SIEMENS NX CAD FOR DESIGN!

We’ve now upgraded our CAD design system to the latest version of Siemens NX, having previously used Siemens Solid Edge. NX is recognised by many in the automotive & motorsport industry as the premier design software to use, so its the perfect design tool for us.

We actually have extensive experience with NX. Modatek founder Matt Grant has been using NX and its predecessor Unigraphics for over 25 years to design a variety of motorsport & high performance engines.

Siemens NX

NX is actually a CAD (computer aided design) and CAM (computer aided manufacturing) package. We use the CAD modules of NX for our design work, but many of our machinists can take this data and use their own CAM software to create machining programs directly from our three-dimensional models.

One of the big benefits of NX is that the models we create can be fully parametric. This means that its easy for us to change certain key parameters, such as the distance between centres on a connecting rod model. All of the other geometry can be linked to these key parameters so that they update seamlessly whenever a change is made.

Having used NX for so long, we prefer to use the original feature-based method for modelling. This was the recommended approach for creating CAD models in Unigraphics and NX, and is one that has stood the test of time. The model begins life as a series of datum planes, axis and sketches, and then these sketches are used to create solid geometry with extrusions and revolutions. The last step is to then add the required blends, chamfers, holes and threads.

However, NX also includes what they term as ‘synchronous modelling’. This can make it easier to build and manipulate models, as features like bosses and holes can be dragged around, and the model is intelligent enough to be able to update the surrounding geometry. We tend to use synchronous modelling when we have to edit CAD models from other software packages such as Catia and Creo.

The other advantage of NX is that it has excellent drafting tools, which in our opinion is better than the other CAD packages. This is especially true for what are called ‘ordinate dimensions’, which are a series of horizontal and vertical linear dimensions on a drawing view that all refer back to the same origin. Ordinate dimensions can make the drawing of a complex part like a cylinder head or block much easier to both construct and comprehend.

Reverse Engineering

One of our largest requirements for our NX CAD system now is the reverse engineering of existing components. As already mentioned, our machinists require a three-dimensional CAD model, so we take the original 2D drawings and then construct the 3D model.

Occasionally we work with optical scanning companies, who can scan an existing component to create an array of thousands of points for the entire external surface of the component. We then construct the 3D model to match up with these points, and because the model is parametric, we can then make quick design changes that might be needed to improve the original design.

However, even though we have what we think is the world’s best CAD software at our fingertips, there is nothing like a bit of old-school design – where would be without our trusty old Zeus booklet (if you know, you know!).

Looking for CAD Services?

We don’t just use NX for our own component designs, we can also provide design services to other engineering companies. We’ve worked with some of the world’s largest and well-known motorsport engineering companies over the last few years, who have all been able to capitalise on our extensive design experience. We’ve also been able to help out small companies who can’t afford to employ full-time designers in addition to paying for expensive CAD licences. Sadly we can’t name the majority of these customers for confidentiality reasons!

One of the frustrations of NX (and, to be fair, other CAD packages too) is that it isn’t backwards-compatible. If a model or drawing is created in a certain version of NX then it can’t be opened in an earlier version. However, we can very quickly install and use whatever NX version our customer requests, which then overcomes this problem.

In addition, because we use a fully-licensed NX package, there are no issues with models and drawings not opening properly that might arise from using unlicensed NX software.

If you need our off-site engine design services then get in touch. Just send us a message using our contact form.