CAD – Computer-Aided Design in manufacturing

CAD software at a glance: Computer-Aided Design fundamentals, a comparison of CAD kernels, vendors and products, and criteria for buying a CAD system.

Process

CAD is where computer-aided manufacturing begins: this is where the digital model is created that is later programmed in CAM and machined on the CNC machine.

Computer-Aided Design

CAD (Computer-Aided Design) software is specialized software for creating digital models and drawings of objects, components or products. It lets you design and construct precise 2D and 3D models.

CAD software provides a wide range of tools that support the design process: creating geometric shapes, defining dimensions, assigning materials, building assemblies, adding surface textures, creating animations and much more. Complex designs can thus be created, reviewed and optimized virtually before they go into physical production.

Technology

Software can be thought of as a machine made of assemblies and subassemblies. As with a machine, it makes no sense to manufacture components or entire assemblies yourself if they can be bought. If Festo offers a pneumatic cylinder that fits, you don’t develop and build your own.

The same applies to software. A CAD system is highly complex, yet much of its functionality is the same across products: extrusion, revolved features, holes and so on exist in most CAD systems. It therefore makes little sense for a vendor to develop all of this from scratch as long as suppliers on the market offer software components and modules that cover these functions.

This is where the CAD kernel comes into play. A CAD kernel is the central software component of a CAD system that provides the basic functions for creating, editing and managing CAD data. It is often split into several modules: a geometry kernel, for example, handles the modeling of 2D and 3D geometry and provides functions for creating, manipulating and analyzing geometric elements such as points, lines, surfaces and solids. Other modules cover assembly modeling, design history, drawing generation, collision checking and tolerance analysis, among other things.

CAD kernels

The following table lists various CAD kernels and their vendors. Not all CAD kernels are available on the market as software components: Autodesk’s ShapeManager, for example, cannot be licensed for use in your own product. The most widely used kernel is probably Parasolid from Siemens – it powers products such as Solid Edge, SolidWorks, Siemens NX, PowerSHAPE and Alibre Design.

Vendors

There are many CAD vendors, and especially in the field of specialized solutions there are numerous niche products. The table does not cover every CAD vendor, but it helps to get an overview of the products offered on the market.

Purchasing

Buying a CAD system deserves careful consideration. Depending on the situation, some criteria matter more than others: for a large company, the financial aspect may be less important than integrating the product into existing processes. For a small company with five employees, the financial factor is often more decisive, since its processes are more flexible.

The following points deserve particular attention:

Costs

The total cost is made up of several items:

• Purchase price
• Maintenance costs (often a percentage of the purchase price)
• Services (e.g. installation)
• Possible purchase of new hardware
• Training

Interoperability

• How compatible is the system with other CAD systems?
• Which file formats are supported?

Ease of use

• How accessible are frequently used functions?
• How often does the mouse have to travel from A to B to complete a task?

Future-proofing

• How well is the product positioned for the future?
• Can the CAD files be opened by another system if you switch products later?
• How dependent do you become on the vendor?

Training

How accessible is the knowledge needed to work with the product? Can it only be acquired through paid training, or are there freely available guides and tutorials on the web? A quick search on a search engine or on YouTube (e.g. for “SolidWorks tutorial”) provides answers here.

Lock-in effect

The lock-in effect describes a situation in which a company or user is tied to a particular CAD system for technical, economic or organizational reasons, making a switch to another system difficult. The consequences: high switching costs, limited flexibility and restricted interoperability.

The lock-in effect occurs when a company has created a substantial amount of CAD data, models and drawings in a specific format that is not well compatible with other CAD systems. Moving to another system can then involve high conversion costs and potential data loss – investments in time and resources that make many companies hesitant to switch.

From the software vendor’s perspective, the lock-in effect is a good thing, as it reduces the likelihood of existing customers switching to a competitor – and with it the risk of losing maintenance revenue. Vendors therefore sometimes deliberately implement features that reinforce the lock-in effect – for example a PDM (Product Data Management) system integrated into the product that blocks or severely restricts access by other vendors.

The lock-in effect should be taken into account when selecting a CAD system, and it pays to develop strategies to minimize its impact: choose CAD systems with open standards and interoperable interfaces, use neutral file formats and keep them accessible, plan for future extensions, and back up and document CAD data regularly. Careful evaluation and planning reduce the lock-in effect and improve the long-term flexibility of your CAD deployment.