Designing dreams: 3D CAD aids the process

You’re cruising down the highway when a truck ahead of you loses its load. You swerve to avoid a collision, but debris hits the passenger door.

You pull over and inspect the damage. You’ll need a new door. Not wanting to waste time, you call the supplier on your mobile phone, telling them the car’s design number. “It’s the front passenger door,” you say. The engineer retrieves your vehicle’s 3D CAD design and starts making you a replacement door.

This may sound far fetched, but developments in CAD/CAM software are bringing scenes like this onto the horizon.

Autodesk’s Mike Romans said new generations of CAD software are improving efficiency and reducing design time, and this is bringing the flexibility to cost effectively create “one-offs” like the exclusive car above.

Modelling designs in 3D, helps engineers and designers understand how their products will function and interact before physical models are made. Romans told Manufactures’ Monthly this increases the scope for rapidly modifying designs, which in turn reduces design costs.

“The longer you wait to make a change, the higher the costs become. 3D CAD...allows companies to made decisions early in the design cycle when the costs are as low as possible.”

Romans said modern CAD systems also allow greater information sharing between departments, which allows everybody involved to start their design tasks earlier and get the job done more quickly.

Data can also be shared more effectively with external parties such as outsourced component manufacturers, or plants in remote locations by sending files electronically.

“Not to mention the obvious thing with 3D, which is everybody who sees the 3D model can comprehend and understand what it looks like straight away,” Romans said. This would be very important to anyone wanting to design their dream car.

Many manufacturers are yet to embrace 3D CAD/CAM software and Romans says that although a lot of organisations want to adopt 3D design, “It’s not as easy as snapping your fingers.”

Existing projects created in 2D packages may need to be maintained, modified and supported.

“There’s a definite transition phase, and that phase, depending on the size of the organisation and the size of the legacy data, could last from one year to five or ten years,” Romans said.

Intercad managing director, Paul Ganz said companies should bear in mind that it may not be essential to use 3D.

“For some activities, 2D serves them perfectly well,” he told Manufacturers’ Monthly.

For tasks such as laying out equipment on factory floors or setting up offices, Ganz says 2D is perfectly acceptable. Although he adds, “I still can’t think of a mechanical design that wouldn’t benefit from 3D.”

Ganz said today’s CAD tools produce true 3D objects. “An object is an object. It occupies a volume of space, it has a mass, it has a centre of gravity, you can apply materials to it and subject it to stress to check if it will break when it is used in a certain way in an assembly,” he said.

Defining shapes in the CAD system as objects allows the system to recognise design components as physical parts, seeing a bolt as a bolt rather than a collection of lines and arcs for example. This allows data to be transferred more easily into a bill of materials.

“These objects carry not only their physical properties, but also information of cost, material, or supplier,” Ganz said.

This information can automatically flow up to the ERP system in real time and this gives designers access to the actual costs of the project at any given stage. Ganz says the real benefit of this is that design changes automatically flow through the system and into parts of the organisation impacted by the changes, but not directly involved in creating the design.

Manufacturing departments, for example have to design jigs and fixtures to use in the part’s production. Romans said using 2D software, manufacturing would have to wait for the 2D design; create designs for jigs and fixtures, again in 2D; manually program the CNC machines; and wait for the physical part to be made before functional tests can be carried out and rework started if necessary.

With 3D designs, functional testing can be done on-line, eliminating rework requirements. CNC programs are also created automatically, which saves time and reduces errors.

Romans said designers can also reuse data from previous designs more easily using 3D software.

“An engineer can very quickly and easily go in and search for products they’ve built in the past, find what’s relevant to them and make duplicates of those, rename them, copy them, reuse them and start a new project,” he said.

This would help make special projects, such as the one-off car, a more viable proposition. It would also allow individual parts, like the damaged door, to be reproduced on demand.