCAD. I started with no CAD experience at all,’ said Leanders. ‘The software’s ease of use allowed me to catch on quickly. It helped me capture the best design through trial and error. I was never locked into a single design, and if I wanted to make a change it was possible, no matter how far along in the design I was.’

This demonstrates the flexibility of the system. The user can take advantage of the parametric capabilities to build constraint-driven variations of the clutch design and make changes at any stage that do not abide by the constraints using the direct face modelling abilities.

SolidWorks, on the other hand, has just introduced SolidWorks 2008, which allows users to focus on ‘design’ rather than how to use their CAD software. It has a timesaving user interface and photorealistic 3D graphics. It is an extension of its SolidWorks Intelligent Feature Technology (SWIFT), which speeds up the design process and includes advanced design analysis capabilities. The system also provides feedback about quality and manufacturability at the outset.

Sweden’s Leanders Brothers Racing dragsters have been fitted with a customised clutch unit that is said to improve heat dissipation during races

The intuitive workflow predicts the tools needed for the next task. The interface increases useful screen area, reduces mouse travel, provides innovative customisation options and a task-based command selection.

SWIFT Instant3D allows for the creation and modification of 3D model features by manipulating drag handles directly on the model — there is no need to manipulate specialist commands, dialogue boxes, or provide extensive data input to modify the model. ‘Live cross-sections’ allows the model to be edited by dragging edges while looking at a 2D slice of it.

SWIFT DimXpert automatically sets geometric dimensions and tolerances on parts, and provides visual feedback on whether the model has been properly described and is ready for manufacturing. It creates views, dimensions and tolerances automatically in 2D drawings for complete design documentation.

The Design Clipart facility allows the user to search for sketches, tables, images, features, views, or even [AutoCAD] DWG blocks that are part of existing designs. Once the item is located, Clipart dissects target files, allowing the item to be dragged and incorporated into the new design. It also allows quick access to any portion of an AutoCAD DWG file without the need for translation.

Some additional tools also make it easier for engineers to work with large assemblies. A Quick View/Selective Open feature lets the user view large assemblies quickly then select components on-the-fly to open and work with, without having to load unnecessary parts into memory. Customisable pop-up toolbars and a new CommandManager layout deliver faster access to commonly used commands while increasing the useable screen area for design work.

There are also a variety of simulation tool enhancements. TolAnalyst is a tolerance analysis tool used to determine the effect tolerances have on parts and assemblies. COSMOSWorks Design Insight identifies the areas in a design that contribute most to structural integrity, helping users zero in to remove unnecessary material. The MotionManager feature means users can see how an assembly moves and how components interact in a single set-up. DriveWorksXpress lets them capture the design process numerically, allowing them to simply enter new dimensions into a dialogue box to automatically generate variant products.

DFMXpress is a handy tool for checking manufacturability and is aimed at preventing common design errors that could result in the creation of parts that are too costly or difficult to manufacture.

Meanwhile, Autodesk has been busy re-inventing the wheel or rather Magic Wheels, a developer of multi-gear wheel systems for manual wheelchairs. The company sought to improve the wheel systems for rear-push chairs, which had remained unchanged for 150 years. Traditionally these wheels provide only one gear, which makes it difficult for users to go up and down hills or navigate rough and uneven surfaces.

To address these challenges, Magic Wheels developed the two-gear wheelchair drive. This system works much like a two-speed bicycle, so the user is able to navigate ramps, hills and many other types of terrain. Having different gears also lessens the incidence of repetitive stress injury (RSI) to the shoulders, arms and hands due to high driving loads.

Autodesk Inventor software was integral to the development of the product, which evolved over nine years. As the foundation for digital prototyping, Inventor allows manufacturers to simulate the real-world performance of a design before it is built.

‘In this process, we had to explore many different design ideas,’ said Cisco Sabin, mechanical design engineer at Magic Wheels. ‘By creating digital prototypes in Inventor, we were able to fully explore and optimise our designs before producing expensive physical prototypes.’